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Check that SIGSEGV handlers work

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Tools such as ASAN may trap violations instead of our handlers,
making the sodium_utils{2,3} test fail.

This has been documented for a long time, but it's probably better
to detect this and ignore tests depending on working signal handlers.
This commit is contained in:
Frank Denis 2017-06-23 11:11:16 +02:00
parent 00777f7f10
commit c3045e2cb0
4 changed files with 48 additions and 4 deletions
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2
configure.ac
View File

@ -295,6 +295,8 @@ AX_CHECK_LINK_FLAG([-Wl,-z,relro], [LDFLAGS="$LDFLAGS -Wl,-z,relro"])
AX_CHECK_LINK_FLAG([-Wl,-z,now], [LDFLAGS="$LDFLAGS -Wl,-z,now"])
AX_CHECK_LINK_FLAG([-Wl,-z,noexecstack], [LDFLAGS="$LDFLAGS -Wl,-z,noexecstack"])
AX_CHECK_CATCHABLE_SEGV
LT_INIT
AC_SUBST(LIBTOOL_DEPS)

42
m4/ax_check_catchable_segv.m4 Normal file
View File

@ -0,0 +1,42 @@
# SYNOPSIS
#
# AX_CHECK_CATCHABLE_SEGV
#
# DESCRIPTION
#
# Check whether segmentation violations can be caught using signal handlers.
#serial 1
AC_DEFUN([AX_CHECK_CATCHABLE_SEGV], [dnl
AC_PREREQ(2.64)
AS_VAR_PUSHDEF([CACHEVAR], [ax_cv_check_[]_AC_LANG_ABBREV[]CATCHABLE_SEGV])dnl
AC_CACHE_CHECK([whether segmentation violations can be caught when using the _AC_LANG compiler], CACHEVAR, [
AC_RUN_IFELSE([
AC_LANG_PROGRAM([[
#include <signal.h>
#include <stdlib.h>
static void sig(int _) { exit(0); }
]], [[
volatile unsigned char * volatile x = malloc(8);
size_t i;
signal(SIGSEGV, sig);
signal(SIGBUS, sig);
#ifndef __SANITIZE_ADDRESS__
for (i = 0; i < 10000000; i += 1024) { x[-i] = x[i] = (unsigned char) i; }
#endif
free((void *) x);
exit(1)
]])],
[AS_VAR_SET(CACHEVAR, [yes])],
[AS_VAR_SET(CACHEVAR, [no])],
[AS_VAR_SET(CACHEVAR, [unknown])]
)
])
AS_VAR_IF(CACHEVAR, yes,
[AC_DEFINE([HAVE_CATCHABLE_SEGV], [1], [Define if segmentation violations can be caught using signal handlers])],
[AC_MSG_WARN([On this platform, segmentation violations cannot be caught using signal handlers. This is expected if you enabled a tool such as Address Sanitizer (-fsanitize=address), but be aware that using Address Sanitizer may also significantly reduce performance.])]
)
AS_VAR_POPDEF([CACHEVAR])dnl
])

4
test/default/sodium_utils2.c
View File

@ -9,7 +9,7 @@
#include "cmptest.h"
#ifdef __SANITIZE_ADDRESS__
#warning The sodium_utils2 test is expected to fail with address sanitizer
# warning The sodium_utils2 test is expected to fail with address sanitizer
#endif
__attribute__((noreturn)) static void
@ -81,7 +81,7 @@ main(void)
assert(buf != NULL);
sodium_mprotect_readonly(buf);
sodium_mprotect_readwrite(buf);
#ifndef __EMSCRIPTEN__
#if defined(HAVE_CATCHABLE_SEGV) && !defined(__EMSCRIPTEN__) && !defined(__SANITIZE_ADDRESS__)
sodium_memzero(((unsigned char *) buf) + size, 1U);
sodium_mprotect_noaccess(buf);
sodium_free(buf);

4
test/default/sodium_utils3.c
View File

@ -9,7 +9,7 @@
#include "cmptest.h"
#ifdef __SANITIZE_ADDRESS__
#warning The sodium_utils3 test is expected to fail with address sanitizer
# warning The sodium_utils3 test is expected to fail with address sanitizer
#endif
__attribute__((noreturn)) static void
@ -51,7 +51,7 @@ main(void)
assert(buf != NULL);
sodium_mprotect_noaccess(buf);
sodium_mprotect_readwrite(buf);
#ifndef __EMSCRIPTEN__
#if defined(HAVE_CATCHABLE_SEGV) && !defined(__EMSCRIPTEN__) && !defined(__SANITIZE_ADDRESS__)
sodium_memzero(((unsigned char *) buf) - 8, 8U);
sodium_mprotect_readonly(buf);
sodium_free(buf);