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>
88 lines
1.9 KiB
C
88 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* syscall_nt.c - checks syscalls with NT set
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* Copyright (c) 2014-2015 Andrew Lutomirski
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*
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* Some obscure user-space code requires the ability to make system calls
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* with FLAGS.NT set. Make sure it works.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <signal.h>
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#include <err.h>
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#include <sys/syscall.h>
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#include <asm/processor-flags.h>
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#ifdef __x86_64__
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# define WIDTH "q"
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#else
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# define WIDTH "l"
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#endif
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static unsigned int nerrs;
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static unsigned long get_eflags(void)
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{
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unsigned long eflags;
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asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags));
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return eflags;
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}
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static void set_eflags(unsigned long eflags)
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{
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asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH
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: : "rm" (eflags) : "flags");
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}
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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 void sigtrap(int sig, siginfo_t *si, void *ctx_void)
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{
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}
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static void do_it(unsigned long extraflags)
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{
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unsigned long flags;
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set_eflags(get_eflags() | extraflags);
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syscall(SYS_getpid);
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flags = get_eflags();
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if ((flags & extraflags) == extraflags) {
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printf("[OK]\tThe syscall worked and flags are still set\n");
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} else {
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printf("[FAIL]\tThe syscall worked but flags were cleared (flags = 0x%lx but expected 0x%lx set)\n",
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flags, extraflags);
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nerrs++;
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}
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}
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int main(void)
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{
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printf("[RUN]\tSet NT and issue a syscall\n");
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do_it(X86_EFLAGS_NT);
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/*
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* Now try it again with TF set -- TF forces returns via IRET in all
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* cases except non-ptregs-using 64-bit full fast path syscalls.
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*/
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sethandler(SIGTRAP, sigtrap, 0);
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printf("[RUN]\tSet NT|TF and issue a syscall\n");
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do_it(X86_EFLAGS_NT | X86_EFLAGS_TF);
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return nerrs == 0 ? 0 : 1;
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}
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