[PATCH] net: fix NULL pointer reference in cipso_v4_doi_free
王贇
yun.wang at linux.alibaba.com
Thu Aug 26 03:42:42 UTC 2021
In netlbl_cipsov4_add_std() when 'doi_def->map.std' alloc
failed, we sometime observe panic:
BUG: kernel NULL pointer dereference, address:
...
RIP: 0010:cipso_v4_doi_free+0x3a/0x80
...
Call Trace:
netlbl_cipsov4_add_std+0xf4/0x8c0
netlbl_cipsov4_add+0x13f/0x1b0
genl_family_rcv_msg_doit.isra.15+0x132/0x170
genl_rcv_msg+0x125/0x240
This is because in cipso_v4_doi_free() there is no check
on 'doi_def->map.std' when 'doi_def->type' equal 1, which
is possibe, since netlbl_cipsov4_add_std() haven't initialize
it before alloc 'doi_def->map.std'.
This patch just add the check to prevent panic happen for similar
cases.
Reported-by: Abaci <abaci at linux.alibaba.com>
Signed-off-by: Michael Wang <yun.wang at linux.alibaba.com>
---
net/ipv4/cipso_ipv4.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 099259f..7fbd0b5 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -465,14 +465,16 @@ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
if (!doi_def)
return;
- switch (doi_def->type) {
- case CIPSO_V4_MAP_TRANS:
- kfree(doi_def->map.std->lvl.cipso);
- kfree(doi_def->map.std->lvl.local);
- kfree(doi_def->map.std->cat.cipso);
- kfree(doi_def->map.std->cat.local);
- kfree(doi_def->map.std);
- break;
+ if (doi_def->map.std) {
+ switch (doi_def->type) {
+ case CIPSO_V4_MAP_TRANS:
+ kfree(doi_def->map.std->lvl.cipso);
+ kfree(doi_def->map.std->lvl.local);
+ kfree(doi_def->map.std->cat.cipso);
+ kfree(doi_def->map.std->cat.local);
+ kfree(doi_def->map.std);
+ break;
+ }
}
kfree(doi_def);
}
--
1.8.3.1
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