strace/tests/signal_receive.c
Dmitry V. Levin 34c7794cc1 tests: robustify signal delivery test against kernel bugs
Recent kernel siginfo changes, namely, v4.14-rc1~60^2^2~1,
v4.16-rc1~159^2~37, and v4.16-rc1~159^2~39, introduced ABI regressions
that render the whole siginfo interface unreliable.

Looks like the kernel side is not eager to fix the breakage,
so here is a workaround.

* tests/signal_receive.c (s_sig, s_code, s_pid, s_uid): New volatile
variables.
(handler): Add siginfo_t parameter, save siginfo_t fields.
(sig_print): Remove.
(main): Rewrite.  Use variables saved by handler to print expected
siginfo output. Print diagnostics in case of siginfo mismatch.
* strace.spec.in (%check): Extract the diagnostics.

Closes: https://github.com/strace/strace/issues/21
2018-04-11 22:01:37 +00:00

130 lines
3.9 KiB
C

/*
* Check decoding of signal delivery.
*
* Copyright (c) 2016-2018 The strace developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "tests.h"
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
static volatile int s_sig, s_code, s_pid, s_uid;
static void
handler(int sig, siginfo_t *info, void *ucontext)
{
s_sig = info->si_signo;
s_code = info->si_code;
s_pid = info->si_pid;
s_uid = info->si_uid;
}
int
main(void)
{
static const char prefix[] = "KERNEL BUG";
int printed = 0;
const int pid = getpid();
const int uid = geteuid();
for (int sig = 1; sig <= 31; ++sig) {
if (sig == SIGKILL || sig == SIGSTOP)
continue;
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, sig);
if (sigprocmask(SIG_UNBLOCK, &mask, NULL))
perror_msg_and_fail("sigprocmask");
static const struct sigaction act = {
.sa_sigaction = handler,
.sa_flags = SA_SIGINFO
};
if (sigaction(sig, &act, NULL))
perror_msg_and_fail("sigaction: %d", sig);
if (kill(pid, sig) != 0)
perror_msg_and_fail("kill: %d", sig);
#ifdef MPERS_IS_m32
/*
* The tracee has received a compat siginfo_t but
* the tracer has received a native siginfo_t.
*/
const int e_sig = sig;
const int e_pid = pid;
const int e_uid = uid;
#else
/*
* If the tracee is a native process,
* then the tracer is also native.
* If the tracee is a compat process,
* then the tracer is also compat.
* Anyway, both the tracee and the tracer
* have received the same siginfo_t.
*/
const int e_sig = s_sig;
const int e_pid = s_pid;
const int e_uid = s_uid;
#endif
printf("kill(%d, %s) = 0\n", pid, signal2name(sig));
printf("--- %s {si_signo=%s, si_code=SI_USER, si_pid=%d"
", si_uid=%d} ---\n",
signal2name(sig), signal2name(e_sig), e_pid, e_uid);
if (s_code || sig != s_sig || pid != s_pid || uid != s_uid) {
/*
* The kernel has failed to initialize siginfo_t
* properly. There is nothing that could be done
* on the strace side to workaround the kernel bug,
* so just print some useful diagnostics.
*/
if (!printed) {
printed = 1;
fprintf(stderr, "%s: siginfo_t\n", prefix);
}
fprintf(stderr,
"%s: expected: si_signo=%d, si_code=%d"
", si_pid=%d, si_uid=%d\n"
"%s: received: si_signo=%d, si_code=%d"
", si_pid=%d, si_uid=%d\n",
prefix, sig, SI_USER, pid, uid,
prefix, sig, s_code, s_pid, s_uid);
}
}
if (printed) {
fprintf(stderr, "%s: end of diagnostics\n"
"*** PLEASE FIX THE KERNEL ***\n", prefix);
}
puts("+++ exited with 0 +++");
return 0;
}