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183 lines
4.2 KiB
183 lines
4.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* unwind_vdso.c - tests unwind info for AT_SYSINFO in the vDSO |
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* Copyright (c) 2014-2015 Andrew Lutomirski |
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* |
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* This tests __kernel_vsyscall's unwind info. |
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*/ |
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#define _GNU_SOURCE |
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#include <features.h> |
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#include <stdio.h> |
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#include "helpers.h" |
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#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16 |
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int main() |
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{ |
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/* We need getauxval(). */ |
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printf("[SKIP]\tGLIBC before 2.16 cannot compile this test\n"); |
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return 0; |
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} |
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#else |
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#include <sys/time.h> |
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#include <stdlib.h> |
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#include <syscall.h> |
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#include <unistd.h> |
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#include <string.h> |
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#include <inttypes.h> |
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#include <sys/mman.h> |
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#include <signal.h> |
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#include <sys/ucontext.h> |
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#include <err.h> |
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#include <stddef.h> |
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#include <stdbool.h> |
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#include <sys/ptrace.h> |
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#include <sys/user.h> |
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#include <link.h> |
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#include <sys/auxv.h> |
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#include <dlfcn.h> |
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#include <unwind.h> |
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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 nerrs; |
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static unsigned long sysinfo; |
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static bool got_sysinfo = false; |
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static unsigned long return_address; |
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struct unwind_state { |
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unsigned long ip; /* trap source */ |
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int depth; /* -1 until we hit the trap source */ |
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}; |
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_Unwind_Reason_Code trace_fn(struct _Unwind_Context * ctx, void *opaque) |
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{ |
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struct unwind_state *state = opaque; |
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unsigned long ip = _Unwind_GetIP(ctx); |
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if (state->depth == -1) { |
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if (ip == state->ip) |
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state->depth = 0; |
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else |
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return _URC_NO_REASON; /* Not there yet */ |
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} |
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printf("\t 0x%lx\n", ip); |
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if (ip == return_address) { |
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/* Here we are. */ |
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unsigned long eax = _Unwind_GetGR(ctx, 0); |
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unsigned long ecx = _Unwind_GetGR(ctx, 1); |
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unsigned long edx = _Unwind_GetGR(ctx, 2); |
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unsigned long ebx = _Unwind_GetGR(ctx, 3); |
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unsigned long ebp = _Unwind_GetGR(ctx, 5); |
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unsigned long esi = _Unwind_GetGR(ctx, 6); |
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unsigned long edi = _Unwind_GetGR(ctx, 7); |
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bool ok = (eax == SYS_getpid || eax == getpid()) && |
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ebx == 1 && ecx == 2 && edx == 3 && |
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esi == 4 && edi == 5 && ebp == 6; |
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if (!ok) |
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nerrs++; |
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printf("[%s]\t NR = %ld, args = %ld, %ld, %ld, %ld, %ld, %ld\n", |
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(ok ? "OK" : "FAIL"), |
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eax, ebx, ecx, edx, esi, edi, ebp); |
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return _URC_NORMAL_STOP; |
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} else { |
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state->depth++; |
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return _URC_NO_REASON; |
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} |
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} |
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static void sigtrap(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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struct unwind_state state; |
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unsigned long ip = ctx->uc_mcontext.gregs[REG_EIP]; |
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if (!got_sysinfo && ip == sysinfo) { |
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got_sysinfo = true; |
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/* Find the return address. */ |
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return_address = *(unsigned long *)(unsigned long)ctx->uc_mcontext.gregs[REG_ESP]; |
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printf("\tIn vsyscall at 0x%lx, returning to 0x%lx\n", |
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ip, return_address); |
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} |
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if (!got_sysinfo) |
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return; /* Not there yet */ |
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if (ip == return_address) { |
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ctx->uc_mcontext.gregs[REG_EFL] &= ~X86_EFLAGS_TF; |
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printf("\tVsyscall is done\n"); |
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return; |
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} |
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printf("\tSIGTRAP at 0x%lx\n", ip); |
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state.ip = ip; |
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state.depth = -1; |
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_Unwind_Backtrace(trace_fn, &state); |
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} |
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int main() |
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{ |
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sysinfo = getauxval(AT_SYSINFO); |
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printf("\tAT_SYSINFO is 0x%lx\n", sysinfo); |
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Dl_info info; |
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if (!dladdr((void *)sysinfo, &info)) { |
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printf("[WARN]\tdladdr failed on AT_SYSINFO\n"); |
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} else { |
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printf("[OK]\tAT_SYSINFO maps to %s, loaded at 0x%p\n", |
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info.dli_fname, info.dli_fbase); |
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} |
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sethandler(SIGTRAP, sigtrap, 0); |
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syscall(SYS_getpid); /* Force symbol binding without TF set. */ |
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printf("[RUN]\tSet TF and check a fast syscall\n"); |
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set_eflags(get_eflags() | X86_EFLAGS_TF); |
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syscall(SYS_getpid, 1, 2, 3, 4, 5, 6); |
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if (!got_sysinfo) { |
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set_eflags(get_eflags() & ~X86_EFLAGS_TF); |
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/* |
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* The most likely cause of this is that you're on Debian or |
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* a Debian-based distro, you're missing libc6-i686, and you're |
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* affected by libc/19006 (https://sourceware.org/PR19006). |
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*/ |
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printf("[WARN]\tsyscall(2) didn't enter AT_SYSINFO\n"); |
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} |
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if (get_eflags() & X86_EFLAGS_TF) { |
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printf("[FAIL]\tTF is still set\n"); |
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nerrs++; |
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} |
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if (nerrs) { |
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printf("[FAIL]\tThere were errors\n"); |
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return 1; |
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} else { |
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printf("[OK]\tAll is well\n"); |
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return 0; |
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} |
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} |
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#endif /* New enough libc */
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