ocfs2: Don't walk off the end of fast symlinks.
ocfs2 fast symlinks are NUL terminated strings stored inline in the
inode data area. However, disk corruption or a local attacker could, in
theory, remove that NUL. Because we're using strlen() (my fault,
introduced in a731d1 when removing vfs_follow_link()), we could walk off
the end of that string.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Cc: stable@kernel.org
diff --git a/fs/ocfs2/symlink.c b/fs/ocfs2/symlink.c
index 32499d21..9975457 100644
--- a/fs/ocfs2/symlink.c
+++ b/fs/ocfs2/symlink.c
@@ -128,7 +128,7 @@
}
/* Fast symlinks can't be large */
- len = strlen(target);
+ len = strnlen(target, ocfs2_fast_symlink_chars(inode->i_sb));
link = kzalloc(len + 1, GFP_NOFS);
if (!link) {
status = -ENOMEM;
