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Fix GSSAPI PUB/SUB subscription corruption on reconnection #4848

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Fix GSSAPI PUB/SUB subscription corruption on reconnection #4848

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8 changes: 8 additions & 0 deletions src/gssapi_mechanism_base.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,10 @@ int zmq::gssapi_mechanism_base_t::encode_message (msg_t *msg_)
flags |= 0x01;
if (msg_->flags () & msg_t::command)
flags |= 0x02;
if (msg_->is_subscribe ())
flags |= 0x04;
else if (msg_->is_cancel ())
flags |= 0x08;

uint8_t *plaintext_buffer =
static_cast<uint8_t *> (malloc (msg_->size () + 1));
Expand Down Expand Up @@ -174,6 +178,10 @@ int zmq::gssapi_mechanism_base_t::decode_message (msg_t *msg_)
msg_->set_flags (msg_t::more);
if (flags & 0x02)
msg_->set_flags (msg_t::command);
if (flags & 0x04)
msg_->set_flags (msg_t::subscribe);
else if (flags & 0x08)
msg_->set_flags (msg_t::cancel);

memcpy (msg_->data (), static_cast<char *> (plaintext.value) + 1,
plaintext.length - 1);
Expand Down
127 changes: 127 additions & 0 deletions tests/test_security_gssapi.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -141,6 +141,131 @@ void tearDown ()
zmq_threadclose (zap_thread);
}

static void setup_gssapi_client_socket (void *client_)
{
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
client_, ZMQ_GSSAPI_SERVICE_PRINCIPAL, name, strlen (name) + 1));
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
client_, ZMQ_GSSAPI_PRINCIPAL, name, strlen (name) + 1));
int name_type = ZMQ_GSSAPI_NT_HOSTBASED;
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
client_, ZMQ_GSSAPI_PRINCIPAL_NAMETYPE, &name_type, sizeof (name_type)));
}

// Test that PUB/SUB subscriptions work correctly with GSSAPI encryption.
// This is a regression test for the bug where subscribe/cancel flags were
// lost during GSSAPI encode_message(), causing subscriptions to be silently
// dropped or corrupted after reconnection.
void test_pubsub_subscription ()
{
// Create a PUB socket acting as server
void *pub = test_context_socket (ZMQ_PUB);
int as_server = 1;
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_SERVER, &as_server, sizeof (int)));
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_PRINCIPAL, name, strlen (name) + 1));
int name_type = ZMQ_GSSAPI_NT_HOSTBASED;
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
pub, ZMQ_GSSAPI_PRINCIPAL_NAMETYPE, &name_type, sizeof (name_type)));

char pub_endpoint[MAX_SOCKET_STRING];
bind_loopback_ipv4 (pub, pub_endpoint, sizeof pub_endpoint);

// Create a SUB socket acting as client
void *sub = test_context_socket (ZMQ_SUB);
setup_gssapi_client_socket (sub);

// Subscribe to topic "test"
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (sub, ZMQ_SUBSCRIBE, "test", 4));

TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (sub, pub_endpoint));

// Give time for connection and subscription to be established
msleep (500);

// Send a matching message
send_string_expect_success (pub, "test message", 0);

// Should receive the message
int timeout = 1000;
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (sub, ZMQ_RCVTIMEO, &timeout, sizeof (timeout)));
recv_string_expect_success (sub, "test message", 0);

test_context_socket_close (sub);
test_context_socket_close (pub);
}

// Test that PUB/SUB subscriptions survive reconnection with GSSAPI encryption.
// Specifically tests the bug where xhiccuped() re-sends subscriptions through
// GSSAPI encode_message() and the subscribe flag was lost, causing the
// subscription to be silently dropped on the PUB side after reconnect.
void test_pubsub_subscription_after_reconnect ()
{
// Create a PUB socket acting as server
void *pub = test_context_socket (ZMQ_PUB);
int as_server = 1;
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_SERVER, &as_server, sizeof (int)));
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_PRINCIPAL, name, strlen (name) + 1));
int name_type = ZMQ_GSSAPI_NT_HOSTBASED;
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
pub, ZMQ_GSSAPI_PRINCIPAL_NAMETYPE, &name_type, sizeof (name_type)));

char pub_endpoint[MAX_SOCKET_STRING];
bind_loopback_ipv4 (pub, pub_endpoint, sizeof pub_endpoint);

// Create a SUB socket, subscribe, and connect
void *sub = test_context_socket (ZMQ_SUB);
setup_gssapi_client_socket (sub);
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (sub, ZMQ_SUBSCRIBE, "test", 4));
TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (sub, pub_endpoint));

// Give time for connection and subscription to be established
msleep (500);

// Verify initial subscription works
send_string_expect_success (pub, "test hello", 0);
int timeout = 1000;
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (sub, ZMQ_RCVTIMEO, &timeout, sizeof (timeout)));
recv_string_expect_success (sub, "test hello", 0);

// Simulate server restart: close and rebind PUB on same endpoint
test_context_socket_close (pub);
msleep (100);

pub = test_context_socket (ZMQ_PUB);
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_SERVER, &as_server, sizeof (int)));
TEST_ASSERT_SUCCESS_ERRNO (
zmq_setsockopt (pub, ZMQ_GSSAPI_PRINCIPAL, name, strlen (name) + 1));
TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
pub, ZMQ_GSSAPI_PRINCIPAL_NAMETYPE, &name_type, sizeof (name_type)));
TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (pub, pub_endpoint));

// Give time for the SUB to reconnect and re-send subscriptions
msleep (1000);

// Send a matching message - subscription should still be active
send_string_expect_success (pub, "test world", 0);
recv_string_expect_success (sub, "test world", 0);

// Also verify that a non-matching message is filtered
send_string_expect_success (pub, "other message", 0);
char buf[64];
int rc = zmq_recv (sub, buf, sizeof buf, 0);
TEST_ASSERT_EQUAL_INT (-1, rc);
TEST_ASSERT_EQUAL_INT (EAGAIN, errno);

test_context_socket_close (sub);
test_context_socket_close (pub);
}

void test_valid_creds ()
{
void *client = test_context_socket (ZMQ_DEALER);
Expand Down Expand Up @@ -243,5 +368,7 @@ int main (void)
RUN_TEST (test_plain_creds);
RUN_TEST (test_vanilla_socket);
RUN_TEST (test_unauth_creds);
RUN_TEST (test_pubsub_subscription);
RUN_TEST (test_pubsub_subscription_after_reconnect);
return UNITY_END ();
}
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