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authorCarlos Maiolino <cmaiolino@redhat.com>2011-11-07 20:10:24 +0400
committerAlex Elder <aelder@sgi.com>2011-11-08 20:48:23 +0400
commitb52a360b2aa1c59ba9970fb0f52bbb093fcc7a24 (patch)
treeb8710ad524592faac1427d2155aaf4ba29a80cf8 /fs
parent1ea6b8f48918282bdca0b32a34095504ee65bab5 (diff)
downloadlinux-b52a360b2aa1c59ba9970fb0f52bbb093fcc7a24.tar.xz
xfs: Fix possible memory corruption in xfs_readlink
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>
Diffstat (limited to 'fs')
-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 4ecf2a549060..ce9268a2f56b 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -112,7 +112,7 @@ xfs_readlink(
char *link)
{
xfs_mount_t *mp = ip->i_mount;
- int pathlen;
+ xfs_fsize_t pathlen;
int error = 0;
trace_xfs_readlink(ip);
@@ -122,13 +122,19 @@ 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);
+ 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';