diff mbox series

[RFC,v3,16/19] selftests/landlock: Test that accept(2) is not restricted

Message ID 20240904104824.1844082-17-ivanov.mikhail1@huawei-partners.com (mailing list archive)
State Handled Elsewhere
Headers show
Series Support socket access-control | expand

Commit Message

Mikhail Ivanov Sept. 4, 2024, 10:48 a.m. UTC 
Add test validating that socket creation with accept(2) is not restricted
by Landlock.

Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@huawei-partners.com>
---
 .../testing/selftests/landlock/socket_test.c  | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)

Comments

Günther Noack Sept. 27, 2024, 2:53 p.m. UTC | #1 
On Wed, Sep 04, 2024 at 06:48:21PM +0800, Mikhail Ivanov wrote:
> Add test validating that socket creation with accept(2) is not restricted
> by Landlock.
> 
> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@huawei-partners.com>
> ---
>  .../testing/selftests/landlock/socket_test.c  | 71 +++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/tools/testing/selftests/landlock/socket_test.c b/tools/testing/selftests/landlock/socket_test.c
> index 2ab27196fa3d..052dbe0d1227 100644
> --- a/tools/testing/selftests/landlock/socket_test.c
> +++ b/tools/testing/selftests/landlock/socket_test.c
> @@ -939,4 +939,75 @@ TEST_F(socket_creation, sctp_peeloff)
>  	ASSERT_EQ(0, close(server_fd));
>  }
>  
> +TEST_F(socket_creation, accept)
> +{
> +	int status;
> +	pid_t child;
> +	struct sockaddr_in addr;
> +	int server_fd, client_fd;
> +	char buf;
> +	const struct landlock_ruleset_attr ruleset_attr = {
> +		.handled_access_socket = LANDLOCK_ACCESS_SOCKET_CREATE,
> +	};
> +	struct landlock_socket_attr tcp_socket_create = {
        ^^^^^^

Could be const as well, just like the ruleset_attr?

(I probably overlooked this as well in some of the other tests.)


> +		.allowed_access = LANDLOCK_ACCESS_SOCKET_CREATE,
> +		.family = AF_INET,
> +		.type = SOCK_STREAM,
> +	};
> +
> +	server_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
> +	ASSERT_LE(0, server_fd);
> +
> +	addr.sin_family = AF_INET;
> +	addr.sin_port = htons(loopback_port);
> +	addr.sin_addr.s_addr = inet_addr(loopback_ipv4);
> +
> +	ASSERT_EQ(0, bind(server_fd, &addr, sizeof(addr)));
> +	ASSERT_EQ(0, listen(server_fd, backlog));
> +
> +	child = fork();
> +	ASSERT_LE(0, child);
> +	if (child == 0) {

Nit:
I feel like the child code would benefit from a higher level comment,
like "Connects to the server once and exits." or such.

> +		/* Closes listening socket for the child. */
> +		ASSERT_EQ(0, close(server_fd));
> +
> +		client_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
> +		ASSERT_LE(0, client_fd);
> +
> +		ASSERT_EQ(0, connect(client_fd, &addr, sizeof(addr)));
> +		EXPECT_EQ(1, write(client_fd, ".", 1));
> +
> +		ASSERT_EQ(0, close(client_fd));
> +		_exit(_metadata->exit_code);
> +		return;
> +	}
> +
> +	if (self->sandboxed) {
> +		int ruleset_fd = landlock_create_ruleset(
> +			&ruleset_attr, sizeof(ruleset_attr), 0);
> +		ASSERT_LE(0, ruleset_fd);
> +		if (self->allowed) {
> +			ASSERT_EQ(0, landlock_add_rule(ruleset_fd,
> +						       LANDLOCK_RULE_SOCKET,
> +						       &tcp_socket_create, 0));
> +		}
> +		enforce_ruleset(_metadata, ruleset_fd);
> +		ASSERT_EQ(0, close(ruleset_fd));
> +	}
> +
> +	client_fd = accept(server_fd, NULL, 0);
> +
> +	/* accept(2) should not be restricted by Landlock. */
> +	EXPECT_LE(0, client_fd);

Should be an ASSERT, IMHO.
If this fails, client_fd will be -1,
and a lot of the stuff afterwards will fail as well.

> +
> +	EXPECT_EQ(1, read(client_fd, &buf, 1));
> +	EXPECT_EQ('.', buf);

I'm torn on whether the "." write and the check for it is very useful in this test.
It muddies the test's purpose a bit, and makes it harder to recognize the main use case.
Might make the test a bit simpler to drop it.

> +
> +	ASSERT_EQ(child, waitpid(child, &status, 0));
> +	ASSERT_EQ(1, WIFEXITED(status));
> +	ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
> +
> +	ASSERT_EQ(0, close(server_fd));

You are missing to close client_fd.

> +}
> +
>  TEST_HARNESS_MAIN
> -- 
> 2.34.1
>
Mikhail Ivanov Oct. 3, 2024, 12:41 p.m. UTC | #2 
On 9/27/2024 5:53 PM, Günther Noack wrote:
> On Wed, Sep 04, 2024 at 06:48:21PM +0800, Mikhail Ivanov wrote:
>> Add test validating that socket creation with accept(2) is not restricted
>> by Landlock.
>>
>> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@huawei-partners.com>
>> ---
>>   .../testing/selftests/landlock/socket_test.c  | 71 +++++++++++++++++++
>>   1 file changed, 71 insertions(+)
>>
>> diff --git a/tools/testing/selftests/landlock/socket_test.c b/tools/testing/selftests/landlock/socket_test.c
>> index 2ab27196fa3d..052dbe0d1227 100644
>> --- a/tools/testing/selftests/landlock/socket_test.c
>> +++ b/tools/testing/selftests/landlock/socket_test.c
>> @@ -939,4 +939,75 @@ TEST_F(socket_creation, sctp_peeloff)
>>   	ASSERT_EQ(0, close(server_fd));
>>   }
>>   
>> +TEST_F(socket_creation, accept)
>> +{
>> +	int status;
>> +	pid_t child;
>> +	struct sockaddr_in addr;
>> +	int server_fd, client_fd;
>> +	char buf;
>> +	const struct landlock_ruleset_attr ruleset_attr = {
>> +		.handled_access_socket = LANDLOCK_ACCESS_SOCKET_CREATE,
>> +	};
>> +	struct landlock_socket_attr tcp_socket_create = {
>          ^^^^^^
> 
> Could be const as well, just like the ruleset_attr?
> 
> (I probably overlooked this as well in some of the other tests.)

Yeap, I'll fix this for each test.

> 
> 
>> +		.allowed_access = LANDLOCK_ACCESS_SOCKET_CREATE,
>> +		.family = AF_INET,
>> +		.type = SOCK_STREAM,
>> +	};
>> +
>> +	server_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
>> +	ASSERT_LE(0, server_fd);
>> +
>> +	addr.sin_family = AF_INET;
>> +	addr.sin_port = htons(loopback_port);
>> +	addr.sin_addr.s_addr = inet_addr(loopback_ipv4);
>> +
>> +	ASSERT_EQ(0, bind(server_fd, &addr, sizeof(addr)));
>> +	ASSERT_EQ(0, listen(server_fd, backlog));
>> +
>> +	child = fork();
>> +	ASSERT_LE(0, child);
>> +	if (child == 0) {
> 
> Nit:
> I feel like the child code would benefit from a higher level comment,
> like "Connects to the server once and exits." or such.

Agreed, I'll add this

> 
>> +		/* Closes listening socket for the child. */
>> +		ASSERT_EQ(0, close(server_fd));
>> +
>> +		client_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
>> +		ASSERT_LE(0, client_fd);
>> +
>> +		ASSERT_EQ(0, connect(client_fd, &addr, sizeof(addr)));
>> +		EXPECT_EQ(1, write(client_fd, ".", 1));
>> +
>> +		ASSERT_EQ(0, close(client_fd));
>> +		_exit(_metadata->exit_code);
>> +		return;
>> +	}
>> +
>> +	if (self->sandboxed) {
>> +		int ruleset_fd = landlock_create_ruleset(
>> +			&ruleset_attr, sizeof(ruleset_attr), 0);
>> +		ASSERT_LE(0, ruleset_fd);
>> +		if (self->allowed) {
>> +			ASSERT_EQ(0, landlock_add_rule(ruleset_fd,
>> +						       LANDLOCK_RULE_SOCKET,
>> +						       &tcp_socket_create, 0));
>> +		}
>> +		enforce_ruleset(_metadata, ruleset_fd);
>> +		ASSERT_EQ(0, close(ruleset_fd));
>> +	}
>> +
>> +	client_fd = accept(server_fd, NULL, 0);
>> +
>> +	/* accept(2) should not be restricted by Landlock. */
>> +	EXPECT_LE(0, client_fd);
> 
> Should be an ASSERT, IMHO.
> If this fails, client_fd will be -1,
> and a lot of the stuff afterwards will fail as well.

Agreed, thank you!

> 
>> +
>> +	EXPECT_EQ(1, read(client_fd, &buf, 1));
>> +	EXPECT_EQ('.', buf);
> 
> I'm torn on whether the "." write and the check for it is very useful in this test.
> It muddies the test's purpose a bit, and makes it harder to recognize the main use case.
> Might make the test a bit simpler to drop it.

Agreed, this check is really not that important.

> 
>> +
>> +	ASSERT_EQ(child, waitpid(child, &status, 0));
>> +	ASSERT_EQ(1, WIFEXITED(status));
>> +	ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
>> +
>> +	ASSERT_EQ(0, close(server_fd));
> 
> You are missing to close client_fd.

will be fixed

> 
>> +}
>> +
>>   TEST_HARNESS_MAIN
>> -- 
>> 2.34.1
>>
diff mbox series

Patch

diff --git a/tools/testing/selftests/landlock/socket_test.c b/tools/testing/selftests/landlock/socket_test.c
index 2ab27196fa3d..052dbe0d1227 100644
--- a/tools/testing/selftests/landlock/socket_test.c
+++ b/tools/testing/selftests/landlock/socket_test.c
@@ -939,4 +939,75 @@  TEST_F(socket_creation, sctp_peeloff)
 	ASSERT_EQ(0, close(server_fd));
 }
 
+TEST_F(socket_creation, accept)
+{
+	int status;
+	pid_t child;
+	struct sockaddr_in addr;
+	int server_fd, client_fd;
+	char buf;
+	const struct landlock_ruleset_attr ruleset_attr = {
+		.handled_access_socket = LANDLOCK_ACCESS_SOCKET_CREATE,
+	};
+	struct landlock_socket_attr tcp_socket_create = {
+		.allowed_access = LANDLOCK_ACCESS_SOCKET_CREATE,
+		.family = AF_INET,
+		.type = SOCK_STREAM,
+	};
+
+	server_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
+	ASSERT_LE(0, server_fd);
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(loopback_port);
+	addr.sin_addr.s_addr = inet_addr(loopback_ipv4);
+
+	ASSERT_EQ(0, bind(server_fd, &addr, sizeof(addr)));
+	ASSERT_EQ(0, listen(server_fd, backlog));
+
+	child = fork();
+	ASSERT_LE(0, child);
+	if (child == 0) {
+		/* Closes listening socket for the child. */
+		ASSERT_EQ(0, close(server_fd));
+
+		client_fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
+		ASSERT_LE(0, client_fd);
+
+		ASSERT_EQ(0, connect(client_fd, &addr, sizeof(addr)));
+		EXPECT_EQ(1, write(client_fd, ".", 1));
+
+		ASSERT_EQ(0, close(client_fd));
+		_exit(_metadata->exit_code);
+		return;
+	}
+
+	if (self->sandboxed) {
+		int ruleset_fd = landlock_create_ruleset(
+			&ruleset_attr, sizeof(ruleset_attr), 0);
+		ASSERT_LE(0, ruleset_fd);
+		if (self->allowed) {
+			ASSERT_EQ(0, landlock_add_rule(ruleset_fd,
+						       LANDLOCK_RULE_SOCKET,
+						       &tcp_socket_create, 0));
+		}
+		enforce_ruleset(_metadata, ruleset_fd);
+		ASSERT_EQ(0, close(ruleset_fd));
+	}
+
+	client_fd = accept(server_fd, NULL, 0);
+
+	/* accept(2) should not be restricted by Landlock. */
+	EXPECT_LE(0, client_fd);
+
+	EXPECT_EQ(1, read(client_fd, &buf, 1));
+	EXPECT_EQ('.', buf);
+
+	ASSERT_EQ(child, waitpid(child, &status, 0));
+	ASSERT_EQ(1, WIFEXITED(status));
+	ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
+
+	ASSERT_EQ(0, close(server_fd));
+}
+
 TEST_HARNESS_MAIN