From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44682C433FE for ; Mon, 2 May 2022 08:20:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359303AbiEBIYM (ORCPT ); Mon, 2 May 2022 04:24:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383749AbiEBIXz (ORCPT ); Mon, 2 May 2022 04:23:55 -0400 Received: from mail104.syd.optusnet.com.au (mail104.syd.optusnet.com.au [211.29.132.246]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 671E1644B for ; Mon, 2 May 2022 01:20:26 -0700 (PDT) Received: from dread.disaster.area (pa49-181-2-147.pa.nsw.optusnet.com.au [49.181.2.147]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id 94012534BB3 for ; Mon, 2 May 2022 18:20:22 +1000 (AEST) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92.3) (envelope-from ) id 1nlRI4-0073Tg-ML for linux-xfs@vger.kernel.org; Mon, 02 May 2022 18:20:20 +1000 Received: from dave by discord.disaster.area with local (Exim 4.95) (envelope-from ) id 1nlRI4-004WM9-L5 for linux-xfs@vger.kernel.org; Mon, 02 May 2022 18:20:20 +1000 From: Dave Chinner To: linux-xfs@vger.kernel.org Subject: [PATCH 1/4] xfs: detect self referencing btree sibling pointers Date: Mon, 2 May 2022 18:20:15 +1000 Message-Id: <20220502082018.1076561-2-david@fromorbit.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220502082018.1076561-1-david@fromorbit.com> References: <20220502082018.1076561-1-david@fromorbit.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=deDjYVbe c=1 sm=1 tr=0 ts=626f9446 a=ivVLWpVy4j68lT4lJFbQgw==:117 a=ivVLWpVy4j68lT4lJFbQgw==:17 a=oZkIemNP1mAA:10 a=20KFwNOVAAAA:8 a=h5XfSTf-C_0QDq3dHd0A:9 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner To catch the obvious graph cycle problem and hence potential endless looping. Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_btree.c | 137 ++++++++++++++++++++++++++++---------- 1 file changed, 102 insertions(+), 35 deletions(-) diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index a8c79e760d8a..991fae6f500a 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -51,6 +51,50 @@ xfs_btree_magic( return magic; } +static xfs_failaddr_t +xfs_btree_check_lblock_siblings( + struct xfs_mount *mp, + struct xfs_btree_cur *cur, + int level, + xfs_fsblock_t fsb, + xfs_fsblock_t sibling) +{ + if (sibling == NULLFSBLOCK) + return NULL; + if (sibling == fsb) + return __this_address; + if (level >= 0) { + if (!xfs_btree_check_lptr(cur, sibling, level + 1)) + return __this_address; + } else if (!xfs_verify_fsbno(mp, sibling)) { + return __this_address; + } + + return NULL; +} + +static xfs_failaddr_t +xfs_btree_check_sblock_siblings( + struct xfs_mount *mp, + struct xfs_btree_cur *cur, + int level, + xfs_agnumber_t agno, + xfs_agblock_t agbno, + xfs_agblock_t sibling) +{ + if (sibling == NULLAGBLOCK) + return NULL; + if (sibling == agbno) + return __this_address; + if (level >= 0) { + if (!xfs_btree_check_sptr(cur, sibling, level + 1)) + return __this_address; + } else if (!xfs_verify_agbno(mp, agno, sibling)) { + return __this_address; + } + return NULL; +} + /* * Check a long btree block header. Return the address of the failing check, * or NULL if everything is ok. @@ -65,6 +109,8 @@ __xfs_btree_check_lblock( struct xfs_mount *mp = cur->bc_mp; xfs_btnum_t btnum = cur->bc_btnum; int crc = xfs_has_crc(mp); + xfs_failaddr_t fa; + xfs_fsblock_t fsb = NULLFSBLOCK; if (crc) { if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid)) @@ -83,16 +129,16 @@ __xfs_btree_check_lblock( if (be16_to_cpu(block->bb_numrecs) > cur->bc_ops->get_maxrecs(cur, level)) return __this_address; - if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) && - !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_leftsib), - level + 1)) - return __this_address; - if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) && - !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_rightsib), - level + 1)) - return __this_address; - return NULL; + if (bp) + fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp)); + + fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb, + be64_to_cpu(block->bb_u.l.bb_leftsib)); + if (!fa) + fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb, + be64_to_cpu(block->bb_u.l.bb_rightsib)); + return fa; } /* Check a long btree block header. */ @@ -130,6 +176,9 @@ __xfs_btree_check_sblock( struct xfs_mount *mp = cur->bc_mp; xfs_btnum_t btnum = cur->bc_btnum; int crc = xfs_has_crc(mp); + xfs_failaddr_t fa; + xfs_agblock_t agbno = NULLAGBLOCK; + xfs_agnumber_t agno = NULLAGNUMBER; if (crc) { if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid)) @@ -146,16 +195,18 @@ __xfs_btree_check_sblock( if (be16_to_cpu(block->bb_numrecs) > cur->bc_ops->get_maxrecs(cur, level)) return __this_address; - if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) && - !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_leftsib), - level + 1)) - return __this_address; - if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) && - !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_rightsib), - level + 1)) - return __this_address; - return NULL; + if (bp) { + agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp)); + agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp)); + } + + fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno, agbno, + be32_to_cpu(block->bb_u.s.bb_leftsib)); + if (!fa) + fa = xfs_btree_check_sblock_siblings(mp, cur, level, agno, + agbno, be32_to_cpu(block->bb_u.s.bb_rightsib)); + return fa; } /* Check a short btree block header. */ @@ -4271,6 +4322,20 @@ xfs_btree_visit_block( if (xfs_btree_ptr_is_null(cur, &rptr)) return -ENOENT; + /* + * We only visit blocks once in this walk, so we have to avoid the + * internal xfs_btree_lookup_get_block() optimisation where it will + * return the same block without checking if the right sibling points + * back to us and creates a cyclic reference in the btree. + */ + if (cur->bc_flags & XFS_BTREE_LONG_PTRS) { + if (be64_to_cpu(rptr.l) == + XFS_DADDR_TO_FSB(cur->bc_mp, xfs_buf_daddr(bp))) + return -EFSCORRUPTED; + } else if (be32_to_cpu(rptr.s) == + xfs_daddr_to_agbno(cur->bc_mp, xfs_buf_daddr(bp))) { + return -EFSCORRUPTED; + } return xfs_btree_lookup_get_block(cur, level, &rptr, &block); } @@ -4445,20 +4510,21 @@ xfs_btree_lblock_verify( { struct xfs_mount *mp = bp->b_mount; struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp); + xfs_fsblock_t fsb; + xfs_failaddr_t fa; /* numrecs verification */ if (be16_to_cpu(block->bb_numrecs) > max_recs) return __this_address; /* sibling pointer verification */ - if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) && - !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_leftsib))) - return __this_address; - if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) && - !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_rightsib))) - return __this_address; - - return NULL; + fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp)); + fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb, + be64_to_cpu(block->bb_u.l.bb_leftsib)); + if (!fa) + fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb, + be64_to_cpu(block->bb_u.l.bb_rightsib)); + return fa; } /** @@ -4499,7 +4565,9 @@ xfs_btree_sblock_verify( { struct xfs_mount *mp = bp->b_mount; struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp); - xfs_agblock_t agno; + xfs_agnumber_t agno; + xfs_agblock_t agbno; + xfs_failaddr_t fa; /* numrecs verification */ if (be16_to_cpu(block->bb_numrecs) > max_recs) @@ -4507,14 +4575,13 @@ xfs_btree_sblock_verify( /* sibling pointer verification */ agno = xfs_daddr_to_agno(mp, xfs_buf_daddr(bp)); - if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) && - !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_leftsib))) - return __this_address; - if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) && - !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_rightsib))) - return __this_address; - - return NULL; + agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp)); + fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno, + be32_to_cpu(block->bb_u.s.bb_leftsib)); + if (!fa) + fa = xfs_btree_check_sblock_siblings(mp, NULL, -1, agno, agbno, + be32_to_cpu(block->bb_u.s.bb_rightsib)); + return fa; } /* -- 2.35.1