On 16/09/2020 1:11 pm, Amit Kachhap wrote:
> On 8/31/20 4:34 PM, Boyan Karatotev wrote:
>> PAuth signs and verifies return addresses on the stack. It does so by
>> +
>> +/* check that a corrupted PAC results in SIGSEGV */
>> +TEST_SIGNAL(corrupt_pac, SIGSEGV)
>> +{
>> + ASSERT_PAUTH_ENABLED();
>> +
>> + pac_corruptor();
>
> With 8.6-Pauth extension merged in arm tree [1]. It makes sense to
> verify PAC corruption for both SIGSEGV and SIGILL signals.
>
> Code something like below handles both the cases.
>
>
-----------------------------------------------------------------------------------
>
> int exec_sign_all(struct signatures *signed_vals, size_t val)
> @@ -187,12 +188,29 @@ int exec_sign_all(struct signatures *signed_vals,
> size_t val)
> return 0;
> }
>
> -/* check that a corrupted PAC results in SIGSEGV */
> -TEST_SIGNAL(corrupt_pac, SIGSEGV)
> +sigjmp_buf jmpbuf;
> +void pac_signal_handler(int signum, siginfo_t *si, void *uc)
> {
> - ASSERT_PAUTH_ENABLED();
> + if (signum == SIGSEGV || signum == SIGILL) {
> + siglongjmp(jmpbuf, 1);
> + }
> +}
> +
> +/* check that a corrupted PAC results in SIGSEGV or SIGILL */
> +TEST(corrupt_pac)
> +{
> + struct sigaction sa;
>
> - pac_corruptor();
> + ASSERT_PAUTH_ENABLED();
> + if (sigsetjmp(jmpbuf, 1) == 0) {
> + sa.sa_sigaction = pac_signal_handler;
> + sa.sa_flags = SA_SIGINFO;
> + sigemptyset(&sa.sa_mask);
> + sigaction(SIGSEGV, &sa, NULL);
> + sigaction(SIGILL, &sa, NULL);
> + pac_corruptor();
> + ASSERT_TRUE(0) TH_LOG("SIGSEGV/SIGILL signal did not
> occur");
> + }
> }
>
> /*
> @@ -265,7 +283,7 @@ TEST(single_thread_different_keys)
>
> tmp = n_same_single_set(&signed_vals, nkeys);
>
---------------------------------------------------------------------------------------
>
>
>
> Thanks,
> Amit Daniel
>
> [1]:
>
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/ptrauth
Okay, I will add this and post it with the next version.
Regards,
Boyan