Re: [PATCH v5 09/15] seltests/landlock: add tests for bind() hooks

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





5/19/2022 5:29 PM, Mickaël Salaün пишет:

On 19/05/2022 14:10, Konstantin Meskhidze wrote:


5/17/2022 12:11 AM, Mickaël Salaün пишет:

On 16/05/2022 17:20, Konstantin Meskhidze wrote:
Adds selftests for bind socket action.
The first is with no landlock restrictions:
     - bind_no_restrictions_ip4;
     - bind_no_restrictions_ip6;
The second ones is with mixed landlock rules:
     - bind_with_restrictions_ip4;
     - bind_with_restrictions_ip6;

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---

Changes since v3:
* Split commit.
* Add helper create_socket.
* Add FIXTURE_SETUP.

Changes since v4:
* Adds port[MAX_SOCKET_NUM], struct sockaddr_in addr4
and struct sockaddr_in addr6 in FIXTURE.
* Refactoring FIXTURE_SETUP:
     - initializing self->port, self->addr4 and self->addr6.
     - adding network namespace.
* Refactoring code with self->port, self->addr4 and
self->addr6 variables.
* Adds selftests for IP6 family:
     - bind_no_restrictions_ip6.
     - bind_with_restrictions_ip6.
* Refactoring selftests/landlock/config
* Moves enforce_ruleset() into common.h

---
  tools/testing/selftests/landlock/common.h   |   9 +
  tools/testing/selftests/landlock/config     |   5 +-
  tools/testing/selftests/landlock/fs_test.c  |  10 -
  tools/testing/selftests/landlock/net_test.c | 237 ++++++++++++++++++++
  4 files changed, 250 insertions(+), 11 deletions(-)
  create mode 100644 tools/testing/selftests/landlock/net_test.c

diff --git a/tools/testing/selftests/landlock/common.h b/tools/testing/selftests/landlock/common.h
index 7ba18eb23783..c5381e641dfd 100644
--- a/tools/testing/selftests/landlock/common.h
+++ b/tools/testing/selftests/landlock/common.h
@@ -102,6 +102,15 @@ static inline int landlock_restrict_self(const int ruleset_fd,
  }
  #endif

+static void enforce_ruleset(struct __test_metadata *const _metadata,
+        const int ruleset_fd)
+{
+    ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+    ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)) {
+        TH_LOG("Failed to enforce ruleset: %s", strerror(errno));
+    }
+}
+

Please create a commit which moves all the needed code for all network tests. I think there is only this helper though.

   Ok. I will create one additional commit for moving this helper.
   But after I have moved the helper to common.h, I got warnings while compiling seltests where I don't use the one (base_test and ptrace_test)

Move it after clear_cap() and use the same attributes.

  Ok. Thank you.
[...]

 >>> diff --git a/tools/testing/selftests/landlock/config
 >>> b/tools/testing/selftests/landlock/config
 >>> index 0f0a65287bac..b56f3274d3f5 100644
 >>> --- a/tools/testing/selftests/landlock/config
 >>> +++ b/tools/testing/selftests/landlock/config
 >>> @@ -1,7 +1,10 @@
 >>> +CONFIG_INET=y
 >>> +CONFIG_IPV6=y
 >>> +CONFIG_NET=y
 >>>   CONFIG_OVERLAY_FS=y
 >>>   CONFIG_SECURITY_LANDLOCK=y
 >>>   CONFIG_SECURITY_PATH=y
 >>>   CONFIG_SECURITY=y
 >>>   CONFIG_SHMEM=y
 >>>   CONFIG_TMPFS_XATTR=y
 >>> -CONFIG_TMPFS=y
 >>> +CONFIG_TMPFS=y
 >>> \ No newline at end of file

You also need to add CONFIG_NET_NS.

  Yep. I have forgotten about it. Thanks.

[...]


+        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 = htonl(INADDR_ANY);

Could you use the local addr (127.0.0.1) instead?

   Why cant I use INADDR_ANY here?

You can, but it is cleaner to bind to a specified address (i.e. you control where a connection come from), and I guess this variable/address could be used to establish connections as well.

 Ok. I got it.

+        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]);
+        self->addr6[i].sin6_addr = in6addr_any;

ditto

   Why cant I use in6addr_any here?

Same as for IPV4.

  Ok.



+    }
+
+    set_cap(_metadata, CAP_SYS_ADMIN);
+    ASSERT_EQ(0, unshare(CLONE_NEWNET));
+    ASSERT_EQ(0, system("ip link set dev lo up"));

If this is really required, could you avoid calling system() but set up the network in C? You can strace it to see what is going on underneath.

  I did check. It's a lot of code to be run under the hood (more than one line) and it will just will complicate the test so I suggest to leave just ONE line of code here.

OK



+    clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+FIXTURE_TEARDOWN(socket_test)
+{ }
+
+TEST_F_FORK(socket_test, bind_no_restrictions_ip4) {
+
+    int sockfd;
+
+    sockfd = create_socket(_metadata, false, false);
+    ASSERT_LE(0, sockfd);
+
+    /* Binds a socket to port[0] */

This comment is not very useful in this context considering the below line. It will be even more clear with the bind_variant() call.

  Ok. I will fix it.

+    ASSERT_EQ(0, bind(sockfd, (struct sockaddr *)&self->addr4[0], sizeof(self->addr4[0])));
+
+    ASSERT_EQ(0, close(sockfd));
+}
+
+TEST_F_FORK(socket_test, bind_no_restrictions_ip6) {
+
+    int sockfd;
+
+    sockfd = create_socket(_metadata, true, false);
+    ASSERT_LE(0, sockfd);
+
+    /* Binds a socket to port[0] */
+    ASSERT_EQ(0, bind(sockfd, (struct sockaddr *)&self->addr6[0], sizeof(self->addr6[0])));
+
+    ASSERT_EQ(0, close(sockfd));
+}
+
+TEST_F_FORK(socket_test, bind_with_restrictions_ip4) {
+
+    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. */

This comment is useful though because the below call is more complex.

   So I can leave it as it's, cant I?

Yes, keep it, I'd just like a fair amount of useful comments. ;)

  Ok. Thank you!
.



[Index of Archives]     [Netfitler Users]     [Berkeley Packet Filter]     [LARTC]     [Bugtraq]     [Yosemite Forum]

  Powered by Linux