diff options
| author | Lukas Johannes Möller <research@johannes-moeller.dev> | 2026-03-10 21:49:01 +0000 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2026-03-13 15:31:14 +0100 |
| commit | fbce58e719a17aa215c724473fd5baaa4a8dc57c (patch) | |
| tree | 1af7b9ef58c64b66f30e26b8c7b97bc05af72e27 /net | |
| parent | f900e1d77ee0ef87bfb5ab3fe60f0b3d8ad5ba05 (diff) | |
netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()
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 <research@johannes-moeller.dev>
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_conntrack_sip.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index ca748f8dbff1..4ab5ef71d96d 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1534,11 +1534,12 @@ 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 && @@ -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' && |