From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2A15D23ED5B; Mon, 20 Apr 2026 13:16:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690968; cv=none; b=XwKKR0IQ/3SLVN9EM4CzbM6CnqaUyeYVaoEoaQLo2bNLl2yL7sz6iMlmlOVHvtmyzyS/HWkMBPYesLmwK0+3DsD30NVoTxkmE06zECil6ZlWHANYPSkuEt5v+gapva5RhmQPiSe6r5Op3evRZvO52kw+8bkGpJah41uwGOcgbdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776690968; c=relaxed/simple; bh=PY00X5IV4JpUSmoJ41N7TTVq2lNmpdVturPjoc87vBE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A+Gd5bpps9HPNlsG2wKTmhEwsn72CreNr3PYD38p+TPPc145sEaoU9EAwQlfqsXGSXFkrvqMnRN9cZzpU0tjb/Lidtz00X2qMbGhO5G/Z8GxlmzBp25DLaZ8cVPCxCv+8BNVoa4b6HBNE5Cz4PG9eohJYyWlrFubkynxROZNzz4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eSFWE5at; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eSFWE5at" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4738C2BCB4; Mon, 20 Apr 2026 13:16:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776690967; bh=PY00X5IV4JpUSmoJ41N7TTVq2lNmpdVturPjoc87vBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eSFWE5atr2IlZCpKkm3Xbngja437Kg45hCRI3yvoR4ZoOwwzG6ri5NpVTLe6Fxxqv wpEbHcQfR6uBHkVwhT5WyhQRRNcosTzFOqOaUXOth7aG8qIm03jZkhnVT3CCl8eem8 f+qwyeWeLDIQS3z+cJ9pW2WP4Vv0Bh83EsJCdjw9dCzzo/Avrx3j6h1K92nnead54m dqFqXu0kzjSN0KUmn9vGHezQwP2leTDN4B4wTFghAaBDgFOqZl2/fMrB2078aeyjIg NU1dTwbhgDq5R0cs0IvQfkQJd/CPc0A56Y/Q91nocYYop4V5Bin5mMsLLSFRbHnfo1 j9ZbimYBUBeFQ== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Ren Wei , Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Yuhang Zheng , Florian Westphal , Sasha Levin , pablo@netfilter.org, kadlec@netfilter.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, yasuyuki.kozakai@toshiba.co.jp, kaber@trash.net, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.18] netfilter: xt_multiport: validate range encoding in checkentry Date: Mon, 20 Apr 2026 09:08:02 -0400 Message-ID: <20260420131539.986432-16-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420131539.986432-1-sashal@kernel.org> References: <20260420131539.986432-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.23 Content-Transfer-Encoding: 8bit From: Ren Wei [ Upstream commit ff64c5bfef12461df8450e0f50bb693b5269c720 ] ports_match_v1() treats any non-zero pflags entry as the start of a port range and unconditionally consumes the next ports[] element as the range end. The checkentry path currently validates protocol, flags and count, but it does not validate the range encoding itself. As a result, malformed rules can mark the last slot as a range start or place two range starts back to back, leaving ports_match_v1() to step past the last valid ports[] element while interpreting the rule. Reject malformed multiport v1 rules in checkentry by validating that each range start has a following element and that the following element is not itself marked as another range start. Fixes: a89ecb6a2ef7 ("[NETFILTER]: x_tables: unify IPv4/IPv6 multiport match") Reported-by: Yifan Wu Reported-by: Juefei Pu Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Tested-by: Yuhang Zheng Signed-off-by: Ren Wei Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Error: Failed to generate final synthesis net/netfilter/xt_multiport.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/net/netfilter/xt_multiport.c b/net/netfilter/xt_multiport.c index 44a00f5acde8a..a1691ff405d3c 100644 --- a/net/netfilter/xt_multiport.c +++ b/net/netfilter/xt_multiport.c @@ -105,6 +105,28 @@ multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); } +static bool +multiport_valid_ranges(const struct xt_multiport_v1 *multiinfo) +{ + unsigned int i; + + for (i = 0; i < multiinfo->count; i++) { + if (!multiinfo->pflags[i]) + continue; + + if (++i >= multiinfo->count) + return false; + + if (multiinfo->pflags[i]) + return false; + + if (multiinfo->ports[i - 1] > multiinfo->ports[i]) + return false; + } + + return true; +} + static inline bool check(u_int16_t proto, u_int8_t ip_invflags, @@ -127,8 +149,10 @@ static int multiport_mt_check(const struct xt_mtchk_param *par) const struct ipt_ip *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; - return check(ip->proto, ip->invflags, multiinfo->flags, - multiinfo->count) ? 0 : -EINVAL; + if (!check(ip->proto, ip->invflags, multiinfo->flags, multiinfo->count)) + return -EINVAL; + + return multiport_valid_ranges(multiinfo) ? 0 : -EINVAL; } static int multiport_mt6_check(const struct xt_mtchk_param *par) @@ -136,8 +160,10 @@ static int multiport_mt6_check(const struct xt_mtchk_param *par) const struct ip6t_ip6 *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; - return check(ip->proto, ip->invflags, multiinfo->flags, - multiinfo->count) ? 0 : -EINVAL; + if (!check(ip->proto, ip->invflags, multiinfo->flags, multiinfo->count)) + return -EINVAL; + + return multiport_valid_ranges(multiinfo) ? 0 : -EINVAL; } static struct xt_match multiport_mt_reg[] __read_mostly = { -- 2.53.0