diff options
| author | Carlos Maiolino <cmaiolino@redhat.com> | 2011-11-19 13:13:44 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-11-26 09:10:06 -0800 |
| commit | 626ff2d51fc1127814fa28bdfb1df761ea894755 (patch) | |
| tree | 885735d33631ba30e562ffa4a83d5c0417fec71b /fs/xfs | |
| parent | 70f589ceb96bbf1d4c2c2f5b6c3d6dff19ddd31d (diff) | |
xfs: Fix possible memory corruption in xfs_readlink
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>
Diffstat (limited to 'fs/xfs')
| -rw-r--r-- | fs/xfs/xfs_vnodeops.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index 619720705bc..6cc4d41fb0d 100644 --- 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'; |