tests/qtest/migration-test: Free QCRyptoTLSTestCertReq objects

In the migration test we create several TLS certificates with
the TLS_* macros from crypto-tls-x509-helpers.h. These macros
create both a QCryptoTLSCertReq object which must be deinitialized
and also an on-disk certificate file. The migration test currently
removes the on-disk file in test_migrate_tls_x509_finish() but
never deinitializes the QCryptoTLSCertReq, which means that memory
allocated as part of it is leaked:

Indirect leak of 2 byte(s) in 1 object(s) allocated from:
    #0 0x5558ba33712e in malloc (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/tests/qtest/migration-test+0x22f12e) (BuildId: 4c8618f663e538538cad19d35233124cea161491)
    #1 0x7f64afc131f4  (/lib/x86_64-linux-gnu/libtasn1.so.6+0x81f4) (BuildId: 2fde6ecb43c586fe4077118f771077aa1298e7ea)
    #2 0x7f64afc18d58 in asn1_write_value (/lib/x86_64-linux-gnu/libtasn1.so.6+0xdd58) (BuildId: 2fde6ecb43c586fe4077118f771077aa1298e7ea)
    #3 0x7f64af8fc678 in gnutls_x509_crt_set_version (/lib/x86_64-linux-gnu/libgnutls.so.30+0xe7678) (BuildId: 97b8f99f392f1fd37b969a7164bcea884e23649b)
    #4 0x5558ba470035 in test_tls_generate_cert tests/unit/crypto-tls-x509-helpers.c:234:5
    qemu#5 0x5558ba464e4a in test_migrate_tls_x509_start_common tests/qtest/migration-test.c:1058:5
    qemu#6 0x5558ba462c8a in test_migrate_tls_x509_start_default_host tests/qtest/migration-test.c:1123:12
    qemu#7 0x5558ba45ab40 in test_precopy_common tests/qtest/migration-test.c:1786:21
    qemu#8 0x5558ba450015 in test_precopy_unix_tls_x509_default_host tests/qtest/migration-test.c:2077:5
    qemu#9 0x5558ba46d3c7 in migration_test_wrapper tests/qtest/migration-helpers.c:456:5

(and similar reports).

The only function currently provided to deinit a QCryptoTLSCertReq is
test_tls_discard_cert(), which also removes the on-disk certificate
file.  For the migration tests we need to retain the on-disk files
until we've finished running the test, so the simplest fix is to
provide a new function test_tls_deinit_cert() which does only the
cleanup of the QCryptoTLSCertReq, and call it in the right places.

Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Fabiano Rosas <[email protected]>
Signed-off-by: Fabiano Rosas <[email protected]>

Author: pm215

tests/qtest/migration-test.c

@@ -1061,12 +1061,15 @@ test_migrate_tls_x509_start_common(QTestState *from,
                                    QCRYPTO_TLS_TEST_CLIENT_HOSTILE_NAME :
                                    QCRYPTO_TLS_TEST_CLIENT_NAME,
                                    data->clientcert);
+        test_tls_deinit_cert(&servercertreq);
     }
 
     TLS_CERT_REQ_SIMPLE_SERVER(clientcertreq, cacertreq,
                                data->servercert,
                                args->certhostname,
                                args->certipaddr);
+    test_tls_deinit_cert(&clientcertreq);
+    test_tls_deinit_cert(&cacertreq);
 
     qtest_qmp_assert_success(from,
                              "{ 'execute': 'object-add',"

tests/unit/crypto-tls-x509-helpers.c

@@ -502,15 +502,23 @@ void test_tls_write_cert_chain(const char *filename,
     g_free(buffer);
 }
 
-
-void test_tls_discard_cert(QCryptoTLSTestCertReq *req)
+void test_tls_deinit_cert(QCryptoTLSTestCertReq *req)
 {
     if (!req->crt) {
         return;
     }
 
     gnutls_x509_crt_deinit(req->crt);
     req->crt = NULL;
+}
+
+void test_tls_discard_cert(QCryptoTLSTestCertReq *req)
+{
+    if (!req->crt) {
+        return;
+    }
+
+    test_tls_deinit_cert(req);
 
     if (getenv("QEMU_TEST_DEBUG_CERTS") == NULL) {
         unlink(req->filename);

tests/unit/crypto-tls-x509-helpers.h

@@ -73,6 +73,12 @@ void test_tls_generate_cert(QCryptoTLSTestCertReq *req,
 void test_tls_write_cert_chain(const char *filename,
                                gnutls_x509_crt_t *certs,
                                size_t ncerts);
+/*
+ * Deinitialize the QCryptoTLSTestCertReq, but don't delete the certificate
+ * file on disk. (The caller is then responsible for doing that themselves.
+ */
+void test_tls_deinit_cert(QCryptoTLSTestCertReq *req);
+/* Deinit the QCryptoTLSTestCertReq, and delete the certificate file */
 void test_tls_discard_cert(QCryptoTLSTestCertReq *req);
 
 void test_tls_init(const char *keyfile);