Fix Record-Route parsing for large headers.

Record-Route parsing copied the header into a char[256] array, which can
be a problem if the header is longer than that. This patch parses the
header in place, without the copy, avoiding the issue.

In addition to the original patch, I added a unit test for the new
get_in_brackets_const function.

(closes issue ASTERISK-20837)
Reported by: Corey Farrell
Patches:
	chan_sip-build_route-optimized-rev1.patch uploaded by Corey Farrell (license 5909)
	(with minor changes by dlee)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@379392 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -14727,21 +14727,25 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
 	/* 1st we pass through all the hops in any Record-Route headers */
 	for (;;) {
 		/* Each Record-Route header */
-		char rr_copy[256];
-		char *rr_copy_ptr;
-		char *rr_iter;
+		int len = 0;
+		const char *uri;
 		rr = __get_header(req, "Record-Route", &start);
 		if (*rr == '\0') {
 			break;
 		}
-		ast_copy_string(rr_copy, rr, sizeof(rr_copy));
-		rr_copy_ptr = rr_copy;
-		while ((rr_iter = strsep(&rr_copy_ptr, ","))) { /* Each route entry */
-			char *uri = get_in_brackets(rr_iter);
-			len = strlen(uri) + 1;
-			/* Make a struct route */
+		while (!get_in_brackets_const(rr, &uri, &len)) {
+			len++;
+			rr = strchr(rr, ',');
+			if(rr >= uri && rr < (uri + len)) {
+				/* comma inside brackets*/
+				const char *next_br = strchr(rr, '<');
+				if (next_br && next_br < (uri + len)) {
+					rr++;
+					continue;
+				}
+				continue;
+			}
 			if ((thishop = ast_malloc(sizeof(*thishop) + len))) {
-				/* ast_calloc is not needed because all fields are initialized in this block */
 				ast_copy_string(thishop->hop, uri, len);
 				ast_debug(2, "build_route: Record-Route hop: <%s>\n", thishop->hop);
 				/* Link in */
@@ -14764,6 +14768,13 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
 					tail = thishop;
 				}
 			}
+			rr = strchr(uri + len, ',');
+			if (rr == NULL) {
+				/* No more field-values, we're done with this header */
+				break;
+			}
+			/* Advance past comma */
+			rr++;
 		}
 	}
 
@@ -31343,6 +31354,59 @@ AST_TEST_DEFINE(test_tcp_message_fragmentation)
 	return res;
 }
 
+AST_TEST_DEFINE(get_in_brackets_const_test)
+{
+	const char *input;
+	const char *start = NULL;
+	int len = 0;
+	int res;
+
+#define CHECK_RESULTS(in, expected_res, expected_start, expected_len)	do {	\
+		input = (in);						\
+		res = get_in_brackets_const(input, &start, &len);	\
+		if ((expected_res) != res) {				\
+			ast_test_status_update(test, "Unexpected result: %d != %d\n", expected_res, res); \
+			return AST_TEST_FAIL;				\
+		}							\
+		if ((expected_start) != start) {			\
+			const char *e = expected_start ? expected_start : "(null)"; \
+			const char *a = start ? start : "(null)";	\
+			ast_test_status_update(test, "Unexpected start: %s != %s\n", e, a); \
+			return AST_TEST_FAIL;				\
+		}							\
+		if ((expected_len) != len) {				\
+			ast_test_status_update(test, "Unexpected len: %d != %d\n", expected_len, len); \
+			return AST_TEST_FAIL;				\
+		}							\
+	} while(0)
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = __func__;
+		info->category = "/channels/chan_sip/";
+		info->summary = "get_in_brackets_const test";
+		info->description =
+			"Tests the get_in_brackets_const function";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	CHECK_RESULTS("", 1, NULL, -1);
+	CHECK_RESULTS("normal <test>", 0, input + 8, 4);
+	CHECK_RESULTS("\"normal\" <test>", 0, input + 10, 4);
+	CHECK_RESULTS("not normal <test", -1, NULL, -1);
+	CHECK_RESULTS("\"yes < really\" <test>", 0, input + 16, 4);
+	CHECK_RESULTS("\"even > this\" <test>", 0, input + 15, 4);
+	CHECK_RESULTS("<sip:id1@10.10.10.10;lr>", 0, input + 1, 22);
+	CHECK_RESULTS("<sip:id1@10.10.10.10;lr>, <sip:id1@10.10.10.20;lr>", 0, input + 1, 22);
+	CHECK_RESULTS("<sip:id1,id2@10.10.10.10;lr>", 0, input + 1, 26);
+	CHECK_RESULTS("<sip:id1@10., <sip:id2@10.10.10.10;lr>", 0, input + 1, 36);
+	CHECK_RESULTS("\"quoted text\" <sip:dlg1@10.10.10.10;lr>", 0, input + 15, 23);
+
+	return AST_TEST_PASS;
+}
+
 #endif
 
 #define DATA_EXPORT_SIP_PEER(MEMBER)				\
@@ -31566,6 +31630,7 @@ static int load_module(void)
 	AST_TEST_REGISTER(test_sip_peers_get);
 	AST_TEST_REGISTER(test_sip_mwi_subscribe_parse);
 	AST_TEST_REGISTER(test_tcp_message_fragmentation);
+	AST_TEST_REGISTER(get_in_brackets_const_test);
 #endif
 
 	/* Register AstData providers */
@@ -31679,6 +31744,7 @@ static int unload_module(void)
 	AST_TEST_UNREGISTER(test_sip_peers_get);
 	AST_TEST_UNREGISTER(test_sip_mwi_subscribe_parse);
 	AST_TEST_UNREGISTER(test_tcp_message_fragmentation);
+	AST_TEST_UNREGISTER(get_in_brackets_const_test);
 #endif
 	/* Unregister all the AstData providers */
 	ast_data_unregister(NULL);

channels/sip/include/reqresp_parser.h

@@ -90,6 +90,17 @@ int get_name_and_number(const char *hdr, char **name, char **number);
  */
 char *get_in_brackets(char *tmp);
 
+/*! \brief Get text in brackets on a const without copy
+ *
+ * \param src String to search
+ * \param[out] start Set to first character inside left bracket.
+ * \param[out] length Set to lenght of string inside brackets
+ * \retval 0 success
+ * \retval -1 failure
+ * \retval 1 no brackets so got all
+ */
+int get_in_brackets_const(const char *src,const char **start,int *length);
+
 /*! \brief Get text in brackets and any trailing residue
  *
  * \retval 0 success

channels/sip/reqresp_parser.c

@@ -948,6 +948,59 @@ AST_TEST_DEFINE(get_name_and_number_test)
 	return res;
 }
 
+int get_in_brackets_const(const char *src,const char **start,int *length)
+{
+	const char *parse = src;
+	const char *first_bracket;
+	const char *second_bracket;
+
+	if (start == NULL) {
+		return -1;
+	}
+	if (length == NULL) {
+		return -1;
+	}
+	*start = NULL;
+	*length = -1;
+	if (ast_strlen_zero(src)) {
+		return 1;
+	}
+
+	/*
+	 * Skip any quoted text until we find the part in brackets.
+	 * On any error give up and return -1
+	 */
+	while ( (first_bracket = strchr(parse, '<')) ) {
+		const char *first_quote = strchr(parse, '"');
+		first_bracket++;
+		if (!first_quote || first_quote >= first_bracket) {
+			break; /* no need to look at quoted part */
+		}
+		/* the bracket is within quotes, so ignore it */
+		parse = find_closing_quote(first_quote + 1, NULL);
+		if (!*parse) {
+			ast_log(LOG_WARNING, "No closing quote found in '%s'\n", src);
+			return  -1;
+		}
+		parse++;
+	}
+
+	/* Require a first bracket.  Unlike get_in_brackets_full, this procedure is passed a const,
+	 * so it can expect a pointer to an original value */
+	if (!first_bracket) {
+		ast_log(LOG_WARNING, "No opening bracket found in '%s'\n", src);
+		return 1;
+	}
+
+	if ((second_bracket = strchr(first_bracket, '>'))) {
+		*start = first_bracket;
+		*length = second_bracket - first_bracket;
+		return 0;
+	}
+	ast_log(LOG_WARNING, "No closing bracket found in '%s'\n", src);
+	return -1;
+}
+
 int get_in_brackets_full(char *tmp,char **out,char **residue)
 {
 	const char *parse = tmp;