2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Carlos Maiolino <[email protected]> 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 <[email protected]> Signed-off-by: Carlos Maiolino <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <[email protected]> --- fs/xfs/xfs_vnodeops.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-) diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index 8f32f50..1638884 100644 --- a/fs/xfs/xfs_vnodeops.c +++ b/fs/xfs/xfs_vnodeops.c @@ -554,7 +554,7 @@ xfs_readlink( char *link) { xfs_mount_t *mp = ip->i_mount; - int pathlen; + xfs_fsize_t pathlen; int error = 0; xfs_itrace_entry(ip); @@ -564,13 +564,20 @@ 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_fs_cmn_err(CE_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'; -- 1.7.2.1.45.g54fbc -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
