From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Carlos Maiolino <cmaiolino@redhat.com>,
xfs@oss.sgi.com, Alex Elder <aelder@sgi.com>,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
alan@lxorguk.ukuu.org.uk
Subject: [49/53] xfs: Fix possible memory corruption in xfs_readlink
Date: Tue, 22 Nov 2011 16:23:56 -0800 [thread overview]
Message-ID: <20111123002409.195639830@clark.kroah.org> (raw)
In-Reply-To: <20111123002419.GA8531@kroah.com>
3.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Carlos Maiolino <cmaiolino@redhat.com>
commit b52a360b2aa1c59ba9970fb0f52bbb093fcc7a24 upstream.
Fixes a possible memory corruption when the link is larger than
MAXPATHLEN and XFS_DEBUG is not enabled. This also remove the
S_ISLNK assert, since the inode mode is checked previously in
xfs_readlink_by_handle() and via VFS.
Updated to address concerns raised by Ben Hutchings about the loose
attention paid to 32- vs 64-bit values, and the lack of handling a
potentially negative pathlen value:
- Changed type of "pathlen" to be xfs_fsize_t, to match that of
ip->i_d.di_size
- Added checking for a negative pathlen to the too-long pathlen
test, and generalized the message that gets reported in that case
to reflect the change
As a result, if a negative pathlen were encountered, this function
would return EFSCORRUPTED (and would fail an assertion for a debug
build)--just as would a too-long pathlen.
Signed-off-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/xfs/xfs_vnodeops.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -535,7 +535,7 @@ xfs_readlink(
char *link)
{
xfs_mount_t *mp = ip->i_mount;
- int pathlen;
+ xfs_fsize_t pathlen;
int error = 0;
trace_xfs_readlink(ip);
@@ -545,13 +545,19 @@ xfs_readlink(
xfs_ilock(ip, XFS_ILOCK_SHARED);
- ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFLNK);
- ASSERT(ip->i_d.di_size <= MAXPATHLEN);
-
pathlen = ip->i_d.di_size;
if (!pathlen)
goto out;
+ if (pathlen < 0 || pathlen > MAXPATHLEN) {
+ xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
+ __func__, (unsigned long long) ip->i_ino,
+ (long long) pathlen);
+ ASSERT(0);
+ return XFS_ERROR(EFSCORRUPTED);
+ }
+
+
if (ip->i_df.if_flags & XFS_IFINLINE) {
memcpy(link, ip->i_df.if_u1.if_data, pathlen);
link[pathlen] = '\0';
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next prev parent reply other threads:[~2011-11-23 0:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111123002419.GA8531@kroah.com>
2011-11-23 0:23 ` [43/53] xfs: fix error handling for synchronous writes Greg KH
2011-11-23 0:23 ` [44/53] xfs: fix xfs_mark_inode_dirty during umount Greg KH
2011-11-23 0:23 ` [45/53] xfs: dont serialise direct IO reads on page cache Greg KH
2011-11-23 0:23 ` [46/53] xfs: avoid direct I/O write vs buffered I/O race Greg KH
2011-11-23 0:23 ` [47/53] xfs: Return -EIO when xfs_vn_getattr() failed Greg KH
2011-11-23 0:23 ` [48/53] xfs: fix buffer flushing during unmount Greg KH
2011-11-23 0:23 ` Greg KH [this message]
2011-11-23 0:23 ` [50/53] xfs: use doalloc flag in xfs_qm_dqattach_one() Greg KH
2011-11-23 0:23 ` [51/53] xfs: fix ->write_inode return values Greg KH
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