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
This commit is contained in:
Joel Becker 2010-09-29 17:33:05 -07:00
parent 899611ee7d
commit 1fc8a11786

View file

@ -128,7 +128,7 @@ static void *ocfs2_fast_follow_link(struct dentry *dentry,
}
/* 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;