From 1bcabc81ee94c0a65989128258f8c1d3e1c1b0ea Mon Sep 17 00:00:00 2001 From: Marco Angaroni Date: Tue, 30 Aug 2016 18:52:22 +0200 Subject: [PATCH] netfilter: nf_ct_sip: allow tab character in SIP headers Current parsing methods for SIP headers do not allow the presence of tab characters between header name and header value. As a result Call-ID SIP headers like the following are discarded by IPVS SIP persistence engine: "Call-ID\t: mycallid@abcde" "Call-ID:\tmycallid@abcde" In above examples Call-IDs are represented as strings in C language. Obviously in real message we have byte "09" before/after colon (":"). Proposed fix is in nf_conntrack_sip module. Function sip_skip_whitespace() should skip tabs in addition to spaces, since in SIP grammar whitespace (WSP) corresponds to space or tab. Below is an extract of relevant SIP ABNF syntax. Call-ID = ( "Call-ID" / "i" ) HCOLON callid callid = word [ "@" word ] HCOLON = *( SP / HTAB ) ":" SWS SWS = [LWS] ; sep whitespace LWS = [*WSP CRLF] 1*WSP ; linear whitespace WSP = SP / HTAB word = 1*(alphanum / "-" / "." / "!" / "%" / "*" / "_" / "+" / "`" / "'" / "~" / "(" / ")" / "<" / ">" / ":" / "\" / DQUOTE / "/" / "[" / "]" / "?" / "{" / "}" ) Signed-off-by: Marco Angaroni Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_sip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index d8035351aff5..621b81c7bddc 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -330,7 +330,7 @@ static const char *sip_follow_continuation(const char *dptr, const char *limit) static const char *sip_skip_whitespace(const char *dptr, const char *limit) { for (; dptr < limit; dptr++) { - if (*dptr == ' ') + if (*dptr == ' ' || *dptr == '\t') continue; if (*dptr != '\r' && *dptr != '\n') break; -- 2.30.2