Merge "CVE-2013-0169: Make CBC decoding constant time"
diff --git a/Ssl.mk b/Ssl.mk
index 856f3a6..d4a7e95 100644
--- a/Ssl.mk
+++ b/Ssl.mk
@@ -23,6 +23,7 @@
ssl/s2_pkt.c \
ssl/s2_srvr.c \
ssl/s3_both.c \
+ ssl/s3_cbc.c \
ssl/s3_clnt.c \
ssl/s3_enc.c \
ssl/s3_lib.c \
diff --git a/crypto/cryptlib.c b/crypto/cryptlib.c
index 50fd492..d47ab55 100644
--- a/crypto/cryptlib.c
+++ b/crypto/cryptlib.c
@@ -924,3 +924,16 @@
}
void *OPENSSL_stderr(void) { return stderr; }
+
+int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len)
+ {
+ size_t i;
+ const unsigned char *a = in_a;
+ const unsigned char *b = in_b;
+ unsigned char x = 0;
+
+ for (i = 0; i < len; i++)
+ x |= a[i] ^ b[i];
+
+ return x;
+ }
diff --git a/crypto/crypto.h b/crypto/crypto.h
index 6aeda0a..793a325 100644
--- a/crypto/crypto.h
+++ b/crypto/crypto.h
@@ -574,6 +574,13 @@
#define fips_cipher_abort(alg) while(0)
#endif
+/* CRYPTO_memcmp returns zero iff the |len| bytes at |a| and |b| are equal. It
+ * takes an amount of time dependent on |len|, but independent of the contents
+ * of |a| and |b|. Unlike memcmp, it cannot be used to put elements into a
+ * defined order as the return value when a != b is undefined, other than to be
+ * non-zero. */
+int CRYPTO_memcmp(const void *a, const void *b, size_t len);
+
/* BEGIN ERROR CODES */
/* The following lines are auto generated by the script mkerr.pl. Any changes
* made after this point may be overwritten when the script is next run.
diff --git a/crypto/evp/c_allc.c b/crypto/evp/c_allc.c
index 2a45d43..e230e60 100644
--- a/crypto/evp/c_allc.c
+++ b/crypto/evp/c_allc.c
@@ -195,11 +195,13 @@
EVP_add_cipher(EVP_aes_256_xts());
EVP_add_cipher_alias(SN_aes_256_cbc,"AES256");
EVP_add_cipher_alias(SN_aes_256_cbc,"aes256");
+#if 0 /* Disabled because of timing side-channel leaks. */
#if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1)
EVP_add_cipher(EVP_aes_128_cbc_hmac_sha1());
EVP_add_cipher(EVP_aes_256_cbc_hmac_sha1());
#endif
#endif
+#endif
#ifndef OPENSSL_NO_CAMELLIA
EVP_add_cipher(EVP_camellia_128_ecb());
diff --git a/crypto/rsa/rsa_oaep.c b/crypto/rsa/rsa_oaep.c
index 553d212..af4d24a 100644
--- a/crypto/rsa/rsa_oaep.c
+++ b/crypto/rsa/rsa_oaep.c
@@ -149,7 +149,7 @@
if (!EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1(), NULL))
return -1;
- if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
+ if (CRYPTO_memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
goto decoding_err;
else
{
diff --git a/include/openssl/crypto.h b/include/openssl/crypto.h
index 6aeda0a..793a325 100644
--- a/include/openssl/crypto.h
+++ b/include/openssl/crypto.h
@@ -574,6 +574,13 @@
#define fips_cipher_abort(alg) while(0)
#endif
+/* CRYPTO_memcmp returns zero iff the |len| bytes at |a| and |b| are equal. It
+ * takes an amount of time dependent on |len|, but independent of the contents
+ * of |a| and |b|. Unlike memcmp, it cannot be used to put elements into a
+ * defined order as the return value when a != b is undefined, other than to be
+ * non-zero. */
+int CRYPTO_memcmp(const void *a, const void *b, size_t len);
+
/* BEGIN ERROR CODES */
/* The following lines are auto generated by the script mkerr.pl. Any changes
* made after this point may be overwritten when the script is next run.
diff --git a/include/openssl/ssl3.h b/include/openssl/ssl3.h
index f4578aa..879be13 100644
--- a/include/openssl/ssl3.h
+++ b/include/openssl/ssl3.h
@@ -355,6 +355,10 @@
/*r */ unsigned char *comp; /* only used with decompression - malloc()ed */
/*r */ unsigned long epoch; /* epoch number, needed by DTLS1 */
/*r */ unsigned char seq_num[8]; /* sequence number, needed by DTLS1 */
+/*rw*/ unsigned int orig_len; /* How many bytes were available before padding
+ was removed? This is used to implement the
+ MAC check in constant time for CBC records.
+ */
} SSL3_RECORD;
typedef struct ssl3_buffer_st
diff --git a/openssl.config b/openssl.config
index a2c31d8..9c20b62 100644
--- a/openssl.config
+++ b/openssl.config
@@ -206,6 +206,8 @@
channelid.patch \
clang.patch \
recursive_lock_fix.patch \
+0001-Add-and-use-a-constant-time-memcmp.patch \
+0002-Make-CBC-decoding-constant-time.patch \
"
OPENSSL_PATCHES_progs_SOURCES="\
diff --git a/patches/0001-Add-and-use-a-constant-time-memcmp.patch b/patches/0001-Add-and-use-a-constant-time-memcmp.patch
new file mode 100644
index 0000000..a593d49
--- /dev/null
+++ b/patches/0001-Add-and-use-a-constant-time-memcmp.patch
@@ -0,0 +1,155 @@
+From 306d003174cb4e5994734b20d741867aeeebf918 Mon Sep 17 00:00:00 2001
+From: Adam Langley <agl@chromium.org>
+Date: Wed, 16 Jan 2013 11:02:35 -0500
+Subject: [PATCH 1/2] Add and use a constant-time memcmp.
+
+This change adds CRYPTO_memcmp, which compares two vectors of bytes in
+an amount of time that's independent of their contents. It also changes
+several MAC compares in the code to use this over the standard memcmp,
+which may leak information about the size of a matching prefix.
+---
+ crypto/cryptlib.c | 13 +++++++++++++
+ crypto/crypto.h | 7 +++++++
+ crypto/rsa/rsa_oaep.c | 2 +-
+ ssl/d1_pkt.c | 2 +-
+ ssl/s2_clnt.c | 2 +-
+ ssl/s2_pkt.c | 3 +--
+ ssl/s3_both.c | 2 +-
+ ssl/s3_pkt.c | 2 +-
+ ssl/t1_lib.c | 2 +-
+ 9 files changed, 27 insertions(+), 8 deletions(-)
+
+diff --git a/crypto/cryptlib.c b/crypto/cryptlib.c
+index a7cb420..304c6b7 100644
+--- a/crypto/cryptlib.c
++++ b/crypto/cryptlib.c
+@@ -925,3 +925,16 @@ void OpenSSLDie(const char *file,int line,const char *assertion)
+ }
+
+ void *OPENSSL_stderr(void) { return stderr; }
++
++int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len)
++ {
++ size_t i;
++ const unsigned char *a = in_a;
++ const unsigned char *b = in_b;
++ unsigned char x = 0;
++
++ for (i = 0; i < len; i++)
++ x |= a[i] ^ b[i];
++
++ return x;
++ }
+diff --git a/crypto/crypto.h b/crypto/crypto.h
+index 6160576..f92fc51 100644
+--- a/crypto/crypto.h
++++ b/crypto/crypto.h
+@@ -574,6 +574,13 @@ void OPENSSL_init(void);
+ #define fips_cipher_abort(alg) while(0)
+ #endif
+
++/* CRYPTO_memcmp returns zero iff the |len| bytes at |a| and |b| are equal. It
++ * takes an amount of time dependent on |len|, but independent of the contents
++ * of |a| and |b|. Unlike memcmp, it cannot be used to put elements into a
++ * defined order as the return value when a != b is undefined, other than to be
++ * non-zero. */
++int CRYPTO_memcmp(const void *a, const void *b, size_t len);
++
+ /* BEGIN ERROR CODES */
+ /* The following lines are auto generated by the script mkerr.pl. Any changes
+ * made after this point may be overwritten when the script is next run.
+diff --git a/crypto/rsa/rsa_oaep.c b/crypto/rsa/rsa_oaep.c
+index 553d212..af4d24a 100644
+--- a/crypto/rsa/rsa_oaep.c
++++ b/crypto/rsa/rsa_oaep.c
+@@ -149,7 +149,7 @@ int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
+ if (!EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1(), NULL))
+ return -1;
+
+- if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
++ if (CRYPTO_memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
+ goto decoding_err;
+ else
+ {
+diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
+index 987af60..5e2c56c 100644
+--- a/ssl/d1_pkt.c
++++ b/ssl/d1_pkt.c
+@@ -463,7 +463,7 @@ printf("\n");
+ else
+ rr->length = 0;
+ i=s->method->ssl3_enc->mac(s,md,0);
+- if (i < 0 || mac == NULL || memcmp(md, mac, mac_size) != 0)
++ if (i < 0 || mac == NULL || CRYPTO_memcmp(md,mac,mac_size) != 0)
+ {
+ decryption_failed_or_bad_record_mac = 1;
+ }
+diff --git a/ssl/s2_clnt.c b/ssl/s2_clnt.c
+index 76b690e..03b6cf9 100644
+--- a/ssl/s2_clnt.c
++++ b/ssl/s2_clnt.c
+@@ -939,7 +939,7 @@ static int get_server_verify(SSL *s)
+ s->msg_callback(0, s->version, 0, p, len, s, s->msg_callback_arg); /* SERVER-VERIFY */
+ p += 1;
+
+- if (memcmp(p,s->s2->challenge,s->s2->challenge_length) != 0)
++ if (CRYPTO_memcmp(p,s->s2->challenge,s->s2->challenge_length) != 0)
+ {
+ ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
+ SSLerr(SSL_F_GET_SERVER_VERIFY,SSL_R_CHALLENGE_IS_DIFFERENT);
+diff --git a/ssl/s2_pkt.c b/ssl/s2_pkt.c
+index ac963b2..8bb6ab8 100644
+--- a/ssl/s2_pkt.c
++++ b/ssl/s2_pkt.c
+@@ -269,8 +269,7 @@ static int ssl2_read_internal(SSL *s, void *buf, int len, int peek)
+ s->s2->ract_data_length-=mac_size;
+ ssl2_mac(s,mac,0);
+ s->s2->ract_data_length-=s->s2->padding;
+- if ( (memcmp(mac,s->s2->mac_data,
+- (unsigned int)mac_size) != 0) ||
++ if ( (CRYPTO_memcmp(mac,s->s2->mac_data,mac_size) != 0) ||
+ (s->s2->rlength%EVP_CIPHER_CTX_block_size(s->enc_read_ctx) != 0))
+ {
+ SSLerr(SSL_F_SSL2_READ_INTERNAL,SSL_R_BAD_MAC_DECODE);
+diff --git a/ssl/s3_both.c b/ssl/s3_both.c
+index 918da35..ead01c8 100644
+--- a/ssl/s3_both.c
++++ b/ssl/s3_both.c
+@@ -265,7 +265,7 @@ int ssl3_get_finished(SSL *s, int a, int b)
+ goto f_err;
+ }
+
+- if (memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
++ if (CRYPTO_memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
+ {
+ al=SSL_AD_DECRYPT_ERROR;
+ SSLerr(SSL_F_SSL3_GET_FINISHED,SSL_R_DIGEST_CHECK_FAILED);
+diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
+index dca3458..3e11140 100644
+--- a/ssl/s3_pkt.c
++++ b/ssl/s3_pkt.c
+@@ -463,7 +463,7 @@ printf("\n");
+ #endif
+ }
+ i=s->method->ssl3_enc->mac(s,md,0);
+- if (i < 0 || mac == NULL || memcmp(md, mac, (size_t)mac_size) != 0)
++ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+ {
+ decryption_failed_or_bad_record_mac = 1;
+ }
+diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
+index d8df062..27010dd 100644
+--- a/ssl/t1_lib.c
++++ b/ssl/t1_lib.c
+@@ -2226,7 +2226,7 @@ static int tls_decrypt_ticket(SSL *s, const unsigned char *etick, int eticklen,
+ HMAC_Update(&hctx, etick, eticklen);
+ HMAC_Final(&hctx, tick_hmac, NULL);
+ HMAC_CTX_cleanup(&hctx);
+- if (memcmp(tick_hmac, etick + eticklen, mlen))
++ if (CRYPTO_memcmp(tick_hmac, etick + eticklen, mlen))
+ return 2;
+ /* Attempt to decrypt session data */
+ /* Move p after IV to start of encrypted ticket, update length */
+--
+1.8.1
+
diff --git a/patches/0002-Make-CBC-decoding-constant-time.patch b/patches/0002-Make-CBC-decoding-constant-time.patch
new file mode 100644
index 0000000..1893aa2
--- /dev/null
+++ b/patches/0002-Make-CBC-decoding-constant-time.patch
@@ -0,0 +1,1621 @@
+From fb402b7cdeffc907a9464cb84aa1311b1f77832a Mon Sep 17 00:00:00 2001
+From: Adam Langley <agl@chromium.org>
+Date: Wed, 16 Jan 2013 11:18:19 -0500
+Subject: [PATCH 2/2] Make CBC decoding constant time.
+
+This patch makes the decoding of SSLv3 and TLS CBC records constant
+time. Without this, a timing side-channel can be used to build a padding
+oracle and mount Vaudenay's attack.
+
+This patch also disables the stitched AESNI+SHA mode pending a similar
+fix to that code.
+
+In order to be easy to backport, this change is implemented in ssl/,
+rather than as a generic AEAD mode. In the future this should be changed
+around so that HMAC isn't in ssl/, but crypto/ as FIPS expects.
+---
+ crypto/evp/c_allc.c | 2 +
+ ssl/Makefile | 4 +-
+ ssl/d1_enc.c | 59 ++---
+ ssl/d1_pkt.c | 87 ++++---
+ ssl/s3_cbc.c | 696 ++++++++++++++++++++++++++++++++++++++++++++++++++++
+ ssl/s3_enc.c | 119 +++++----
+ ssl/s3_pkt.c | 94 +++----
+ ssl/ssl3.h | 4 +
+ ssl/ssl_algs.c | 3 +
+ ssl/ssl_locl.h | 34 +++
+ ssl/t1_enc.c | 144 +++++------
+ 11 files changed, 993 insertions(+), 253 deletions(-)
+ create mode 100644 ssl/s3_cbc.c
+
+diff --git a/crypto/evp/c_allc.c b/crypto/evp/c_allc.c
+index 2a45d43..e230e60 100644
+--- a/crypto/evp/c_allc.c
++++ b/crypto/evp/c_allc.c
+@@ -195,11 +195,13 @@ void OpenSSL_add_all_ciphers(void)
+ EVP_add_cipher(EVP_aes_256_xts());
+ EVP_add_cipher_alias(SN_aes_256_cbc,"AES256");
+ EVP_add_cipher_alias(SN_aes_256_cbc,"aes256");
++#if 0 /* Disabled because of timing side-channel leaks. */
+ #if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1)
+ EVP_add_cipher(EVP_aes_128_cbc_hmac_sha1());
+ EVP_add_cipher(EVP_aes_256_cbc_hmac_sha1());
+ #endif
+ #endif
++#endif
+
+ #ifndef OPENSSL_NO_CAMELLIA
+ EVP_add_cipher(EVP_camellia_128_ecb());
+diff --git a/ssl/Makefile b/ssl/Makefile
+index feaf3e3..bdb49e2 100644
+--- a/ssl/Makefile
++++ b/ssl/Makefile
+@@ -22,7 +22,7 @@ LIB=$(TOP)/libssl.a
+ SHARED_LIB= libssl$(SHLIB_EXT)
+ LIBSRC= \
+ s2_meth.c s2_srvr.c s2_clnt.c s2_lib.c s2_enc.c s2_pkt.c \
+- s3_meth.c s3_srvr.c s3_clnt.c s3_lib.c s3_enc.c s3_pkt.c s3_both.c \
++ s3_meth.c s3_srvr.c s3_clnt.c s3_lib.c s3_enc.c s3_pkt.c s3_both.c s3_cbc.c \
+ s23_meth.c s23_srvr.c s23_clnt.c s23_lib.c s23_pkt.c \
+ t1_meth.c t1_srvr.c t1_clnt.c t1_lib.c t1_enc.c \
+ d1_meth.c d1_srvr.c d1_clnt.c d1_lib.c d1_pkt.c \
+@@ -33,7 +33,7 @@ LIBSRC= \
+ bio_ssl.c ssl_err.c kssl.c tls_srp.c t1_reneg.c
+ LIBOBJ= \
+ s2_meth.o s2_srvr.o s2_clnt.o s2_lib.o s2_enc.o s2_pkt.o \
+- s3_meth.o s3_srvr.o s3_clnt.o s3_lib.o s3_enc.o s3_pkt.o s3_both.o \
++ s3_meth.o s3_srvr.o s3_clnt.o s3_lib.o s3_enc.o s3_pkt.o s3_both.o s3_cbc.o \
+ s23_meth.o s23_srvr.o s23_clnt.o s23_lib.o s23_pkt.o \
+ t1_meth.o t1_srvr.o t1_clnt.o t1_lib.o t1_enc.o \
+ d1_meth.o d1_srvr.o d1_clnt.o d1_lib.o d1_pkt.o \
+diff --git a/ssl/d1_enc.c b/ssl/d1_enc.c
+index 07a5e97..712c464 100644
+--- a/ssl/d1_enc.c
++++ b/ssl/d1_enc.c
+@@ -126,20 +126,28 @@
+ #include <openssl/des.h>
+ #endif
+
++/* dtls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
++ *
++ * Returns:
++ * 0: (in non-constant time) if the record is publically invalid (i.e. too
++ * short etc).
++ * 1: if the record's padding is valid / the encryption was successful.
++ * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
++ * an internal error occured. */
+ int dtls1_enc(SSL *s, int send)
+ {
+ SSL3_RECORD *rec;
+ EVP_CIPHER_CTX *ds;
+ unsigned long l;
+- int bs,i,ii,j,k,n=0;
++ int bs,i,j,k,mac_size=0;
+ const EVP_CIPHER *enc;
+
+ if (send)
+ {
+ if (EVP_MD_CTX_md(s->write_hash))
+ {
+- n=EVP_MD_CTX_size(s->write_hash);
+- if (n < 0)
++ mac_size=EVP_MD_CTX_size(s->write_hash);
++ if (mac_size < 0)
+ return -1;
+ }
+ ds=s->enc_write_ctx;
+@@ -164,9 +172,8 @@ int dtls1_enc(SSL *s, int send)
+ {
+ if (EVP_MD_CTX_md(s->read_hash))
+ {
+- n=EVP_MD_CTX_size(s->read_hash);
+- if (n < 0)
+- return -1;
++ mac_size=EVP_MD_CTX_size(s->read_hash);
++ OPENSSL_assert(mac_size >= 0);
+ }
+ ds=s->enc_read_ctx;
+ rec= &(s->s3->rrec);
+@@ -231,7 +238,7 @@ int dtls1_enc(SSL *s, int send)
+ if (!send)
+ {
+ if (l == 0 || l%bs != 0)
+- return -1;
++ return 0;
+ }
+
+ EVP_Cipher(ds,rec->data,rec->input,l);
+@@ -246,43 +253,7 @@ int dtls1_enc(SSL *s, int send)
+ #endif /* KSSL_DEBUG */
+
+ if ((bs != 1) && !send)
+- {
+- ii=i=rec->data[l-1]; /* padding_length */
+- i++;
+- if (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
+- {
+- /* First packet is even in size, so check */
+- if ((memcmp(s->s3->read_sequence,
+- "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
+- s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
+- if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
+- i--;
+- }
+- /* TLS 1.0 does not bound the number of padding bytes by the block size.
+- * All of them must have value 'padding_length'. */
+- if (i + bs > (int)rec->length)
+- {
+- /* Incorrect padding. SSLerr() and ssl3_alert are done
+- * by caller: we don't want to reveal whether this is
+- * a decryption error or a MAC verification failure
+- * (see http://www.openssl.org/~bodo/tls-cbc.txt)
+- */
+- return -1;
+- }
+- for (j=(int)(l-i); j<(int)l; j++)
+- {
+- if (rec->data[j] != ii)
+- {
+- /* Incorrect padding */
+- return -1;
+- }
+- }
+- rec->length-=i;
+-
+- rec->data += bs; /* skip the implicit IV */
+- rec->input += bs;
+- rec->length -= bs;
+- }
++ return tls1_cbc_remove_padding(s, rec, bs, mac_size);
+ }
+ return(1);
+ }
+diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
+index 5e2c56c..02c881a 100644
+--- a/ssl/d1_pkt.c
++++ b/ssl/d1_pkt.c
+@@ -376,15 +376,11 @@ static int
+ dtls1_process_record(SSL *s)
+ {
+ int i,al;
+- int clear=0;
+ int enc_err;
+ SSL_SESSION *sess;
+ SSL3_RECORD *rr;
+ unsigned int mac_size;
+ unsigned char md[EVP_MAX_MD_SIZE];
+- int decryption_failed_or_bad_record_mac = 0;
+- unsigned char *mac = NULL;
+-
+
+ rr= &(s->s3->rrec);
+ sess = s->session;
+@@ -414,14 +410,19 @@ dtls1_process_record(SSL *s)
+
+ /* decrypt in place in 'rr->input' */
+ rr->data=rr->input;
++ rr->orig_len=rr->length;
+
+ enc_err = s->method->ssl3_enc->enc(s,0);
+- if (enc_err <= 0)
++ /* enc_err is:
++ * 0: (in non-constant time) if the record is publically invalid.
++ * 1: if the padding is valid
++ * -1: if the padding is invalid */
++ if (enc_err == 0)
+ {
+- /* To minimize information leaked via timing, we will always
+- * perform all computations before discarding the message.
+- */
+- decryption_failed_or_bad_record_mac = 1;
++ /* For DTLS we simply ignore bad packets. */
++ rr->length = 0;
++ s->packet_length = 0;
++ goto err;
+ }
+
+ #ifdef TLS_DEBUG
+@@ -431,45 +432,59 @@ printf("\n");
+ #endif
+
+ /* r->length is now the compressed data plus mac */
+- if ( (sess == NULL) ||
+- (s->enc_read_ctx == NULL) ||
+- (s->read_hash == NULL))
+- clear=1;
+-
+- if (!clear)
++ if ((sess != NULL) &&
++ (s->enc_read_ctx != NULL) &&
++ (EVP_MD_CTX_md(s->read_hash) != NULL))
+ {
+- /* !clear => s->read_hash != NULL => mac_size != -1 */
+- int t;
+- t=EVP_MD_CTX_size(s->read_hash);
+- OPENSSL_assert(t >= 0);
+- mac_size=t;
+-
+- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
++ /* s->read_hash != NULL => mac_size != -1 */
++ unsigned char *mac = NULL;
++ unsigned char mac_tmp[EVP_MAX_MD_SIZE];
++ mac_size=EVP_MD_CTX_size(s->read_hash);
++ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
++
++ /* orig_len is the length of the record before any padding was
++ * removed. This is public information, as is the MAC in use,
++ * therefore we can safely process the record in a different
++ * amount of time if it's too short to possibly contain a MAC.
++ */
++ if (rr->orig_len < mac_size ||
++ /* CBC records must have a padding length byte too. */
++ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
++ rr->orig_len < mac_size+1))
+ {
+-#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
+- al=SSL_AD_RECORD_OVERFLOW;
+- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
++ al=SSL_AD_DECODE_ERROR;
++ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
+ goto f_err;
+-#else
+- decryption_failed_or_bad_record_mac = 1;
+-#endif
+ }
+- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
+- if (rr->length >= mac_size)
++
++ if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
+ {
++ /* We update the length so that the TLS header bytes
++ * can be constructed correctly but we need to extract
++ * the MAC in constant time from within the record,
++ * without leaking the contents of the padding bytes.
++ * */
++ mac = mac_tmp;
++ ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+ rr->length -= mac_size;
+- mac = &rr->data[rr->length];
+ }
+ else
+- rr->length = 0;
+- i=s->method->ssl3_enc->mac(s,md,0);
+- if (i < 0 || mac == NULL || CRYPTO_memcmp(md,mac,mac_size) != 0)
+ {
+- decryption_failed_or_bad_record_mac = 1;
++ /* In this case there's no padding, so |rec->orig_len|
++ * equals |rec->length| and we checked that there's
++ * enough bytes for |mac_size| above. */
++ rr->length -= mac_size;
++ mac = &rr->data[rr->length];
+ }
++
++ i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
++ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
++ enc_err = -1;
++ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
++ enc_err = -1;
+ }
+
+- if (decryption_failed_or_bad_record_mac)
++ if (enc_err < 0)
+ {
+ /* decryption failed, silently discard message */
+ rr->length = 0;
+diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c
+new file mode 100644
+index 0000000..e9b112c
+--- /dev/null
++++ b/ssl/s3_cbc.c
+@@ -0,0 +1,696 @@
++/* ssl/s3_cbc.c */
++/* ====================================================================
++ * Copyright (c) 2012 The OpenSSL Project. All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ *
++ * 1. Redistributions of source code must retain the above copyright
++ * notice, this list of conditions and the following disclaimer.
++ *
++ * 2. Redistributions in binary form must reproduce the above copyright
++ * notice, this list of conditions and the following disclaimer in
++ * the documentation and/or other materials provided with the
++ * distribution.
++ *
++ * 3. All advertising materials mentioning features or use of this
++ * software must display the following acknowledgment:
++ * "This product includes software developed by the OpenSSL Project
++ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
++ *
++ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
++ * endorse or promote products derived from this software without
++ * prior written permission. For written permission, please contact
++ * openssl-core@openssl.org.
++ *
++ * 5. Products derived from this software may not be called "OpenSSL"
++ * nor may "OpenSSL" appear in their names without prior written
++ * permission of the OpenSSL Project.
++ *
++ * 6. Redistributions of any form whatsoever must retain the following
++ * acknowledgment:
++ * "This product includes software developed by the OpenSSL Project
++ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
++ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
++ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
++ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
++ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
++ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
++ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
++ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
++ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
++ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
++ * OF THE POSSIBILITY OF SUCH DAMAGE.
++ * ====================================================================
++ *
++ * This product includes cryptographic software written by Eric Young
++ * (eay@cryptsoft.com). This product includes software written by Tim
++ * Hudson (tjh@cryptsoft.com).
++ *
++ */
++
++#include <stdint.h>
++
++#include "ssl_locl.h"
++
++#include <openssl/md5.h>
++#include <openssl/sha.h>
++
++/* MAX_HASH_BIT_COUNT_BYTES is the maximum number of bytes in the hash's length
++ * field. (SHA-384/512 have 128-bit length.) */
++#define MAX_HASH_BIT_COUNT_BYTES 16
++
++/* MAX_HASH_BLOCK_SIZE is the maximum hash block size that we'll support.
++ * Currently SHA-384/512 has a 128-byte block size and that's the largest
++ * supported by TLS.) */
++#define MAX_HASH_BLOCK_SIZE 128
++
++/* Some utility functions are needed:
++ *
++ * These macros return the given value with the MSB copied to all the other
++ * bits. They use the fact that arithmetic shift shifts-in the sign bit.
++ * However, this is not ensured by the C standard so you may need to replace
++ * them with something else on odd CPUs. */
++#define DUPLICATE_MSB_TO_ALL(x) ( (unsigned)( (int)(x) >> (sizeof(int)*8-1) ) )
++#define DUPLICATE_MSB_TO_ALL_8(x) ((unsigned char)(DUPLICATE_MSB_TO_ALL(x)))
++
++/* constant_time_ge returns 0xff if a>=b and 0x00 otherwise. */
++static unsigned constant_time_ge(unsigned a, unsigned b)
++ {
++ a -= b;
++ return DUPLICATE_MSB_TO_ALL(~a);
++ }
++
++/* constant_time_eq_8 returns 0xff if a==b and 0x00 otherwise. */
++static unsigned char constant_time_eq_8(unsigned char a, unsigned char b)
++ {
++ unsigned c = a ^ b;
++ c--;
++ return DUPLICATE_MSB_TO_ALL_8(c);
++ }
++
++/* ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
++ * record in |rec| by updating |rec->length| in constant time.
++ *
++ * block_size: the block size of the cipher used to encrypt the record.
++ * returns:
++ * 0: (in non-constant time) if the record is publicly invalid.
++ * 1: if the padding was valid
++ * -1: otherwise. */
++int ssl3_cbc_remove_padding(const SSL* s,
++ SSL3_RECORD *rec,
++ unsigned block_size,
++ unsigned mac_size)
++ {
++ unsigned padding_length, good;
++ const unsigned overhead = 1 /* padding length byte */ + mac_size;
++
++ /* These lengths are all public so we can test them in non-constant
++ * time. */
++ if (overhead > rec->length)
++ return 0;
++
++ padding_length = rec->data[rec->length-1];
++ good = constant_time_ge(rec->length, padding_length+overhead);
++ /* SSLv3 requires that the padding is minimal. */
++ good &= constant_time_ge(block_size, padding_length+1);
++ rec->length -= good & (padding_length+1);
++ return (int)((good & 1) | (~good & -1));
++}
++
++/* tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
++ * record in |rec| in constant time and returns 1 if the padding is valid and
++ * -1 otherwise. It also removes any explicit IV from the start of the record
++ * without leaking any timing about whether there was enough space after the
++ * padding was removed.
++ *
++ * block_size: the block size of the cipher used to encrypt the record.
++ * returns:
++ * 0: (in non-constant time) if the record is publicly invalid.
++ * 1: if the padding was valid
++ * -1: otherwise. */
++int tls1_cbc_remove_padding(const SSL* s,
++ SSL3_RECORD *rec,
++ unsigned block_size,
++ unsigned mac_size)
++ {
++ unsigned padding_length, good, to_check, i;
++ const char has_explicit_iv =
++ s->version >= TLS1_1_VERSION || s->version == DTLS1_VERSION;
++ const unsigned overhead = 1 /* padding length byte */ +
++ mac_size +
++ (has_explicit_iv ? block_size : 0);
++
++ /* These lengths are all public so we can test them in non-constant
++ * time. */
++ if (overhead > rec->length)
++ return 0;
++
++ padding_length = rec->data[rec->length-1];
++
++ /* NB: if compression is in operation the first packet may not be of
++ * even length so the padding bug check cannot be performed. This bug
++ * workaround has been around since SSLeay so hopefully it is either
++ * fixed now or no buggy implementation supports compression [steve]
++ */
++ if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG) && !s->expand)
++ {
++ /* First packet is even in size, so check */
++ if ((memcmp(s->s3->read_sequence, "\0\0\0\0\0\0\0\0",8) == 0) &&
++ !(padding_length & 1))
++ {
++ s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
++ }
++ if ((s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG) &&
++ padding_length > 0)
++ {
++ padding_length--;
++ }
++ }
++
++ good = constant_time_ge(rec->length, overhead+padding_length);
++ /* The padding consists of a length byte at the end of the record and
++ * then that many bytes of padding, all with the same value as the
++ * length byte. Thus, with the length byte included, there are i+1
++ * bytes of padding.
++ *
++ * We can't check just |padding_length+1| bytes because that leaks
++ * decrypted information. Therefore we always have to check the maximum
++ * amount of padding possible. (Again, the length of the record is
++ * public information so we can use it.) */
++ to_check = 255; /* maximum amount of padding. */
++ if (to_check > rec->length-1)
++ to_check = rec->length-1;
++
++ for (i = 0; i < to_check; i++)
++ {
++ unsigned char mask = constant_time_ge(padding_length, i);
++ unsigned char b = rec->data[rec->length-1-i];
++ /* The final |padding_length+1| bytes should all have the value
++ * |padding_length|. Therefore the XOR should be zero. */
++ good &= ~(mask&(padding_length ^ b));
++ }
++
++ /* If any of the final |padding_length+1| bytes had the wrong value,
++ * one or more of the lower eight bits of |good| will be cleared. We
++ * AND the bottom 8 bits together and duplicate the result to all the
++ * bits. */
++ good &= good >> 4;
++ good &= good >> 2;
++ good &= good >> 1;
++ good <<= sizeof(good)*8-1;
++ good = DUPLICATE_MSB_TO_ALL(good);
++
++ rec->length -= good & (padding_length+1);
++
++ /* We can always safely skip the explicit IV. We check at the beginning
++ * of this function that the record has at least enough space for the
++ * IV, MAC and padding length byte. (These can be checked in
++ * non-constant time because it's all public information.) So, if the
++ * padding was invalid, then we didn't change |rec->length| and this is
++ * safe. If the padding was valid then we know that we have at least
++ * overhead+padding_length bytes of space and so this is still safe
++ * because overhead accounts for the explicit IV. */
++ if (has_explicit_iv)
++ {
++ rec->data += block_size;
++ rec->input += block_size;
++ rec->length -= block_size;
++ rec->orig_len -= block_size;
++ }
++
++ return (int)((good & 1) | (~good & -1));
++ }
++
++#if defined(_M_AMD64) || defined(__x86_64__)
++#define CBC_MAC_ROTATE_IN_PLACE
++#endif
++
++/* ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
++ * constant time (independent of the concrete value of rec->length, which may
++ * vary within a 256-byte window).
++ *
++ * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
++ * this function.
++ *
++ * On entry:
++ * rec->orig_len >= md_size
++ * md_size <= EVP_MAX_MD_SIZE
++ *
++ * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
++ * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
++ * a single cache-line, then the variable memory accesses don't actually affect
++ * the timing. This has been tested to be true on Intel amd64 chips.
++ */
++void ssl3_cbc_copy_mac(unsigned char* out,
++ const SSL3_RECORD *rec,
++ unsigned md_size)
++ {
++#if defined(CBC_MAC_ROTATE_IN_PLACE)
++ unsigned char rotated_mac_buf[EVP_MAX_MD_SIZE*2];
++ unsigned char *rotated_mac;
++#else
++ unsigned char rotated_mac[EVP_MAX_MD_SIZE];
++#endif
++
++ /* mac_end is the index of |rec->data| just after the end of the MAC. */
++ unsigned mac_end = rec->length;
++ unsigned mac_start = mac_end - md_size;
++ /* scan_start contains the number of bytes that we can ignore because
++ * the MAC's position can only vary by 255 bytes. */
++ unsigned scan_start = 0;
++ unsigned i, j;
++ unsigned div_spoiler;
++ unsigned rotate_offset;
++
++ OPENSSL_assert(rec->orig_len >= md_size);
++ OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
++
++#if defined(CBC_MAC_ROTATE_IN_PLACE)
++ rotated_mac = (unsigned char*) (((intptr_t)(rotated_mac_buf + 64)) & ~63);
++#endif
++
++ /* This information is public so it's safe to branch based on it. */
++ if (rec->orig_len > md_size + 255 + 1)
++ scan_start = rec->orig_len - (md_size + 255 + 1);
++ /* div_spoiler contains a multiple of md_size that is used to cause the
++ * modulo operation to be constant time. Without this, the time varies
++ * based on the amount of padding when running on Intel chips at least.
++ *
++ * The aim of right-shifting md_size is so that the compiler doesn't
++ * figure out that it can remove div_spoiler as that would require it
++ * to prove that md_size is always even, which I hope is beyond it. */
++ div_spoiler = md_size >> 1;
++ div_spoiler <<= (sizeof(div_spoiler)-1)*8;
++ rotate_offset = (div_spoiler + mac_start - scan_start) % md_size;
++
++ memset(rotated_mac, 0, md_size);
++ for (i = scan_start; i < rec->orig_len;)
++ {
++ for (j = 0; j < md_size && i < rec->orig_len; i++, j++)
++ {
++ unsigned char mac_started = constant_time_ge(i, mac_start);
++ unsigned char mac_ended = constant_time_ge(i, mac_end);
++ unsigned char b = 0;
++ b = rec->data[i];
++ rotated_mac[j] |= b & mac_started & ~mac_ended;
++ }
++ }
++
++ /* Now rotate the MAC */
++#if defined(CBC_MAC_ROTATE_IN_PLACE)
++ j = 0;
++ for (i = 0; i < md_size; i++)
++ {
++ unsigned char offset = (div_spoiler + rotate_offset + i) % md_size;
++ out[j++] = rotated_mac[offset];
++ }
++#else
++ memset(out, 0, md_size);
++ for (i = 0; i < md_size; i++)
++ {
++ unsigned char offset = (div_spoiler + md_size - rotate_offset + i) % md_size;
++ for (j = 0; j < md_size; j++)
++ out[j] |= rotated_mac[i] & constant_time_eq_8(j, offset);
++ }
++#endif
++ }
++
++/* These functions serialize the state of a hash and thus perform the standard
++ * "final" operation without adding the padding and length that such a function
++ * typically does. */
++static void tls1_md5_final_raw(void* ctx, unsigned char *md_out)
++ {
++ MD5_CTX *md5 = ctx;
++ l2n(md5->A, md_out);
++ l2n(md5->B, md_out);
++ l2n(md5->C, md_out);
++ l2n(md5->D, md_out);
++ }
++
++static void tls1_sha1_final_raw(void* ctx, unsigned char *md_out)
++ {
++ SHA_CTX *sha1 = ctx;
++ l2n(sha1->h0, md_out);
++ l2n(sha1->h1, md_out);
++ l2n(sha1->h2, md_out);
++ l2n(sha1->h3, md_out);
++ l2n(sha1->h4, md_out);
++ }
++
++static void tls1_sha256_final_raw(void* ctx, unsigned char *md_out)
++ {
++ SHA256_CTX *sha256 = ctx;
++ unsigned i;
++
++ for (i = 0; i < 8; i++)
++ {
++ l2n(sha256->h[i], md_out);
++ }
++ }
++
++static void tls1_sha512_final_raw(void* ctx, unsigned char *md_out)
++ {
++ SHA512_CTX *sha512 = ctx;
++ unsigned i;
++
++ for (i = 0; i < 8; i++)
++ {
++ l2n8(sha512->h[i], md_out);
++ }
++ }
++
++/* ssl3_cbc_record_digest_supported returns 1 iff |ctx| uses a hash function
++ * which ssl3_cbc_digest_record supports. */
++char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx)
++ {
++ switch (ctx->digest->type)
++ {
++ case NID_md5:
++ case NID_sha1:
++ case NID_sha224:
++ case NID_sha256:
++ case NID_sha384:
++ case NID_sha512:
++ return 1;
++ default:
++ return 0;
++ }
++ }
++
++/* ssl3_cbc_digest_record computes the MAC of a decrypted, padded SSLv3/TLS
++ * record.
++ *
++ * ctx: the EVP_MD_CTX from which we take the hash function.
++ * ssl3_cbc_record_digest_supported must return true for this EVP_MD_CTX.
++ * md_out: the digest output. At most EVP_MAX_MD_SIZE bytes will be written.
++ * md_out_size: if non-NULL, the number of output bytes is written here.
++ * header: the 13-byte, TLS record header.
++ * data: the record data itself, less any preceeding explicit IV.
++ * data_plus_mac_size: the secret, reported length of the data and MAC
++ * once the padding has been removed.
++ * data_plus_mac_plus_padding_size: the public length of the whole
++ * record, including padding.
++ * is_sslv3: non-zero if we are to use SSLv3. Otherwise, TLS.
++ *
++ * On entry: by virtue of having been through one of the remove_padding
++ * functions, above, we know that data_plus_mac_size is large enough to contain
++ * a padding byte and MAC. (If the padding was invalid, it might contain the
++ * padding too. ) */
++void ssl3_cbc_digest_record(
++ const EVP_MD_CTX *ctx,
++ unsigned char* md_out,
++ size_t* md_out_size,
++ const unsigned char header[13],
++ const unsigned char *data,
++ size_t data_plus_mac_size,
++ size_t data_plus_mac_plus_padding_size,
++ const unsigned char *mac_secret,
++ unsigned mac_secret_length,
++ char is_sslv3)
++ {
++ unsigned char md_state[sizeof(SHA512_CTX)];
++ void (*md_final_raw)(void *ctx, unsigned char *md_out);
++ void (*md_transform)(void *ctx, const unsigned char *block);
++ unsigned md_size, md_block_size = 64;
++ unsigned sslv3_pad_length = 40, header_length, variance_blocks,
++ len, max_mac_bytes, num_blocks,
++ num_starting_blocks, k, mac_end_offset, c, index_a, index_b;
++ uint64_t bits;
++ unsigned char length_bytes[MAX_HASH_BIT_COUNT_BYTES];
++ /* hmac_pad is the masked HMAC key. */
++ unsigned char hmac_pad[MAX_HASH_BLOCK_SIZE];
++ unsigned char first_block[MAX_HASH_BLOCK_SIZE];
++ unsigned char mac_out[EVP_MAX_MD_SIZE];
++ unsigned i, j, md_out_size_u;
++ EVP_MD_CTX md_ctx;
++ /* mdLengthSize is the number of bytes in the length field that terminates
++ * the hash. */
++ unsigned md_length_size = 8;
++
++ /* This is a, hopefully redundant, check that allows us to forget about
++ * many possible overflows later in this function. */
++ OPENSSL_assert(data_plus_mac_plus_padding_size < 1024*1024);
++
++ switch (ctx->digest->type)
++ {
++ case NID_md5:
++ MD5_Init((MD5_CTX*)md_state);
++ md_final_raw = tls1_md5_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) MD5_Transform;
++ md_size = 16;
++ sslv3_pad_length = 48;
++ break;
++ case NID_sha1:
++ SHA1_Init((SHA_CTX*)md_state);
++ md_final_raw = tls1_sha1_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA1_Transform;
++ md_size = 20;
++ break;
++ case NID_sha224:
++ SHA224_Init((SHA256_CTX*)md_state);
++ md_final_raw = tls1_sha256_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
++ md_size = 224/8;
++ break;
++ case NID_sha256:
++ SHA256_Init((SHA256_CTX*)md_state);
++ md_final_raw = tls1_sha256_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
++ md_size = 32;
++ break;
++ case NID_sha384:
++ SHA384_Init((SHA512_CTX*)md_state);
++ md_final_raw = tls1_sha512_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
++ md_size = 384/8;
++ md_block_size = 128;
++ md_length_size = 16;
++ break;
++ case NID_sha512:
++ SHA512_Init((SHA512_CTX*)md_state);
++ md_final_raw = tls1_sha512_final_raw;
++ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
++ md_size = 64;
++ md_block_size = 128;
++ md_length_size = 16;
++ break;
++ default:
++ /* ssl3_cbc_record_digest_supported should have been
++ * called first to check that the hash function is
++ * supported. */
++ OPENSSL_assert(0);
++ if (md_out_size)
++ *md_out_size = -1;
++ return;
++ }
++
++ OPENSSL_assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES);
++ OPENSSL_assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
++ OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
++
++ header_length = 13;
++ if (is_sslv3)
++ {
++ header_length =
++ mac_secret_length +
++ sslv3_pad_length +
++ 8 /* sequence number */ +
++ 1 /* record type */ +
++ 2 /* record length */;
++ }
++
++ /* variance_blocks is the number of blocks of the hash that we have to
++ * calculate in constant time because they could be altered by the
++ * padding value.
++ *
++ * In SSLv3, the padding must be minimal so the end of the plaintext
++ * varies by, at most, 15+20 = 35 bytes. (We conservatively assume that
++ * the MAC size varies from 0..20 bytes.) In case the 9 bytes of hash
++ * termination (0x80 + 64-bit length) don't fit in the final block, we
++ * say that the final two blocks can vary based on the padding.
++ *
++ * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not
++ * required to be minimal. Therefore we say that the final six blocks
++ * can vary based on the padding.
++ *
++ * Later in the function, if the message is short and there obviously
++ * cannot be this many blocks then variance_blocks can be reduced. */
++ variance_blocks = is_sslv3 ? 2 : 6;
++ /* From now on we're dealing with the MAC, which conceptually has 13
++ * bytes of `header' before the start of the data (TLS) or 71/75 bytes
++ * (SSLv3) */
++ len = data_plus_mac_plus_padding_size + header_length;
++ /* max_mac_bytes contains the maximum bytes of bytes in the MAC, including
++ * |header|, assuming that there's no padding. */
++ max_mac_bytes = len - md_size - 1;
++ /* num_blocks is the maximum number of hash blocks. */
++ num_blocks = (max_mac_bytes + 1 + md_length_size + md_block_size - 1) / md_block_size;
++ /* In order to calculate the MAC in constant time we have to handle
++ * the final blocks specially because the padding value could cause the
++ * end to appear somewhere in the final |variance_blocks| blocks and we
++ * can't leak where. However, |num_starting_blocks| worth of data can
++ * be hashed right away because no padding value can affect whether
++ * they are plaintext. */
++ num_starting_blocks = 0;
++ /* k is the starting byte offset into the conceptual header||data where
++ * we start processing. */
++ k = 0;
++ /* mac_end_offset is the index just past the end of the data to be
++ * MACed. */
++ mac_end_offset = data_plus_mac_size + header_length - md_size;
++ /* c is the index of the 0x80 byte in the final hash block that
++ * contains application data. */
++ c = mac_end_offset % md_block_size;
++ /* index_a is the hash block number that contains the 0x80 terminating
++ * value. */
++ index_a = mac_end_offset / md_block_size;
++ /* index_b is the hash block number that contains the 64-bit hash
++ * length, in bits. */
++ index_b = (mac_end_offset + md_length_size) / md_block_size;
++ /* bits is the hash-length in bits. It includes the additional hash
++ * block for the masked HMAC key, or whole of |header| in the case of
++ * SSLv3. */
++
++ /* For SSLv3, if we're going to have any starting blocks then we need
++ * at least two because the header is larger than a single block. */
++ if (num_blocks > variance_blocks + (is_sslv3 ? 1 : 0))
++ {
++ num_starting_blocks = num_blocks - variance_blocks;
++ k = md_block_size*num_starting_blocks;
++ }
++
++ bits = 8*mac_end_offset;
++ if (!is_sslv3)
++ {
++ /* Compute the initial HMAC block. For SSLv3, the padding and
++ * secret bytes are included in |header| because they take more
++ * than a single block. */
++ bits += 8*md_block_size;
++ memset(hmac_pad, 0, md_block_size);
++ OPENSSL_assert(mac_secret_length <= sizeof(hmac_pad));
++ memcpy(hmac_pad, mac_secret, mac_secret_length);
++ for (i = 0; i < md_block_size; i++)
++ hmac_pad[i] ^= 0x36;
++
++ md_transform(md_state, hmac_pad);
++ }
++
++ j = 0;
++ if (md_length_size == 16)
++ {
++ memset(length_bytes, 0, 8);
++ j = 8;
++ }
++ for (i = 0; i < 8; i++)
++ length_bytes[i+j] = bits >> (8*(7-i));
++
++ if (k > 0)
++ {
++ if (is_sslv3)
++ {
++ /* The SSLv3 header is larger than a single block.
++ * overhang is the number of bytes beyond a single
++ * block that the header consumes: either 7 bytes
++ * (SHA1) or 11 bytes (MD5). */
++ unsigned overhang = header_length-md_block_size;
++ md_transform(md_state, header);
++ memcpy(first_block, header + md_block_size, overhang);
++ memcpy(first_block + overhang, data, md_block_size-overhang);
++ md_transform(md_state, first_block);
++ for (i = 1; i < k/md_block_size - 1; i++)
++ md_transform(md_state, data + md_block_size*i - overhang);
++ }
++ else
++ {
++ /* k is a multiple of md_block_size. */
++ memcpy(first_block, header, 13);
++ memcpy(first_block+13, data, md_block_size-13);
++ md_transform(md_state, first_block);
++ for (i = 1; i < k/md_block_size; i++)
++ md_transform(md_state, data + md_block_size*i - 13);
++ }
++ }
++
++ memset(mac_out, 0, sizeof(mac_out));
++
++ /* We now process the final hash blocks. For each block, we construct
++ * it in constant time. If the |i==index_a| then we'll include the 0x80
++ * bytes and zero pad etc. For each block we selectively copy it, in
++ * constant time, to |mac_out|. */
++ for (i = num_starting_blocks; i <= num_starting_blocks+variance_blocks; i++)
++ {
++ unsigned char block[MAX_HASH_BLOCK_SIZE];
++ unsigned char is_block_a = constant_time_eq_8(i, index_a);
++ unsigned char is_block_b = constant_time_eq_8(i, index_b);
++ for (j = 0; j < md_block_size; j++)
++ {
++ unsigned char b = 0, is_past_c, is_past_cp1;
++ if (k < header_length)
++ b = header[k];
++ else if (k < data_plus_mac_plus_padding_size + header_length)
++ b = data[k-header_length];
++ k++;
++
++ is_past_c = is_block_a & constant_time_ge(j, c);
++ is_past_cp1 = is_block_a & constant_time_ge(j, c+1);
++ /* If this is the block containing the end of the
++ * application data, and we are at the offset for the
++ * 0x80 value, then overwrite b with 0x80. */
++ b = (b&~is_past_c) | (0x80&is_past_c);
++ /* If this the the block containing the end of the
++ * application data and we're past the 0x80 value then
++ * just write zero. */
++ b = b&~is_past_cp1;
++ /* If this is index_b (the final block), but not
++ * index_a (the end of the data), then the 64-bit
++ * length didn't fit into index_a and we're having to
++ * add an extra block of zeros. */
++ b &= ~is_block_b | is_block_a;
++
++ /* The final bytes of one of the blocks contains the
++ * length. */
++ if (j >= md_block_size - md_length_size)
++ {
++ /* If this is index_b, write a length byte. */
++ b = (b&~is_block_b) | (is_block_b&length_bytes[j-(md_block_size-md_length_size)]);
++ }
++ block[j] = b;
++ }
++
++ md_transform(md_state, block);
++ md_final_raw(md_state, block);
++ /* If this is index_b, copy the hash value to |mac_out|. */
++ for (j = 0; j < md_size; j++)
++ mac_out[j] |= block[j]&is_block_b;
++ }
++
++ EVP_MD_CTX_init(&md_ctx);
++ EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */);
++ if (is_sslv3)
++ {
++ /* We repurpose |hmac_pad| to contain the SSLv3 pad2 block. */
++ memset(hmac_pad, 0x5c, sslv3_pad_length);
++
++ EVP_DigestUpdate(&md_ctx, mac_secret, mac_secret_length);
++ EVP_DigestUpdate(&md_ctx, hmac_pad, sslv3_pad_length);
++ EVP_DigestUpdate(&md_ctx, mac_out, md_size);
++ }
++ else
++ {
++ /* Complete the HMAC in the standard manner. */
++ for (i = 0; i < md_block_size; i++)
++ hmac_pad[i] ^= 0x6a;
++
++ EVP_DigestUpdate(&md_ctx, hmac_pad, md_block_size);
++ EVP_DigestUpdate(&md_ctx, mac_out, md_size);
++ }
++ EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u);
++ if (md_out_size)
++ *md_out_size = md_out_size_u;
++ EVP_MD_CTX_cleanup(&md_ctx);
++ }
+diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
+index c5df2cb..a0eac77 100644
+--- a/ssl/s3_enc.c
++++ b/ssl/s3_enc.c
+@@ -466,12 +466,21 @@ void ssl3_cleanup_key_block(SSL *s)
+ s->s3->tmp.key_block_length=0;
+ }
+
++/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
++ *
++ * Returns:
++ * 0: (in non-constant time) if the record is publically invalid (i.e. too
++ * short etc).
++ * 1: if the record's padding is valid / the encryption was successful.
++ * -1: if the record's padding is invalid or, if sending, an internal error
++ * occured.
++ */
+ int ssl3_enc(SSL *s, int send)
+ {
+ SSL3_RECORD *rec;
+ EVP_CIPHER_CTX *ds;
+ unsigned long l;
+- int bs,i;
++ int bs,i,mac_size=0;
+ const EVP_CIPHER *enc;
+
+ if (send)
+@@ -522,32 +531,16 @@ int ssl3_enc(SSL *s, int send)
+ if (!send)
+ {
+ if (l == 0 || l%bs != 0)
+- {
+- SSLerr(SSL_F_SSL3_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
+- ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
+ return 0;
+- }
+ /* otherwise, rec->length >= bs */
+ }
+
+ EVP_Cipher(ds,rec->data,rec->input,l);
+
++ if (EVP_MD_CTX_md(s->read_hash) != NULL)
++ mac_size = EVP_MD_CTX_size(s->read_hash);
+ if ((bs != 1) && !send)
+- {
+- i=rec->data[l-1]+1;
+- /* SSL 3.0 bounds the number of padding bytes by the block size;
+- * padding bytes (except the last one) are arbitrary */
+- if (i > bs)
+- {
+- /* Incorrect padding. SSLerr() and ssl3_alert are done
+- * by caller: we don't want to reveal whether this is
+- * a decryption error or a MAC verification failure
+- * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
+- return -1;
+- }
+- /* now i <= bs <= rec->length */
+- rec->length-=i;
+- }
++ return ssl3_cbc_remove_padding(s, rec, bs, mac_size);
+ }
+ return(1);
+ }
+@@ -716,7 +709,7 @@ int n_ssl3_mac(SSL *ssl, unsigned char *md, int send)
+ EVP_MD_CTX md_ctx;
+ const EVP_MD_CTX *hash;
+ unsigned char *p,rec_char;
+- unsigned int md_size;
++ size_t md_size;
+ int npad;
+ int t;
+
+@@ -741,28 +734,68 @@ int n_ssl3_mac(SSL *ssl, unsigned char *md, int send)
+ md_size=t;
+ npad=(48/md_size)*md_size;
+
+- /* Chop the digest off the end :-) */
+- EVP_MD_CTX_init(&md_ctx);
+-
+- EVP_MD_CTX_copy_ex( &md_ctx,hash);
+- EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+- EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
+- EVP_DigestUpdate(&md_ctx,seq,8);
+- rec_char=rec->type;
+- EVP_DigestUpdate(&md_ctx,&rec_char,1);
+- p=md;
+- s2n(rec->length,p);
+- EVP_DigestUpdate(&md_ctx,md,2);
+- EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
+- EVP_DigestFinal_ex( &md_ctx,md,NULL);
+-
+- EVP_MD_CTX_copy_ex( &md_ctx,hash);
+- EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+- EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
+- EVP_DigestUpdate(&md_ctx,md,md_size);
+- EVP_DigestFinal_ex( &md_ctx,md,&md_size);
+-
+- EVP_MD_CTX_cleanup(&md_ctx);
++ if (!send &&
++ EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
++ ssl3_cbc_record_digest_supported(hash))
++ {
++ /* This is a CBC-encrypted record. We must avoid leaking any
++ * timing-side channel information about how many blocks of
++ * data we are hashing because that gives an attacker a
++ * timing-oracle. */
++
++ /* npad is, at most, 48 bytes and that's with MD5:
++ * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
++ *
++ * With SHA-1 (the largest hash speced for SSLv3) the hash size
++ * goes up 4, but npad goes down by 8, resulting in a smaller
++ * total size. */
++ unsigned char header[75];
++ unsigned j = 0;
++ memcpy(header+j, mac_sec, md_size);
++ j += md_size;
++ memcpy(header+j, ssl3_pad_1, npad);
++ j += npad;
++ memcpy(header+j, seq, 8);
++ j += 8;
++ header[j++] = rec->type;
++ header[j++] = rec->length >> 8;
++ header[j++] = rec->length & 0xff;
++
++ ssl3_cbc_digest_record(
++ hash,
++ md, &md_size,
++ header, rec->input,
++ rec->length + md_size, rec->orig_len,
++ mac_sec, md_size,
++ 1 /* is SSLv3 */);
++ }
++ else
++ {
++ unsigned int md_size_u;
++ /* Chop the digest off the end :-) */
++ EVP_MD_CTX_init(&md_ctx);
++
++ EVP_MD_CTX_copy_ex( &md_ctx,hash);
++ EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
++ EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
++ EVP_DigestUpdate(&md_ctx,seq,8);
++ rec_char=rec->type;
++ EVP_DigestUpdate(&md_ctx,&rec_char,1);
++ p=md;
++ s2n(rec->length,p);
++ EVP_DigestUpdate(&md_ctx,md,2);
++ EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
++ EVP_DigestFinal_ex( &md_ctx,md,NULL);
++
++ EVP_MD_CTX_copy_ex( &md_ctx,hash);
++ EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
++ EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
++ EVP_DigestUpdate(&md_ctx,md,md_size);
++ EVP_DigestFinal_ex( &md_ctx,md,&md_size_u);
++ md_size = md_size_u;
++
++ EVP_MD_CTX_cleanup(&md_ctx);
++ }
+
+ ssl3_record_sequence_update(seq);
+ return(md_size);
+diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
+index 3e11140..dba6653 100644
+--- a/ssl/s3_pkt.c
++++ b/ssl/s3_pkt.c
+@@ -290,11 +290,8 @@ static int ssl3_get_record(SSL *s)
+ unsigned char *p;
+ unsigned char md[EVP_MAX_MD_SIZE];
+ short version;
+- int mac_size;
+- int clear=0;
++ unsigned mac_size;
+ size_t extra;
+- int decryption_failed_or_bad_record_mac = 0;
+- unsigned char *mac = NULL;
+
+ rr= &(s->s3->rrec);
+ sess=s->session;
+@@ -401,19 +398,18 @@ fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
+
+ /* decrypt in place in 'rr->input' */
+ rr->data=rr->input;
++ rr->orig_len=rr->length;
+
+ enc_err = s->method->ssl3_enc->enc(s,0);
+- if (enc_err <= 0)
++ /* enc_err is:
++ * 0: (in non-constant time) if the record is publically invalid.
++ * 1: if the padding is valid
++ * -1: if the padding is invalid */
++ if (enc_err == 0)
+ {
+- if (enc_err == 0)
+- /* SSLerr() and ssl3_send_alert() have been called */
+- goto err;
+-
+- /* Otherwise enc_err == -1, which indicates bad padding
+- * (rec->length has not been changed in this case).
+- * To minimize information leaked via timing, we will perform
+- * the MAC computation anyway. */
+- decryption_failed_or_bad_record_mac = 1;
++ al=SSL_AD_DECRYPTION_FAILED;
++ SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
++ goto f_err;
+ }
+
+ #ifdef TLS_DEBUG
+@@ -423,53 +419,59 @@ printf("\n");
+ #endif
+
+ /* r->length is now the compressed data plus mac */
+- if ( (sess == NULL) ||
+- (s->enc_read_ctx == NULL) ||
+- (EVP_MD_CTX_md(s->read_hash) == NULL))
+- clear=1;
+-
+- if (!clear)
++ if ((sess != NULL) &&
++ (s->enc_read_ctx != NULL) &&
++ (EVP_MD_CTX_md(s->read_hash) != NULL))
+ {
+- /* !clear => s->read_hash != NULL => mac_size != -1 */
++ /* s->read_hash != NULL => mac_size != -1 */
++ unsigned char *mac = NULL;
++ unsigned char mac_tmp[EVP_MAX_MD_SIZE];
+ mac_size=EVP_MD_CTX_size(s->read_hash);
+- OPENSSL_assert(mac_size >= 0);
++ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
+
+- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
++ /* orig_len is the length of the record before any padding was
++ * removed. This is public information, as is the MAC in use,
++ * therefore we can safely process the record in a different
++ * amount of time if it's too short to possibly contain a MAC.
++ */
++ if (rr->orig_len < mac_size ||
++ /* CBC records must have a padding length byte too. */
++ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
++ rr->orig_len < mac_size+1))
+ {
+-#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
+- al=SSL_AD_RECORD_OVERFLOW;
+- SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
++ al=SSL_AD_DECODE_ERROR;
++ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
+ goto f_err;
+-#else
+- decryption_failed_or_bad_record_mac = 1;
+-#endif
+ }
+- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
+- if (rr->length >= (unsigned int)mac_size)
++
++ if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
+ {
++ /* We update the length so that the TLS header bytes
++ * can be constructed correctly but we need to extract
++ * the MAC in constant time from within the record,
++ * without leaking the contents of the padding bytes.
++ * */
++ mac = mac_tmp;
++ ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+ rr->length -= mac_size;
+- mac = &rr->data[rr->length];
+ }
+ else
+ {
+- /* record (minus padding) is too short to contain a MAC */
+-#if 0 /* OK only for stream ciphers */
+- al=SSL_AD_DECODE_ERROR;
+- SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
+- goto f_err;
+-#else
+- decryption_failed_or_bad_record_mac = 1;
+- rr->length = 0;
+-#endif
++ /* In this case there's no padding, so |rec->orig_len|
++ * equals |rec->length| and we checked that there's
++ * enough bytes for |mac_size| above. */
++ rr->length -= mac_size;
++ mac = &rr->data[rr->length];
+ }
+- i=s->method->ssl3_enc->mac(s,md,0);
++
++ i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
+ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+- {
+- decryption_failed_or_bad_record_mac = 1;
+- }
++ enc_err = -1;
++ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
++ enc_err = -1;
+ }
+
+- if (decryption_failed_or_bad_record_mac)
++ if (enc_err < 0)
+ {
+ /* A separate 'decryption_failed' alert was introduced with TLS 1.0,
+ * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
+diff --git a/ssl/ssl3.h b/ssl/ssl3.h
+index 247e88c..87d3e0f 100644
+--- a/ssl/ssl3.h
++++ b/ssl/ssl3.h
+@@ -355,6 +355,10 @@ typedef struct ssl3_record_st
+ /*r */ unsigned char *comp; /* only used with decompression - malloc()ed */
+ /*r */ unsigned long epoch; /* epoch number, needed by DTLS1 */
+ /*r */ unsigned char seq_num[8]; /* sequence number, needed by DTLS1 */
++/*rw*/ unsigned int orig_len; /* How many bytes were available before padding
++ was removed? This is used to implement the
++ MAC check in constant time for CBC records.
++ */
+ } SSL3_RECORD;
+
+ typedef struct ssl3_buffer_st
+diff --git a/ssl/ssl_algs.c b/ssl/ssl_algs.c
+index d443143..41ccbaa 100644
+--- a/ssl/ssl_algs.c
++++ b/ssl/ssl_algs.c
+@@ -90,11 +90,14 @@ int SSL_library_init(void)
+ EVP_add_cipher(EVP_aes_256_cbc());
+ EVP_add_cipher(EVP_aes_128_gcm());
+ EVP_add_cipher(EVP_aes_256_gcm());
++#if 0 /* Disabled because of timing side-channel leaks. */
+ #if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1)
+ EVP_add_cipher(EVP_aes_128_cbc_hmac_sha1());
+ EVP_add_cipher(EVP_aes_256_cbc_hmac_sha1());
+ #endif
+ #endif
++
++#endif
+ #ifndef OPENSSL_NO_CAMELLIA
+ EVP_add_cipher(EVP_camellia_128_cbc());
+ EVP_add_cipher(EVP_camellia_256_cbc());
+diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
+index 0572e10..dd8388c 100644
+--- a/ssl/ssl_locl.h
++++ b/ssl/ssl_locl.h
+@@ -215,6 +215,15 @@
+ *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
+ *((c)++)=(unsigned char)(((l) )&0xff))
+
++#define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \
++ *((c)++)=(unsigned char)(((l)>>48)&0xff), \
++ *((c)++)=(unsigned char)(((l)>>40)&0xff), \
++ *((c)++)=(unsigned char)(((l)>>32)&0xff), \
++ *((c)++)=(unsigned char)(((l)>>24)&0xff), \
++ *((c)++)=(unsigned char)(((l)>>16)&0xff), \
++ *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
++ *((c)++)=(unsigned char)(((l) )&0xff))
++
+ #define n2l6(c,l) (l =((BN_ULLONG)(*((c)++)))<<40, \
+ l|=((BN_ULLONG)(*((c)++)))<<32, \
+ l|=((BN_ULLONG)(*((c)++)))<<24, \
+@@ -1133,4 +1142,29 @@ int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al
+ int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen);
+ int ssl_parse_serverhello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al);
+
++/* s3_cbc.c */
++void ssl3_cbc_copy_mac(unsigned char* out,
++ const SSL3_RECORD *rec,
++ unsigned md_size);
++int ssl3_cbc_remove_padding(const SSL* s,
++ SSL3_RECORD *rec,
++ unsigned block_size,
++ unsigned mac_size);
++int tls1_cbc_remove_padding(const SSL* s,
++ SSL3_RECORD *rec,
++ unsigned block_size,
++ unsigned mac_size);
++char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx);
++void ssl3_cbc_digest_record(
++ const EVP_MD_CTX *ctx,
++ unsigned char* md_out,
++ size_t* md_out_size,
++ const unsigned char header[13],
++ const unsigned char *data,
++ size_t data_plus_mac_size,
++ size_t data_plus_mac_plus_padding_size,
++ const unsigned char *mac_secret,
++ unsigned mac_secret_length,
++ char is_sslv3);
++
+ #endif
+diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
+index b37678f..bb46f7f 100644
+--- a/ssl/t1_enc.c
++++ b/ssl/t1_enc.c
+@@ -667,12 +667,21 @@ err:
+ return(ret);
+ }
+
++/* tls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
++ *
++ * Returns:
++ * 0: (in non-constant time) if the record is publically invalid (i.e. too
++ * short etc).
++ * 1: if the record's padding is valid / the encryption was successful.
++ * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
++ * an internal error occured.
++ */
+ int tls1_enc(SSL *s, int send)
+ {
+ SSL3_RECORD *rec;
+ EVP_CIPHER_CTX *ds;
+ unsigned long l;
+- int bs,i,ii,j,k,pad=0;
++ int bs,i,j,k,pad=0,ret,mac_size=0;
+ const EVP_CIPHER *enc;
+
+ if (send)
+@@ -729,11 +738,11 @@ int tls1_enc(SSL *s, int send)
+ printf("tls1_enc(%d)\n", send);
+ #endif /* KSSL_DEBUG */
+
+- if ((s->session == NULL) || (ds == NULL) ||
+- (enc == NULL))
++ if ((s->session == NULL) || (ds == NULL) || (enc == NULL))
+ {
+ memmove(rec->data,rec->input,rec->length);
+ rec->input=rec->data;
++ ret = 1;
+ }
+ else
+ {
+@@ -797,13 +806,13 @@ int tls1_enc(SSL *s, int send)
+
+ #ifdef KSSL_DEBUG
+ {
+- unsigned long ui;
++ unsigned long ui;
+ printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",
+- ds,rec->data,rec->input,l);
++ ds,rec->data,rec->input,l);
+ printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%d %d], %d iv_len\n",
+- ds->buf_len, ds->cipher->key_len,
+- DES_KEY_SZ, DES_SCHEDULE_SZ,
+- ds->cipher->iv_len);
++ ds->buf_len, ds->cipher->key_len,
++ DES_KEY_SZ, DES_SCHEDULE_SZ,
++ ds->cipher->iv_len);
+ printf("\t\tIV: ");
+ for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);
+ printf("\n");
+@@ -816,13 +825,7 @@ int tls1_enc(SSL *s, int send)
+ if (!send)
+ {
+ if (l == 0 || l%bs != 0)
+- {
+- if (s->version >= TLS1_1_VERSION)
+- return -1;
+- SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
+- ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
+ return 0;
+- }
+ }
+
+ i = EVP_Cipher(ds,rec->data,rec->input,l);
+@@ -839,68 +842,24 @@ int tls1_enc(SSL *s, int send)
+
+ #ifdef KSSL_DEBUG
+ {
+- unsigned long i;
+- printf("\trec->data=");
++ unsigned long i;
++ printf("\trec->data=");
+ for (i=0; i<l; i++)
+- printf(" %02x", rec->data[i]); printf("\n");
+- }
++ printf(" %02x", rec->data[i]); printf("\n");
++ }
+ #endif /* KSSL_DEBUG */
+
++ ret = 1;
++ if (EVP_MD_CTX_md(s->read_hash) != NULL)
++ mac_size = EVP_MD_CTX_size(s->read_hash);
+ if ((bs != 1) && !send)
+- {
+- ii=i=rec->data[l-1]; /* padding_length */
+- i++;
+- /* NB: if compression is in operation the first packet
+- * may not be of even length so the padding bug check
+- * cannot be performed. This bug workaround has been
+- * around since SSLeay so hopefully it is either fixed
+- * now or no buggy implementation supports compression
+- * [steve]
+- */
+- if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
+- && !s->expand)
+- {
+- /* First packet is even in size, so check */
+- if ((memcmp(s->s3->read_sequence,
+- "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
+- s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
+- if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
+- i--;
+- }
+- /* TLS 1.0 does not bound the number of padding bytes by the block size.
+- * All of them must have value 'padding_length'. */
+- if (i > (int)rec->length)
+- {
+- /* Incorrect padding. SSLerr() and ssl3_alert are done
+- * by caller: we don't want to reveal whether this is
+- * a decryption error or a MAC verification failure
+- * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
+- return -1;
+- }
+- for (j=(int)(l-i); j<(int)l; j++)
+- {
+- if (rec->data[j] != ii)
+- {
+- /* Incorrect padding */
+- return -1;
+- }
+- }
+- rec->length -=i;
+- if (s->version >= TLS1_1_VERSION
+- && EVP_CIPHER_CTX_mode(ds) == EVP_CIPH_CBC_MODE)
+- {
+- if (bs > (int)rec->length)
+- return -1;
+- rec->data += bs; /* skip the explicit IV */
+- rec->input += bs;
+- rec->length -= bs;
+- }
+- }
++ ret = tls1_cbc_remove_padding(s, rec, bs, mac_size);
+ if (pad && !send)
+ rec->length -= pad;
+ }
+- return(1);
++ return ret;
+ }
++
+ int tls1_cert_verify_mac(SSL *s, int md_nid, unsigned char *out)
+ {
+ unsigned int ret;
+@@ -993,7 +952,7 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
+ size_t md_size;
+ int i;
+ EVP_MD_CTX hmac, *mac_ctx;
+- unsigned char buf[5];
++ unsigned char header[13];
+ int stream_mac = (send?(ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM):(ssl->mac_flags&SSL_MAC_FLAG_READ_MAC_STREAM));
+ int t;
+
+@@ -1014,12 +973,6 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
+ OPENSSL_assert(t >= 0);
+ md_size=t;
+
+- buf[0]=rec->type;
+- buf[1]=(unsigned char)(ssl->version>>8);
+- buf[2]=(unsigned char)(ssl->version);
+- buf[3]=rec->length>>8;
+- buf[4]=rec->length&0xff;
+-
+ /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
+ if (stream_mac)
+ {
+@@ -1038,17 +991,44 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
+ s2n(send?ssl->d1->w_epoch:ssl->d1->r_epoch, p);
+ memcpy (p,&seq[2],6);
+
+- EVP_DigestSignUpdate(mac_ctx,dtlsseq,8);
++ memcpy(header, dtlsseq, 8);
+ }
+ else
+- EVP_DigestSignUpdate(mac_ctx,seq,8);
++ memcpy(header, seq, 8);
+
+- EVP_DigestSignUpdate(mac_ctx,buf,5);
+- EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
+- t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
+- OPENSSL_assert(t > 0);
++ header[8]=rec->type;
++ header[9]=(unsigned char)(ssl->version>>8);
++ header[10]=(unsigned char)(ssl->version);
++ header[11]=(rec->length)>>8;
++ header[12]=(rec->length)&0xff;
++
++ if (!send &&
++ EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
++ ssl3_cbc_record_digest_supported(mac_ctx))
++ {
++ /* This is a CBC-encrypted record. We must avoid leaking any
++ * timing-side channel information about how many blocks of
++ * data we are hashing because that gives an attacker a
++ * timing-oracle. */
++ ssl3_cbc_digest_record(
++ mac_ctx,
++ md, &md_size,
++ header, rec->input,
++ rec->length + md_size, rec->orig_len,
++ ssl->s3->read_mac_secret,
++ ssl->s3->read_mac_secret_size,
++ 0 /* not SSLv3 */);
++ }
++ else
++ {
++ EVP_DigestSignUpdate(mac_ctx,header,sizeof(header));
++ EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
++ t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
++ OPENSSL_assert(t > 0);
++ }
+
+- if (!stream_mac) EVP_MD_CTX_cleanup(&hmac);
++ if (!stream_mac)
++ EVP_MD_CTX_cleanup(&hmac);
+ #ifdef TLS_DEBUG
+ printf("sec=");
+ {unsigned int z; for (z=0; z<md_size; z++) printf("%02X ",mac_sec[z]); printf("\n"); }
+--
+1.8.1
+
diff --git a/patches/README b/patches/README
index 17422b1..a1d5313 100644
--- a/patches/README
+++ b/patches/README
@@ -31,6 +31,7 @@
Implements TLS Channel ID support as both a client and a server.
See http://tools.ietf.org/html/draft-balfanz-tls-channelid-00.
+
clang.patch
Fixes two minor compilation errors when building with the Clang compiler.
@@ -42,3 +43,15 @@
See http://cvs.openssl.org/chngview?cn=22568 for upstream patch, and
https://groups.google.com/d/topic/mailing.openssl.dev/4Z67vaaTChk/discussion
for the most recent discussion.
+
+
+0001-Add-and-use-a-constant-time-memcmp.patch
+
+constant time memcmp
+
+
+0002-Make-CBC-decoding-constant-time.patch
+
+Make CBC decoding constant time CVE-2013-0169
+
+
diff --git a/ssl/d1_enc.c b/ssl/d1_enc.c
index 07a5e97..712c464 100644
--- a/ssl/d1_enc.c
+++ b/ssl/d1_enc.c
@@ -126,20 +126,28 @@
#include <openssl/des.h>
#endif
+/* dtls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ * 0: (in non-constant time) if the record is publically invalid (i.e. too
+ * short etc).
+ * 1: if the record's padding is valid / the encryption was successful.
+ * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
+ * an internal error occured. */
int dtls1_enc(SSL *s, int send)
{
SSL3_RECORD *rec;
EVP_CIPHER_CTX *ds;
unsigned long l;
- int bs,i,ii,j,k,n=0;
+ int bs,i,j,k,mac_size=0;
const EVP_CIPHER *enc;
if (send)
{
if (EVP_MD_CTX_md(s->write_hash))
{
- n=EVP_MD_CTX_size(s->write_hash);
- if (n < 0)
+ mac_size=EVP_MD_CTX_size(s->write_hash);
+ if (mac_size < 0)
return -1;
}
ds=s->enc_write_ctx;
@@ -164,9 +172,8 @@
{
if (EVP_MD_CTX_md(s->read_hash))
{
- n=EVP_MD_CTX_size(s->read_hash);
- if (n < 0)
- return -1;
+ mac_size=EVP_MD_CTX_size(s->read_hash);
+ OPENSSL_assert(mac_size >= 0);
}
ds=s->enc_read_ctx;
rec= &(s->s3->rrec);
@@ -231,7 +238,7 @@
if (!send)
{
if (l == 0 || l%bs != 0)
- return -1;
+ return 0;
}
EVP_Cipher(ds,rec->data,rec->input,l);
@@ -246,43 +253,7 @@
#endif /* KSSL_DEBUG */
if ((bs != 1) && !send)
- {
- ii=i=rec->data[l-1]; /* padding_length */
- i++;
- if (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
- {
- /* First packet is even in size, so check */
- if ((memcmp(s->s3->read_sequence,
- "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
- s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
- if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
- i--;
- }
- /* TLS 1.0 does not bound the number of padding bytes by the block size.
- * All of them must have value 'padding_length'. */
- if (i + bs > (int)rec->length)
- {
- /* Incorrect padding. SSLerr() and ssl3_alert are done
- * by caller: we don't want to reveal whether this is
- * a decryption error or a MAC verification failure
- * (see http://www.openssl.org/~bodo/tls-cbc.txt)
- */
- return -1;
- }
- for (j=(int)(l-i); j<(int)l; j++)
- {
- if (rec->data[j] != ii)
- {
- /* Incorrect padding */
- return -1;
- }
- }
- rec->length-=i;
-
- rec->data += bs; /* skip the implicit IV */
- rec->input += bs;
- rec->length -= bs;
- }
+ return tls1_cbc_remove_padding(s, rec, bs, mac_size);
}
return(1);
}
diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index 987af60..02c881a 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -376,15 +376,11 @@
dtls1_process_record(SSL *s)
{
int i,al;
- int clear=0;
int enc_err;
SSL_SESSION *sess;
SSL3_RECORD *rr;
unsigned int mac_size;
unsigned char md[EVP_MAX_MD_SIZE];
- int decryption_failed_or_bad_record_mac = 0;
- unsigned char *mac = NULL;
-
rr= &(s->s3->rrec);
sess = s->session;
@@ -414,14 +410,19 @@
/* decrypt in place in 'rr->input' */
rr->data=rr->input;
+ rr->orig_len=rr->length;
enc_err = s->method->ssl3_enc->enc(s,0);
- if (enc_err <= 0)
+ /* enc_err is:
+ * 0: (in non-constant time) if the record is publically invalid.
+ * 1: if the padding is valid
+ * -1: if the padding is invalid */
+ if (enc_err == 0)
{
- /* To minimize information leaked via timing, we will always
- * perform all computations before discarding the message.
- */
- decryption_failed_or_bad_record_mac = 1;
+ /* For DTLS we simply ignore bad packets. */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto err;
}
#ifdef TLS_DEBUG
@@ -431,45 +432,59 @@
#endif
/* r->length is now the compressed data plus mac */
- if ( (sess == NULL) ||
- (s->enc_read_ctx == NULL) ||
- (s->read_hash == NULL))
- clear=1;
-
- if (!clear)
+ if ((sess != NULL) &&
+ (s->enc_read_ctx != NULL) &&
+ (EVP_MD_CTX_md(s->read_hash) != NULL))
{
- /* !clear => s->read_hash != NULL => mac_size != -1 */
- int t;
- t=EVP_MD_CTX_size(s->read_hash);
- OPENSSL_assert(t >= 0);
- mac_size=t;
+ /* s->read_hash != NULL => mac_size != -1 */
+ unsigned char *mac = NULL;
+ unsigned char mac_tmp[EVP_MAX_MD_SIZE];
+ mac_size=EVP_MD_CTX_size(s->read_hash);
+ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
+ /* orig_len is the length of the record before any padding was
+ * removed. This is public information, as is the MAC in use,
+ * therefore we can safely process the record in a different
+ * amount of time if it's too short to possibly contain a MAC.
+ */
+ if (rr->orig_len < mac_size ||
+ /* CBC records must have a padding length byte too. */
+ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+ rr->orig_len < mac_size+1))
{
-#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
- al=SSL_AD_RECORD_OVERFLOW;
- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
+ al=SSL_AD_DECODE_ERROR;
+ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
-#endif
}
- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
- if (rr->length >= mac_size)
+
+ if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
{
+ /* We update the length so that the TLS header bytes
+ * can be constructed correctly but we need to extract
+ * the MAC in constant time from within the record,
+ * without leaking the contents of the padding bytes.
+ * */
+ mac = mac_tmp;
+ ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+ rr->length -= mac_size;
+ }
+ else
+ {
+ /* In this case there's no padding, so |rec->orig_len|
+ * equals |rec->length| and we checked that there's
+ * enough bytes for |mac_size| above. */
rr->length -= mac_size;
mac = &rr->data[rr->length];
}
- else
- rr->length = 0;
- i=s->method->ssl3_enc->mac(s,md,0);
- if (i < 0 || mac == NULL || memcmp(md, mac, mac_size) != 0)
- {
- decryption_failed_or_bad_record_mac = 1;
- }
+
+ i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
+ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+ enc_err = -1;
+ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
+ enc_err = -1;
}
- if (decryption_failed_or_bad_record_mac)
+ if (enc_err < 0)
{
/* decryption failed, silently discard message */
rr->length = 0;
diff --git a/ssl/s2_clnt.c b/ssl/s2_clnt.c
index 00ac158..954f398 100644
--- a/ssl/s2_clnt.c
+++ b/ssl/s2_clnt.c
@@ -937,7 +937,7 @@
s->msg_callback(0, s->version, 0, p, len, s, s->msg_callback_arg); /* SERVER-VERIFY */
p += 1;
- if (memcmp(p,s->s2->challenge,s->s2->challenge_length) != 0)
+ if (CRYPTO_memcmp(p,s->s2->challenge,s->s2->challenge_length) != 0)
{
ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
SSLerr(SSL_F_GET_SERVER_VERIFY,SSL_R_CHALLENGE_IS_DIFFERENT);
diff --git a/ssl/s2_pkt.c b/ssl/s2_pkt.c
index ac963b2..8bb6ab8 100644
--- a/ssl/s2_pkt.c
+++ b/ssl/s2_pkt.c
@@ -269,8 +269,7 @@
s->s2->ract_data_length-=mac_size;
ssl2_mac(s,mac,0);
s->s2->ract_data_length-=s->s2->padding;
- if ( (memcmp(mac,s->s2->mac_data,
- (unsigned int)mac_size) != 0) ||
+ if ( (CRYPTO_memcmp(mac,s->s2->mac_data,mac_size) != 0) ||
(s->s2->rlength%EVP_CIPHER_CTX_block_size(s->enc_read_ctx) != 0))
{
SSLerr(SSL_F_SSL2_READ_INTERNAL,SSL_R_BAD_MAC_DECODE);
diff --git a/ssl/s3_both.c b/ssl/s3_both.c
index c8a7d18..c775cd8 100644
--- a/ssl/s3_both.c
+++ b/ssl/s3_both.c
@@ -263,7 +263,7 @@
goto f_err;
}
- if (memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
+ if (CRYPTO_memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
{
al=SSL_AD_DECRYPT_ERROR;
SSLerr(SSL_F_SSL3_GET_FINISHED,SSL_R_DIGEST_CHECK_FAILED);
diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c
new file mode 100644
index 0000000..e9b112c
--- /dev/null
+++ b/ssl/s3_cbc.c
@@ -0,0 +1,696 @@
+/* ssl/s3_cbc.c */
+/* ====================================================================
+ * Copyright (c) 2012 The OpenSSL Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ * software must display the following acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com). This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+
+#include <stdint.h>
+
+#include "ssl_locl.h"
+
+#include <openssl/md5.h>
+#include <openssl/sha.h>
+
+/* MAX_HASH_BIT_COUNT_BYTES is the maximum number of bytes in the hash's length
+ * field. (SHA-384/512 have 128-bit length.) */
+#define MAX_HASH_BIT_COUNT_BYTES 16
+
+/* MAX_HASH_BLOCK_SIZE is the maximum hash block size that we'll support.
+ * Currently SHA-384/512 has a 128-byte block size and that's the largest
+ * supported by TLS.) */
+#define MAX_HASH_BLOCK_SIZE 128
+
+/* Some utility functions are needed:
+ *
+ * These macros return the given value with the MSB copied to all the other
+ * bits. They use the fact that arithmetic shift shifts-in the sign bit.
+ * However, this is not ensured by the C standard so you may need to replace
+ * them with something else on odd CPUs. */
+#define DUPLICATE_MSB_TO_ALL(x) ( (unsigned)( (int)(x) >> (sizeof(int)*8-1) ) )
+#define DUPLICATE_MSB_TO_ALL_8(x) ((unsigned char)(DUPLICATE_MSB_TO_ALL(x)))
+
+/* constant_time_ge returns 0xff if a>=b and 0x00 otherwise. */
+static unsigned constant_time_ge(unsigned a, unsigned b)
+ {
+ a -= b;
+ return DUPLICATE_MSB_TO_ALL(~a);
+ }
+
+/* constant_time_eq_8 returns 0xff if a==b and 0x00 otherwise. */
+static unsigned char constant_time_eq_8(unsigned char a, unsigned char b)
+ {
+ unsigned c = a ^ b;
+ c--;
+ return DUPLICATE_MSB_TO_ALL_8(c);
+ }
+
+/* ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
+ * record in |rec| by updating |rec->length| in constant time.
+ *
+ * block_size: the block size of the cipher used to encrypt the record.
+ * returns:
+ * 0: (in non-constant time) if the record is publicly invalid.
+ * 1: if the padding was valid
+ * -1: otherwise. */
+int ssl3_cbc_remove_padding(const SSL* s,
+ SSL3_RECORD *rec,
+ unsigned block_size,
+ unsigned mac_size)
+ {
+ unsigned padding_length, good;
+ const unsigned overhead = 1 /* padding length byte */ + mac_size;
+
+ /* These lengths are all public so we can test them in non-constant
+ * time. */
+ if (overhead > rec->length)
+ return 0;
+
+ padding_length = rec->data[rec->length-1];
+ good = constant_time_ge(rec->length, padding_length+overhead);
+ /* SSLv3 requires that the padding is minimal. */
+ good &= constant_time_ge(block_size, padding_length+1);
+ rec->length -= good & (padding_length+1);
+ return (int)((good & 1) | (~good & -1));
+}
+
+/* tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
+ * record in |rec| in constant time and returns 1 if the padding is valid and
+ * -1 otherwise. It also removes any explicit IV from the start of the record
+ * without leaking any timing about whether there was enough space after the
+ * padding was removed.
+ *
+ * block_size: the block size of the cipher used to encrypt the record.
+ * returns:
+ * 0: (in non-constant time) if the record is publicly invalid.
+ * 1: if the padding was valid
+ * -1: otherwise. */
+int tls1_cbc_remove_padding(const SSL* s,
+ SSL3_RECORD *rec,
+ unsigned block_size,
+ unsigned mac_size)
+ {
+ unsigned padding_length, good, to_check, i;
+ const char has_explicit_iv =
+ s->version >= TLS1_1_VERSION || s->version == DTLS1_VERSION;
+ const unsigned overhead = 1 /* padding length byte */ +
+ mac_size +
+ (has_explicit_iv ? block_size : 0);
+
+ /* These lengths are all public so we can test them in non-constant
+ * time. */
+ if (overhead > rec->length)
+ return 0;
+
+ padding_length = rec->data[rec->length-1];
+
+ /* NB: if compression is in operation the first packet may not be of
+ * even length so the padding bug check cannot be performed. This bug
+ * workaround has been around since SSLeay so hopefully it is either
+ * fixed now or no buggy implementation supports compression [steve]
+ */
+ if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG) && !s->expand)
+ {
+ /* First packet is even in size, so check */
+ if ((memcmp(s->s3->read_sequence, "\0\0\0\0\0\0\0\0",8) == 0) &&
+ !(padding_length & 1))
+ {
+ s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
+ }
+ if ((s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG) &&
+ padding_length > 0)
+ {
+ padding_length--;
+ }
+ }
+
+ good = constant_time_ge(rec->length, overhead+padding_length);
+ /* The padding consists of a length byte at the end of the record and
+ * then that many bytes of padding, all with the same value as the
+ * length byte. Thus, with the length byte included, there are i+1
+ * bytes of padding.
+ *
+ * We can't check just |padding_length+1| bytes because that leaks
+ * decrypted information. Therefore we always have to check the maximum
+ * amount of padding possible. (Again, the length of the record is
+ * public information so we can use it.) */
+ to_check = 255; /* maximum amount of padding. */
+ if (to_check > rec->length-1)
+ to_check = rec->length-1;
+
+ for (i = 0; i < to_check; i++)
+ {
+ unsigned char mask = constant_time_ge(padding_length, i);
+ unsigned char b = rec->data[rec->length-1-i];
+ /* The final |padding_length+1| bytes should all have the value
+ * |padding_length|. Therefore the XOR should be zero. */
+ good &= ~(mask&(padding_length ^ b));
+ }
+
+ /* If any of the final |padding_length+1| bytes had the wrong value,
+ * one or more of the lower eight bits of |good| will be cleared. We
+ * AND the bottom 8 bits together and duplicate the result to all the
+ * bits. */
+ good &= good >> 4;
+ good &= good >> 2;
+ good &= good >> 1;
+ good <<= sizeof(good)*8-1;
+ good = DUPLICATE_MSB_TO_ALL(good);
+
+ rec->length -= good & (padding_length+1);
+
+ /* We can always safely skip the explicit IV. We check at the beginning
+ * of this function that the record has at least enough space for the
+ * IV, MAC and padding length byte. (These can be checked in
+ * non-constant time because it's all public information.) So, if the
+ * padding was invalid, then we didn't change |rec->length| and this is
+ * safe. If the padding was valid then we know that we have at least
+ * overhead+padding_length bytes of space and so this is still safe
+ * because overhead accounts for the explicit IV. */
+ if (has_explicit_iv)
+ {
+ rec->data += block_size;
+ rec->input += block_size;
+ rec->length -= block_size;
+ rec->orig_len -= block_size;
+ }
+
+ return (int)((good & 1) | (~good & -1));
+ }
+
+#if defined(_M_AMD64) || defined(__x86_64__)
+#define CBC_MAC_ROTATE_IN_PLACE
+#endif
+
+/* ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
+ * constant time (independent of the concrete value of rec->length, which may
+ * vary within a 256-byte window).
+ *
+ * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
+ * this function.
+ *
+ * On entry:
+ * rec->orig_len >= md_size
+ * md_size <= EVP_MAX_MD_SIZE
+ *
+ * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
+ * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
+ * a single cache-line, then the variable memory accesses don't actually affect
+ * the timing. This has been tested to be true on Intel amd64 chips.
+ */
+void ssl3_cbc_copy_mac(unsigned char* out,
+ const SSL3_RECORD *rec,
+ unsigned md_size)
+ {
+#if defined(CBC_MAC_ROTATE_IN_PLACE)
+ unsigned char rotated_mac_buf[EVP_MAX_MD_SIZE*2];
+ unsigned char *rotated_mac;
+#else
+ unsigned char rotated_mac[EVP_MAX_MD_SIZE];
+#endif
+
+ /* mac_end is the index of |rec->data| just after the end of the MAC. */
+ unsigned mac_end = rec->length;
+ unsigned mac_start = mac_end - md_size;
+ /* scan_start contains the number of bytes that we can ignore because
+ * the MAC's position can only vary by 255 bytes. */
+ unsigned scan_start = 0;
+ unsigned i, j;
+ unsigned div_spoiler;
+ unsigned rotate_offset;
+
+ OPENSSL_assert(rec->orig_len >= md_size);
+ OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
+
+#if defined(CBC_MAC_ROTATE_IN_PLACE)
+ rotated_mac = (unsigned char*) (((intptr_t)(rotated_mac_buf + 64)) & ~63);
+#endif
+
+ /* This information is public so it's safe to branch based on it. */
+ if (rec->orig_len > md_size + 255 + 1)
+ scan_start = rec->orig_len - (md_size + 255 + 1);
+ /* div_spoiler contains a multiple of md_size that is used to cause the
+ * modulo operation to be constant time. Without this, the time varies
+ * based on the amount of padding when running on Intel chips at least.
+ *
+ * The aim of right-shifting md_size is so that the compiler doesn't
+ * figure out that it can remove div_spoiler as that would require it
+ * to prove that md_size is always even, which I hope is beyond it. */
+ div_spoiler = md_size >> 1;
+ div_spoiler <<= (sizeof(div_spoiler)-1)*8;
+ rotate_offset = (div_spoiler + mac_start - scan_start) % md_size;
+
+ memset(rotated_mac, 0, md_size);
+ for (i = scan_start; i < rec->orig_len;)
+ {
+ for (j = 0; j < md_size && i < rec->orig_len; i++, j++)
+ {
+ unsigned char mac_started = constant_time_ge(i, mac_start);
+ unsigned char mac_ended = constant_time_ge(i, mac_end);
+ unsigned char b = 0;
+ b = rec->data[i];
+ rotated_mac[j] |= b & mac_started & ~mac_ended;
+ }
+ }
+
+ /* Now rotate the MAC */
+#if defined(CBC_MAC_ROTATE_IN_PLACE)
+ j = 0;
+ for (i = 0; i < md_size; i++)
+ {
+ unsigned char offset = (div_spoiler + rotate_offset + i) % md_size;
+ out[j++] = rotated_mac[offset];
+ }
+#else
+ memset(out, 0, md_size);
+ for (i = 0; i < md_size; i++)
+ {
+ unsigned char offset = (div_spoiler + md_size - rotate_offset + i) % md_size;
+ for (j = 0; j < md_size; j++)
+ out[j] |= rotated_mac[i] & constant_time_eq_8(j, offset);
+ }
+#endif
+ }
+
+/* These functions serialize the state of a hash and thus perform the standard
+ * "final" operation without adding the padding and length that such a function
+ * typically does. */
+static void tls1_md5_final_raw(void* ctx, unsigned char *md_out)
+ {
+ MD5_CTX *md5 = ctx;
+ l2n(md5->A, md_out);
+ l2n(md5->B, md_out);
+ l2n(md5->C, md_out);
+ l2n(md5->D, md_out);
+ }
+
+static void tls1_sha1_final_raw(void* ctx, unsigned char *md_out)
+ {
+ SHA_CTX *sha1 = ctx;
+ l2n(sha1->h0, md_out);
+ l2n(sha1->h1, md_out);
+ l2n(sha1->h2, md_out);
+ l2n(sha1->h3, md_out);
+ l2n(sha1->h4, md_out);
+ }
+
+static void tls1_sha256_final_raw(void* ctx, unsigned char *md_out)
+ {
+ SHA256_CTX *sha256 = ctx;
+ unsigned i;
+
+ for (i = 0; i < 8; i++)
+ {
+ l2n(sha256->h[i], md_out);
+ }
+ }
+
+static void tls1_sha512_final_raw(void* ctx, unsigned char *md_out)
+ {
+ SHA512_CTX *sha512 = ctx;
+ unsigned i;
+
+ for (i = 0; i < 8; i++)
+ {
+ l2n8(sha512->h[i], md_out);
+ }
+ }
+
+/* ssl3_cbc_record_digest_supported returns 1 iff |ctx| uses a hash function
+ * which ssl3_cbc_digest_record supports. */
+char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx)
+ {
+ switch (ctx->digest->type)
+ {
+ case NID_md5:
+ case NID_sha1:
+ case NID_sha224:
+ case NID_sha256:
+ case NID_sha384:
+ case NID_sha512:
+ return 1;
+ default:
+ return 0;
+ }
+ }
+
+/* ssl3_cbc_digest_record computes the MAC of a decrypted, padded SSLv3/TLS
+ * record.
+ *
+ * ctx: the EVP_MD_CTX from which we take the hash function.
+ * ssl3_cbc_record_digest_supported must return true for this EVP_MD_CTX.
+ * md_out: the digest output. At most EVP_MAX_MD_SIZE bytes will be written.
+ * md_out_size: if non-NULL, the number of output bytes is written here.
+ * header: the 13-byte, TLS record header.
+ * data: the record data itself, less any preceeding explicit IV.
+ * data_plus_mac_size: the secret, reported length of the data and MAC
+ * once the padding has been removed.
+ * data_plus_mac_plus_padding_size: the public length of the whole
+ * record, including padding.
+ * is_sslv3: non-zero if we are to use SSLv3. Otherwise, TLS.
+ *
+ * On entry: by virtue of having been through one of the remove_padding
+ * functions, above, we know that data_plus_mac_size is large enough to contain
+ * a padding byte and MAC. (If the padding was invalid, it might contain the
+ * padding too. ) */
+void ssl3_cbc_digest_record(
+ const EVP_MD_CTX *ctx,
+ unsigned char* md_out,
+ size_t* md_out_size,
+ const unsigned char header[13],
+ const unsigned char *data,
+ size_t data_plus_mac_size,
+ size_t data_plus_mac_plus_padding_size,
+ const unsigned char *mac_secret,
+ unsigned mac_secret_length,
+ char is_sslv3)
+ {
+ unsigned char md_state[sizeof(SHA512_CTX)];
+ void (*md_final_raw)(void *ctx, unsigned char *md_out);
+ void (*md_transform)(void *ctx, const unsigned char *block);
+ unsigned md_size, md_block_size = 64;
+ unsigned sslv3_pad_length = 40, header_length, variance_blocks,
+ len, max_mac_bytes, num_blocks,
+ num_starting_blocks, k, mac_end_offset, c, index_a, index_b;
+ uint64_t bits;
+ unsigned char length_bytes[MAX_HASH_BIT_COUNT_BYTES];
+ /* hmac_pad is the masked HMAC key. */
+ unsigned char hmac_pad[MAX_HASH_BLOCK_SIZE];
+ unsigned char first_block[MAX_HASH_BLOCK_SIZE];
+ unsigned char mac_out[EVP_MAX_MD_SIZE];
+ unsigned i, j, md_out_size_u;
+ EVP_MD_CTX md_ctx;
+ /* mdLengthSize is the number of bytes in the length field that terminates
+ * the hash. */
+ unsigned md_length_size = 8;
+
+ /* This is a, hopefully redundant, check that allows us to forget about
+ * many possible overflows later in this function. */
+ OPENSSL_assert(data_plus_mac_plus_padding_size < 1024*1024);
+
+ switch (ctx->digest->type)
+ {
+ case NID_md5:
+ MD5_Init((MD5_CTX*)md_state);
+ md_final_raw = tls1_md5_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) MD5_Transform;
+ md_size = 16;
+ sslv3_pad_length = 48;
+ break;
+ case NID_sha1:
+ SHA1_Init((SHA_CTX*)md_state);
+ md_final_raw = tls1_sha1_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA1_Transform;
+ md_size = 20;
+ break;
+ case NID_sha224:
+ SHA224_Init((SHA256_CTX*)md_state);
+ md_final_raw = tls1_sha256_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
+ md_size = 224/8;
+ break;
+ case NID_sha256:
+ SHA256_Init((SHA256_CTX*)md_state);
+ md_final_raw = tls1_sha256_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
+ md_size = 32;
+ break;
+ case NID_sha384:
+ SHA384_Init((SHA512_CTX*)md_state);
+ md_final_raw = tls1_sha512_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
+ md_size = 384/8;
+ md_block_size = 128;
+ md_length_size = 16;
+ break;
+ case NID_sha512:
+ SHA512_Init((SHA512_CTX*)md_state);
+ md_final_raw = tls1_sha512_final_raw;
+ md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
+ md_size = 64;
+ md_block_size = 128;
+ md_length_size = 16;
+ break;
+ default:
+ /* ssl3_cbc_record_digest_supported should have been
+ * called first to check that the hash function is
+ * supported. */
+ OPENSSL_assert(0);
+ if (md_out_size)
+ *md_out_size = -1;
+ return;
+ }
+
+ OPENSSL_assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES);
+ OPENSSL_assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
+ OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
+
+ header_length = 13;
+ if (is_sslv3)
+ {
+ header_length =
+ mac_secret_length +
+ sslv3_pad_length +
+ 8 /* sequence number */ +
+ 1 /* record type */ +
+ 2 /* record length */;
+ }
+
+ /* variance_blocks is the number of blocks of the hash that we have to
+ * calculate in constant time because they could be altered by the
+ * padding value.
+ *
+ * In SSLv3, the padding must be minimal so the end of the plaintext
+ * varies by, at most, 15+20 = 35 bytes. (We conservatively assume that
+ * the MAC size varies from 0..20 bytes.) In case the 9 bytes of hash
+ * termination (0x80 + 64-bit length) don't fit in the final block, we
+ * say that the final two blocks can vary based on the padding.
+ *
+ * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not
+ * required to be minimal. Therefore we say that the final six blocks
+ * can vary based on the padding.
+ *
+ * Later in the function, if the message is short and there obviously
+ * cannot be this many blocks then variance_blocks can be reduced. */
+ variance_blocks = is_sslv3 ? 2 : 6;
+ /* From now on we're dealing with the MAC, which conceptually has 13
+ * bytes of `header' before the start of the data (TLS) or 71/75 bytes
+ * (SSLv3) */
+ len = data_plus_mac_plus_padding_size + header_length;
+ /* max_mac_bytes contains the maximum bytes of bytes in the MAC, including
+ * |header|, assuming that there's no padding. */
+ max_mac_bytes = len - md_size - 1;
+ /* num_blocks is the maximum number of hash blocks. */
+ num_blocks = (max_mac_bytes + 1 + md_length_size + md_block_size - 1) / md_block_size;
+ /* In order to calculate the MAC in constant time we have to handle
+ * the final blocks specially because the padding value could cause the
+ * end to appear somewhere in the final |variance_blocks| blocks and we
+ * can't leak where. However, |num_starting_blocks| worth of data can
+ * be hashed right away because no padding value can affect whether
+ * they are plaintext. */
+ num_starting_blocks = 0;
+ /* k is the starting byte offset into the conceptual header||data where
+ * we start processing. */
+ k = 0;
+ /* mac_end_offset is the index just past the end of the data to be
+ * MACed. */
+ mac_end_offset = data_plus_mac_size + header_length - md_size;
+ /* c is the index of the 0x80 byte in the final hash block that
+ * contains application data. */
+ c = mac_end_offset % md_block_size;
+ /* index_a is the hash block number that contains the 0x80 terminating
+ * value. */
+ index_a = mac_end_offset / md_block_size;
+ /* index_b is the hash block number that contains the 64-bit hash
+ * length, in bits. */
+ index_b = (mac_end_offset + md_length_size) / md_block_size;
+ /* bits is the hash-length in bits. It includes the additional hash
+ * block for the masked HMAC key, or whole of |header| in the case of
+ * SSLv3. */
+
+ /* For SSLv3, if we're going to have any starting blocks then we need
+ * at least two because the header is larger than a single block. */
+ if (num_blocks > variance_blocks + (is_sslv3 ? 1 : 0))
+ {
+ num_starting_blocks = num_blocks - variance_blocks;
+ k = md_block_size*num_starting_blocks;
+ }
+
+ bits = 8*mac_end_offset;
+ if (!is_sslv3)
+ {
+ /* Compute the initial HMAC block. For SSLv3, the padding and
+ * secret bytes are included in |header| because they take more
+ * than a single block. */
+ bits += 8*md_block_size;
+ memset(hmac_pad, 0, md_block_size);
+ OPENSSL_assert(mac_secret_length <= sizeof(hmac_pad));
+ memcpy(hmac_pad, mac_secret, mac_secret_length);
+ for (i = 0; i < md_block_size; i++)
+ hmac_pad[i] ^= 0x36;
+
+ md_transform(md_state, hmac_pad);
+ }
+
+ j = 0;
+ if (md_length_size == 16)
+ {
+ memset(length_bytes, 0, 8);
+ j = 8;
+ }
+ for (i = 0; i < 8; i++)
+ length_bytes[i+j] = bits >> (8*(7-i));
+
+ if (k > 0)
+ {
+ if (is_sslv3)
+ {
+ /* The SSLv3 header is larger than a single block.
+ * overhang is the number of bytes beyond a single
+ * block that the header consumes: either 7 bytes
+ * (SHA1) or 11 bytes (MD5). */
+ unsigned overhang = header_length-md_block_size;
+ md_transform(md_state, header);
+ memcpy(first_block, header + md_block_size, overhang);
+ memcpy(first_block + overhang, data, md_block_size-overhang);
+ md_transform(md_state, first_block);
+ for (i = 1; i < k/md_block_size - 1; i++)
+ md_transform(md_state, data + md_block_size*i - overhang);
+ }
+ else
+ {
+ /* k is a multiple of md_block_size. */
+ memcpy(first_block, header, 13);
+ memcpy(first_block+13, data, md_block_size-13);
+ md_transform(md_state, first_block);
+ for (i = 1; i < k/md_block_size; i++)
+ md_transform(md_state, data + md_block_size*i - 13);
+ }
+ }
+
+ memset(mac_out, 0, sizeof(mac_out));
+
+ /* We now process the final hash blocks. For each block, we construct
+ * it in constant time. If the |i==index_a| then we'll include the 0x80
+ * bytes and zero pad etc. For each block we selectively copy it, in
+ * constant time, to |mac_out|. */
+ for (i = num_starting_blocks; i <= num_starting_blocks+variance_blocks; i++)
+ {
+ unsigned char block[MAX_HASH_BLOCK_SIZE];
+ unsigned char is_block_a = constant_time_eq_8(i, index_a);
+ unsigned char is_block_b = constant_time_eq_8(i, index_b);
+ for (j = 0; j < md_block_size; j++)
+ {
+ unsigned char b = 0, is_past_c, is_past_cp1;
+ if (k < header_length)
+ b = header[k];
+ else if (k < data_plus_mac_plus_padding_size + header_length)
+ b = data[k-header_length];
+ k++;
+
+ is_past_c = is_block_a & constant_time_ge(j, c);
+ is_past_cp1 = is_block_a & constant_time_ge(j, c+1);
+ /* If this is the block containing the end of the
+ * application data, and we are at the offset for the
+ * 0x80 value, then overwrite b with 0x80. */
+ b = (b&~is_past_c) | (0x80&is_past_c);
+ /* If this the the block containing the end of the
+ * application data and we're past the 0x80 value then
+ * just write zero. */
+ b = b&~is_past_cp1;
+ /* If this is index_b (the final block), but not
+ * index_a (the end of the data), then the 64-bit
+ * length didn't fit into index_a and we're having to
+ * add an extra block of zeros. */
+ b &= ~is_block_b | is_block_a;
+
+ /* The final bytes of one of the blocks contains the
+ * length. */
+ if (j >= md_block_size - md_length_size)
+ {
+ /* If this is index_b, write a length byte. */
+ b = (b&~is_block_b) | (is_block_b&length_bytes[j-(md_block_size-md_length_size)]);
+ }
+ block[j] = b;
+ }
+
+ md_transform(md_state, block);
+ md_final_raw(md_state, block);
+ /* If this is index_b, copy the hash value to |mac_out|. */
+ for (j = 0; j < md_size; j++)
+ mac_out[j] |= block[j]&is_block_b;
+ }
+
+ EVP_MD_CTX_init(&md_ctx);
+ EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */);
+ if (is_sslv3)
+ {
+ /* We repurpose |hmac_pad| to contain the SSLv3 pad2 block. */
+ memset(hmac_pad, 0x5c, sslv3_pad_length);
+
+ EVP_DigestUpdate(&md_ctx, mac_secret, mac_secret_length);
+ EVP_DigestUpdate(&md_ctx, hmac_pad, sslv3_pad_length);
+ EVP_DigestUpdate(&md_ctx, mac_out, md_size);
+ }
+ else
+ {
+ /* Complete the HMAC in the standard manner. */
+ for (i = 0; i < md_block_size; i++)
+ hmac_pad[i] ^= 0x6a;
+
+ EVP_DigestUpdate(&md_ctx, hmac_pad, md_block_size);
+ EVP_DigestUpdate(&md_ctx, mac_out, md_size);
+ }
+ EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u);
+ if (md_out_size)
+ *md_out_size = md_out_size_u;
+ EVP_MD_CTX_cleanup(&md_ctx);
+ }
diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index c5df2cb..a0eac77 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -466,12 +466,21 @@
s->s3->tmp.key_block_length=0;
}
+/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ * 0: (in non-constant time) if the record is publically invalid (i.e. too
+ * short etc).
+ * 1: if the record's padding is valid / the encryption was successful.
+ * -1: if the record's padding is invalid or, if sending, an internal error
+ * occured.
+ */
int ssl3_enc(SSL *s, int send)
{
SSL3_RECORD *rec;
EVP_CIPHER_CTX *ds;
unsigned long l;
- int bs,i;
+ int bs,i,mac_size=0;
const EVP_CIPHER *enc;
if (send)
@@ -522,32 +531,16 @@
if (!send)
{
if (l == 0 || l%bs != 0)
- {
- SSLerr(SSL_F_SSL3_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
- ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
return 0;
- }
/* otherwise, rec->length >= bs */
}
EVP_Cipher(ds,rec->data,rec->input,l);
+ if (EVP_MD_CTX_md(s->read_hash) != NULL)
+ mac_size = EVP_MD_CTX_size(s->read_hash);
if ((bs != 1) && !send)
- {
- i=rec->data[l-1]+1;
- /* SSL 3.0 bounds the number of padding bytes by the block size;
- * padding bytes (except the last one) are arbitrary */
- if (i > bs)
- {
- /* Incorrect padding. SSLerr() and ssl3_alert are done
- * by caller: we don't want to reveal whether this is
- * a decryption error or a MAC verification failure
- * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
- return -1;
- }
- /* now i <= bs <= rec->length */
- rec->length-=i;
- }
+ return ssl3_cbc_remove_padding(s, rec, bs, mac_size);
}
return(1);
}
@@ -716,7 +709,7 @@
EVP_MD_CTX md_ctx;
const EVP_MD_CTX *hash;
unsigned char *p,rec_char;
- unsigned int md_size;
+ size_t md_size;
int npad;
int t;
@@ -741,28 +734,68 @@
md_size=t;
npad=(48/md_size)*md_size;
- /* Chop the digest off the end :-) */
- EVP_MD_CTX_init(&md_ctx);
+ if (!send &&
+ EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+ ssl3_cbc_record_digest_supported(hash))
+ {
+ /* This is a CBC-encrypted record. We must avoid leaking any
+ * timing-side channel information about how many blocks of
+ * data we are hashing because that gives an attacker a
+ * timing-oracle. */
- EVP_MD_CTX_copy_ex( &md_ctx,hash);
- EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
- EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
- EVP_DigestUpdate(&md_ctx,seq,8);
- rec_char=rec->type;
- EVP_DigestUpdate(&md_ctx,&rec_char,1);
- p=md;
- s2n(rec->length,p);
- EVP_DigestUpdate(&md_ctx,md,2);
- EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
- EVP_DigestFinal_ex( &md_ctx,md,NULL);
+ /* npad is, at most, 48 bytes and that's with MD5:
+ * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
+ *
+ * With SHA-1 (the largest hash speced for SSLv3) the hash size
+ * goes up 4, but npad goes down by 8, resulting in a smaller
+ * total size. */
+ unsigned char header[75];
+ unsigned j = 0;
+ memcpy(header+j, mac_sec, md_size);
+ j += md_size;
+ memcpy(header+j, ssl3_pad_1, npad);
+ j += npad;
+ memcpy(header+j, seq, 8);
+ j += 8;
+ header[j++] = rec->type;
+ header[j++] = rec->length >> 8;
+ header[j++] = rec->length & 0xff;
- EVP_MD_CTX_copy_ex( &md_ctx,hash);
- EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
- EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
- EVP_DigestUpdate(&md_ctx,md,md_size);
- EVP_DigestFinal_ex( &md_ctx,md,&md_size);
+ ssl3_cbc_digest_record(
+ hash,
+ md, &md_size,
+ header, rec->input,
+ rec->length + md_size, rec->orig_len,
+ mac_sec, md_size,
+ 1 /* is SSLv3 */);
+ }
+ else
+ {
+ unsigned int md_size_u;
+ /* Chop the digest off the end :-) */
+ EVP_MD_CTX_init(&md_ctx);
- EVP_MD_CTX_cleanup(&md_ctx);
+ EVP_MD_CTX_copy_ex( &md_ctx,hash);
+ EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+ EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
+ EVP_DigestUpdate(&md_ctx,seq,8);
+ rec_char=rec->type;
+ EVP_DigestUpdate(&md_ctx,&rec_char,1);
+ p=md;
+ s2n(rec->length,p);
+ EVP_DigestUpdate(&md_ctx,md,2);
+ EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
+ EVP_DigestFinal_ex( &md_ctx,md,NULL);
+
+ EVP_MD_CTX_copy_ex( &md_ctx,hash);
+ EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+ EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
+ EVP_DigestUpdate(&md_ctx,md,md_size);
+ EVP_DigestFinal_ex( &md_ctx,md,&md_size_u);
+ md_size = md_size_u;
+
+ EVP_MD_CTX_cleanup(&md_ctx);
+ }
ssl3_record_sequence_update(seq);
return(md_size);
diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index adf8c38..5289092 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -290,11 +290,8 @@
unsigned char *p;
unsigned char md[EVP_MAX_MD_SIZE];
short version;
- int mac_size;
- int clear=0;
+ unsigned mac_size;
size_t extra;
- int decryption_failed_or_bad_record_mac = 0;
- unsigned char *mac = NULL;
rr= &(s->s3->rrec);
sess=s->session;
@@ -401,19 +398,18 @@
/* decrypt in place in 'rr->input' */
rr->data=rr->input;
+ rr->orig_len=rr->length;
enc_err = s->method->ssl3_enc->enc(s,0);
- if (enc_err <= 0)
+ /* enc_err is:
+ * 0: (in non-constant time) if the record is publically invalid.
+ * 1: if the padding is valid
+ * -1: if the padding is invalid */
+ if (enc_err == 0)
{
- if (enc_err == 0)
- /* SSLerr() and ssl3_send_alert() have been called */
- goto err;
-
- /* Otherwise enc_err == -1, which indicates bad padding
- * (rec->length has not been changed in this case).
- * To minimize information leaked via timing, we will perform
- * the MAC computation anyway. */
- decryption_failed_or_bad_record_mac = 1;
+ al=SSL_AD_DECRYPTION_FAILED;
+ SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
+ goto f_err;
}
#ifdef TLS_DEBUG
@@ -423,53 +419,59 @@
#endif
/* r->length is now the compressed data plus mac */
- if ( (sess == NULL) ||
- (s->enc_read_ctx == NULL) ||
- (EVP_MD_CTX_md(s->read_hash) == NULL))
- clear=1;
-
- if (!clear)
+ if ((sess != NULL) &&
+ (s->enc_read_ctx != NULL) &&
+ (EVP_MD_CTX_md(s->read_hash) != NULL))
{
- /* !clear => s->read_hash != NULL => mac_size != -1 */
+ /* s->read_hash != NULL => mac_size != -1 */
+ unsigned char *mac = NULL;
+ unsigned char mac_tmp[EVP_MAX_MD_SIZE];
mac_size=EVP_MD_CTX_size(s->read_hash);
- OPENSSL_assert(mac_size >= 0);
+ OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
- if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
+ /* orig_len is the length of the record before any padding was
+ * removed. This is public information, as is the MAC in use,
+ * therefore we can safely process the record in a different
+ * amount of time if it's too short to possibly contain a MAC.
+ */
+ if (rr->orig_len < mac_size ||
+ /* CBC records must have a padding length byte too. */
+ (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+ rr->orig_len < mac_size+1))
{
-#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
- al=SSL_AD_RECORD_OVERFLOW;
- SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
- goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
-#endif
- }
- /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
- if (rr->length >= (unsigned int)mac_size)
- {
- rr->length -= mac_size;
- mac = &rr->data[rr->length];
- }
- else
- {
- /* record (minus padding) is too short to contain a MAC */
-#if 0 /* OK only for stream ciphers */
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
-#else
- decryption_failed_or_bad_record_mac = 1;
- rr->length = 0;
-#endif
}
- i=s->method->ssl3_enc->mac(s,md,0);
- if (i < 0 || mac == NULL || memcmp(md, mac, (size_t)mac_size) != 0)
+
+ if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
{
- decryption_failed_or_bad_record_mac = 1;
+ /* We update the length so that the TLS header bytes
+ * can be constructed correctly but we need to extract
+ * the MAC in constant time from within the record,
+ * without leaking the contents of the padding bytes.
+ * */
+ mac = mac_tmp;
+ ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+ rr->length -= mac_size;
}
+ else
+ {
+ /* In this case there's no padding, so |rec->orig_len|
+ * equals |rec->length| and we checked that there's
+ * enough bytes for |mac_size| above. */
+ rr->length -= mac_size;
+ mac = &rr->data[rr->length];
+ }
+
+ i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
+ if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+ enc_err = -1;
+ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
+ enc_err = -1;
}
- if (decryption_failed_or_bad_record_mac)
+ if (enc_err < 0)
{
/* A separate 'decryption_failed' alert was introduced with TLS 1.0,
* SSL 3.0 only has 'bad_record_mac'. But unless a decryption
diff --git a/ssl/ssl3.h b/ssl/ssl3.h
index f4578aa..879be13 100644
--- a/ssl/ssl3.h
+++ b/ssl/ssl3.h
@@ -355,6 +355,10 @@
/*r */ unsigned char *comp; /* only used with decompression - malloc()ed */
/*r */ unsigned long epoch; /* epoch number, needed by DTLS1 */
/*r */ unsigned char seq_num[8]; /* sequence number, needed by DTLS1 */
+/*rw*/ unsigned int orig_len; /* How many bytes were available before padding
+ was removed? This is used to implement the
+ MAC check in constant time for CBC records.
+ */
} SSL3_RECORD;
typedef struct ssl3_buffer_st
diff --git a/ssl/ssl_algs.c b/ssl/ssl_algs.c
index d443143..41ccbaa 100644
--- a/ssl/ssl_algs.c
+++ b/ssl/ssl_algs.c
@@ -90,11 +90,14 @@
EVP_add_cipher(EVP_aes_256_cbc());
EVP_add_cipher(EVP_aes_128_gcm());
EVP_add_cipher(EVP_aes_256_gcm());
+#if 0 /* Disabled because of timing side-channel leaks. */
#if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1)
EVP_add_cipher(EVP_aes_128_cbc_hmac_sha1());
EVP_add_cipher(EVP_aes_256_cbc_hmac_sha1());
#endif
#endif
+
+#endif
#ifndef OPENSSL_NO_CAMELLIA
EVP_add_cipher(EVP_camellia_128_cbc());
EVP_add_cipher(EVP_camellia_256_cbc());
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 2116913..9ca3b4a 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -215,6 +215,15 @@
*((c)++)=(unsigned char)(((l)>> 8)&0xff), \
*((c)++)=(unsigned char)(((l) )&0xff))
+#define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \
+ *((c)++)=(unsigned char)(((l)>>48)&0xff), \
+ *((c)++)=(unsigned char)(((l)>>40)&0xff), \
+ *((c)++)=(unsigned char)(((l)>>32)&0xff), \
+ *((c)++)=(unsigned char)(((l)>>24)&0xff), \
+ *((c)++)=(unsigned char)(((l)>>16)&0xff), \
+ *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
+ *((c)++)=(unsigned char)(((l) )&0xff))
+
#define n2l6(c,l) (l =((BN_ULLONG)(*((c)++)))<<40, \
l|=((BN_ULLONG)(*((c)++)))<<32, \
l|=((BN_ULLONG)(*((c)++)))<<24, \
@@ -1137,4 +1146,29 @@
int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen);
int ssl_parse_serverhello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al);
+/* s3_cbc.c */
+void ssl3_cbc_copy_mac(unsigned char* out,
+ const SSL3_RECORD *rec,
+ unsigned md_size);
+int ssl3_cbc_remove_padding(const SSL* s,
+ SSL3_RECORD *rec,
+ unsigned block_size,
+ unsigned mac_size);
+int tls1_cbc_remove_padding(const SSL* s,
+ SSL3_RECORD *rec,
+ unsigned block_size,
+ unsigned mac_size);
+char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx);
+void ssl3_cbc_digest_record(
+ const EVP_MD_CTX *ctx,
+ unsigned char* md_out,
+ size_t* md_out_size,
+ const unsigned char header[13],
+ const unsigned char *data,
+ size_t data_plus_mac_size,
+ size_t data_plus_mac_plus_padding_size,
+ const unsigned char *mac_secret,
+ unsigned mac_secret_length,
+ char is_sslv3);
+
#endif
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index f7bdeb3..643e3e6 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -667,12 +667,21 @@
return(ret);
}
+/* tls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ * 0: (in non-constant time) if the record is publically invalid (i.e. too
+ * short etc).
+ * 1: if the record's padding is valid / the encryption was successful.
+ * -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
+ * an internal error occured.
+ */
int tls1_enc(SSL *s, int send)
{
SSL3_RECORD *rec;
EVP_CIPHER_CTX *ds;
unsigned long l;
- int bs,i,ii,j,k,pad=0;
+ int bs,i,j,k,pad=0,ret,mac_size=0;
const EVP_CIPHER *enc;
if (send)
@@ -729,11 +738,11 @@
printf("tls1_enc(%d)\n", send);
#endif /* KSSL_DEBUG */
- if ((s->session == NULL) || (ds == NULL) ||
- (enc == NULL))
+ if ((s->session == NULL) || (ds == NULL) || (enc == NULL))
{
memmove(rec->data,rec->input,rec->length);
rec->input=rec->data;
+ ret = 1;
}
else
{
@@ -797,13 +806,13 @@
#ifdef KSSL_DEBUG
{
- unsigned long ui;
+ unsigned long ui;
printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",
- ds,rec->data,rec->input,l);
+ ds,rec->data,rec->input,l);
printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%d %d], %d iv_len\n",
- ds->buf_len, ds->cipher->key_len,
- DES_KEY_SZ, DES_SCHEDULE_SZ,
- ds->cipher->iv_len);
+ ds->buf_len, ds->cipher->key_len,
+ DES_KEY_SZ, DES_SCHEDULE_SZ,
+ ds->cipher->iv_len);
printf("\t\tIV: ");
for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);
printf("\n");
@@ -816,13 +825,7 @@
if (!send)
{
if (l == 0 || l%bs != 0)
- {
- if (s->version >= TLS1_1_VERSION)
- return -1;
- SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
- ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
return 0;
- }
}
i = EVP_Cipher(ds,rec->data,rec->input,l);
@@ -839,68 +842,24 @@
#ifdef KSSL_DEBUG
{
- unsigned long i;
- printf("\trec->data=");
+ unsigned long i;
+ printf("\trec->data=");
for (i=0; i<l; i++)
- printf(" %02x", rec->data[i]); printf("\n");
- }
+ printf(" %02x", rec->data[i]); printf("\n");
+ }
#endif /* KSSL_DEBUG */
+ ret = 1;
+ if (EVP_MD_CTX_md(s->read_hash) != NULL)
+ mac_size = EVP_MD_CTX_size(s->read_hash);
if ((bs != 1) && !send)
- {
- ii=i=rec->data[l-1]; /* padding_length */
- i++;
- /* NB: if compression is in operation the first packet
- * may not be of even length so the padding bug check
- * cannot be performed. This bug workaround has been
- * around since SSLeay so hopefully it is either fixed
- * now or no buggy implementation supports compression
- * [steve]
- */
- if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
- && !s->expand)
- {
- /* First packet is even in size, so check */
- if ((memcmp(s->s3->read_sequence,
- "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
- s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
- if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
- i--;
- }
- /* TLS 1.0 does not bound the number of padding bytes by the block size.
- * All of them must have value 'padding_length'. */
- if (i > (int)rec->length)
- {
- /* Incorrect padding. SSLerr() and ssl3_alert are done
- * by caller: we don't want to reveal whether this is
- * a decryption error or a MAC verification failure
- * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
- return -1;
- }
- for (j=(int)(l-i); j<(int)l; j++)
- {
- if (rec->data[j] != ii)
- {
- /* Incorrect padding */
- return -1;
- }
- }
- rec->length -=i;
- if (s->version >= TLS1_1_VERSION
- && EVP_CIPHER_CTX_mode(ds) == EVP_CIPH_CBC_MODE)
- {
- if (bs > (int)rec->length)
- return -1;
- rec->data += bs; /* skip the explicit IV */
- rec->input += bs;
- rec->length -= bs;
- }
- }
+ ret = tls1_cbc_remove_padding(s, rec, bs, mac_size);
if (pad && !send)
rec->length -= pad;
}
- return(1);
+ return ret;
}
+
int tls1_cert_verify_mac(SSL *s, int md_nid, unsigned char *out)
{
unsigned int ret;
@@ -993,7 +952,7 @@
size_t md_size;
int i;
EVP_MD_CTX hmac, *mac_ctx;
- unsigned char buf[5];
+ unsigned char header[13];
int stream_mac = (send?(ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM):(ssl->mac_flags&SSL_MAC_FLAG_READ_MAC_STREAM));
int t;
@@ -1014,12 +973,6 @@
OPENSSL_assert(t >= 0);
md_size=t;
- buf[0]=rec->type;
- buf[1]=(unsigned char)(ssl->version>>8);
- buf[2]=(unsigned char)(ssl->version);
- buf[3]=rec->length>>8;
- buf[4]=rec->length&0xff;
-
/* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
if (stream_mac)
{
@@ -1038,17 +991,44 @@
s2n(send?ssl->d1->w_epoch:ssl->d1->r_epoch, p);
memcpy (p,&seq[2],6);
- EVP_DigestSignUpdate(mac_ctx,dtlsseq,8);
+ memcpy(header, dtlsseq, 8);
}
else
- EVP_DigestSignUpdate(mac_ctx,seq,8);
+ memcpy(header, seq, 8);
- EVP_DigestSignUpdate(mac_ctx,buf,5);
- EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
- t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
- OPENSSL_assert(t > 0);
+ header[8]=rec->type;
+ header[9]=(unsigned char)(ssl->version>>8);
+ header[10]=(unsigned char)(ssl->version);
+ header[11]=(rec->length)>>8;
+ header[12]=(rec->length)&0xff;
+
+ if (!send &&
+ EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+ ssl3_cbc_record_digest_supported(mac_ctx))
+ {
+ /* This is a CBC-encrypted record. We must avoid leaking any
+ * timing-side channel information about how many blocks of
+ * data we are hashing because that gives an attacker a
+ * timing-oracle. */
+ ssl3_cbc_digest_record(
+ mac_ctx,
+ md, &md_size,
+ header, rec->input,
+ rec->length + md_size, rec->orig_len,
+ ssl->s3->read_mac_secret,
+ ssl->s3->read_mac_secret_size,
+ 0 /* not SSLv3 */);
+ }
+ else
+ {
+ EVP_DigestSignUpdate(mac_ctx,header,sizeof(header));
+ EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
+ t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
+ OPENSSL_assert(t > 0);
+ }
- if (!stream_mac) EVP_MD_CTX_cleanup(&hmac);
+ if (!stream_mac)
+ EVP_MD_CTX_cleanup(&hmac);
#ifdef TLS_DEBUG
printf("sec=");
{unsigned int z; for (z=0; z<md_size; z++) printf("%02X ",mac_sec[z]); printf("\n"); }
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 26d19e9..9972b1a 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -2215,7 +2215,7 @@
HMAC_Update(&hctx, etick, eticklen);
HMAC_Final(&hctx, tick_hmac, NULL);
HMAC_CTX_cleanup(&hctx);
- if (memcmp(tick_hmac, etick + eticklen, mlen))
+ if (CRYPTO_memcmp(tick_hmac, etick + eticklen, mlen))
return 2;
/* Attempt to decrypt session data */
/* Move p after IV to start of encrypted ticket, update length */
