kernel

linux-6.8.1/tools/include/nolibc/stackprotector.h

@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Stack protector support for NOLIBC
+ * Copyright (C) 2023 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_STACKPROTECTOR_H
+#define _NOLIBC_STACKPROTECTOR_H
+
+#include "compiler.h"
+
+#if defined(_NOLIBC_STACKPROTECTOR)
+
+#include "sys.h"
+#include "stdlib.h"
+
+/* The functions in this header are using raw syscall macros to avoid
+ * triggering stack protector errors themselves
+ */
+
+__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
+void __stack_chk_fail(void)
+{
+	pid_t pid;
+	my_syscall3(__NR_write, STDERR_FILENO, "!!Stack smashing detected!!\n", 28);
+	pid = my_syscall0(__NR_getpid);
+	my_syscall2(__NR_kill, pid, SIGABRT);
+	for (;;);
+}
+
+__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
+void __stack_chk_fail_local(void)
+{
+	__stack_chk_fail();
+}
+
+__attribute__((weak,section(".data.nolibc_stack_chk")))
+uintptr_t __stack_chk_guard;
+
+static __no_stack_protector void __stack_chk_init(void)
+{
+	my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
+	/* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */
+	if (__stack_chk_guard != (uintptr_t) &__stack_chk_guard)
+		__stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
+}
+#else /* !defined(_NOLIBC_STACKPROTECTOR) */
+static void __stack_chk_init(void) {}
+#endif /* defined(_NOLIBC_STACKPROTECTOR) */
+
+#endif /* _NOLIBC_STACKPROTECTOR_H */