lkml.org 
[lkml]   [2021]   [Aug]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] ceph: fix possible null-pointer dereference in ceph_mdsmap_decode()
Date
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
\
 
 \ /
  Last update: 2021-08-05 17:17    [W:0.096 / U:0.320 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site