From: Gao Xiang <gaoxiang25@huawei.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
<stable@vger.kernel.org>, Chao Yu <yuchao0@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>, linux-erofs@lists.ozlabs.org
Subject: [PATCH for-5.3 4/5] staging: erofs: avoid endless loop of invalid lookback distance 0
Date: Wed, 9 Oct 2019 18:05:53 +0800 [thread overview]
Message-ID: <20191009100554.165048-4-gaoxiang25@huawei.com> (raw)
In-Reply-To: <20191009100554.165048-1-gaoxiang25@huawei.com>
commit 598bb8913d015150b7734b55443c0e53e7189fc7 upstream.
As reported by erofs-utils fuzzer, Lookback distance should
be a positive number, so it should be actually looked back
rather than spinning.
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190819103426.87579-7-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Gao Xiang: Since earlier kernels don't define EFSCORRUPTED,
let's use EIO instead. ]
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
drivers/staging/erofs/zmap.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/staging/erofs/zmap.c b/drivers/staging/erofs/zmap.c
index c2359321ca13..30e6d02d30de 100644
--- a/drivers/staging/erofs/zmap.c
+++ b/drivers/staging/erofs/zmap.c
@@ -350,6 +350,12 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m,
switch (m->type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ if (!m->delta[0]) {
+ errln("invalid lookback distance 0 at nid %llu",
+ vi->nid);
+ DBG_BUGON(1);
+ return -EIO;
+ }
return vle_extent_lookback(m, m->delta[0]);
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
map->m_flags &= ~EROFS_MAP_ZIPPED;
--
2.17.1
next prev parent reply other threads:[~2019-10-09 10:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 10:05 [PATCH for-5.3 1/5] staging: erofs: fix an error handling in erofs_readdir() Gao Xiang
2019-10-09 10:05 ` [PATCH for-5.3 2/5] staging: erofs: some compressed cluster should be submitted for corrupted images Gao Xiang
2019-10-09 13:27 ` Patch "staging: erofs: some compressed cluster should be submitted for corrupted images" has been added to the 5.3-stable tree gregkh
2019-10-09 10:05 ` [PATCH for-5.3 3/5] staging: erofs: add two missing erofs_workgroup_put for corrupted images Gao Xiang
2019-10-09 13:27 ` Patch "staging: erofs: add two missing erofs_workgroup_put for corrupted images" has been added to the 5.3-stable tree gregkh
2019-10-09 10:05 ` Gao Xiang [this message]
2019-10-09 13:27 ` Patch "staging: erofs: avoid endless loop of invalid lookback distance 0" " gregkh
2019-10-09 10:05 ` [PATCH for-5.3 5/5] staging: erofs: detect potential multiref due to corrupted images Gao Xiang
2019-10-09 13:27 ` Patch "staging: erofs: detect potential multiref due to corrupted images" has been added to the 5.3-stable tree gregkh
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