Add support for -fstack-protector (#22229)

Fixes: #9780

Author: sbc100

system/lib/libc/musl/src/env/__stack_chk_fail.c

@@ -23,6 +23,11 @@ void __init_ssp(void *entropy)
 
 void __stack_chk_fail(void)
 {
+#if defined(__EMSCRIPTEN__) && !defined(NDEBUG)
+	// Report the reason for the crash, at least in debug builds.
+	// This is the same message that glibc outputs (even in release builds).
+	emscripten_err("*** stack smashing detected ***");
+#endif
 	a_crash();
 }
 

test/core/test_dlfcn_self.exports

@@ -9,6 +9,7 @@ __progname_full
 __sig_actions
 __sig_pending
 __signgam
+__stack_chk_guard
 __threwValue
 __timezone
 __tzname

test/other/test_stack_protector.c

@@ -0,0 +1,14 @@
+#include <alloca.h>
+#include <memory.h>
+#include <string.h>
+#include <stdio.h>
+
+char mystring[] = "Hello world";
+
+int main() {
+  char buf[10];
+  // This is not valid since mystring is larger than `buf`
+  strcpy(buf, mystring);
+  printf("buf: %s\n", buf);
+  return 0;
+}

test/other/test_stack_protector.out

@@ -0,0 +1,2 @@
+buf: Hello world
+*** stack smashing detected ***

test/test_other.py

@@ -14937,3 +14937,6 @@ def test_std_promise_link(self, *args):
       }
     ''')
     self.run_process([EMXX, 'src.cpp', '-pthread'] + list(args))
+
+  def test_stack_protector(self):
+    self.do_other_test('test_stack_protector.c', emcc_args=['-fstack-protector'], assert_returncode=NON_ZERO)

tools/system_libs.py

@@ -1103,7 +1103,7 @@ def get_files(self):
         'fork.c', 'vfork.c', 'posix_spawn.c', 'posix_spawnp.c', 'execve.c', 'waitid.c', 'system.c',
         '_Fork.c',
         # 'env' exclusion
-        '__reset_tls.c', '__init_tls.c', '__libc_start_main.c', '__stack_chk_fail.c',
+        '__reset_tls.c', '__init_tls.c', '__libc_start_main.c',
     ]
 
     ignore += LIBC_SOCKETS