path: root/fs
diff options
authorCarlos Maiolino <>2011-12-01 17:27:43 -0600
committerGreg Kroah-Hartman <>2011-12-09 08:54:30 -0800
commitc38aeb8cd119fddc37d7cd648d6c43e782711247 (patch)
tree4b5f2283dd7bc6bdb00c78e3b7eea7f0f61c3aca /fs
parent7f9fae139e1b34b0ecb0ff8ab051c4497d68db2c (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 <> Signed-off-by: Carlos Maiolino <> Reviewed-by: Christoph Hellwig <> Cc: Ben Myers <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'fs')
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 51fc429527bc..b9e28730bbd6 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -113,7 +113,7 @@ xfs_readlink(
char *link)
xfs_mount_t *mp = ip->i_mount;
- int pathlen;
+ xfs_fsize_t pathlen;
int error = 0;
@@ -123,13 +123,19 @@ xfs_readlink(
xfs_ilock(ip, XFS_ILOCK_SHARED);
- ASSERT(S_ISLNK(ip->i_d.di_mode));
- 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);
+ }
if (ip->i_df.if_flags & XFS_IFINLINE) {
memcpy(link, ip->i_df.if_u1.if_data, pathlen);
link[pathlen] = '\0';