Messages in this thread Patch in this message | | | From | Walter Harms <> | Subject | AW: [PATCH][next] netfilter: nf_tables: Fix dereference of null pointer flow | Date | Fri, 25 Jun 2021 10:06:26 +0000 |
| |
hi Colin, most free_something_functions accept NULL these days, perhaps it would be more efficient to add a check in nft_flow_rule_destroy(). There is a chance that this will catch the same mistake in future also.
jm2c, re, wh ________________________________________ Von: Colin King <colin.king@canonical.com> Gesendet: Donnerstag, 24. Juni 2021 21:57:18 An: Pablo Neira Ayuso; Jozsef Kadlecsik; Florian Westphal; David S . Miller; Jakub Kicinski; netfilter-devel@vger.kernel.org; coreteam@netfilter.org; netdev@vger.kernel.org Cc: kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org Betreff: [PATCH][next] netfilter: nf_tables: Fix dereference of null pointer flow
WARNUNG: Diese E-Mail kam von außerhalb der Organisation. Klicken Sie nicht auf Links oder öffnen Sie keine Anhänge, es sei denn, Sie kennen den/die Absender*in und wissen, dass der Inhalt sicher ist.
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
| |