Re: [PATCH v3 4/4] selftest/x86/signal: Include test cases for validating sigaltstack

Borislav Petkov
2021-01-08T18:08:19Z

On Tue, Dec 22, 2020 at 05:53:12PM -0800, Chang S. Bae wrote:
> +static int setup_altstack(void *start, unsigned long size)
> +{
> + stack_t ss;
> +
> + memset(&ss, 0, sizeof(ss));
> + ss.ss_size = size;
> + ss.ss_sp = start;
> +
> + return sigaltstack(&ss, NULL);
> +}
> +
> +static jmp_buf jmpbuf;
> +
> +static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
> +{
> + if (sigalrm_expected) {
> + printf("[FAIL]\tSIGSEGV signal delivery is wrong.\n");

"Wrong signal delivered: SIGSEGV (expected SIGALRM)."

> + nerrs++;
> + } else {
> + printf("[OK]\tSIGSEGV signal is delivered.\n");

s/is //

> + }
> +
> + siglongjmp(jmpbuf, 1);
> +}
> +
> +static void sigalrm(int sig, siginfo_t *info, void *ctx_void)
> +{
> + if (!sigalrm_expected) {
> + printf("[FAIL]\tSIGALRM sigal delivery is wrong.\n");

See above.

> + nerrs++;
> + } else {
> + printf("[OK]\tSIGALRM signal is delivered.\n");

Ditto.

> + }
> +}
> +
> +static void test_sigaltstack(void *altstack, unsigned long size)
> +{
> + if (setup_altstack(altstack, size))
> + err(1, "sigaltstack()");
> +
> + sigalrm_expected = (size > at_minstack_size) ? true : false;
> +
> + sethandler(SIGSEGV, sigsegv, 0);
> + sethandler(SIGALRM, sigalrm, SA_ONSTACK);
> +
> + if (sigsetjmp(jmpbuf, 1) == 0) {

if (!sigsetjmp...)

> + printf("[RUN]\tTest an (%s) alternate signal stack\n",

"Test an alternate signal stack of %ssufficient size.\n"

> + sigalrm_expected ? "enough" : "too-small");

"" : "in");

> + printf("\tRaise SIGALRM. %s is expected to be delivered.\n",
> + sigalrm_expected ? "It" : "But SIGSEGV");

"It" : "SIGSEGV"

Drop "But".

Ask if something's not clear.

--
Regards/Gruss,
Boris.

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