Fix some SSL_export_keying_material() issues

Fix some issues in tls13_hkdf_expand() which impact the above function
for TLSv1.3. In particular test that we can use the maximum label length
in TLSv1.3.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7755)

2 files changed, 37 insertions, 13 deletions

diff --git a/test/sslapitest.c b/test/sslapitest.c
index 108d57e478..a4bbb4fead 100644
--- a/test/sslapitest.c
+++ b/test/sslapitest.c
@@ -4028,20 +4028,25 @@ static int test_serverinfo(int tst)
  * no test vectors so all we do is test that both sides of the communication
  * produce the same results for different protocol versions.
  */
+#define SMALL_LABEL_LEN 10
+#define LONG_LABEL_LEN  249
 static int test_export_key_mat(int tst)
 {
     int testresult = 0;
     SSL_CTX *cctx = NULL, *sctx = NULL, *sctx2 = NULL;
     SSL *clientssl = NULL, *serverssl = NULL;
-    const char label[] = "test label";
+    const char label[LONG_LABEL_LEN + 1] = "test label";
     const unsigned char context[] = "context";
     const unsigned char *emptycontext = NULL;
     unsigned char ckeymat1[80], ckeymat2[80], ckeymat3[80];
     unsigned char skeymat1[80], skeymat2[80], skeymat3[80];
+    size_t labellen;
     const int protocols[] = {
         TLS1_VERSION,
         TLS1_1_VERSION,
         TLS1_2_VERSION,
+        TLS1_3_VERSION,
+        TLS1_3_VERSION,
         TLS1_3_VERSION
     };
 
@@ -4058,7 +4063,7 @@ static int test_export_key_mat(int tst)
         return 1;
 #endif
 #ifdef OPENSSL_NO_TLS1_3
-    if (tst == 3)
+    if (tst >= 3)
         return 1;
 #endif
     if (!TEST_true(create_ssl_ctx_pair(TLS_server_method(), TLS_client_method(),
@@ -4076,33 +4081,52 @@ static int test_export_key_mat(int tst)
                                                 SSL_ERROR_NONE)))
         goto end;
 
+    if (tst == 5) {
+        /*
+         * TLSv1.3 imposes a maximum label len of 249 bytes. Check we fail if we
+         * go over that.
+         */
+        if (!TEST_int_le(SSL_export_keying_material(clientssl, ckeymat1,
+                                                    sizeof(ckeymat1), label,
+                                                    LONG_LABEL_LEN + 1, context,
+                                                    sizeof(context) - 1, 1), 0))
+            goto end;
+
+        testresult = 1;
+        goto end;
+    } else if (tst == 4) {
+        labellen = LONG_LABEL_LEN;
+    } else {
+        labellen = SMALL_LABEL_LEN;
+    }
+
     if (!TEST_int_eq(SSL_export_keying_material(clientssl, ckeymat1,
                                                 sizeof(ckeymat1), label,
-                                                sizeof(label) - 1, context,
+                                                labellen, context,
                                                 sizeof(context) - 1, 1), 1)
             || !TEST_int_eq(SSL_export_keying_material(clientssl, ckeymat2,
                                                        sizeof(ckeymat2), label,
-                                                       sizeof(label) - 1,
+                                                       labellen,
                                                        emptycontext,
                                                        0, 1), 1)
             || !TEST_int_eq(SSL_export_keying_material(clientssl, ckeymat3,
                                                        sizeof(ckeymat3), label,
-                                                       sizeof(label) - 1,
+                                                       labellen,
                                                        NULL, 0, 0), 1)
             || !TEST_int_eq(SSL_export_keying_material(serverssl, skeymat1,
                                                        sizeof(skeymat1), label,
-                                                       sizeof(label) - 1,
+                                                       labellen,
                                                        context,
                                                        sizeof(context) -1, 1),
                             1)
             || !TEST_int_eq(SSL_export_keying_material(serverssl, skeymat2,
                                                        sizeof(skeymat2), label,
-                                                       sizeof(label) - 1,
+                                                       labellen,
                                                        emptycontext,
                                                        0, 1), 1)
             || !TEST_int_eq(SSL_export_keying_material(serverssl, skeymat3,
                                                        sizeof(skeymat3), label,
-                                                       sizeof(label) - 1,
+                                                       labellen,
                                                        NULL, 0, 0), 1)
                /*
                 * Check that both sides created the same key material with the
@@ -4131,10 +4155,10 @@ static int test_export_key_mat(int tst)
      * Check that an empty context and no context produce different results in
      * protocols less than TLSv1.3. In TLSv1.3 they should be the same.
      */
-    if ((tst != 3 && !TEST_mem_ne(ckeymat2, sizeof(ckeymat2), ckeymat3,
+    if ((tst < 3 && !TEST_mem_ne(ckeymat2, sizeof(ckeymat2), ckeymat3,
                                   sizeof(ckeymat3)))
-            || (tst ==3 && !TEST_mem_eq(ckeymat2, sizeof(ckeymat2), ckeymat3,
-                                        sizeof(ckeymat3))))
+            || (tst >= 3 && !TEST_mem_eq(ckeymat2, sizeof(ckeymat2), ckeymat3,
+                                         sizeof(ckeymat3))))
         goto end;
 
     testresult = 1;
@@ -5909,7 +5933,7 @@ int setup_tests(void)
     ADD_ALL_TESTS(test_custom_exts, 3);
 #endif
     ADD_ALL_TESTS(test_serverinfo, 8);
-    ADD_ALL_TESTS(test_export_key_mat, 4);
+    ADD_ALL_TESTS(test_export_key_mat, 6);
 #ifndef OPENSSL_NO_TLS1_3
     ADD_ALL_TESTS(test_export_key_mat_early, 3);
 #endif
diff --git a/test/tls13secretstest.c b/test/tls13secretstest.c
index 319df17bab..de318df02b 100644
--- a/test/tls13secretstest.c
+++ b/test/tls13secretstest.c
@@ -226,7 +226,7 @@ static int test_secret(SSL *s, unsigned char *prk,
     }
 
     if (!tls13_hkdf_expand(s, md, prk, label, labellen, hash, hashsize,
-                           gensecret, hashsize)) {
+                           gensecret, hashsize, 1)) {
         TEST_error("Secret generation failed");
         return 0;
     }