From 644a728506c794e9e4f5fb9845ed4f7014cf46d9 Mon Sep 17 00:00:00 2001
From: Tahera Fahimi <fahimitahera@gmail.com>
Date: Wed, 4 Sep 2024 18:14:00 -0600
Subject: [PATCH] selftests/landlock: Test inherited restriction of abstract
UNIX socket
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A socket can be shared between multiple processes, so it can connect and
send data to them. Provide a test scenario where a sandboxed process
inherits a socket's file descriptor. The process cannot connect or send
data to the inherited socket since the process is scoped.
Test coverage for security/landlock is 92.0% of 1013 lines according to
gcc/gcov-14.
Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com>
Link: https://lore.kernel.org/r/1428574deec13603b6ab2f2ed68ecbfa3b63bcb3.1725494372.git.fahimitahera@gmail.com
[mic: Remove negative ASSERT, fix potential race condition because of
closed connections, remove useless buffer, add test coverage]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
---
.../landlock/scoped_abstract_unix_test.c | 64 +++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
index ad97f14f97dea..a6b59d2ab1b42 100644
--- a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
+++ b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
@@ -974,4 +974,68 @@ TEST(datagram_sockets)
_metadata->exit_code = KSFT_FAIL;
}
+TEST(self_connect)
+{
+ struct service_fixture connected_addr, non_connected_addr;
+ int connected_socket, non_connected_socket, status;
+ pid_t child;
+
+ drop_caps(_metadata);
+ memset(&connected_addr, 0, sizeof(connected_addr));
+ set_unix_address(&connected_addr, 0);
+ memset(&non_connected_addr, 0, sizeof(non_connected_addr));
+ set_unix_address(&non_connected_addr, 1);
+
+ connected_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
+ non_connected_socket = socket(AF_UNIX, SOCK_DGRAM, 0);
+ ASSERT_LE(0, connected_socket);
+ ASSERT_LE(0, non_connected_socket);
+
+ ASSERT_EQ(0, bind(connected_socket, &connected_addr.unix_addr,
+ connected_addr.unix_addr_len));
+ ASSERT_EQ(0, bind(non_connected_socket, &non_connected_addr.unix_addr,
+ non_connected_addr.unix_addr_len));
+
+ child = fork();
+ ASSERT_LE(0, child);
+ if (child == 0) {
+ /* Child's domain is scoped. */
+ create_scoped_domain(_metadata,
+ LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET);
+
+ /*
+ * The child inherits the sockets, and cannot connect or
+ * send data to them.
+ */
+ ASSERT_EQ(-1,
+ connect(connected_socket, &connected_addr.unix_addr,
+ connected_addr.unix_addr_len));
+ ASSERT_EQ(EPERM, errno);
+
+ ASSERT_EQ(-1, sendto(connected_socket, ".", 1, 0,
+ &connected_addr.unix_addr,
+ connected_addr.unix_addr_len));
+ ASSERT_EQ(EPERM, errno);
+
+ ASSERT_EQ(-1, sendto(non_connected_socket, ".", 1, 0,
+ &non_connected_addr.unix_addr,
+ non_connected_addr.unix_addr_len));
+ ASSERT_EQ(EPERM, errno);
+
+ EXPECT_EQ(0, close(connected_socket));
+ EXPECT_EQ(0, close(non_connected_socket));
+ _exit(_metadata->exit_code);
+ return;
+ }
+
+ /* Waits for all tests to finish. */
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ EXPECT_EQ(0, close(connected_socket));
+ EXPECT_EQ(0, close(non_connected_socket));
+
+ if (WIFSIGNALED(status) || !WIFEXITED(status) ||
+ WEXITSTATUS(status) != EXIT_SUCCESS)
+ _metadata->exit_code = KSFT_FAIL;
+}
+
TEST_HARNESS_MAIN
--
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