From a3d26594e50001b93f35f2117421927f5ffeae22 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lukas=20Johannes=20M=C3=B6ller?= Date: Wed, 11 Mar 2026 05:49:01 +0800 Subject: [PATCH] netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ANBZ: #32806 commit fbce58e719a17aa215c724473fd5baaa4a8dc57c upstream. sip_help_tcp() parses the SIP Content-Length header with simple_strtoul(), which returns unsigned long, but stores the result in unsigned int clen. On 64-bit systems, values exceeding UINT_MAX are silently truncated before computing the SIP message boundary. For example, Content-Length 4294967328 (2^32 + 32) is truncated to 32, causing the parser to miscalculate where the current message ends. The loop then treats trailing data in the TCP segment as a second SIP message and processes it through the SDP parser. Fix this by changing clen to unsigned long to match the return type of simple_strtoul(), and reject Content-Length values that exceed the remaining TCP payload length. Fixes: f5b321bd37fb ("netfilter: nf_conntrack_sip: add TCP support") Signed-off-by: Lukas Johannes Möller Signed-off-by: Florian Westphal Fixes: CVE-2026-23457 Signed-off-by: PatchPilot Signed-off-by: Ferry Meng --- net/netfilter/nf_conntrack_sip.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index b83dc9bf0a5d..36f65241fc97 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1529,11 +1529,12 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, { struct tcphdr *th, _tcph; unsigned int dataoff, datalen; - unsigned int matchoff, matchlen, clen; + unsigned int matchoff, matchlen; unsigned int msglen, origlen; const char *dptr, *end; s16 diff, tdiff = 0; int ret = NF_ACCEPT; + unsigned long clen; bool term; if (ctinfo != IP_CT_ESTABLISHED && @@ -1568,6 +1569,9 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, if (dptr + matchoff == end) break; + if (clen > datalen) + break; + term = false; for (; end + strlen("\r\n\r\n") <= dptr + datalen; end++) { if (end[0] == '\r' && end[1] == '\n' && -- Gitee