From 626ff2d51fc1127814fa28bdfb1df761ea894755 Mon Sep 17 00:00:00 2001 From: Carlos Maiolino Date: Sat, 19 Nov 2011 13:13:44 -0500 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_vnodeops.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index 6197207..6cc4d41 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'; -- cgit v1.1