Adds ast_escape_encoded utility to properly handle escaping of quoted field before uri.

This commit backports a feature in trunk affecting initreqprep so that display name won't
be encoded improperly. Also includes unit tests for the ast_escape_quoted function.
This patch gives 1.8 a much improved outlook in countries which don't use standard
ASCII characters.

(closes issue ASTERISK-16949)
Reported by: Örn Arnarson
Review: https://reviewboard.asterisk.org/r/1235/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@322585 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -11537,7 +11537,7 @@ static void initreqprep(struct sip_request *req, struct sip_pvt *p, int sipmetho
 		ast_string_field_set(p, fromname, n);
 
 	if (sip_cfg.pedanticsipchecking) {
-		ast_uri_encode(n, tmp_n, sizeof(tmp_n), 0);
+		ast_escape_quoted(n, tmp_n, sizeof(tmp_n));
 		n = tmp_n;
 		ast_uri_encode(l, tmp_l, sizeof(tmp_l), 0);
 		l = tmp_l;

include/asterisk/utils.h

@@ -273,6 +273,19 @@ char *ast_uri_encode(const char *string, char *outbuf, int buflen, int do_specia
  */
 void ast_uri_decode(char *s);
 
+/*!
+ * \brief Escape characters found in a quoted string.
+ *
+ * \note This function escapes quoted characters based on the 'qdtext' set of
+ * allowed characters from RFC 3261 section 25.1.
+ *
+ * \param string string to be escaped
+ * \param outbuf resulting escaped string
+ * \param buflen size of output buffer
+ * \return a pointer to the escaped string
+ */
+char *ast_escape_quoted(const char *string, char *outbuf, int buflen);
+
 static force_inline void ast_slinear_saturated_add(short *input, short *value)
 {
 	int res;

main/utils.c

@@ -415,6 +415,37 @@ char *ast_uri_encode(const char *string, char *outbuf, int buflen, int do_specia
 	return outbuf;
 }
 
+/*! \brief escapes characters specified for quoted portions of sip messages */
+char *ast_escape_quoted(const char *string, char *outbuf, int buflen)
+{
+	const char *ptr  = string;
+	char *out = outbuf;
+	char *allow = "\t\v !"; /* allow LWS (minus \r and \n) and "!" */
+
+	while (*ptr && out - outbuf < buflen - 1) {
+		if (!(strchr(allow, *ptr))
+			&& !(*ptr >= '#' && *ptr <= '[') /* %x23 - %x5b */
+			&& !(*ptr >= ']' && *ptr <= '~') /* %x5d - %x7e */
+			&& !((unsigned char) *ptr > 0x7f)) {             /* UTF8-nonascii */
+
+			if (out - outbuf >= buflen - 2) {
+				break;
+			}
+			out += sprintf(out, "\\%c", (unsigned char) *ptr);
+		} else {
+			*out = *ptr;
+			out++;
+		}
+		ptr++;
+	}
+
+	if (buflen) {
+		*out = '\0';
+	}
+
+	return outbuf;
+}
+
 /*! \brief  ast_uri_decode: Decode SIP URI, URN, URL (overwrite the string)  */
 void ast_uri_decode(char *s) 
 {

tests/test_utils.c

@@ -102,6 +102,54 @@ AST_TEST_DEFINE(uri_encode_decode_test)
 	return res;
 }
 
+AST_TEST_DEFINE(quoted_escape_test)
+{
+	int res = AST_TEST_PASS;
+	const char *in = "a\"bcdefg\"hijkl\\mnopqrs tuv\twxyz";
+	char out[256] = { 0 };
+	char small[4] = { 0 };
+	int i;
+
+	static struct {
+		char *buf;
+		const size_t buflen;
+
+		const char *output;
+	} tests[] = {
+		{0, sizeof(out),
+			"a\\\"bcdefg\\\"hijkl\\\\mnopqrs tuv\twxyz"},
+		{0, sizeof(small),
+			"a\\\""},
+	};
+
+	tests[0].buf = out;
+	tests[1].buf = small;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "quoted_escape_test";
+		info->category = "/main/utils/";
+		info->summary = "escape a quoted string";
+		info->description = "Escape a string to be quoted and check the result.";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	for (i = 0; i < ARRAY_LEN(tests); i++) {
+		ast_escape_quoted(in, tests[i].buf, tests[i].buflen);
+		if (strcmp(tests[i].output, tests[i].buf)) {
+			ast_test_status_update(test, "ESCAPED DOES NOT MATCH EXPECTED, FAIL\n");
+			ast_test_status_update(test, "original: %s\n", in);
+			ast_test_status_update(test, "expected: %s\n", tests[i].output);
+			ast_test_status_update(test, "result: %s\n", tests[i].buf);
+			res = AST_TEST_FAIL;
+		}
+	}
+
+	return res;
+}
+
 AST_TEST_DEFINE(md5_test)
 {
 	static const struct {
@@ -348,6 +396,7 @@ AST_TEST_DEFINE(agi_loaded_test)
 static int unload_module(void)
 {
 	AST_TEST_UNREGISTER(uri_encode_decode_test);
+	AST_TEST_UNREGISTER(quoted_escape_test);
 	AST_TEST_UNREGISTER(md5_test);
 	AST_TEST_UNREGISTER(sha1_test);
 	AST_TEST_UNREGISTER(base64_test);
@@ -360,6 +409,7 @@ static int unload_module(void)
 static int load_module(void)
 {
 	AST_TEST_REGISTER(uri_encode_decode_test);
+	AST_TEST_REGISTER(quoted_escape_test);
 	AST_TEST_REGISTER(md5_test);
 	AST_TEST_REGISTER(sha1_test);
 	AST_TEST_REGISTER(base64_test);