From 60c5ff3d463014006b5474153ab3d84ce139c99c Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Thu, 12 Jun 2014 22:01:56 +0000 Subject: Add regress test for explicit_bzero. --- regress/lib/libc/explicit_bzero/explicit_bzero.c | 138 +++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 regress/lib/libc/explicit_bzero/explicit_bzero.c (limited to 'regress/lib/libc/explicit_bzero/explicit_bzero.c') diff --git a/regress/lib/libc/explicit_bzero/explicit_bzero.c b/regress/lib/libc/explicit_bzero/explicit_bzero.c new file mode 100644 index 00000000000..b4b6c9e559e --- /dev/null +++ b/regress/lib/libc/explicit_bzero/explicit_bzero.c @@ -0,0 +1,138 @@ +/* $OpenBSD: explicit_bzero.c,v 1.1 2014/06/12 22:01:55 matthew Exp $ */ +/* + * Copyright (c) 2014 Google Inc. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include +#include +#include +#include +#include + +#define ASSERT_EQ(a, b) assert((a) == (b)) +#define ASSERT_NE(a, b) assert((a) != (b)) +#define ASSERT_GE(a, b) assert((a) >= (b)) + +static void +call_on_stack(void (*fn)(int), void *stack, size_t stacklen) +{ + /* + * This is a bit more complicated than strictly necessary, but + * it ensures we don't have any flaky test failures due to + * inherited signal masks/actions/etc. + * + * On systems where SA_ONSTACK is not supported, this could + * alternatively be implemented using makecontext() or + * pthread_attr_setstack(). + */ + + const struct sigaction sigact = { + .sa_handler = fn, + .sa_flags = SA_ONSTACK, + }; + const stack_t sigstk = { + .ss_sp = stack, + .ss_size = stacklen, + }; + struct sigaction oldsigact; + stack_t oldsigstk; + sigset_t sigset, oldsigset; + + /* First, block all signals. */ + ASSERT_EQ(0, sigemptyset(&sigset)); + ASSERT_EQ(0, sigfillset(&sigset)); + ASSERT_EQ(0, sigprocmask(SIG_BLOCK, &sigset, &oldsigset)); + + /* Next setup the signal stack and handler for SIGUSR1. */ + ASSERT_EQ(0, sigaltstack(&sigstk, &oldsigstk)); + ASSERT_EQ(0, sigaction(SIGUSR1, &sigact, &oldsigact)); + + /* Raise SIGUSR1 and momentarily unblock it to run the handler. */ + ASSERT_EQ(0, raise(SIGUSR1)); + ASSERT_EQ(0, sigdelset(&sigset, SIGUSR1)); + ASSERT_EQ(-1, sigsuspend(&sigset)); + ASSERT_EQ(EINTR, errno); + + /* Restore the original signal action, stack, and mask. */ + ASSERT_EQ(0, sigaction(SIGUSR1, &oldsigact, NULL)); + ASSERT_EQ(0, sigaltstack(&oldsigstk, NULL)); + ASSERT_EQ(0, sigprocmask(SIG_SETMASK, &oldsigset, NULL)); +} + +/* 128 bits of random data. */ +static const char secret[16] = { + 0xa0, 0x6c, 0x0c, 0x81, 0xba, 0xd8, 0x5b, 0x0c, + 0xb0, 0xd6, 0xd4, 0xe3, 0xeb, 0x52, 0x5f, 0x96, +}; + +enum { + SECRETCOUNT = 16, + SECRETBYTES = SECRETCOUNT * sizeof(secret) +}; + +static void +populate_secret(char *buf, size_t len) +{ + int i, fds[2]; + ASSERT_EQ(0, pipe(fds)); + + for (i = 0; i < SECRETCOUNT; i++) + ASSERT_EQ(sizeof(secret), write(fds[1], secret, sizeof(secret))); + ASSERT_EQ(0, close(fds[1])); + + ASSERT_EQ(len, read(fds[0], buf, len)); + ASSERT_EQ(0, close(fds[0])); +} + +static void +test_without_bzero(int signo) +{ + char buf[SECRETBYTES]; + populate_secret(buf, sizeof(buf)); +} + +static void +test_with_bzero(int signo) +{ + char buf[SECRETBYTES]; + populate_secret(buf, sizeof(buf)); + explicit_bzero(buf, sizeof(buf)); +} + +static char altstack[SIGSTKSZ]; + +int +main() +{ + /* + * First, test that if we *don't* call explicit_bzero, that we + * *are* able to find the secret data on the stack. This + * sanity checks that call_on_stack() and populare_secret() + * work as intended. + */ + memset(altstack, 0, sizeof(altstack)); + call_on_stack(test_without_bzero, altstack, sizeof(altstack)); + ASSERT_NE(NULL, memmem(altstack, sizeof(altstack), secret, sizeof(secret))); + + /* + * Now test with a call to explicit_bzero() and check that we + * *don't* find the secret data. + */ + memset(altstack, 0, sizeof(altstack)); + call_on_stack(test_with_bzero, altstack, sizeof(altstack)); + ASSERT_EQ(NULL, memmem(altstack, sizeof(altstack), secret, sizeof(secret))); + + return (0); +} -- cgit v1.2.3