CVE-2016-7418: Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119)
value: The php_wddx_push_element function in ext/wddx/wddx.c in PHP before 5.6.26 and 7.x before 7.0.11 allows remote attackers to cause a denial of service (invalid pointer access and out-of-bounds read) or possibly have unspecified other impact via an incorrect boolean element in a wddxPacket XML document, leading to mishandling in a wddx_deserialize call.
CWE description: The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
CVSS v3 base score: 7.5
Published: 2016-09-17T21:59Z
Repository: https://github.com/php/php-src
Language: C
Files changed: ext/wddx/tests/bug73065.phpt, ext/wddx/wddx.c
Commit date: 2016-09-12 21:04:23 -0700
Commit message: Fix bug #73065: Out-Of-Bounds Read in php_wddx_push_element of wddx.c

Diff: diff --git a/ext/wddx/tests/bug73065.phpt b/ext/wddx/tests/bug73065.phpt
new file mode 100644
index 00000000000..aa301aa8382
--- /dev/null
+++ b/ext/wddx/tests/bug73065.phpt
@@ -0,0 +1,98 @@
+--TEST--
+Bug #73065: Out-Of-Bounds Read in php_wddx_push_element of wddx.c
+--SKIPIF--
+<?php
+if (!extension_loaded('wddx')) {
+    die('skip. wddx not available');
+}
+?>
+--FILE--
+<?php
+
+$xml1 = <<<XML
+<?xml version='1.0' ?>
+    <!DOCTYPE et SYSTEM 'w'>
+    <wddxPacket ven='1.0'>
+        <array>
+            <var Name="name">
+                <boolean value="keliu"></boolean>
+            </var>
+            <var name="1111">
+                <var name="2222">
+                    <var name="3333"></var>
+                </var>
+            </var>
+        </array>
+    </wddxPacket>
+XML;
+    
+$xml2 = <<<XML
+<?xml version='1.0' ?>
+    <!DOCTYPE et SYSTEM 'w'>
+    <wddxPacket ven='1.0'>
+        <array>
+            <char Name="code">
+                <boolean value="keliu"></boolean>
+            </char>
+        </array>
+    </wddxPacket>
+XML;
+
+$xml3 = <<<XML
+<?xml version='1.0' ?>
+    <!DOCTYPE et SYSTEM 'w'>
+    <wddxPacket ven='1.0'>
+        <array>
+            <boolean Name="value">
+                <boolean value="keliu"></boolean>
+            </boolean>
+        </array>
+    </wddxPacket>
+XML;
+
+$xml4 = <<<XML
+<?xml version='1.0' ?>
+    <!DOCTYPE et SYSTEM 'w'>
+    <wddxPacket ven='1.0'>
+        <array>
+            <recordset Name="fieldNames">
+                <boolean value="keliu"></boolean>
+            </recordset>
+        </array>
+    </wddxPacket>
+XML;
+
+$xml5 = <<<XML
+<?xml version='1.0' ?>
+    <!DOCTYPE et SYSTEM 'w'>
+    <wddxPacket ven='1.0'>
+        <array>
+            <field Name="name">
+                <boolean value="keliu"></boolean>
+            </field>
+        </array>
+    </wddxPacket>
+XML;
+
+for($i=1;$i<=5;$i++) {
+	$xmlvar = "xml$i";
+    $array = wddx_deserialize($$xmlvar);
+    var_dump($array);
+}
+?>
+DONE
+--EXPECTF--
+array(0) {
+}
+array(0) {
+}
+array(0) {
+}
+array(1) {
+  [0]=>
+  array(0) {
+  }
+}
+array(0) {
+}
+DONE
\ No newline at end of file
diff --git a/ext/wddx/wddx.c b/ext/wddx/wddx.c
index b02d2f07ded..0e77826ce84 100644
--- a/ext/wddx/wddx.c
+++ b/ext/wddx/wddx.c
@@ -778,14 +778,14 @@ static void php_wddx_push_element(void *user_data, const XML_Char *name, const X
 		wddx_stack_push((wddx_stack *)stack, &ent, sizeof(st_entry));
 	} else if (!strcmp(name, EL_CHAR)) {
 		int i;
 
 		if (atts) for (i = 0; atts[i]; i++) {
-			if (!strcmp(atts[i], EL_CHAR_CODE) && atts[++i] && atts[i][0]) {
+			if (!strcmp(atts[i], EL_CHAR_CODE) && atts[i+1] && atts[i+1][0]) {
 				char tmp_buf[2];
 
-				snprintf(tmp_buf, sizeof(tmp_buf), "%c", (char)strtol(atts[i], NULL, 16));
+				snprintf(tmp_buf, sizeof(tmp_buf), "%c", (char)strtol(atts[i+1], NULL, 16));
 				php_wddx_process_data(user_data, tmp_buf, strlen(tmp_buf));
 				break;
 			}
 		}
 	} else if (!strcmp(name, EL_NUMBER)) {
@@ -799,19 +799,19 @@ static void php_wddx_push_element(void *user_data, const XML_Char *name, const X
 		wddx_stack_push((wddx_stack *)stack, &ent, sizeof(st_entry));
 	} else if (!strcmp(name, EL_BOOLEAN)) {
 		int i;
 
 		if (atts) for (i = 0; atts[i]; i++) {
-			if (!strcmp(atts[i], EL_VALUE) && atts[++i] && atts[i][0]) {
+			if (!strcmp(atts[i], EL_VALUE) && atts[i+1] && atts[i+1][0]) {
 				ent.type = ST_BOOLEAN;
 				SET_STACK_VARNAME;
 
 				ALLOC_ZVAL(ent.data);
 				INIT_PZVAL(ent.data);
 				Z_TYPE_P(ent.data) = IS_BOOL;
 				wddx_stack_push((wddx_stack *)stack, &ent, sizeof(st_entry));
-				php_wddx_process_data(user_data, atts[i], strlen(atts[i]));
+				php_wddx_process_data(user_data, atts[i+1], strlen(atts[i+1]));
 				break;
 			}
 		}
 	} else if (!strcmp(name, EL_NULL)) {
 		ent.type = ST_NULL;
@@ -840,13 +840,13 @@ static void php_wddx_push_element(void *user_data, const XML_Char *name, const X
 		wddx_stack_push((wddx_stack *)stack, &ent, sizeof(st_entry));
 	} else if (!strcmp(name, EL_VAR)) {
 		int i;
 
 		if (atts) for (i = 0; atts[i]; i++) {
-			if (!strcmp(atts[i], EL_NAME) && atts[++i] && atts[i][0]) {
+			if (!strcmp(atts[i], EL_NAME) && atts[i+1] && atts[i+1][0]) {
 				if (stack->varname) efree(stack->varname);
-				stack->varname = estrdup(atts[i]);
+				stack->varname = estrdup(atts[i+1]);
 				break;
 			}
 		}
 	} else if (!strcmp(name, EL_RECORDSET)) {
 		int i;
@@ -855,15 +855,16 @@ static void php_wddx_push_element(void *user_data, const XML_Char *name, const X
 		SET_STACK_VARNAME;
 		MAKE_STD_ZVAL(ent.data);
 		array_init(ent.data);
 
 		if (atts) for (i = 0; atts[i]; i++) {
-			if (!strcmp(atts[i], "fieldNames") && atts[++i] && atts[i][0]) {
+			if (!strcmp(atts[i], "fieldNames") && atts[i+1] && atts[i+1][0]) {
 				zval *tmp;
 				char *key;
 				char *p1, *p2, *endp;
 
+				i++;
 				endp = (char *)atts[i] + strlen(atts[i]);
 				p1 = (char *)atts[i];
 				while ((p2 = php_memnstr(p1, ",", sizeof(",")-1, endp)) != NULL) {
 					key = estrndup(p1, p2 - p1);
 					MAKE_STD_ZVAL(tmp);
@@ -891,17 +892,17 @@ static void php_wddx_push_element(void *user_data, const XML_Char *name, const X
 		ent.type = ST_FIELD;
 		ent.varname = NULL;
 		ent.data = NULL;
 
 		if (atts) for (i = 0; atts[i]; i++) {
-			if (!strcmp(atts[i], EL_NAME) && atts[++i] && atts[i][0]) {
+			if (!strcmp(atts[i], EL_NAME) && atts[i+1] && atts[i+1][0]) {
 				st_entry *recordset;
 				zval **field;
 
 				if (wddx_stack_top(stack, (void**)&recordset) == SUCCESS &&
 					recordset->type == ST_RECORDSET &&
-					zend_hash_find(Z_ARRVAL_P(recordset->data), (char*)atts[i], strlen(atts[i])+1, (void**)&field) == SUCCESS) {
+					zend_hash_find(Z_ARRVAL_P(recordset->data), (char*)atts[i+1], strlen(atts[i+1])+1, (void**)&field) == SUCCESS) {
 					ent.data = *field;
 				}
 
 				break;
 			}

Vulnerable code: 			if (!strcmp(atts[i], EL_CHAR_CODE) && atts[++i] && atts[i][0]) {
				snprintf(tmp_buf, sizeof(tmp_buf), "%c", (char)strtol(atts[i], NULL, 16));
			if (!strcmp(atts[i], EL_VALUE) && atts[++i] && atts[i][0]) {
				php_wddx_process_data(user_data, atts[i], strlen(atts[i]));
			if (!strcmp(atts[i], EL_NAME) && atts[++i] && atts[i][0]) {
				stack->varname = estrdup(atts[i]);
			if (!strcmp(atts[i], "fieldNames") && atts[++i] && atts[i][0]) {
			if (!strcmp(atts[i], EL_NAME) && atts[++i] && atts[i][0]) {
					zend_hash_find(Z_ARRVAL_P(recordset->data), (char*)atts[i], strlen(atts[i])+1, (void**)&field) == SUCCESS) {
Fixed code: --TEST--
Bug #73065: Out-Of-Bounds Read in php_wddx_push_element of wddx.c
--SKIPIF--
<?php
if (!extension_loaded('wddx')) {
    die('skip. wddx not available');
}
?>
--FILE--
<?php

$xml1 = <<<XML
<?xml version='1.0' ?>
    <!DOCTYPE et SYSTEM 'w'>
    <wddxPacket ven='1.0'>
        <array>
            <var Name="name">
                <boolean value="keliu"></boolean>
            </var>
            <var name="1111">
                <var name="2222">
                    <var name="3333"></var>
                </var>
            </var>
        </array>
    </wddxPacket>
XML;
    
$xml2 = <<<XML
<?xml version='1.0' ?>
    <!DOCTYPE et SYSTEM 'w'>
    <wddxPacket ven='1.0'>
        <array>
            <char Name="code">
                <boolean value="keliu"></boolean>
            </char>
        </array>
    </wddxPacket>
XML;

$xml3 = <<<XML
<?xml version='1.0' ?>
    <!DOCTYPE et SYSTEM 'w'>
    <wddxPacket ven='1.0'>
        <array>
            <boolean Name="value">
                <boolean value="keliu"></boolean>
            </boolean>
        </array>
    </wddxPacket>
XML;

$xml4 = <<<XML
<?xml version='1.0' ?>
    <!DOCTYPE et SYSTEM 'w'>
    <wddxPacket ven='1.0'>
        <array>
            <recordset Name="fieldNames">
                <boolean value="keliu"></boolean>
            </recordset>
        </array>
    </wddxPacket>
XML;

$xml5 = <<<XML
<?xml version='1.0' ?>
    <!DOCTYPE et SYSTEM 'w'>
    <wddxPacket ven='1.0'>
        <array>
            <field Name="name">
                <boolean value="keliu"></boolean>
            </field>
        </array>
    </wddxPacket>
XML;

for($i=1;$i<=5;$i++) {
	$xmlvar = "xml$i";
    $array = wddx_deserialize($$xmlvar);
    var_dump($array);
}
?>
DONE
--EXPECTF--
array(0) {
}
array(0) {
}
array(0) {
}
array(1) {
  [0]=>
  array(0) {
  }
}
array(0) {
}
DONE
			if (!strcmp(atts[i], EL_CHAR_CODE) && atts[i+1] && atts[i+1][0]) {
				snprintf(tmp_buf, sizeof(tmp_buf), "%c", (char)strtol(atts[i+1], NULL, 16));
			if (!strcmp(atts[i], EL_VALUE) && atts[i+1] && atts[i+1][0]) {
				php_wddx_process_data(user_data, atts[i+1], strlen(atts[i+1]));
			if (!strcmp(atts[i], EL_NAME) && atts[i+1] && atts[i+1][0]) {
				stack->varname = estrdup(atts[i+1]);
			if (!strcmp(atts[i], "fieldNames") && atts[i+1] && atts[i+1][0]) {
				i++;
			if (!strcmp(atts[i], EL_NAME) && atts[i+1] && atts[i+1][0]) {
					zend_hash_find(Z_ARRVAL_P(recordset->data), (char*)atts[i+1], strlen(atts[i+1])+1, (void**)&field) == SUCCESS) {