Fix wrong inheriting of Contact-Length hdr.

When moving from multi part to single part, do not inherite the Ct-len hdr of the part.
Fixes #1990

(cherry picked from commit 7dd1151)

msg_translator.c

@@ -1261,7 +1261,8 @@ static unsigned int prep_reassemble_body_parts( struct sip_msg* msg,
 	unsigned int size;
 	unsigned int len = 0;
 	unsigned int orig_offs;
-	char *hdr;
+	struct hdr_field hf;
+	char *hdr, *it;
 
 	/* set the offset (in the original buffer) at the beginning of the body */
 	orig_offs = msg->body->part_count ? msg->body->body.s-msg->buf : msg->len ;
@@ -1366,15 +1367,27 @@ static unsigned int prep_reassemble_body_parts( struct sip_msg* msg,
 						}
 					}
 				} else {
-					hdr = (char*)pkg_malloc( part->headers.len);
-					if (hdr==NULL) {
-						LM_ERR("failed to allocate new ct hdr\n");
-					} else {
-						memcpy( hdr, part->headers.s, part->headers.len);
-						if (insert_new_lump_before(ct, hdr,
-						part->headers.len, HDR_CONTENTTYPE_T) == NULL) {
-							LM_ERR("failed to create insert lump\n");
-							pkg_free(hdr);
+					/* iterate all the SIP hdrs from this part and keep all
+					 * except the "Content-Length" */
+					it = part->headers.s;
+					while ( it<part->headers.s+part->headers.len ) {
+						memset( &hf, 0, sizeof(struct hdr_field));
+						it = get_hdr_field( it, part->headers.s+part->headers.len, &hf);
+						if (hf.type==HDR_ERROR_T || hf.type==HDR_EOH_T)
+							break;
+						if (hf.type==HDR_CONTENTLENGTH_T)
+							continue;
+						/* add this hdr */
+						hdr = (char*)pkg_malloc( hf.len);
+						if (hdr==NULL) {
+							LM_ERR("failed to allocate new ct hdr\n");
+						} else {
+							memcpy( hdr, hf.name.s, hf.len);
+							if (insert_new_lump_before(ct, hdr,
+							hf.len, HDR_CONTENTTYPE_T) == NULL) {
+								LM_ERR("failed to create insert lump\n");
+								pkg_free(hdr);
+							}
 						}
 					}
 				}