Add a test for the certificate callback

Reviewed-by: NBen Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/7257)

(cherry picked from commit cd6fe29f5bad1a350a039673e06f83ec7a7ef619)

test/sslapitest.c

@@ -5497,6 +5497,100 @@ static int test_shutdown(int tst)
     return testresult;
 }
 
+static int cert_cb_cnt;
+
+static int cert_cb(SSL *s, void *arg)
+{
+    SSL_CTX *ctx = (SSL_CTX *)arg;
+
+    if (cert_cb_cnt == 0) {
+        /* Suspend the handshake */
+        cert_cb_cnt++;
+        return -1;
+    } else if (cert_cb_cnt == 1) {
+        /*
+         * Update the SSL_CTX, set the certificate and private key and then
+         * continue the handshake normally.
+         */
+        if (ctx != NULL && !TEST_ptr(SSL_set_SSL_CTX(s, ctx)))
+            return 0;
+
+        if (!TEST_true(SSL_use_certificate_file(s, cert, SSL_FILETYPE_PEM))
+                || !TEST_true(SSL_use_PrivateKey_file(s, privkey,
+                                                      SSL_FILETYPE_PEM))
+                || !TEST_true(SSL_check_private_key(s)))
+            return 0;
+        cert_cb_cnt++;
+        return 1;
+    }
+
+    /* Abort the handshake */
+    return 0;
+}
+
+/*
+ * Test the certificate callback.
+ * Test 0: Callback fails
+ * Test 1: Success - no SSL_set_SSL_CTX() in the callback
+ * Test 2: Success - SSL_set_SSL_CTX() in the callback
+ */
+static int test_cert_cb_int(int prot, int tst)
+{
+    SSL_CTX *cctx = NULL, *sctx = NULL, *snictx = NULL;
+    SSL *clientssl = NULL, *serverssl = NULL;
+    int testresult = 0, ret;
+
+    if (!TEST_true(create_ssl_ctx_pair(TLS_server_method(),
+                                       TLS_client_method(),
+                                       TLS1_VERSION,
+                                       prot,
+                                       &sctx, &cctx, NULL, NULL)))
+        goto end;
+
+    if (tst == 0)
+        cert_cb_cnt = -1;
+    else
+        cert_cb_cnt = 0;
+    if (tst == 2)
+        snictx = SSL_CTX_new(TLS_server_method());
+    SSL_CTX_set_cert_cb(sctx, cert_cb, snictx);
+
+    if (!TEST_true(create_ssl_objects(sctx, cctx, &serverssl, &clientssl,
+                                      NULL, NULL)))
+        goto end;
+
+    ret = create_ssl_connection(serverssl, clientssl, SSL_ERROR_NONE);
+    if (!TEST_true(tst == 0 ? !ret : ret)
+            || (tst > 0 && !TEST_int_eq(cert_cb_cnt, 2))) {
+        goto end;
+    }
+
+    testresult = 1;
+
+ end:
+    SSL_free(serverssl);
+    SSL_free(clientssl);
+    SSL_CTX_free(sctx);
+    SSL_CTX_free(cctx);
+    SSL_CTX_free(snictx);
+
+    return testresult;
+}
+
+static int test_cert_cb(int tst)
+{
+    int testresult = 1;
+
+#ifndef OPENSSL_NO_TLS1_2
+    testresult &= test_cert_cb_int(TLS1_2_VERSION, tst);
+#endif
+#ifdef OPENSSL_NO_TLS1_3
+    testresult &= test_cert_cb_int(TLS1_3_VERSION, tst);
+#endif
+
+    return testresult;
+}
+
 int setup_tests(void)
 {
     if (!TEST_ptr(cert = test_get_argument(0))
@@ -5599,6 +5693,7 @@ int setup_tests(void)
     ADD_ALL_TESTS(test_ssl_get_shared_ciphers, OSSL_NELEM(shared_ciphers_data));
     ADD_ALL_TESTS(test_ticket_callbacks, 12);
     ADD_ALL_TESTS(test_shutdown, 7);
+    ADD_ALL_TESTS(test_cert_cb, 3);
     return 1;
 }
 

test/ssltestlib.c

@@ -712,7 +712,9 @@ int create_bare_ssl_connection(SSL *serverssl, SSL *clientssl, int want)
                 err = SSL_get_error(serverssl, rets);
         }
 
-        if (!servererr && rets <= 0 && err != SSL_ERROR_WANT_READ) {
+        if (!servererr && rets <= 0
+                && err != SSL_ERROR_WANT_READ
+                && err != SSL_ERROR_WANT_X509_LOOKUP) {
             TEST_info("SSL_accept() failed %d, %d", rets, err);
             servererr = 1;
         }