EC_KEY: add EC_KEY_decoded_from_explicit_params()

The function returns 1 when the encoding of a decoded EC key used
explicit encoding of the curve parameters.

Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/12683)

1 files changed, 101 insertions, 0 deletions

diff --git a/test/ec_internal_test.c b/test/ec_internal_test.c
index 38a6ab5b4a..d3db698467 100644
--- a/test/ec_internal_test.c
+++ b/test/ec_internal_test.c
@@ -259,6 +259,106 @@ static int underflow_test(void)
 }
 #endif
 
+/*
+ * Tests behavior of the decoded_from_explicit_params flag and API
+ */
+static int decoded_flag_test(void)
+{
+    EC_GROUP *grp;
+    EC_GROUP *grp_copy = NULL;
+    ECPARAMETERS *ecparams = NULL;
+    ECPKPARAMETERS *ecpkparams = NULL;
+    EC_KEY *key = NULL;
+    unsigned char *encodedparams = NULL;
+    const unsigned char *encp;
+    int encodedlen;
+    int testresult = 0;
+
+    /* Test EC_GROUP_new not setting the flag */
+    grp = EC_GROUP_new(EC_GFp_simple_method());
+    if (!TEST_ptr(grp)
+        || !TEST_int_eq(grp->decoded_from_explicit_params, 0))
+        goto err;
+    EC_GROUP_free(grp);
+
+    /* Test EC_GROUP_new_by_curve_name not setting the flag */
+    grp = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
+    if (!TEST_ptr(grp)
+        || !TEST_int_eq(grp->decoded_from_explicit_params, 0))
+        goto err;
+
+    /* Test EC_GROUP_new_from_ecparameters not setting the flag */
+    if (!TEST_ptr(ecparams = EC_GROUP_get_ecparameters(grp, NULL))
+        || !TEST_ptr(grp_copy = EC_GROUP_new_from_ecparameters(ecparams))
+        || !TEST_int_eq(grp_copy->decoded_from_explicit_params, 0))
+        goto err;
+    EC_GROUP_free(grp_copy);
+    grp_copy = NULL;
+    ECPARAMETERS_free(ecparams);
+    ecparams = NULL;
+
+    /* Test EC_GROUP_new_from_ecpkparameters not setting the flag */
+    if (!TEST_int_eq(EC_GROUP_get_asn1_flag(grp), OPENSSL_EC_NAMED_CURVE)
+        || !TEST_ptr(ecpkparams = EC_GROUP_get_ecpkparameters(grp, NULL))
+        || !TEST_ptr(grp_copy = EC_GROUP_new_from_ecpkparameters(ecpkparams))
+        || !TEST_int_eq(grp_copy->decoded_from_explicit_params, 0)
+        || !TEST_ptr(key = EC_KEY_new())
+    /* Test EC_KEY_decoded_from_explicit_params on key without a group */
+        || !TEST_int_eq(EC_KEY_decoded_from_explicit_params(key), -1)
+        || !TEST_int_eq(EC_KEY_set_group(key, grp_copy), 1)
+    /* Test EC_KEY_decoded_from_explicit_params negative case */
+        || !TEST_int_eq(EC_KEY_decoded_from_explicit_params(key), 0))
+        goto err;
+    EC_GROUP_free(grp_copy);
+    grp_copy = NULL;
+    ECPKPARAMETERS_free(ecpkparams);
+    ecpkparams = NULL;
+
+    /* Test d2i_ECPKParameters with named params not setting the flag */
+    if (!TEST_int_gt(encodedlen = i2d_ECPKParameters(grp, &encodedparams), 0)
+        || !TEST_ptr(encp = encodedparams)
+        || !TEST_ptr(grp_copy = d2i_ECPKParameters(NULL, &encp, encodedlen))
+        || !TEST_int_eq(grp_copy->decoded_from_explicit_params, 0))
+        goto err;
+    EC_GROUP_free(grp_copy);
+    grp_copy = NULL;
+    OPENSSL_free(encodedparams);
+    encodedparams = NULL;
+
+    /* Asn1 flag stays set to explicit with EC_GROUP_new_from_ecpkparameters */
+    EC_GROUP_set_asn1_flag(grp, OPENSSL_EC_EXPLICIT_CURVE);
+    if (!TEST_ptr(ecpkparams = EC_GROUP_get_ecpkparameters(grp, NULL))
+        || !TEST_ptr(grp_copy = EC_GROUP_new_from_ecpkparameters(ecpkparams))
+        || !TEST_int_eq(EC_GROUP_get_asn1_flag(grp_copy), OPENSSL_EC_EXPLICIT_CURVE)
+        || !TEST_int_eq(grp_copy->decoded_from_explicit_params, 0))
+        goto err;
+    EC_GROUP_free(grp_copy);
+    grp_copy = NULL;
+
+    /* Test d2i_ECPKParameters with explicit params setting the flag */
+    if (!TEST_int_gt(encodedlen = i2d_ECPKParameters(grp, &encodedparams), 0)
+        || !TEST_ptr(encp = encodedparams)
+        || !TEST_ptr(grp_copy = d2i_ECPKParameters(NULL, &encp, encodedlen))
+        || !TEST_int_eq(EC_GROUP_get_asn1_flag(grp_copy), OPENSSL_EC_EXPLICIT_CURVE)
+        || !TEST_int_eq(grp_copy->decoded_from_explicit_params, 1)
+        || !TEST_int_eq(EC_KEY_set_group(key, grp_copy), 1)
+    /* Test EC_KEY_decoded_from_explicit_params positive case */
+        || !TEST_int_eq(EC_KEY_decoded_from_explicit_params(key), 1))
+        goto err;
+
+    testresult = 1;
+
+ err:
+    EC_KEY_free(key);
+    EC_GROUP_free(grp);
+    EC_GROUP_free(grp_copy);
+    ECPARAMETERS_free(ecparams);
+    ECPKPARAMETERS_free(ecpkparams);
+    OPENSSL_free(encodedparams);
+
+    return testresult;
+}
+
 int setup_tests(void)
 {
     crv_len = EC_get_builtin_curves(NULL, 0);
@@ -275,6 +375,7 @@ int setup_tests(void)
 #ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
     ADD_TEST(underflow_test);
 #endif
+    ADD_TEST(decoded_flag_test);
     return 1;
 }