tests/bad-buffer-test.c

/*
 * Copyright © 2012 Intel Corporation
 * Copyright © 2013 Collabora, Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "config.h"

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "shared/os-compatibility.h"
#include "weston-test-client-helper.h"

/* These three functions are copied from shared/os-compatibility.c in order to
 * behave like older clients, and allow ftruncate() to shrink the file’s size,
 * so SIGBUS can still happen.
 *
 * There is no reason not to use os_create_anonymous_file() otherwise. */

#ifndef HAVE_MKOSTEMP
static int
set_cloexec_or_close(int fd)
{
	if (os_fd_set_cloexec(fd) != 0) {
		close(fd);
		return -1;
	}
	return fd;
}
#endif

static int
create_tmpfile_cloexec(char *tmpname)
{
	int fd;

#ifdef HAVE_MKOSTEMP
	fd = mkostemp(tmpname, O_CLOEXEC);
	if (fd >= 0)
		unlink(tmpname);
#else
	fd = mkstemp(tmpname);
	if (fd >= 0) {
		fd = set_cloexec_or_close(fd);
		unlink(tmpname);
	}
#endif

	return fd;
}

static int
create_anonymous_file_without_seals(off_t size)
{
	static const char template[] = "/weston-test-XXXXXX";
	const char *path;
	char *name;
	int fd;
	int ret;

	path = getenv("XDG_RUNTIME_DIR");
	if (!path) {
		errno = ENOENT;
		return -1;
	}

	name = malloc(strlen(path) + sizeof(template));
	if (!name)
		return -1;

	strcpy(name, path);
	strcat(name, template);

	fd = create_tmpfile_cloexec(name);

	free(name);

	if (fd < 0)
		return -1;

#ifdef HAVE_POSIX_FALLOCATE
	do {
		ret = posix_fallocate(fd, 0, size);
	} while (ret == EINTR);
	if (ret != 0) {
		close(fd);
		errno = ret;
		return -1;
	}
#else
	do {
		ret = ftruncate(fd, size);
	} while (ret < 0 && errno == EINTR);
	if (ret < 0) {
		close(fd);
		return -1;
	}
#endif

	return fd;
}

/* tests, that attempt to crash the compositor on purpose */

static struct wl_buffer *
create_bad_shm_buffer(struct client *client, int width, int height)
{
	struct wl_shm *shm = client->wl_shm;
	int stride = width * 4;
	int size = stride * height;
	struct wl_shm_pool *pool;
	struct wl_buffer *buffer;
	int fd;

	fd = create_anonymous_file_without_seals(size);
	assert(fd >= 0);

	pool = wl_shm_create_pool(shm, fd, size);
	buffer = wl_shm_pool_create_buffer(pool, 0, width, height, stride,
					   WL_SHM_FORMAT_ARGB8888);
	wl_shm_pool_destroy(pool);

	/* Truncate the file to a small size, so that the compositor
	 * will access it out-of-bounds, and hit SIGBUS.
	 */
	assert(ftruncate(fd, 12) == 0);
	close(fd);

	return buffer;
}

TEST(test_truncated_shm_file)
{
	struct client *client;
	struct wl_buffer *bad_buffer;
	struct wl_surface *surface;
	int frame;

	client = create_client_and_test_surface(46, 76, 111, 134);
	assert(client);
	surface = client->surface->wl_surface;

	bad_buffer = create_bad_shm_buffer(client, 200, 200);

	wl_surface_attach(surface, bad_buffer, 0, 0);
	wl_surface_damage(surface, 0, 0, 200, 200);
	frame_callback_set(surface, &frame);
	wl_surface_commit(surface);
	frame_callback_wait_nofail(client, &frame);

	expect_protocol_error(client, &wl_buffer_interface,
			      WL_SHM_ERROR_INVALID_FD);
}