[PATCH v7 11/18] seltests/landlock: add tests for bind() hooks

[Mickaël Salaün]

On 29/08/2022 19:03, Konstantin Meskhidze wrote:
> Adds selftests for bind() socket action.
> The first is with no landlock restrictions:
>      - bind without restrictions for ip4;
>      - bind without restrictions for ip6;

There is no "ip4" nor "ip6" but "IPv4" and "IPv6" (everywhere).


> The second ones is with mixed landlock rules:
>      - bind with restrictions for ip4;
>      - bind with restrictions for ip6;
> 
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze at huawei.com>
> ---
> 
> Changes since v6:
> * None.
> 
> Changes since v5:
> * Splits commit.
> * Adds local address 127.0.0.1.
> * Adds FIXTURE_VARIANT and FIXTURE_VARIANT_ADD
> helpers to support both ip4 and ip6 family tests and
> shorten the code.
> * Adds create_socket_variant() and bind_variant() helpers.
> * Gets rid of reuse_addr variable in create_socket_variant.
> * Formats code with clang-format-14.
> 
> Changes since v4:
> * Adds port[MAX_SOCKET_NUM], struct sockaddr_in addr4
> and struct sockaddr_in addr6 in FIXTURE.
> * Refactors FIXTURE_SETUP:
>      - initializing self->port, self->addr4 and self->addr6.
>      - adding network namespace.
> * Refactors code with self->port, self->addr4 and
> self->addr6 variables.
> * Adds selftests for IP6 family:
>      - bind_no_restrictions_ip6.
>      - bind_with_restrictions_ip6.
> * Refactors selftests/landlock/config
> * Moves enforce_ruleset() into common.h
> 
> Changes since v3:
> * Split commit.
> * Add helper create_socket.
> * Add FIXTURE_SETUP.
> 
> ---
>   tools/testing/selftests/landlock/config     |   4 +
>   tools/testing/selftests/landlock/net_test.c | 180 ++++++++++++++++++++
>   2 files changed, 184 insertions(+)
>   create mode 100644 tools/testing/selftests/landlock/net_test.c
> 
> diff --git a/tools/testing/selftests/landlock/config b/tools/testing/selftests/landlock/config
> index 0f0a65287bac..71f7e9a8a64c 100644
> --- a/tools/testing/selftests/landlock/config
> +++ b/tools/testing/selftests/landlock/config
> @@ -1,3 +1,7 @@
> +CONFIG_INET=y
> +CONFIG_IPV6=y
> +CONFIG_NET=y
> +CONFIG_NET_NS=y
>   CONFIG_OVERLAY_FS=y
>   CONFIG_SECURITY_LANDLOCK=y
>   CONFIG_SECURITY_PATH=y
> diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c
> new file mode 100644
> index 000000000000..79c71fa37ddb
> --- /dev/null
> +++ b/tools/testing/selftests/landlock/net_test.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Landlock tests - Network
> + *
> + * Copyright (C) 2022 Huawei Tech. Co., Ltd.
> + */
> +
> +#define _GNU_SOURCE
> +#include <arpa/inet.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <linux/landlock.h>
> +#include <netinet/in.h>
> +#include <sched.h>
> +#include <string.h>
> +#include <sys/prctl.h>
> +#include <sys/socket.h>
> +#include <sys/types.h>
> +
> +#include "common.h"
> +
> +#define MAX_SOCKET_NUM 10
> +
> +#define SOCK_PORT_START 3470
> +#define SOCK_PORT_ADD 10
> +
> +#define IP_ADDRESS "127.0.0.1"
> +
> +FIXTURE(socket)
> +{
> +	uint port[MAX_SOCKET_NUM];
> +	struct sockaddr_in addr4[MAX_SOCKET_NUM];
> +	struct sockaddr_in6 addr6[MAX_SOCKET_NUM];
> +};
> +

/* struct _fixture_variant_socket */

> +FIXTURE_VARIANT(socket)
> +{
> +	const bool is_ipv4;
> +};
> +
> +/* clang-format off */
> +FIXTURE_VARIANT_ADD(socket, ipv4) {
> +	/* clang-format on */
> +	.is_ipv4 = true,
> +};
> +
> +/* clang-format off */
> +FIXTURE_VARIANT_ADD(socket, ipv6) {
> +	/* clang-format on */
> +	.is_ipv4 = false,
> +};
> +
> +static int create_socket_variant(const FIXTURE_VARIANT(socket) *const variant,

To avoid scripts/checkpatch.pl errors [1] (and to follow a consistent 
formatting thanks to clang-format), please use the generated struct type 
for FIXTURE_VARIANT and FIXTURE_DATA instead (everywhere), and add a 
comment before the declaration (as for FIXTURE_VARIANT(socket) just above):

FIXTURE_VARIANT(socket) => struct _fixture_variant_socket
FIXTURE_DATA(socket) => struct _test_data_socket


[1] 
https://lore.kernel.org/all/b1cfb8d4-ad54-9cc1-3d9d-e690c81da016@digikod.net/


> +				 const int type)
> +{
> +	if (variant->is_ipv4)
> +		return socket(AF_INET, type | SOCK_CLOEXEC, 0);
> +	else
> +		return socket(AF_INET6, type | SOCK_CLOEXEC, 0);
> +}
> +
> +static int bind_variant(const FIXTURE_VARIANT(socket) *const variant,
> +			const int sockfd,
> +			const FIXTURE_DATA(socket) *const self,
> +			const size_t index)
> +{
> +	if (variant->is_ipv4)
> +		return bind(sockfd, &self->addr4[index],
> +			    sizeof(self->addr4[index]));
> +	else
> +		return bind(sockfd, &self->addr6[index],
> +			    sizeof(self->addr6[index]));
> +}
> +
> +FIXTURE_SETUP(socket)
> +{
> +	int i;

line break


> +	/* Creates IP4 socket addresses. */
> +	for (i = 0; i < MAX_SOCKET_NUM; i++) {
> +		self->port[i] = SOCK_PORT_START + SOCK_PORT_ADD * i;
> +		self->addr4[i].sin_family = AF_INET;
> +		self->addr4[i].sin_port = htons(self->port[i]);
> +		self->addr4[i].sin_addr.s_addr = inet_addr(IP_ADDRESS);
> +		memset(&(self->addr4[i].sin_zero), '\0', 8);
> +	}
> +
> +	/* Creates IP6 socket addresses. */
> +	for (i = 0; i < MAX_SOCKET_NUM; i++) {
> +		self->port[i] = SOCK_PORT_START + SOCK_PORT_ADD * i;
> +		self->addr6[i].sin6_family = AF_INET6;
> +		self->addr6[i].sin6_port = htons(self->port[i]);
> +		inet_pton(AF_INET6, IP_ADDRESS, &(self->addr6[i].sin6_addr));
> +	}
> +
> +	set_cap(_metadata, CAP_SYS_ADMIN);
> +	ASSERT_EQ(0, unshare(CLONE_NEWNET));
> +	ASSERT_EQ(0, system("ip link set dev lo up"));
> +	clear_cap(_metadata, CAP_SYS_ADMIN);
> +}
> +
> +FIXTURE_TEARDOWN(socket)
> +{
> +}
> +
> +TEST_F(socket, bind_no_restrictions)

Please use TEST_F_FORK() everywhere.


> +{
> +	int sockfd;
> +
> +	sockfd = create_socket_variant(variant, SOCK_STREAM);
> +	ASSERT_LE(0, sockfd);
> +
> +	/* Binds a socket to port[0]. */
> +	ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0));
> +
> +	ASSERT_EQ(0, close(sockfd));
> +}
> +
> +TEST_F(socket, bind_with_restrictions)
> +{
> +	int sockfd;
> +
> +	struct landlock_ruleset_attr ruleset_attr = {
> +		.handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
> +				      LANDLOCK_ACCESS_NET_CONNECT_TCP,
> +	};
> +	struct landlock_net_service_attr net_service_1 = {
> +		.allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP |
> +				  LANDLOCK_ACCESS_NET_CONNECT_TCP,
> +		.port = self->port[0],
> +	};
> +	struct landlock_net_service_attr net_service_2 = {
> +		.allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP,
> +		.port = self->port[1],
> +	};
> +	struct landlock_net_service_attr net_service_3 = {
> +		.allowed_access = 0,
> +		.port = self->port[2],
> +	};
> +
> +	const int ruleset_fd =
> +		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
> +	ASSERT_LE(0, ruleset_fd);
> +
> +	/* Allows connect and bind operations to the port[0] socket. */
> +	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
> +				       &net_service_1, 0));
> +	/* Allows connect and deny bind operations to the port[1] socket. */
> +	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
> +				       &net_service_2, 0));
> +	/* Empty allowed_access (i.e. deny rules) are ignored in network actions

Only comment lines ending with "*/" should start with "/*", otherwise 
you need to add a line break after "/*" (everywhere).


> +	 * for port[2] socket.
> +	 */
> +	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
> +					&net_service_3, 0));
> +	ASSERT_EQ(ENOMSG, errno);
> +
> +	/* Enforces the ruleset. */
> +	enforce_ruleset(_metadata, ruleset_fd);
> +
> +	sockfd = create_socket_variant(variant, SOCK_STREAM);
> +	ASSERT_LE(0, sockfd);
> +	/* Binds a socket to port[0]. */
> +	ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0));
> +
> +	/* Close bounded socket. */

Closes

> +	ASSERT_EQ(0, close(sockfd));
> +
> +	sockfd = create_socket_variant(variant, SOCK_STREAM);
> +	ASSERT_LE(0, sockfd);
> +	/* Binds a socket to port[1]. */
> +	ASSERT_EQ(-1, bind_variant(variant, sockfd, self, 1));
> +	ASSERT_EQ(EACCES, errno);
> +
> +	sockfd = create_socket_variant(variant, SOCK_STREAM);
> +	ASSERT_LE(0, sockfd);
> +	/* Binds a socket to port[2]. */
> +	ASSERT_EQ(-1, bind_variant(variant, sockfd, self, 2));
> +	ASSERT_EQ(EACCES, errno);
> +}
> +TEST_HARNESS_MAIN
> --
> 2.25.1
>