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* [PATCH][next] netfilter: nf_tables: Fix dereference of null pointer flow
@ 2021-06-24 19:57 Colin King
  2021-06-25  9:59 ` Dan Carpenter
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Colin King @ 2021-06-24 19:57 UTC (permalink / raw)
  To: Pablo Neira Ayuso, Jozsef Kadlecsik, Florian Westphal,
	David S . Miller, Jakub Kicinski, netfilter-devel, coreteam,
	netdev
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then
nft_flow_rule_create is not called and flow is NULL. The subsequent
error handling execution via label err_destroy_flow_rule will lead
to a null pointer dereference on flow when calling nft_flow_rule_destroy.
Since the error path to err_destroy_flow_rule has to cater for null
and non-null flows, only call nft_flow_rule_destroy if flow is non-null
to fix this issue.

Addresses-Coverity: ("Explicity null dereference")
Fixes: 3c5e44622011 ("netfilter: nf_tables: memleak in hw offload abort path")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 net/netfilter/nf_tables_api.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 390d4466567f..de182d1f7c4e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3446,7 +3446,8 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
 	return 0;
 
 err_destroy_flow_rule:
-	nft_flow_rule_destroy(flow);
+	if (flow)
+		nft_flow_rule_destroy(flow);
 err_release_rule:
 	nf_tables_rule_release(&ctx, rule);
 err_release_expr:
-- 
2.31.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2021-07-02  0:56 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-24 19:57 [PATCH][next] netfilter: nf_tables: Fix dereference of null pointer flow Colin King
2021-06-25  9:59 ` Dan Carpenter
2021-06-25 10:20   ` Pablo Neira Ayuso
2021-06-25 10:33     ` Dan Carpenter
2021-06-25 10:06 ` AW: " Walter Harms
2021-06-25 10:21   ` Pablo Neira Ayuso
2021-07-02  0:56 ` Pablo Neira Ayuso

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