Fix auth via B2B module.

Remove the bogus hooks placed by TM in the outbound SIP buffer (as the buffer may change in local route) and rebuild the B2B invite (with credentials) from the initial sent invite.
Reported by @DMOsipov and @xxReaper on GITHUB.
Closing #577 and #628 .

modules/b2b_entities/dlg.c

@@ -1988,6 +1988,96 @@ int b2b_send_req(b2b_dlg_t* dlg, enum b2b_entity_type etype,
 
 static struct sip_msg dummy_msg;
 
+static int build_extra_headers_from_msg(str buf, str *extra_hdr,
+													str *new_hdrs, str *body)
+{
+	struct sip_msg req;
+	struct hdr_field *hdr;
+	int len;
+	char *p;
+
+	memset( &req, 0, sizeof(req) );
+	req.buf = buf.s;
+	req.len = buf.len;
+	if (parse_msg(buf.s, buf.len, &req)!=0) {
+		LM_CRIT("BUG - buffer parsing failed!");
+		return -1;
+	}
+	/* parse all headers */
+	if (parse_headers(&req, HDR_EOH_F, 0 )<0) {
+		LM_ERR("parse_headers failed\n");
+		goto error;
+	}
+
+	/* first calculate the total len */
+	len = extra_hdr->len;
+	for( hdr=req.headers; hdr ; hdr=hdr->next ) {
+		/* skip all headers that are by default added by build_uac_req()
+		 * We want to propagete only custom headers !!! */
+		switch(hdr->type){
+		case HDR_VIA_T:
+		case HDR_TO_T:
+		case HDR_FROM_T:
+		case HDR_ROUTE_T:
+		case HDR_CSEQ_T:
+		case HDR_CALLID_T:
+		case HDR_MAXFORWARDS_T:
+		case HDR_CONTENTLENGTH_T:
+		case HDR_USERAGENT_T:
+			break;
+		default:
+			/* count the header (includes the CRLF) */
+			len += hdr->len;
+		}
+	}
+
+	/* allocate */
+	new_hdrs->len = len;
+	new_hdrs->s = pkg_malloc( len );
+	if (new_hdrs->s==NULL) {
+		LM_ERR("failed to allocate pkg mem (needed %d)\n",len);
+		goto error;
+	}
+
+	/* copy headers */
+	for( p=new_hdrs->s,hdr=req.headers; hdr ; hdr=hdr->next ) {
+		switch(hdr->type){
+		case HDR_VIA_T:
+		case HDR_TO_T:
+		case HDR_FROM_T:
+		case HDR_ROUTE_T:
+		case HDR_CSEQ_T:
+		case HDR_CALLID_T:
+		case HDR_MAXFORWARDS_T:
+		case HDR_CONTENTLENGTH_T:
+		case HDR_USERAGENT_T:
+			break;
+		default:
+			/* copy the header (includes the CRLF) */
+			memcpy( p, hdr->name.s , hdr->len);
+			p += hdr->len;
+		}
+	}
+	/* and extra */
+	memcpy( p, extra_hdr->s, extra_hdr->len);
+
+	if (get_body( &req, body)<0) {
+		LM_ERR("failed to extract body\n");
+		pkg_free( new_hdrs->s );
+		goto error;
+	}
+
+	free_sip_msg(&req);
+
+	return 0;
+error:
+	free_sip_msg(&req);
+	new_hdrs->s = body->s = NULL;
+	new_hdrs->len = body->len = 0;
+	return -1;
+}
+
+
 void b2b_tm_cback(struct cell *t, b2b_table htable, struct tmcb_params *ps)
 {
 	struct sip_msg * msg;
@@ -2002,6 +2092,7 @@ void b2b_tm_cback(struct cell *t, b2b_table htable, struct tmcb_params *ps)
 	struct to_body* pto;
 	str to_tag, callid, from_tag;
 	str extra_headers = {NULL, 0};
+	str body = {NULL, 0};
 	struct hdr_field* hdr;
 	unsigned int method_id = 0;
 	struct cseq_body cb;
@@ -2302,32 +2393,21 @@ void b2b_tm_cback(struct cell *t, b2b_table htable, struct tmcb_params *ps)
 						lock_release(&htable[hash_index].lock);
 						goto error;
 					}
-					LM_DBG("[%.*s]\n", new_hdr->len, new_hdr->s);
-					LM_DBG("uri [%.*s] with extra_hdrs [%.*s]\n",
-						t->uac[0].uri.len, t->uac[0].uri.s,
-						t->uac[0].extra_headers.len,
-						t->uac[0].extra_headers.s);
-					extra_headers.s = (char*)pkg_malloc(new_hdr->len +
-								t->uac[0].extra_headers.len);
-					if (extra_headers.s == NULL)
-					{
-						LM_ERR("No more private memory\n");
+					LM_DBG("auth is [%.*s]\n", new_hdr->len, new_hdr->s);
+					if (build_extra_headers_from_msg(t->uac[0].request.buffer,
+							new_hdr, &extra_headers, &body) < 0 ) {
+						LM_ERR("failed to build extra msgs after auth\n");
 						dlg->state = B2B_TERMINATED;
 						lock_release(&htable[hash_index].lock);
 						goto error;
 					}
-					memcpy(extra_headers.s, new_hdr->s, new_hdr->len);
-					memcpy(extra_headers.s + new_hdr->len,
-						t->uac[0].extra_headers.s,
-						t->uac[0].extra_headers.len);
-					extra_headers.len = new_hdr->len +
-								t->uac[0].extra_headers.len;
-					LM_DBG("[%.*s]\n", extra_headers.len, extra_headers.s);
+					LM_DBG("extra is [%.*s]\n",
+						extra_headers.len, extra_headers.s);
 					pkg_free(new_hdr->s);
 					new_hdr->s = NULL; new_hdr->len = 0;
 
 					b2b_send_indlg_req(dlg, B2B_CLIENT, b2b_key, &t->method,
-							&extra_headers, &t->uac[0].body, 0);
+							&extra_headers, &body, 0);
 					pkg_free(extra_headers.s);
 
 					dlg->state = B2B_NEW_AUTH;

modules/tm/h_table.h

@@ -148,10 +148,6 @@ typedef struct ua_client
 	str              duri;
 	/* the path vector used for this branch */
 	str              path_vec;
-	/* the list of extra headers in the request sent out from a dlg structure */
-	str              extra_headers;
-	/* the body in the request sent out from a dlg structure */
-	str              body;
 	/* number of RR headers that were locally added for this branch */
 	unsigned int     added_rr;
 	/* if we store a reply (branch picking), this is where it is */

modules/tm/t_msgbuilder.c

@@ -863,17 +863,17 @@ char* build_uac_req(str* method, str* headers, str* body, dlg_t* dialog,
 		append_string(w, user_agent_header.s, user_agent_header.len);
 		append_string(w, CRLF, CRLF_LEN);
 	}
-	if (headers) {
-		t->uac[branch].extra_headers.s = w;
-		t->uac[branch].extra_headers.len = headers->len;
+
+	/* extra headers (containing CRLF) */
+	if (headers)
 		append_string(w, headers->s, headers->len);
-	}
+
+	/* add CRLF between headers and body */
 	append_string(w, CRLF, CRLF_LEN);
-	if (body) {
-		t->uac[branch].body.s = w;
-		t->uac[branch].body.len = body->len;
+
+	/* add body (if required) */
+	if (body)
 		append_string(w, body->s, body->len);
-	}
 
 #ifdef EXTRA_DEBUG
 	if (w-buf != *len ) abort();