2025cf9e19
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 263 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
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* Copyright (c) 2015 Andrew Lutomirski
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*/
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#define _GNU_SOURCE
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/signal.h>
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#include <sys/ucontext.h>
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#include <err.h>
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#include <setjmp.h>
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#include <errno.h>
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/* Our sigaltstack scratch space. */
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static unsigned char altstack_data[SIGSTKSZ];
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static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
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int flags)
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_sigaction = handler;
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sa.sa_flags = SA_SIGINFO | flags;
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sigemptyset(&sa.sa_mask);
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if (sigaction(sig, &sa, 0))
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err(1, "sigaction");
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}
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static volatile sig_atomic_t sig_traps;
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static sigjmp_buf jmpbuf;
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static volatile sig_atomic_t n_errs;
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static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
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{
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ucontext_t *ctx = (ucontext_t*)ctx_void;
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if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) {
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printf("[FAIL]\tAX had the wrong value: 0x%x\n",
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ctx->uc_mcontext.gregs[REG_EAX]);
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n_errs++;
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} else {
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printf("[OK]\tSeems okay\n");
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}
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siglongjmp(jmpbuf, 1);
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}
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static void sigill(int sig, siginfo_t *info, void *ctx_void)
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{
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printf("[SKIP]\tIllegal instruction\n");
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siglongjmp(jmpbuf, 1);
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}
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int main()
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{
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stack_t stack = {
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.ss_sp = altstack_data,
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.ss_size = SIGSTKSZ,
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};
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if (sigaltstack(&stack, NULL) != 0)
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err(1, "sigaltstack");
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sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK);
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/*
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* The actual exception can vary. On Atom CPUs, we get #SS
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* instead of #PF when the vDSO fails to access the stack when
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* ESP is too close to 2^32, and #SS causes SIGBUS.
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*/
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sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK);
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sethandler(SIGILL, sigill, SA_ONSTACK);
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/*
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* Exercise another nasty special case. The 32-bit SYSCALL
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* and SYSENTER instructions (even in compat mode) each
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* clobber one register. A Linux system call has a syscall
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* number and six arguments, and the user stack pointer
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* needs to live in some register on return. That means
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* that we need eight registers, but SYSCALL and SYSENTER
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* only preserve seven registers. As a result, one argument
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* ends up on the stack. The stack is user memory, which
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* means that the kernel can fail to read it.
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*
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* The 32-bit fast system calls don't have a defined ABI:
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* we're supposed to invoke them through the vDSO. So we'll
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* fudge it: we set all regs to invalid pointer values and
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* invoke the entry instruction. The return will fail no
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* matter what, and we completely lose our program state,
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* but we can fix it up with a signal handler.
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*/
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printf("[RUN]\tSYSENTER with invalid state\n");
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if (sigsetjmp(jmpbuf, 1) == 0) {
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asm volatile (
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"movl $-1, %%eax\n\t"
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"movl $-1, %%ebx\n\t"
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"movl $-1, %%ecx\n\t"
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"movl $-1, %%edx\n\t"
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"movl $-1, %%esi\n\t"
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"movl $-1, %%edi\n\t"
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"movl $-1, %%ebp\n\t"
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"movl $-1, %%esp\n\t"
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"sysenter"
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: : : "memory", "flags");
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}
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printf("[RUN]\tSYSCALL with invalid state\n");
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if (sigsetjmp(jmpbuf, 1) == 0) {
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asm volatile (
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"movl $-1, %%eax\n\t"
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"movl $-1, %%ebx\n\t"
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"movl $-1, %%ecx\n\t"
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"movl $-1, %%edx\n\t"
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"movl $-1, %%esi\n\t"
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"movl $-1, %%edi\n\t"
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"movl $-1, %%ebp\n\t"
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"movl $-1, %%esp\n\t"
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"syscall\n\t"
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"pushl $0" /* make sure we segfault cleanly */
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: : : "memory", "flags");
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}
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return 0;
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}
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