129 lines
2.7 KiB
C
129 lines
2.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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#define _GNU_SOURCE
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#include <signal.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <string.h>
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#include <err.h>
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#include <errno.h>
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#include <limits.h>
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#include <sys/mman.h>
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#include <sys/auxv.h>
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#include <sys/prctl.h>
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#include <sys/resource.h>
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#include <setjmp.h>
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/* sigaltstack()-enforced minimum stack */
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#define ENFORCED_MINSIGSTKSZ 2048
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#ifndef AT_MINSIGSTKSZ
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# define AT_MINSIGSTKSZ 51
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#endif
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static int nerrs;
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static bool sigalrm_expected;
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static unsigned long at_minstack_size;
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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 clearhandler(int sig)
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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_handler = SIG_DFL;
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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 int setup_altstack(void *start, unsigned long size)
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{
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stack_t ss;
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memset(&ss, 0, sizeof(ss));
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ss.ss_size = size;
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ss.ss_sp = start;
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return sigaltstack(&ss, NULL);
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}
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static jmp_buf jmpbuf;
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static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
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{
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if (sigalrm_expected) {
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printf("[FAIL]\tWrong signal delivered: SIGSEGV (expected SIGALRM).");
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nerrs++;
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} else {
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printf("[OK]\tSIGSEGV signal delivered.\n");
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}
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siglongjmp(jmpbuf, 1);
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}
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static void sigalrm(int sig, siginfo_t *info, void *ctx_void)
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{
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if (!sigalrm_expected) {
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printf("[FAIL]\tWrong signal delivered: SIGALRM (expected SIGSEGV).");
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nerrs++;
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} else {
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printf("[OK]\tSIGALRM signal delivered.\n");
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}
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}
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static void test_sigaltstack(void *altstack, unsigned long size)
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{
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if (setup_altstack(altstack, size))
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err(1, "sigaltstack()");
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sigalrm_expected = (size > at_minstack_size) ? true : false;
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sethandler(SIGSEGV, sigsegv, 0);
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sethandler(SIGALRM, sigalrm, SA_ONSTACK);
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if (!sigsetjmp(jmpbuf, 1)) {
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printf("[RUN]\tTest an alternate signal stack of %ssufficient size.\n",
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sigalrm_expected ? "" : "in");
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printf("\tRaise SIGALRM. %s is expected to be delivered.\n",
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sigalrm_expected ? "It" : "SIGSEGV");
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raise(SIGALRM);
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}
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clearhandler(SIGALRM);
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clearhandler(SIGSEGV);
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}
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int main(void)
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{
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void *altstack;
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at_minstack_size = getauxval(AT_MINSIGSTKSZ);
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altstack = mmap(NULL, at_minstack_size + SIGSTKSZ, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
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if (altstack == MAP_FAILED)
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err(1, "mmap()");
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if ((ENFORCED_MINSIGSTKSZ + 1) < at_minstack_size)
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test_sigaltstack(altstack, ENFORCED_MINSIGSTKSZ + 1);
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test_sigaltstack(altstack, at_minstack_size + SIGSTKSZ);
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return nerrs == 0 ? 0 : 1;
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}
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