From: Tuo Li <islituo@gmail.com>
To: jlayton@kernel.org, idryomov@gmail.com
Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
baijiaju1990@gmail.com, Tuo Li <islituo@gmail.com>,
TOTE Robot <oslab@tsinghua.edu.cn>
Subject: [PATCH v2] ceph: fix possible null-pointer dereference in ceph_mdsmap_decode()
Date: Thu, 5 Aug 2021 08:14:34 -0700 [thread overview]
Message-ID: <20210805151434.142619-1-islituo@gmail.com> (raw)
kcalloc() is called to allocate memory for m->m_info, and if it fails,
ceph_mdsmap_destroy() behind the label out_err will be called:
ceph_mdsmap_destroy(m);
In ceph_mdsmap_destroy(), m->m_info is dereferenced through:
kfree(m->m_info[i].export_targets);
To fix this possible null-pointer dereference, check m->m_info before the
for loop to free m->m_info[i].export_targets.
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
v2:
* Put an "if (m->m_info)" around the for loop in ceph_mdsmap_destroy()
instead of freeing m and returning -ENOMEM in ceph_mdsmap_decode().
Thank Jeff Layton for helpful advice.
---
fs/ceph/mdsmap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
index abd9af7727ad..26d6fa049b44 100644
--- a/fs/ceph/mdsmap.c
+++ b/fs/ceph/mdsmap.c
@@ -393,9 +393,11 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2)
void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
{
int i;
-
- for (i = 0; i < m->possible_max_rank; i++)
- kfree(m->m_info[i].export_targets);
+
+ if (m->m_info) {
+ for (i = 0; i < m->possible_max_rank; i++)
+ kfree(m->m_info[i].export_targets);
+ }
kfree(m->m_info);
kfree(m->m_data_pg_pools);
kfree(m);
--
2.25.1
next reply other threads:[~2021-08-05 15:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 15:14 Tuo Li [this message]
2021-08-05 19:25 ` [PATCH v2] ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() Jeff Layton
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