From patchwork Wed Jan 24 19:12:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 13529594 X-Patchwork-Delegate: kuba@kernel.org Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 636C5132C04; Wed, 24 Jan 2024 19:12:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.188.207 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706123579; cv=none; b=OoVXW1MYQWDUQ8wv9qmxf7k75nNd9GjR8UJPZP1VrYUe9ixdHzaEEr6FWzPaDY7M8/oHFG1g8ynE0A22cPNnXeh2kpsVU+V6OV4Gq6OP6GkfkHaqnK582mB+SDiLvAVzttoA5/2LknWY6DlKHHJ8RTYRYjydpm7dJfKQboQ2dSM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706123579; c=relaxed/simple; bh=a9RJaQcXDE2ki+6h0E8TsoXaM2cfkPsCs0FQbPPOCQ4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=gAUKj9G1VkmX8QUh2FKiaE96Nsk0jlOJ1AlwY24CSK+FSQvpWdITqwv8HDWWXKI1QxQsytnZoiINvcJVqMLvfAEPNTknOf/PcLZ/FhxUbL0ueje0i5q9DyjK/N6AJ5ZopFdd6zzk1FIYG3hk2QGkTh19WsBGb5pOHm5rFOVkFrM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; arc=none smtp.client-ip=217.70.188.207 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de Subject: [PATCH net 5/6] netfilter: nf_tables: reject QUEUE/DROP verdict parameters Date: Wed, 24 Jan 2024 20:12:47 +0100 Message-Id: <20240124191248.75463-6-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240124191248.75463-1-pablo@netfilter.org> References: <20240124191248.75463-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Florian Westphal This reverts commit e0abdadcc6e1. core.c:nf_hook_slow assumes that the upper 16 bits of NF_DROP verdicts contain a valid errno, i.e. -EPERM, -EHOSTUNREACH or similar, or 0. Due to the reverted commit, its possible to provide a positive value, e.g. NF_ACCEPT (1), which results in use-after-free. Its not clear to me why this commit was made. NF_QUEUE is not used by nftables; "queue" rules in nftables will result in use of "nft_queue" expression. If we later need to allow specifiying errno values from userspace (do not know why), this has to call NF_DROP_GETERR and check that "err <= 0" holds true. Fixes: e0abdadcc6e1 ("netfilter: nf_tables: accept QUEUE/DROP verdict parameters") Cc: stable@vger.kernel.org Reported-by: Notselwyn Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 02f45424644b..c537104411e7 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -10992,16 +10992,10 @@ static int nft_verdict_init(const struct nft_ctx *ctx, struct nft_data *data, data->verdict.code = ntohl(nla_get_be32(tb[NFTA_VERDICT_CODE])); switch (data->verdict.code) { - default: - switch (data->verdict.code & NF_VERDICT_MASK) { - case NF_ACCEPT: - case NF_DROP: - case NF_QUEUE: - break; - default: - return -EINVAL; - } - fallthrough; + case NF_ACCEPT: + case NF_DROP: + case NF_QUEUE: + break; case NFT_CONTINUE: case NFT_BREAK: case NFT_RETURN: @@ -11036,6 +11030,8 @@ static int nft_verdict_init(const struct nft_ctx *ctx, struct nft_data *data, data->verdict.chain = chain; break; + default: + return -EINVAL; } desc->len = sizeof(data->verdict);