Limit stack size (#9104)

.appveyor.yml

@@ -28,6 +28,7 @@ environment:
         #PDO_MYSQL_TEST_PASS: Password12!
         #PGSQL_TEST_CONNSTR: "host=127.0.0.1 dbname=test port=5432 user=postgres password=Password12!"
         #PDO_PGSQL_TEST_DSN: "pgsql:host=127.0.0.1 port=5432 dbname=test user=postgres password=Password12!"
+        STACK_LIMIT_DEFAULTS_CHECK: 1
         #build permutations
         matrix:
                 - THREAD_SAFE: 0

.cirrus.yml

@@ -201,4 +201,5 @@ freebsd_task:
   tests_script:
     - export SKIP_IO_CAPTURE_TESTS=1
     - export CI_NO_IPV6=1
+    - export STACK_LIMIT_DEFAULTS_CHECK=1
     - sapi/cli/php run-tests.php -P -q -j2 -g FAIL,BORK,LEAK,XLEAK --no-progress --offline --show-diff --show-slow 1000 --set-timeout 120 -d zend_extension=opcache.so

.github/actions/test-linux/action.yml

@@ -30,6 +30,7 @@ runs:
         export PDO_OCI_TEST_DSN="oci:dbname=localhost/XEPDB1;charset=AL32UTF8"
         export SKIP_IO_CAPTURE_TESTS=1
         export TEST_PHP_JUNIT=junit.out.xml
+        export STACK_LIMIT_DEFAULTS_CHECK=1
         sapi/cli/php run-tests.php -P -q ${{ inputs.runTestsParameters }} \
           -j$(/usr/bin/nproc) \
           -g FAIL,BORK,LEAK,XLEAK \

.github/actions/test-macos/action.yml

@@ -15,6 +15,7 @@ runs:
         export SKIP_IO_CAPTURE_TESTS=1
         export CI_NO_IPV6=1
         export TEST_PHP_JUNIT=junit.out.xml
+        export STACK_LIMIT_DEFAULTS_CHECK=1
         sapi/cli/php run-tests.php -P -q ${{ inputs.runTestsParameters }} \
           -j$(sysctl -n hw.ncpu) \
           -g FAIL,BORK,LEAK,XLEAK \

Zend/Zend.m4

@@ -146,7 +146,37 @@ _LT_AC_TRY_DLOPEN_SELF([
 ])
 
 dnl Checks for library functions.
-AC_CHECK_FUNCS(getpid kill sigsetjmp)
+AC_CHECK_FUNCS(getpid kill sigsetjmp pthread_getattr_np pthread_attr_get_np pthread_get_stackaddr_np pthread_attr_getstack gettid)
+
+dnl Test whether the stack grows downwards
+dnl Assumes contiguous stack
+AC_MSG_CHECKING(whether the stack grows downwards)
+
+AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <stdint.h>
+
+int (*volatile f)(uintptr_t);
+
+int stack_grows_downwards(uintptr_t arg) {
+    int local;
+    return (uintptr_t)&local < arg;
+}
+
+int main() {
+    int local;
+
+    f = stack_grows_downwards;
+    return f((uintptr_t)&local) ? 0 : 1;
+}
+]])], [
+  AC_DEFINE([ZEND_STACK_GROWS_DOWNWARDS], 1, [Define if the stack grows downwards])
+  AC_DEFINE([ZEND_CHECK_STACK_LIMIT], 1, [Define if checking the stack limit is supported])
+  AC_MSG_RESULT(yes)
+], [
+  AC_MSG_RESULT(no)
+], [
+  AC_MSG_RESULT(no)
+])
 
 ZEND_CHECK_FLOAT_PRECISION
 ])

Zend/tests/stack_limit/stack_limit_001.phpt

@@ -0,0 +1,77 @@
+--TEST--
+Stack limit 001 - Stack limit checks with max_allowed_stack_size detection
+--EXTENSIONS--
+zend_test
+--INI--
+; The test may use a large amount of memory on systems with a large stack limit
+memory_limit=2G
+--FILE--
+<?php
+
+var_dump(zend_test_zend_call_stack_get());
+
+class Test1 {
+    public function __destruct() {
+        new Test1;
+    }
+}
+
+class Test2 {
+    public function __clone() {
+        clone $this;
+    }
+}
+
+class Test3 {
+    public function __sleep()
+    {
+        serialize($this);
+    }
+}
+
+function replace() {
+    return preg_replace_callback('#.#', function () {
+        return replace();
+    }, 'x');
+}
+
+try {
+    new Test1;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    clone new Test2;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    serialize(new Test3);
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    replace();
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECTF--
+array(4) {
+  ["base"]=>
+  string(%d) "0x%x"
+  ["max_size"]=>
+  string(%d) "0x%x"
+  ["position"]=>
+  string(%d) "0x%x"
+  ["EG(stack_limit)"]=>
+  string(%d) "0x%x"
+}
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?

Zend/tests/stack_limit/stack_limit_002.phpt

@@ -0,0 +1,80 @@
+--TEST--
+Stack limit 002 - Stack limit checks with max_allowed_stack_size detection (fibers)
+--EXTENSIONS--
+zend_test
+--INI--
+fiber.stack_size=512k
+--FILE--
+<?php
+
+var_dump(zend_test_zend_call_stack_get());
+
+class Test1 {
+    public function __destruct() {
+        new Test1;
+    }
+}
+
+class Test2 {
+    public function __clone() {
+        clone $this;
+    }
+}
+
+class Test3 {
+    public function __sleep()
+    {
+        serialize($this);
+    }
+}
+
+function replace() {
+    return preg_replace_callback('#.#', function () {
+        return replace();
+    }, 'x');
+}
+
+$fiber = new Fiber(function (): void {
+    try {
+        new Test1;
+    } catch (Error $e) {
+        echo $e->getMessage(), "\n";
+    }
+
+    try {
+        clone new Test2;
+    } catch (Error $e) {
+        echo $e->getMessage(), "\n";
+    }
+
+    try {
+        serialize(new Test3);
+    } catch (Error $e) {
+        echo $e->getMessage(), "\n";
+    }
+
+    try {
+        replace();
+    } catch (Error $e) {
+        echo $e->getMessage(), "\n";
+    }
+});
+
+$fiber->start();
+
+?>
+--EXPECTF--
+array(4) {
+  ["base"]=>
+  string(%d) "0x%x"
+  ["max_size"]=>
+  string(%d) "0x%x"
+  ["position"]=>
+  string(%d) "0x%x"
+  ["EG(stack_limit)"]=>
+  string(%d) "0x%x"
+}
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?

Zend/tests/stack_limit/stack_limit_003.phpt

@@ -0,0 +1,62 @@
+--TEST--
+Stack limit 003 - Stack limit checks with fixed max_allowed_stack_size
+--EXTENSIONS--
+zend_test
+--INI--
+zend.max_allowed_stack_size=128K
+--FILE--
+<?php
+
+var_dump(zend_test_zend_call_stack_get());
+
+class Test1 {
+    public function __destruct() {
+        new Test1;
+    }
+}
+
+class Test2 {
+    public function __clone() {
+        clone $this;
+    }
+}
+
+function replace() {
+    return preg_replace_callback('#.#', function () {
+        return replace();
+    }, 'x');
+}
+
+try {
+    new Test1;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    clone new Test2;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+try {
+    replace();
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECTF--
+array(4) {
+  ["base"]=>
+  string(%d) "0x%x"
+  ["max_size"]=>
+  string(%d) "0x%x"
+  ["position"]=>
+  string(%d) "0x%x"
+  ["EG(stack_limit)"]=>
+  string(%d) "0x%x"
+}
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?
+Maximum call stack size of %d bytes reached. Infinite recursion?

Zend/tests/stack_limit/stack_limit_004.phpt

@@ -0,0 +1,50 @@
+--TEST--
+Stack limit 004 - Stack limit checks with fixed max_allowed_stack_size (fibers)
+--EXTENSIONS--
+zend_test
+--FILE--
+<?php
+
+var_dump(zend_test_zend_call_stack_get());
+
+class Test1 {
+    public function __destruct() {
+        new Test1;
+    }
+}
+
+$callback = function (): int {
+    try {
+        new Test1;
+    } catch (Error $e) {
+        return count($e->getTrace());
+    }
+
+    throw new \Exception();
+};
+
+ini_set('fiber.stack_size', '400K');
+$fiber = new Fiber($callback);
+$fiber->start();
+$depth1 = $fiber->getReturn();
+
+ini_set('fiber.stack_size', '200K');
+$fiber = new Fiber($callback);
+$fiber->start();
+$depth2 = $fiber->getReturn();
+
+var_dump($depth1 > $depth2);
+
+?>
+--EXPECTF--
+array(4) {
+  ["base"]=>
+  string(%d) "0x%x"
+  ["max_size"]=>
+  string(%d) "0x%x"
+  ["position"]=>
+  string(%d) "0x%x"
+  ["EG(stack_limit)"]=>
+  string(%d) "0x%x"
+}
+bool(true)