Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A22463B8409; Mon, 17 Aug 2026 14:33:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977218; cv=none; b=gYdFRi0ILmPUewXwfhc4NElEA7CMAwGZ/4C0Bm9uUtA+IJUMGj0aElnM5ZeQC2zmyXwe57+vLJEgk0cxJF1/HI3ypm8p1WvQY+w3WzEJH/CaDDUi81rTEZWodLMSg0iEkS01PqGQz6T32n/StrGI9lmUT6jjOIKm6+5c0oCq3gc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977218; c=relaxed/simple; bh=1fDHmdUwvf/n2jxaKa8On8GRd9T/lz5hI7DYWNMwmQk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D7xIL0E4kRPa18LTDXddnFnOSsoVv2hCG4/FwbDlKSXQJVriRtRbhEJbKG09lCusaiOap3Frnzn2WvtvQaXbKjiX4PgH8ZBd/59Z0ttJHXWYxQqJ9I2uyyx8Vrv2GLTFgeSyaZYQ+SlHz6YnWx39WzuFXRPlzMY0ZwxC1r6m7Jo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pdVFm+li; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pdVFm+li" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA68D1F000E9; Mon, 17 Aug 2026 14:33:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977217; bh=btoGNslXg0LVV0dRyVt6BnRnQGWV9dnjMfuftVLOmU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pdVFm+liO/nv/A7+9ArDWrhAxepWJC5NE1+aRtXXZ0JTAWSWJYkeYHAq+fo0UCpWQ wDe5H9R36UB0fz10fGqAu7k+T5YtaJ5PLBaT2JcV/geHKcCveObxKR7ny9dl2+8bkE 7ZSsiQWKDZkTRpdDEidL9+4gJLQybswTCsDkDNWM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.15 253/456] netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp() Date: Mon, 17 Aug 2026 15:30:43 +0200 Message-ID: <20260817132549.950189686@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5 ] sip_help_tcp() stores the size change of each NAT-rewritten SIP message in s16 diff and accumulates it in s16 tdiff, but a single message can grow by more than S16_MAX while the packet stays under the 65535 enlarge_skb() limit: nf_nat_sip() rewrites every matching URI, and a long Contact list expands the message by tens of kilobytes. diff then wraps, and "datalen = datalen + diff - msglen" yields a huge unsigned datalen, so the next iteration's ct_sip_get_header() reads past the linearized skb tail. Widen diff, tdiff and the seq_adjust hook to s32. Both are bounded by the 65535 byte packet limit, and the seqadj core is already s32 (nf_ct_seqadj_set() takes s32), so no previously accepted input is rejected. BUG: KASAN: use-after-free in ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464) Read of size 1 at addr ffff888010800000 by task ksoftirqd/1/25 ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464) sip_help_tcp (net/netfilter/nf_conntrack_sip.c:1694) nf_confirm (net/netfilter/nf_conntrack_proto.c:183) nf_hook_slow (net/netfilter/core.c:619) ip6_output (net/ipv6/ip6_output.c:246) ip6_forward (net/ipv6/ip6_output.c:690) ipv6_rcv (net/ipv6/ip6_input.c:351) __netif_receive_skb_one_core (net/core/dev.c:6212) process_backlog (net/core/dev.c:6676) __napi_poll (net/core/dev.c:7735) net_rx_action (net/core/dev.c:7955) handle_softirqs (kernel/softirq.c:622) run_ksoftirqd (kernel/softirq.c:1076) ... Fixes: f5b321bd37fb ("netfilter: nf_conntrack_sip: add TCP support") Reported-by: Weiming Shi Link: https://patch.msgid.link/netfilter-devel/20260712234201.3213635-1-xmei5@asu.edu Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- include/linux/netfilter/nf_conntrack_sip.h | 2 +- net/netfilter/nf_conntrack_sip.c | 2 +- net/netfilter/nf_nat_sip.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h index c620521c42bc6..dfb9708f53404 100644 --- a/include/linux/netfilter/nf_conntrack_sip.h +++ b/include/linux/netfilter/nf_conntrack_sip.h @@ -115,7 +115,7 @@ struct nf_nat_sip_hooks { unsigned int *datalen); void (*seq_adjust)(struct sk_buff *skb, - unsigned int protoff, s16 off); + unsigned int protoff, s32 off); unsigned int (*expect)(struct sk_buff *skb, unsigned int protoff, diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 4326d5ea0400d..0f6147ea9e67b 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1622,7 +1622,7 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, unsigned int matchoff, matchlen; unsigned int msglen, origlen; const char *dptr, *end; - s16 diff, tdiff = 0; + s32 diff, tdiff = 0; int ret = NF_ACCEPT; unsigned long clen; bool term; diff --git a/net/netfilter/nf_nat_sip.c b/net/netfilter/nf_nat_sip.c index 76a8bbb44951c..7687d3d15df22 100644 --- a/net/netfilter/nf_nat_sip.c +++ b/net/netfilter/nf_nat_sip.c @@ -313,7 +313,7 @@ static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff, } static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff, - s16 off) + s32 off) { enum ip_conntrack_info ctinfo; struct nf_conn *ct = nf_ct_get(skb, &ctinfo); -- 2.53.0