From 6058426f0315e917e0334c210bf8fc795947e26b Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 9 Feb 2016 11:09:27 +1100 Subject: [PATCH] metadump: bounds check btree block regions being zeroed Arkadiusz Miskiewicz reported that metadump was crashing on one of his corrupted filesystems, and the trace indicated that it was zeroing unused regions in inode btree blocks when it failed. The btree block had a corrupt nrecs field, which was resulting in an out of bounds memset() occurring. Ensure that the region being generated for zeroing is within bounds before executing the zeroing. Reported-by: Arkadiusz Miskiewicz Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Reviewed-by: Christoph Hellwig Signed-off-by: Dave Chinner --- db/metadump.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/db/metadump.c b/db/metadump.c index a185da5e5..26a3bd58c 100644 --- a/db/metadump.c +++ b/db/metadump.c @@ -246,6 +246,11 @@ write_buf( return seenint() ? -EINTR : 0; } +/* + * We could be processing a corrupt block, so we can't trust any of + * the offsets or lengths to be within the buffer range. Hence check + * carefully! + */ static void zero_btree_node( struct xfs_btree_block *block, @@ -262,10 +267,15 @@ zero_btree_node( char *key_end; nrecs = be16_to_cpu(block->bb_numrecs); + if (nrecs < 0) + return; switch (btype) { case TYP_BMAPBTA: case TYP_BMAPBTD: + if (nrecs > mp->m_bmap_dmxr[1]) + return; + bkp = XFS_BMBT_KEY_ADDR(mp, block, 1); bpp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]); zp1 = (char *)&bkp[nrecs]; @@ -274,6 +284,9 @@ zero_btree_node( break; case TYP_INOBT: case TYP_FINOBT: + if (nrecs > mp->m_inobt_mxr[1]) + return; + ikp = XFS_INOBT_KEY_ADDR(mp, block, 1); ipp = XFS_INOBT_PTR_ADDR(mp, block, 1, mp->m_inobt_mxr[1]); zp1 = (char *)&ikp[nrecs]; @@ -282,6 +295,9 @@ zero_btree_node( break; case TYP_BNOBT: case TYP_CNTBT: + if (nrecs > mp->m_alloc_mxr[1]) + return; + akp = XFS_ALLOC_KEY_ADDR(mp, block, 1); app = XFS_ALLOC_PTR_ADDR(mp, block, 1, mp->m_alloc_mxr[1]); zp1 = (char *)&akp[nrecs]; @@ -300,6 +316,11 @@ zero_btree_node( memset(zp2, 0, (char *)block + mp->m_sb.sb_blocksize - zp2); } +/* + * We could be processing a corrupt block, so we can't trust any of + * the offsets or lengths to be within the buffer range. Hence check + * carefully! + */ static void zero_btree_leaf( struct xfs_btree_block *block, @@ -312,20 +333,31 @@ zero_btree_leaf( char *zp; nrecs = be16_to_cpu(block->bb_numrecs); + if (nrecs < 0) + return; switch (btype) { case TYP_BMAPBTA: case TYP_BMAPBTD: + if (nrecs > mp->m_bmap_dmxr[0]) + return; + brp = XFS_BMBT_REC_ADDR(mp, block, 1); zp = (char *)&brp[nrecs]; break; case TYP_INOBT: case TYP_FINOBT: + if (nrecs > mp->m_inobt_mxr[0]) + return; + irp = XFS_INOBT_REC_ADDR(mp, block, 1); zp = (char *)&irp[nrecs]; break; case TYP_BNOBT: case TYP_CNTBT: + if (nrecs > mp->m_alloc_mxr[0]) + return; + arp = XFS_ALLOC_REC_ADDR(mp, block, 1); zp = (char *)&arp[nrecs]; break; -- 2.47.2