Fix bug #75708: getimagesize with "&$imageinfo" fails on StreamWrappers

ext/standard/image.c

@@ -425,6 +425,20 @@ static int php_skip_variable(php_stream * stream)
 }
 /* }}} */
 
+static size_t php_read_stream_all_chunks(php_stream *stream, char *buffer, size_t length)
+{
+	size_t read_total = 0;
+	do {
+		ssize_t read_now = php_stream_read(stream, buffer, length - read_total);
+		read_total += read_now;
+		if (read_now < stream->chunk_size && read_total != length) {
+			return 0;
+		}
+	} while (read_total < length);
+
+	return read_total;
+}
+
 /* {{{ php_read_APP */
 static int php_read_APP(php_stream * stream, unsigned int marker, zval *info)
 {
@@ -441,7 +455,7 @@ static int php_read_APP(php_stream * stream, unsigned int marker, zval *info)
 
 	buffer = emalloc(length);
 
-	if (php_stream_read(stream, buffer, (size_t) length) != length) {
+	if (php_read_stream_all_chunks(stream, buffer, length) != length) {
 		efree(buffer);
 		return 0;
 	}

ext/standard/tests/image/bug75708.phpt

@@ -0,0 +1,56 @@
+--TEST--
+Bug #75708 (getimagesize with "&$imageinfo" fails on StreamWrappers)
+--FILE--
+<?php
+
+class FSStreamWrapper {
+    function stream_open($file, $mode) {
+        $this->handle = fopen(str_replace('fs://', __DIR__ . '/', $file), $mode);
+        return true;
+    }
+    function stream_read($count) {
+        return fread($this->handle, $count);
+    }
+    function stream_eof() {
+        return feof($this->handle);
+    }
+    function stream_seek($offset, $whence) {
+        return fseek($this->handle, $offset, $whence) === 0;
+    }
+    function stream_stat() {
+        return fstat($this->handle);
+    }
+    function url_stat($file) {
+        return stat(str_replace('fs://', '', $file));
+    }
+    function stream_tell() {
+        return ftell($this->handle);
+    }
+    function stream_close() {
+        fclose($this->handle);
+    }
+}
+
+stream_register_wrapper('fs', 'FSStreamWrapper');
+
+var_dump(getimagesize('fs://bug75708.jpg', $info));
+
+?>
+--EXPECT--
+array(7) {
+  [0]=>
+  int(10)
+  [1]=>
+  int(10)
+  [2]=>
+  int(2)
+  [3]=>
+  string(22) "width="10" height="10""
+  ["bits"]=>
+  int(8)
+  ["channels"]=>
+  int(3)
+  ["mime"]=>
+  string(10) "image/jpeg"
+}
+