On Tue, Aug 30, 2016 at 06:48:19PM +0200, Marco Angaroni wrote: > Current parsing methods for SIP headers do not properly manage > continuation lines: in case of Call-ID header the first character of > Call-ID header value is truncated. As a result IPVS SIP persistence > engine hashes over a call-id that is not exactly the one present in > the originale message. > > Example: "Call-ID: \r\n abcdeABCDE1234" > results in extracted call-id equal to "bcdeABCDE1234". > > In above example Call-ID is represented as a string in C language. > Obviously in real message the first bytes after colon (":") are > "20 0d 0a 20". > > Proposed fix is in nf_conntrack_sip module. > Since sip_follow_continuation() function walks past the leading > spaces or tabs of the continuation line, sip_skip_whitespace() > should simply return the ouput of sip_follow_continuation(). > Otherwise another iteration of the for loop is done and dptr > is incremented by one pointing to the second character of the > first word in the header. > > 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 <marcoangar...@gmail.com> > --- > net/netfilter/nf_conntrack_sip.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/netfilter/nf_conntrack_sip.c > b/net/netfilter/nf_conntrack_sip.c > index 8971109..c23249e 100644 > --- a/net/netfilter/nf_conntrack_sip.c > +++ b/net/netfilter/nf_conntrack_sip.c > @@ -335,8 +335,7 @@ static const char *sip_skip_whitespace(const char *dptr, > const char *limit) > if (*dptr != '\r' && *dptr != '\n') > break; > dptr = sip_follow_continuation(dptr, limit); > - if (dptr == NULL) > - return NULL; > + return dptr;
I'd suggest you use the break statement here instead, ie. - if (dptr == NULL) - return NULL; + break; > } > return dptr; > } > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe lvs-devel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html