From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: darrick.wong@oracle.com, bfoster@redhat.com, sandeen@sandeen.net
Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] fs: xfs: Fix possible null-pointer dereferences in xchk_da_btree_block_check_sibling()
Date: Mon, 29 Jul 2019 11:24:01 +0800 [thread overview]
Message-ID: <20190729032401.28081-1-baijiaju1990@gmail.com> (raw)
In xchk_da_btree_block_check_sibling(), there is an if statement on
line 274 to check whether ds->state->altpath.blk[level].bp is NULL:
if (ds->state->altpath.blk[level].bp)
When ds->state->altpath.blk[level].bp is NULL, it is used on line 281:
xfs_trans_brelse(..., ds->state->altpath.blk[level].bp);
struct xfs_buf_log_item *bip = bp->b_log_item;
ASSERT(bp->b_transp == tp);
Thus, possible null-pointer dereferences may occur.
To fix these bugs, ds->state->altpath.blk[level].bp is checked before
being used.
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
fs/xfs/scrub/dabtree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/scrub/dabtree.c b/fs/xfs/scrub/dabtree.c
index 94c4f1de1922..33ff90c0dd70 100644
--- a/fs/xfs/scrub/dabtree.c
+++ b/fs/xfs/scrub/dabtree.c
@@ -278,7 +278,9 @@ xchk_da_btree_block_check_sibling(
/* Compare upper level pointer to sibling pointer. */
if (ds->state->altpath.blk[level].blkno != sibling)
xchk_da_set_corrupt(ds, level);
- xfs_trans_brelse(ds->dargs.trans, ds->state->altpath.blk[level].bp);
+ if (ds->state->altpath.blk[level].bp)
+ xfs_trans_brelse(ds->dargs.trans,
+ ds->state->altpath.blk[level].bp);
out:
return error;
}
--
2.17.0
next reply other threads:[~2019-07-29 3:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 3:24 Jia-Ju Bai [this message]
2019-07-29 4:20 ` [PATCH] fs: xfs: Fix possible null-pointer dereferences in xchk_da_btree_block_check_sibling() Darrick J. Wong
2019-07-29 7:25 ` Jia-Ju Bai
2019-07-29 14:58 ` Darrick J. Wong
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