proper fix for bug #50006

add modify protection to all user array sorts

diff --git a/ext/standard/array.c b/ext/standard/array.c
index d122faa6485bd5341f35fb16a8a0d72c374d775f..669af82429f91cfffeda02b77e483bd14a43c4fc 100644 (file)
--- a/ext/standard/array.c
+++ b/ext/standard/array.c
@@ -683,6 +683,7 @@ PHP_FUNCTION(usort)
 PHP_FUNCTION(uasort)
 {
        zval *array;
+       int refcount;
        PHP_ARRAY_CMP_FUNC_VARS;
 
        PHP_ARRAY_CMP_FUNC_BACKUP();
@@ -692,12 +693,31 @@ PHP_FUNCTION(uasort)
                return;
        }
 
+       /* Clear the is_ref flag, so the attemts to modify the array in user
+        * comaprison function will create a copy of array and won't affect the
+        * original array. The fact of modification is detected using refcount
+        * comparison. The result of sorting in such case is undefined and the
+        * function returns FALSE.
+        */
+       Z_UNSET_ISREF_P(array);
+       refcount = Z_REFCOUNT_P(array);
+
        if (zend_hash_sort(Z_ARRVAL_P(array), zend_qsort, php_array_user_compare, 0 TSRMLS_CC) == FAILURE) {
-               PHP_ARRAY_CMP_FUNC_RESTORE();
-               RETURN_FALSE;
+               RETVAL_FALSE;
+       } else {
+               if (refcount > Z_REFCOUNT_P(array)) {
+                       php_error_docref(NULL TSRMLS_CC, E_WARNING, "Array was modified by the user comparison function");
+                       RETVAL_FALSE;
+               } else {
+                       RETVAL_TRUE;
+               }
        }
+       
+       if (Z_REFCOUNT_P(array) > 1) {
+               Z_SET_ISREF_P(array);
+       }
+
        PHP_ARRAY_CMP_FUNC_RESTORE();
-       RETURN_TRUE;
 }
 /* }}} */
 
@@ -767,6 +787,7 @@ static int php_array_user_key_compare(const void *a, const void *b TSRMLS_DC) /*
 PHP_FUNCTION(uksort)
 {
        zval *array;
+       int refcount;
        PHP_ARRAY_CMP_FUNC_VARS;
 
        PHP_ARRAY_CMP_FUNC_BACKUP();
@@ -776,14 +797,31 @@ PHP_FUNCTION(uksort)
                return;
        }
 
-       if (zend_hash_sort(Z_ARRVAL_P(array), zend_qsort, php_array_user_key_compare, 0 TSRMLS_CC) == FAILURE) {
-               PHP_ARRAY_CMP_FUNC_RESTORE();
+       /* Clear the is_ref flag, so the attemts to modify the array in user
+        * comaprison function will create a copy of array and won't affect the
+        * original array. The fact of modification is detected using refcount
+        * comparison. The result of sorting in such case is undefined and the
+        * function returns FALSE.
+        */
+       Z_UNSET_ISREF_P(array);
+       refcount = Z_REFCOUNT_P(array);
 
-               RETURN_FALSE;
+       if (zend_hash_sort(Z_ARRVAL_P(array), zend_qsort, php_array_user_key_compare, 0 TSRMLS_CC) == FAILURE) {
+               RETVAL_FALSE;
+       } else {
+               if (refcount > Z_REFCOUNT_P(array)) {
+                       php_error_docref(NULL TSRMLS_CC, E_WARNING, "Array was modified by the user comparison function");
+                       RETVAL_FALSE;
+               } else {
+                       RETVAL_TRUE;
+               }
+       }
+       
+       if (Z_REFCOUNT_P(array) > 1) {
+               Z_SET_ISREF_P(array);
        }
 
        PHP_ARRAY_CMP_FUNC_RESTORE();
-       RETURN_TRUE;
 }
 /* }}} */
 

diff --git a/ext/standard/tests/array/bug50006_1.phpt b/ext/standard/tests/array/bug50006_1.phpt
new file mode 100644 (file)
index 0000000..fbb7ddd
--- /dev/null
+++ b/ext/standard/tests/array/bug50006_1.phpt
@@ -0,0 +1,29 @@
+--TEST--
+Bug #50006 (Segfault caused by uksort()) - usort variant
+--FILE--
+<?php
+
+$data = array(
+    'bar-bazbazbaz.',
+    'bar-bazbazbaz-', 
+    'foo'
+);
+usort($data, 'magic_sort_cmp');
+print_r($data);
+
+function magic_sort_cmp($a, $b) {
+  $a = substr($a, 1);
+  $b = substr($b, 1);
+  if (!$a) return $b ? -1 : 0;
+  if (!$b) return 1;
+  return magic_sort_cmp($a, $b);
+}
+
+?>
+--EXPECTF--
+Array
+(
+    [0] => foo
+    [1] => bar-bazbazbaz-
+    [2] => bar-bazbazbaz.
+)

diff --git a/ext/standard/tests/array/bug50006_2.phpt b/ext/standard/tests/array/bug50006_2.phpt
new file mode 100644 (file)
index 0000000..19c0d14
--- /dev/null
+++ b/ext/standard/tests/array/bug50006_2.phpt
@@ -0,0 +1,29 @@
+--TEST--
+Bug #50006 (Segfault caused by uksort()) - uasort variant
+--FILE--
+<?php
+
+$data = array(
+    'bar-bazbazbaz.',
+    'bar-bazbazbaz-', 
+    'foo'
+);
+uasort($data, 'magic_sort_cmp');
+print_r($data);
+
+function magic_sort_cmp($a, $b) {
+  $a = substr($a, 1);
+  $b = substr($b, 1);
+  if (!$a) return $b ? -1 : 0;
+  if (!$b) return 1;
+  return magic_sort_cmp($a, $b);
+}
+
+?>
+--EXPECTF--
+Array
+(
+    [2] => foo
+    [1] => bar-bazbazbaz-
+    [0] => bar-bazbazbaz.
+)

diff --git a/ext/standard/tests/array/unexpected_array_mod_bug.phpt b/ext/standard/tests/array/unexpected_array_mod_bug.phpt
new file mode 100755 (executable)
index 0000000..58f2249
--- /dev/null
+++ b/ext/standard/tests/array/unexpected_array_mod_bug.phpt
@@ -0,0 +1,21 @@
+--TEST--
+Crash when function parameter modified via reference
+--FILE--
+<?php
+function usercompare($a,$b) {
+  unset($GLOBALS['my_var'][2]); 
+  return 0;
+}
+$my_var = array(1 => "entry_1",
+2 => "entry_2",
+3 => "entry_3",
+4 => "entry_4",
+5 => "entry_5");
+usort($my_var, "usercompare");
+
+echo "Done.\n";
+?>
+--EXPECTF--
+
+Warning: usort(): Array was modified by the user comparison function in %s on line %d
+Done.