From patchwork Thu Oct 12 08:57:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13418604 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 094EB2033F for ; Thu, 12 Oct 2023 08:58:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCF08C9; Thu, 12 Oct 2023 01:58:01 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qqrW1-00078l-9h; Thu, 12 Oct 2023 10:57:57 +0200 From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , =?utf-8?b?Qmxhxb5laiBLcmFqxYjDoWs=?= Subject: [PATCH net 7/7] netfilter: nft_payload: fix wrong mac header matching Date: Thu, 12 Oct 2023 10:57:10 +0200 Message-ID: <20231012085724.15155-8-fw@strlen.de> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231012085724.15155-1-fw@strlen.de> References: <20231012085724.15155-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_PASS, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org mcast packets get looped back to the local machine. Such packets have a 0-length mac header, we should treat this like "mac header not set" and abort rule evaluation. As-is, we just copy data from the network header instead. Fixes: 96518518cc41 ("netfilter: add nftables") Reported-by: Blažej Krajňák Signed-off-by: Florian Westphal --- net/netfilter/nft_payload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 120f6d395b98..0a689c8e0295 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -179,7 +179,7 @@ void nft_payload_eval(const struct nft_expr *expr, switch (priv->base) { case NFT_PAYLOAD_LL_HEADER: - if (!skb_mac_header_was_set(skb)) + if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) == 0) goto err; if (skb_vlan_tag_present(skb) &&