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authorCarlos Maiolino <cmaiolino@redhat.com>2011-11-19 13:13:44 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-11-26 09:10:06 -0800
commit626ff2d51fc1127814fa28bdfb1df761ea894755 (patch)
tree885735d33631ba30e562ffa4a83d5c0417fec71b
parent70f589ceb96bbf1d4c2c2f5b6c3d6dff19ddd31d (diff)
downloadlinux-linaro-stable-626ff2d51fc1127814fa28bdfb1df761ea894755.tar.gz
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>
-rw-r--r--fs/xfs/xfs_vnodeops.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 619720705bc6..6cc4d41fb0db 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';