Message-ID: <1038177a-4f59-6018-0ded-650e032b4b9e@huawei.com>
Date:   Tue, 10 Jan 2023 08:03:27 +0300
From:   "Konstantin Meskhidze (A)" <konstantin.meskhidze@...wei.com>
To:     Mickaël Salaün <mic@...ikod.net>
CC:     <willemdebruijn.kernel@...il.com>, <gnoack3000@...il.com>,
        <linux-security-module@...r.kernel.org>, <netdev@...r.kernel.org>,
        <netfilter-devel@...r.kernel.org>, <artem.kuzin@...wei.com>
Subject: Re: [PATCH v8 10/12] selftests/landlock: Add 10 new test suites
 dedicated to network



1/9/2023 3:46 PM, Mickaël Salaün пишет:
> 
> On 21/10/2022 17:26, Konstantin Meskhidze wrote:
>> These test suites try to check edge cases for TCP sockets
>> bind() and connect() actions.
>> 
>> socket:
>> * bind_no_restrictions: Tests with non-landlocked ipv4 and ipv6 sockets.
>> * bind_with_restrictions: Tests with mixed landlock rules for ipv4 and
>> ipv6 sockets.
>> * connect_no_restrictions: Tests with non-landlocked ipv4 and ipv6 sockets.
>> * connect_with_restrictions: Tests with mixed landlock rules for ipv4 and
>> ipv6 sockets.
>> * connect_afunspec_no_restrictions: Tests with no landlock restrictions
>> allowing to disconnect already connected socket with AF_UNSPEC socket
>> family.
>> * connect_afunspec_with_restrictions: Tests with landlocked process
>> refusing to disconnect already connected socket.
>> * ruleset_overlap: Tests with overlapping rules for one port.
>> * ruleset_expanding: Tests with expanding rulesets in which rules are
>> gradually added one by one, restricting sockets' connections.
>> * inval: Tests with invalid user space supplied data:
>>      - out of range ruleset attribute;
>>      - unhandled allowed access;
>>      - zero port value;
>>      - zero access value;
>>      - legitimate access values;
>> 
>> layout1:
>> * with_net: Tests with network bind() socket action within
>> filesystem directory access test.
>> 
>> Test coverage for security/landlock is 94.3% of 920 lines according
>> to gcc/gcov-11.
>> 
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
>> ---
>> 
>> Changes since v7:
>> * Squashes all selftest commits.
>> * Adds fs test with network bind() socket action.
>> * Minor fixes.
>> 
>> ---
>>   security/landlock/ruleset.h                 |   2 -
>>   tools/testing/selftests/landlock/config     |   4 +
>>   tools/testing/selftests/landlock/fs_test.c  |  65 ++
>>   tools/testing/selftests/landlock/net_test.c | 823 ++++++++++++++++++++
>>   4 files changed, 892 insertions(+), 2 deletions(-)
>>   create mode 100644 tools/testing/selftests/landlock/net_test.c
>> 
>> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
>> index f272d2cd518c..ee1a02a404ce 100644
>> --- a/security/landlock/ruleset.h
>> +++ b/security/landlock/ruleset.h
>> @@ -264,7 +264,6 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset,
>> 
>>   	/* Should already be checked in sys_landlock_create_ruleset(). */
>>   	WARN_ON_ONCE(fs_access_mask != fs_mask);
>> -	// TODO: Add tests to check "|=" and not "="
>>   	ruleset->access_masks[layer_level] |=
>>   		(fs_mask << LANDLOCK_SHIFT_ACCESS_FS);
>>   }
>> @@ -278,7 +277,6 @@ landlock_add_net_access_mask(struct landlock_ruleset *const ruleset,
>> 
>>   	/* Should already be checked in sys_landlock_create_ruleset(). */
>>   	WARN_ON_ONCE(net_access_mask != net_mask);
>> -	// TODO: Add tests to check "|=" and not "="
>>   	ruleset->access_masks[layer_level] |=
>>   		(net_mask << LANDLOCK_SHIFT_ACCESS_NET);
>>   }
>> 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/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
>> index 20c1ac8485f1..5c52da1a5a69 100644
>> --- a/tools/testing/selftests/landlock/fs_test.c
>> +++ b/tools/testing/selftests/landlock/fs_test.c
>> @@ -8,14 +8,17 @@
>>    */
>> 
>>   #define _GNU_SOURCE
>> +#include <arpa/inet.h>
>>   #include <fcntl.h>
>>   #include <linux/landlock.h>
>> +#include <netinet/in.h>
>>   #include <sched.h>
>>   #include <string.h>
>>   #include <sys/capability.h>
>>   #include <sys/mount.h>
>>   #include <sys/prctl.h>
>>   #include <sys/sendfile.h>
>> +#include <sys/socket.h>
>>   #include <sys/stat.h>
>>   #include <sys/sysmacros.h>
>>   #include <unistd.h>
>> @@ -4366,4 +4369,66 @@ TEST_F_FORK(layout2_overlay, same_content_different_file)
>>   	}
>>   }
>> 
>> +#define IP_ADDRESS "127.0.0.1"
>> +
>> +TEST_F_FORK(layout1, with_net)
>> +{
>> +	int sockfd;
>> +	int sock_port = 15000;
>> +	struct sockaddr_in addr4;
>> +
>> +	addr4.sin_family = AF_INET;
>> +	addr4.sin_port = htons(sock_port);
>> +	addr4.sin_addr.s_addr = inet_addr(IP_ADDRESS);
>> +	memset(&addr4.sin_zero, '\0', 8);
>> +
>> +	const struct rule rules[] = {
>> +		{
>> +			.path = dir_s1d2,
>> +			.access = ACCESS_RO,
>> +		},
>> +		{},
>> +	};
>> +
>> +	struct landlock_ruleset_attr ruleset_attr_net = {
>> +		.handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
>> +				      LANDLOCK_ACCESS_NET_CONNECT_TCP,
>> +	};
>> +	struct landlock_net_service_attr net_service = {
>> +		.allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP,
>> +
>> +		.port = sock_port,
>> +	};
>> +
>> +	/* Creates ruleset for network access. */
>> +	const int ruleset_fd_net = landlock_create_ruleset(
>> +		&ruleset_attr_net, sizeof(ruleset_attr_net), 0);
>> +	ASSERT_LE(0, ruleset_fd_net);
>> +
>> +	/* Adds a network rule. */
>> +	ASSERT_EQ(0,
>> +		  landlock_add_rule(ruleset_fd_net, LANDLOCK_RULE_NET_SERVICE,
>> +				    &net_service, 0));
>> +
>> +	enforce_ruleset(_metadata, ruleset_fd_net);
>> +	ASSERT_EQ(0, close(ruleset_fd_net));
>> +
>> +	const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
>> +	ASSERT_LE(0, ruleset_fd);
>> +	enforce_ruleset(_metadata, ruleset_fd);
>> +	ASSERT_EQ(0, close(ruleset_fd));
>> +
>> +	/* Tests on a directory with the network rule loaded. */
>> +	ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY));
>> +	ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
>> +
>> +	sockfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
>> +	ASSERT_LE(0, sockfd);
>> +	/* Binds a socket to port 15000. */
>> +	ASSERT_EQ(0, bind(sockfd, &addr4, sizeof(addr4)));
>> +
>> +	/* Closes bounded socket. */
>> +	ASSERT_EQ(0, close(sockfd));
>> +}
>> +
>>   TEST_HARNESS_MAIN
>> diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c
>> new file mode 100644
>> index 000000000000..d1548bd7ab60
>> --- /dev/null
>> +++ b/tools/testing/selftests/landlock/net_test.c
>> @@ -0,0 +1,823 @@
>> +// 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"
>> +
>> +/* Number pending connections queue to be hold. */
>> +#define BACKLOG 10
>> +
>> +const struct sockaddr addr_unspec = { .sa_family = AF_UNSPEC };
>> +
>> +/* Invalid attribute, out of landlock network access range. */
>> +#define LANDLOCK_INVAL_ATTR 7
>> +
>> +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 struct _fixture_variant_socket *const variant,
>> +		      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 struct _fixture_variant_socket *const variant,
>> +			const int sockfd,
>> +			const struct _test_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]));
>> +}
>> +
>> +static int connect_variant(const struct _fixture_variant_socket *const variant,
>> +			   const int sockfd,
>> +			   const struct _test_data_socket *const self,
>> +			   const size_t index)
>> +{
>> +	if (variant->is_ipv4)
>> +		return connect(sockfd, &self->addr4[index],
>> +			       sizeof(self->addr4[index]));
>> +	else
>> +		return connect(sockfd, &self->addr6[index],
>> +			       sizeof(self->addr6[index]));
>> +}
>> +
>> +FIXTURE_SETUP(socket)
>> +{
>> +	int i;
>> +
>> +	/* Creates IPv4 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 IPv6 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_FORK(socket, bind_no_restrictions)
>> +{
>> +	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_FORK(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
>> +	 * 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));
>> +
>> +	/* Closes bounded socket. */
>> +	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);
> 
> This is inconsistent with the bind_no_restrictions test. If you
> deduplicate the tests with and without restrictions (i.e. only one
> "bind" test, and another "connect"…), you can extend
> FIXTURE_VARIANT(socket) with a new const bool enforce_landlock, and
> check that in all tests to either do Landlock syscalls or not. You can
> still initialize most variable whatever Landlock should be enforced or
> not (e.g. ruleset_attr, net_service_1…) to make it easiear to read.
> 

   I think it's not a deduplication. Tests enforeced with landlock are 
more various regarding port and net_service attributes used. The number 
of landlock atributes vary from test ot test. I'dont see how to unify it
with FIXTURE_VARIANT and enforce_landlock const will it make harder 
merging tests.
Please your opinion and suggestions?

> 
>> +}
>> +
>> +TEST_F_FORK(socket, connect_no_restrictions)
> .

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