Files
runc/libcontainer/dmz/nolibc/stackprotector.h
T
Rodrigo Campos 90f5da651a libct/dmz: Reduce the binary size using nolibc
Linux repo has under `tools/include/nolibc` very simple include files
that we can use to generate very small binaries that don't depend on
libc.

To make things even better, since Linux 6.6 it supports all the
architectures we support in runc, which is just beautiful.

The runc-dmz binary on x86_64 before this patch (on my debian host) was
taking 636K, with this patch it takes only 8K.

Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
2023-09-26 14:55:04 +02:00

52 lines
1.4 KiB
C

/* 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 */