[PATCH] x86_64: Fix access check in ptrace compat
We can't safely directly access an compat_alloc_user_space() pointer
with the siginfo copy functions. Bounce it through the stack.
Noticed by Al Viro using sparse
[ This was only added post 2.6.17, not in any released kernel ]
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/ia32/ptrace32.c b/arch/x86_64/ia32/ptrace32.c
index a590b7a..659c072 100644
--- a/arch/x86_64/ia32/ptrace32.c
+++ b/arch/x86_64/ia32/ptrace32.c
@@ -202,17 +202,24 @@
{
int ret;
compat_siginfo_t *si32 = (compat_siginfo_t *)compat_ptr(data);
+ siginfo_t ssi;
siginfo_t *si = compat_alloc_user_space(sizeof(siginfo_t));
if (request == PTRACE_SETSIGINFO) {
- ret = copy_siginfo_from_user32(si, si32);
+ memset(&ssi, 0, sizeof(siginfo_t));
+ ret = copy_siginfo_from_user32(&ssi, si32);
if (ret)
return ret;
+ if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
+ return -EFAULT;
}
ret = sys_ptrace(request, pid, addr, (unsigned long)si);
if (ret)
return ret;
- if (request == PTRACE_GETSIGINFO)
- ret = copy_siginfo_to_user32(si32, si);
+ if (request == PTRACE_GETSIGINFO) {
+ if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
+ return -EFAULT;
+ ret = copy_siginfo_to_user32(si32, &ssi);
+ }
return ret;
}
