From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33714 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731801AbeGZR6Z (ORCPT ); Thu, 26 Jul 2018 13:58:25 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E40DD72621 for ; Thu, 26 Jul 2018 16:40:46 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-121-63.rdu2.redhat.com [10.10.121.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id BEC202142F20 for ; Thu, 26 Jul 2018 16:40:46 +0000 (UTC) From: Bill O'Donnell Subject: [PATCH v4] libxfs: add more bounds checking to sb sanity checks Date: Thu, 26 Jul 2018 11:40:46 -0500 Message-Id: <20180726164046.18503-1-billodo@redhat.com> In-Reply-To: <20180713131003.31121-1-billodo@redhat.com> References: <20180713131003.31121-1-billodo@redhat.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org Current sb verifier doesn't check bounds on sb_fdblocks and sb_ifree. Add sanity checks for these parameters. Signed-off-by: Bill O'Donnell --- v4: adjust control flow to standard error checking. Add more descriptive comment. Add validation for sb_icount. v3: eliminate need for additional write_flag, doing those unique checks in xfs_sb_write_verify() v2: make extra sanity checks exclusive to writes fs/xfs/libxfs/xfs_sb.c | 46 +++++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c index b3ad15956366..8d8e579ca426 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -599,22 +599,16 @@ xfs_sb_to_disk( static int xfs_sb_verify( struct xfs_buf *bp, + struct xfs_sb *sb, bool check_version) { struct xfs_mount *mp = bp->b_target->bt_mount; - struct xfs_sb sb; - - /* - * Use call variant which doesn't convert quota flags from disk - * format, because xfs_mount_validate_sb checks the on-disk flags. - */ - __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false); /* * Only check the in progress field for the primary superblock as * mkfs.xfs doesn't clear it from secondary superblocks. */ - return xfs_mount_validate_sb(mp, &sb, + return xfs_mount_validate_sb(mp, sb, bp->b_maps[0].bm_bn == XFS_SB_DADDR, check_version); } @@ -637,6 +631,7 @@ xfs_sb_read_verify( { struct xfs_mount *mp = bp->b_target->bt_mount; struct xfs_dsb *dsb = XFS_BUF_TO_SBP(bp); + struct xfs_sb sb; int error; /* @@ -657,7 +652,13 @@ xfs_sb_read_verify( } } } - error = xfs_sb_verify(bp, true); + + /* + * Use call variant which doesn't convert quota flags from disk + * format, because xfs_mount_validate_sb checks the on-disk flags. + */ + __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false); + error = xfs_sb_verify(bp, &sb, true); out_error: if (error == -EFSCORRUPTED || error == -EFSBADCRC) @@ -693,9 +694,34 @@ xfs_sb_write_verify( { struct xfs_mount *mp = bp->b_target->bt_mount; struct xfs_buf_log_item *bip = bp->b_log_item; + struct xfs_sb sb; int error; - error = xfs_sb_verify(bp, false); + /* + * Use call variant which doesn't convert quota flags from disk + * format, because xfs_mount_validate_sb checks the on-disk flags. + */ + __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false); + + error = xfs_sb_verify(bp, &sb, false); + if (error) + goto err; + + /* + * Carry out additional sb sanity checks exclusively for writes. + * We don't do these checks for reads, since faulty parameters could + * already be on disk, and we shouldn't preclude reads for those + * cases. + */ + if (sb.sb_fdblocks > sb.sb_dblocks || + sb.sb_icount / sb.sb_inopblock > sb.sb_dblocks || + sb.sb_ifree > sb.sb_icount) { + xfs_notice(mp, "SB sanity check failed"); + error = -EFSCORRUPTED; + goto err; + } + +err: if (error) { xfs_verifier_error(bp, error, __this_address); return; -- 2.17.1