glibc/debug/tst-longjmp_chk2.c
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

129 lines
3.0 KiB
C

/* Verify longjmp fortify checking does not reject signal stacks. */
#include <assert.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
static int do_test (void);
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
static jmp_buf mainloop;
static sigset_t mainsigset;
static volatile sig_atomic_t pass;
static void
write_indented (const char *str)
{
for (int i = 0; i < pass; ++i)
write_message (" ");
write_message (str);
}
static void
stackoverflow_handler (int sig)
{
stack_t altstack;
/* Sanity check to keep test from looping forever (in case the longjmp
chk code is slightly broken). */
pass++;
sigaltstack (NULL, &altstack);
write_indented ("in signal handler\n");
if (altstack.ss_flags & SS_ONSTACK)
write_indented ("on alternate stack\n");
siglongjmp (mainloop, pass);
}
static volatile int *
recurse_1 (int n, volatile int *p)
{
if (n >= 0)
*recurse_1 (n + 1, p) += n;
return p;
}
static int
recurse (int n)
{
int sum = 0;
return *recurse_1 (n, &sum);
}
static int
do_test (void)
{
char mystack[SIGSTKSZ];
stack_t altstack;
struct sigaction action;
sigset_t emptyset;
/* Before starting the endless recursion, try to be friendly to the user's
machine. On some Linux 2.2.x systems, there is no stack limit for user
processes at all. We don't want to kill such systems. */
struct rlimit rl;
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
setrlimit (RLIMIT_STACK, &rl);
/* Install the alternate stack. */
altstack.ss_sp = mystack;
altstack.ss_size = sizeof (mystack);
altstack.ss_flags = 0; /* no SS_DISABLE */
if (sigaltstack (&altstack, NULL) < 0)
{
puts ("first sigaltstack failed");
return 0;
}
/* Install the SIGSEGV handler. */
sigemptyset (&action.sa_mask);
action.sa_handler = &stackoverflow_handler;
action.sa_flags = SA_ONSTACK;
sigaction (SIGSEGV, &action, (struct sigaction *) NULL);
sigaction (SIGBUS, &action, (struct sigaction *) NULL);
/* Save the current signal mask. */
sigemptyset (&emptyset);
sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);
/* Provoke two stack overflows in a row. */
if (sigsetjmp (mainloop, 1) != 0)
{
assert (pass != 0);
printf ("%*sout of signal handler\n", pass, "");
}
else
assert (pass == 0);
sigaltstack (NULL, &altstack);
if (altstack.ss_flags & SS_ONSTACK)
printf ("%*son alternate stack\n", pass, "");
else
printf ("%*snot on alternate stack\n", pass, "");
if (pass < 2)
{
recurse (0);
puts ("recurse call returned");
return 2;
}
altstack.ss_flags |= SS_DISABLE;
if (sigaltstack (&altstack, NULL) == -1)
printf ("disabling alternate stack failed\n");
else
printf ("disabling alternate stack succeeded \n");
/* Restore the signal handlers, in case we trigger a crash after the
tests above. */
signal (SIGBUS, SIG_DFL);
signal (SIGSEGV, SIG_DFL);
return 0;
}