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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>
108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* 32-bit test to check vDSO mremap.
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*
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* Copyright (c) 2016 Dmitry Safonov
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* Suggested-by: Andrew Lutomirski
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*/
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/*
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* Can be built statically:
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* gcc -Os -Wall -static -m32 test_mremap_vdso.c
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/auxv.h>
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#include <sys/syscall.h>
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#include <sys/wait.h>
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#define PAGE_SIZE 4096
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static int try_to_remap(void *vdso_addr, unsigned long size)
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{
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void *dest_addr, *new_addr;
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/* Searching for memory location where to remap */
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dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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if (dest_addr == MAP_FAILED) {
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printf("[WARN]\tmmap failed (%d): %m\n", errno);
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return 0;
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}
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printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n",
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vdso_addr, (unsigned long)vdso_addr + size,
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dest_addr, (unsigned long)dest_addr + size);
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fflush(stdout);
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new_addr = mremap(vdso_addr, size, size,
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MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr);
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if ((unsigned long)new_addr == (unsigned long)-1) {
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munmap(dest_addr, size);
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if (errno == EINVAL) {
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printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n");
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return -1; /* Retry with larger */
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}
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printf("[FAIL]\tmremap failed (%d): %m\n", errno);
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return 1;
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}
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return 0;
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}
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int main(int argc, char **argv, char **envp)
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{
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pid_t child;
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child = fork();
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if (child == -1) {
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printf("[WARN]\tfailed to fork (%d): %m\n", errno);
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return 1;
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}
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if (child == 0) {
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unsigned long vdso_size = PAGE_SIZE;
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unsigned long auxval;
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int ret = -1;
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auxval = getauxval(AT_SYSINFO_EHDR);
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printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval);
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if (!auxval || auxval == -ENOENT) {
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printf("[WARN]\tgetauxval failed\n");
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return 0;
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}
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/* Simpler than parsing ELF header */
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while (ret < 0) {
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ret = try_to_remap((void *)auxval, vdso_size);
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vdso_size += PAGE_SIZE;
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}
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#ifdef __i386__
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/* Glibc is likely to explode now - exit with raw syscall */
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asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret));
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#else /* __x86_64__ */
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syscall(SYS_exit, ret);
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#endif
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} else {
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int status;
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if (waitpid(child, &status, 0) != child ||
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!WIFEXITED(status)) {
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printf("[FAIL]\tmremap() of the vDSO does not work on this kernel!\n");
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return 1;
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} else if (WEXITSTATUS(status) != 0) {
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printf("[FAIL]\tChild failed with %d\n",
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WEXITSTATUS(status));
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return 1;
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}
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printf("[OK]\n");
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}
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return 0;
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}
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