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") Cc: stable@vger.kernel.org Signed-off-by: Lukas Johannes Möller --- Note: simple_strtoul() is deprecated; a follow-up patch could convert to kstrtoul() with stricter input validation. 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 ca748f8dbff1..eb6295f0e08c 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1534,7 +1534,8 @@ 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 long clen; unsigned int msglen, origlen; const char *dptr, *end; s16 diff, tdiff = 0; @@ -1573,6 +1574,9 @@ 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' && base-commit: 1f318b96cc84d7c2ab792fcc0bfd42a7ca890681 -- 2.43.0