From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36136 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730085AbeGZSh3 (ORCPT ); Thu, 26 Jul 2018 14:37:29 -0400 Date: Thu, 26 Jul 2018 12:19:41 -0500 From: Bill O'Donnell Subject: Re: [PATCH v4] libxfs: add more bounds checking to sb sanity checks Message-ID: <20180726171941.GA19621@redhat.com> References: <20180713131003.31121-1-billodo@redhat.com> <20180726164046.18503-1-billodo@redhat.com> <20180726170734.GF30972@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180726170734.GF30972@magnolia> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org On Thu, Jul 26, 2018 at 10:07:34AM -0700, Darrick J. Wong wrote: > On Thu, Jul 26, 2018 at 11:40:46AM -0500, Bill O'Donnell wrote: > > 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 || > > This is a 64-bit division, which won't work on 32-bit builds. > > That said, I also wrote a xfs_verify_icount function for the fs summary > scrub patch, so perhaps we should collaborate to land both of these? > Send a v5 without this test and I'll immediately send a patch adding > both the _verify_icount and putting it to use here. > > Actually, I could just modify your patch, add mine, and send both of > them. That'd be easier... That sounds fine. Thanks! Bill > > --D > > > + 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 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html