From 48b428d5f8b1f11810ff9ef10dfabb5a07a9f927 Mon Sep 17 00:00:00 2001 From: twilson Date: Fri, 19 Nov 2010 20:53:36 +0000 Subject: Discard responses with more than one Via This is not a perfect solution as headers that are joined via commas are not detected. This is a parsing issue that to fix "correctly" would necessitate a new SIP parser. Review: https://reviewboard.asterisk.org/r/1019/ git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@295628 f38db490-d61c-443f-a65b-d21fe96a405b --- channels/chan_sip.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'channels') diff --git a/channels/chan_sip.c b/channels/chan_sip.c index e5a97ae3d..a06726bd6 100644 --- a/channels/chan_sip.c +++ b/channels/chan_sip.c @@ -16788,6 +16788,9 @@ static int handle_request(struct sip_pvt *p, struct sip_request *req, struct soc const char *cmd; const char *cseq; const char *useragent; + const char *via; + const char *callid; + int via_pos = 0; int seqno; int len; int ignore = FALSE; @@ -16799,13 +16802,19 @@ static int handle_request(struct sip_pvt *p, struct sip_request *req, struct soc int oldmethod = p->method; int acked = 0; - /* Get Method and Cseq */ + /* RFC 3261 - 8.1.1 A valid SIP request must contain To, From, CSeq, Call-ID and Via. + * 8.2.6.2 Response must have To, From, Call-ID CSeq, and Via related to the request, + * so we can check to make sure these fields exist for all requests and responses */ cseq = get_header(req, "Cseq"); cmd = req->header[0]; + /* Save the via_pos so we can check later that responses only have 1 Via header */ + via = __get_header(req, "Via", &via_pos); + /* This must exist already because we've called find_call by now */ + callid = get_header(req, "Call-ID"); /* Must have Cseq */ - if (ast_strlen_zero(cmd) || ast_strlen_zero(cseq)) { - ast_log(LOG_ERROR, "Missing Cseq. Dropping this SIP message, it's incomplete.\n"); + if (ast_strlen_zero(cmd) || ast_strlen_zero(cseq) || ast_strlen_zero(via)) { + ast_log(LOG_ERROR, "Dropping this SIP message with Call-ID '%s', it's incomplete.\n", callid); error = 1; } if (!error && sscanf(cseq, "%30d%n", &seqno, &len) != 1) { @@ -16841,6 +16850,13 @@ static int handle_request(struct sip_pvt *p, struct sip_request *req, struct soc ast_log(LOG_WARNING, "Invalid SIP response code: '%d'\n", respid); return 0; } + /* RFC 3261 - 8.1.3.3 If more than one Via header field value is present in a reponse + * the UAC SHOULD discard the message. This is not perfect, as it will not catch multiple + * headers joined with a comma. Fixing that would pretty much involve writing a new parser */ + if (!ast_strlen_zero(__get_header(req, "via", &via_pos))) { + ast_log(LOG_WARNING, "Misrouted SIP response '%s' with Call-ID '%s', too many vias\n", e, callid); + return 0; + } if (!p->initreq.headers) { if (option_debug) ast_log(LOG_DEBUG, "That's odd... Got a response on a call we don't know about. Cseq %d Cmd %s\n", seqno, cmd); -- cgit v1.2.3