Date:   Mon, 6 Mar 2023 15:03:49 +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>, <yusongping@...wei.com>,
        <artem.kuzin@...wei.com>
Subject: Re: [PATCH v9 10/12] selftests/landlock: Add 10 new test suites
 dedicated to network



2/21/2023 9:05 PM, Mickaël Salaün пишет:
> 
> On 16/01/2023 09:58, Konstantin Meskhidze wrote:
>> These test suites try to check edge cases for TCP sockets
>> bind() and connect() actions.
>> 
>> socket:
>> * bind: Tests with non-landlocked/landlocked ipv4 and ipv6 sockets.
>> * connect: Tests with non-landlocked/landlocked ipv4 and ipv6 sockets.
>> * bind_afunspec: Tests with non-landlocked/landlocked restrictions
>> for bind action with AF_UNSPEC socket family.
>> * connect_afunspec: Tests with non-landlocked/landlocked restrictions
>> for connect action with AF_UNSPEC socket family.
>> * 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;
>> * bind_connect_inval_addrlen: Tests with invalid address length
>> for ipv4/ipv6 sockets.
>> * inval_port_format: Tests with wrong port format for ipv4/ipv6 sockets.
>> 
>> layout1:
>> * with_net: Tests with network bind() socket action within
>> filesystem directory access test.
>> 
>> Test coverage for security/landlock is 94.1% of 946 lines according
>> to gcc/gcov-11.
>> 
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
>> ---
>> 
>> Changes since v8:
>> * Adds is_sandboxed const for FIXTURE_VARIANT(socket).
>> * Refactors AF_UNSPEC tests.
>> * Adds address length checking tests.
>> * Convert ports in all tests to __be16.
>> * Adds invalid port values tests.
>> * Minor fixes.
>> 
>> Changes since v7:
>> * Squashes all selftest commits.
>> * Adds fs test with network bind() socket action.
>> * Minor fixes.
>> 
>> ---
>>   tools/testing/selftests/landlock/config     |    4 +
>>   tools/testing/selftests/landlock/fs_test.c  |   65 ++
>>   tools/testing/selftests/landlock/net_test.c | 1157 +++++++++++++++++++
>>   3 files changed, 1226 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/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
>> index b762b5419a89..5de4559c7fbb 100644
>> --- a/tools/testing/selftests/landlock/fs_test.c
>> +++ b/tools/testing/selftests/landlock/fs_test.c
>> @@ -8,8 +8,10 @@
>>    */
>>   
>>   #define _GNU_SOURCE
>> +#include <arpa/inet.h>
>>   #include <fcntl.h>
>>   #include <linux/landlock.h>
>> +#include <netinet/in.h>
>>   #include <sched.h>
>>   #include <stdio.h>
>>   #include <string.h>
>> @@ -17,6 +19,7 @@
>>   #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>
>> @@ -4413,4 +4416,66 @@ 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 = htons(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..b9543089a4d3
>> --- /dev/null
>> +++ b/tools/testing/selftests/landlock/net_test.c
>> @@ -0,0 +1,1157 @@
>> +// 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 <linux/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_IPv4 "127.0.0.1"
> 
> Please use a capital "V".

   Ok. Got it.
> 
>> +#define IP_ADDRESS_IPv6 "::1"
> 
> ditto

   Ok.
> 
> 
>> +#define SOCK_PORT 15000
>> +
>> +/* 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;
>> +	const bool is_sandboxed;
>> +};
>> +
>> +/* clang-format off */
>> +FIXTURE_VARIANT_ADD(socket, ipv4) {
>> +	/* clang-format on */
>> +	.is_ipv4 = true,
>> +	.is_sandboxed = false,
>> +};
>> +
>> +/* clang-format off */
>> +FIXTURE_VARIANT_ADD(socket, ipv4_sandboxed) {
>> +	/* clang-format on */
>> +	.is_ipv4 = true,
>> +	.is_sandboxed = true,
>> +};
>> +
>> +/* clang-format off */
>> +FIXTURE_VARIANT_ADD(socket, ipv6) {
>> +	/* clang-format on */
>> +	.is_ipv4 = false,
>> +	.is_sandboxed = false,
>> +};
>> +
>> +/* clang-format off */
>> +FIXTURE_VARIANT_ADD(socket, ipv6_sandboxed) {
>> +	/* clang-format on */
>> +	.is_ipv4 = false,
>> +	.is_sandboxed = true,
>> +};
>> +
>> +static int
>> +create_socket_variant(const struct _fixture_variant_socket *const variant,
> 
> If all "struct _fixture_variant_socket" can be replaced with
> "FIXTURE_VARIANT(socket)" while keeping clang-format and checkpatch.pl
> happy, please do it. It seems that some clang-format issues have been
> fixed. Same for _test_data and FIXTURE_DATA. Please remove the outdated
> comments about these structs (see socket_standalone, and socket variant
> definitions).
> 
   Ok. Thanks.
> 
>> +		      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, const bool zero_size)
>> +
> 
> Extra new line.

   Will be deleted. Thanks.
> 
>> +{
>> +	if (variant->is_ipv4)
>> +		return bind(sockfd, &self->addr4[index],
>> +			    (zero_size ? 0 : sizeof(self->addr4[index])));
> 
> Is the zero_size really useful? Do calling bind and connect with this
> argument reaches the Landlock code (check_addrlen) or is it caught by
> the network code beforehand?

   In __sys_bind() syscall security_socket_bind() function goes before
   sock->ops->bind() method. Selinux and Smacks provide such checks in
   bind()/connect() hooks, so I think Landlock should do the same.
   What do you think?
> 
> 
>> +	else
>> +		return bind(sockfd, &self->addr6[index],
>> +			    (zero_size ? 0 : 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, const bool zero_size)
>> +{
>> +	if (variant->is_ipv4)
>> +		return connect(sockfd, &self->addr4[index],
>> +			       (zero_size ? 0 : sizeof(self->addr4[index])));
>> +	else
>> +		return connect(sockfd, &self->addr6[index],
>> +			       (zero_size ? 0 : sizeof(self->addr6[index])));
>> +}
> 
> 
> [...]
> 
>> +
>> +TEST_F_FORK(socket, bind)
>> +{
>> +	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 = htons(self->port[0]),
>> +	};
>> +	struct landlock_net_service_attr net_service_2 = {
>> +		.allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP,
>> +		.port = htons(self->port[1]),
>> +	};
>> +	struct landlock_net_service_attr net_service_3 = {
>> +		.allowed_access = 0,
>> +		.port = htons(self->port[2]),
>> +	};
>> +	int ruleset_fd, ret;
>> +
>> +	if (variant->is_sandboxed) {
>> +		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]. */
>> +	ret = bind_variant(variant, sockfd, self, 0, false);
>> +	if (variant->is_sandboxed) {
>> +		ASSERT_EQ(0, ret);
>> +	} else {
>> +		ASSERT_EQ(0, ret);
>> +	
> The condition is useless here. Same on multiple other locations.
> 
   Ok. Will be fixed.
> 
>> +
>> +	/* 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]. */
>> +	ret = bind_variant(variant, sockfd, self, 1, false);
>> +	if (variant->is_sandboxed) {
>> +		ASSERT_EQ(-1, ret);
>> +		ASSERT_EQ(EACCES, errno);
>> +	} else {
>> +		ASSERT_EQ(0, ret);
>> +	}
>> +
>> +	sockfd = create_socket_variant(variant, SOCK_STREAM);
>> +	ASSERT_LE(0, sockfd);
>> +	/* Binds a socket to port[2]. */
>> +	ret = bind_variant(variant, sockfd, self, 2, false);
>> +	if (variant->is_sandboxed) {
>> +		ASSERT_EQ(-1, ret);
>> +		ASSERT_EQ(EACCES, errno);
>> +	} else {
>> +		ASSERT_EQ(0, ret);
>> +	}
>> +}
> .

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