Implemented FR #51634: Can't post multiple fields with the same name

This PR allows for multiple values with the same field name to be sent to an
HTTP server. This server can't be PHP, because PHP's POST processing does not
allow for two the same field names. But sending multiple fields with the same
name is required for some operations by RFC 7578.

This PR allows you to attach an array of values to a field name, and each of
these will then be sent as its own distinct multipart/form-data field.

Author: derickr

ext/curl/interface.c

@@ -1991,6 +1991,54 @@ static void free_cb(void *arg) /* {{{ */
 /* }}} */
 #endif
 
+static inline CURLcode add_simple_field(curl_mime *mime, zend_string *string_key, zval *current)
+{
+	CURLcode error = CURLE_OK;
+#if LIBCURL_VERSION_NUM >= 0x073800 /* 7.56.0 */
+	curl_mimepart *part;
+	CURLcode form_error;
+#else
+	struct HttpPost *first = NULL;
+	struct HttpPost *last  = NULL;
+	CURLFORMcode form_error;
+#endif
+	zend_string *postval, *tmp_postval;
+
+	postval = zval_get_tmp_string(current, &tmp_postval);
+
+#if LIBCURL_VERSION_NUM >= 0x073800 /* 7.56.0 */
+	part = curl_mime_addpart(mime);
+	if (part == NULL) {
+		zend_tmp_string_release(tmp_postval);
+		zend_string_release_ex(string_key, 0);
+		return CURLE_OUT_OF_MEMORY;
+	}
+	if ((form_error = curl_mime_name(part, ZSTR_VAL(string_key))) != CURLE_OK
+		|| (form_error = curl_mime_data(part, ZSTR_VAL(postval), ZSTR_LEN(postval))) != CURLE_OK) {
+		error = form_error;
+	}
+#else
+	/* The arguments after _NAMELENGTH and _CONTENTSLENGTH
+		* must be explicitly cast to long in curl_formadd
+		* use since curl needs a long not an int. */
+	form_error = curl_formadd(&first, &last,
+		CURLFORM_COPYNAME, ZSTR_VAL(string_key),
+		CURLFORM_NAMELENGTH, ZSTR_LEN(string_key),
+		CURLFORM_COPYCONTENTS, ZSTR_VAL(postval),
+		CURLFORM_CONTENTSLENGTH, ZSTR_LEN(postval),
+		CURLFORM_END
+	);
+
+	if (form_error != CURL_FORMADD_OK) {
+		/* Not nice to convert between enums but we only have place for one error type */
+		error = (CURLcode)form_error;
+	}
+#endif
+	zend_tmp_string_release(tmp_postval);
+
+	return error;
+}
+
 static inline zend_result build_mime_structure_from_hash(php_curl *ch, zval *zpostfields) /* {{{ */
 {
 	HashTable *postfields = Z_ARRVAL_P(zpostfields);
@@ -2018,7 +2066,7 @@ static inline zend_result build_mime_structure_from_hash(php_curl *ch, zval *zpo
 #endif
 
 	ZEND_HASH_FOREACH_KEY_VAL(postfields, num_key, string_key, current) {
-		zend_string *postval, *tmp_postval;
+		zend_string *postval;
 		/* Pretend we have a string_key here */
 		if (!string_key) {
 			string_key = zend_long_to_str(num_key);
@@ -2181,36 +2229,19 @@ static inline zend_result build_mime_structure_from_hash(php_curl *ch, zval *zpo
 			continue;
 		}
 
-		postval = zval_get_tmp_string(current, &tmp_postval);
+		if (Z_TYPE_P(current) == IS_ARRAY) {
+			zval *current_element;
+
+			ZEND_HASH_FOREACH_VAL(HASH_OF(current), current_element) {
+				add_simple_field(mime, string_key, current_element);
+			} ZEND_HASH_FOREACH_END();
 
-#if LIBCURL_VERSION_NUM >= 0x073800 /* 7.56.0 */
-		part = curl_mime_addpart(mime);
-		if (part == NULL) {
-			zend_tmp_string_release(tmp_postval);
 			zend_string_release_ex(string_key, 0);
-			return FAILURE;
-		}
-		if ((form_error = curl_mime_name(part, ZSTR_VAL(string_key))) != CURLE_OK
-			|| (form_error = curl_mime_data(part, ZSTR_VAL(postval), ZSTR_LEN(postval))) != CURLE_OK) {
-			error = form_error;
+			continue;
 		}
-#else
-		/* The arguments after _NAMELENGTH and _CONTENTSLENGTH
-			* must be explicitly cast to long in curl_formadd
-			* use since curl needs a long not an int. */
-		form_error = curl_formadd(&first, &last,
-								CURLFORM_COPYNAME, ZSTR_VAL(string_key),
-								CURLFORM_NAMELENGTH, ZSTR_LEN(string_key),
-								CURLFORM_COPYCONTENTS, ZSTR_VAL(postval),
-								CURLFORM_CONTENTSLENGTH, ZSTR_LEN(postval),
-								CURLFORM_END);
 
-		if (form_error != CURL_FORMADD_OK) {
-			/* Not nice to convert between enums but we only have place for one error type */
-			error = (CURLcode)form_error;
-		}
-#endif
-		zend_tmp_string_release(tmp_postval);
+		add_simple_field(mime, string_key, current);
+
 		zend_string_release_ex(string_key, 0);
 	} ZEND_HASH_FOREACH_END();
 

ext/curl/tests/curl_postfields_array.phpt

@@ -0,0 +1,63 @@
+--TEST--
+CURLOPT_POSTFIELDS with multi-value fields
+--EXTENSIONS--
+sockets
+--FILE--
+<?php
+$socket = stream_socket_server("tcp://0.0.0.0:29999", $errno, $errstr);
+
+if (!$socket) {
+	echo "$errstr ($errno)<br />\n";
+	return;
+}
+
+$url = "http://127.0.0.1:29999/get.inc?test=raw";
+
+$fields = [
+	'single' => 'SingleValue',
+	'multi' => [
+		'Multi1',
+		'Multi2',
+	]
+];
+
+$options = [
+	CURLOPT_POST => 1,
+	CURLOPT_HEADER => 0,
+	CURLOPT_URL => $url,
+	CURLOPT_FRESH_CONNECT => 1,
+	CURLOPT_RETURNTRANSFER => 1,
+	CURLOPT_FORBID_REUSE => 1,
+	CURLOPT_TIMEOUT => 1,
+	CURLOPT_POSTFIELDS => $fields,
+];
+
+$ch = curl_init();
+curl_setopt_array($ch, $options);
+
+$curl_content = curl_exec($ch);
+curl_close($ch);
+	
+$conn = stream_socket_accept($socket);
+echo stream_get_contents($conn);
+?>
+--EXPECTF--
+POST /get.inc?test=raw HTTP/1.1
+Host: %s
+Accept: */*
+Content-Length: %d
+Content-Type: multipart/form-data; boundary=------------------------%s
+
+--------------------------%s
+Content-Disposition: form-data; name="single"
+
+SingleValue
+--------------------------%s
+Content-Disposition: form-data; name="multi"
+
+Multi1
+--------------------------%s
+Content-Disposition: form-data; name="multi"
+
+Multi2
+--------------------------%s--