Fixed modular reduction bug in the special field for P-256 (in some rare cases, value...

[BearSSL] / test / test_crypto.c

diff --git a/test/test_crypto.c b/test/test_crypto.c
index fd0b396..ae0c712 100644 (file)
--- a/test/test_crypto.c
+++ b/test/test_crypto.c
@@ -5062,6 +5062,39 @@ test_EC_inner(const char *sk, const char *sU,
        fflush(stdout);
 }
 
+static void
+test_EC_P256_carry_inner(const br_ec_impl *impl, const char *sP, const char *sQ)
+{
+       unsigned char P[65], Q[sizeof P], k[1];
+       size_t plen, qlen;
+
+       plen = hextobin(P, sP);
+       qlen = hextobin(Q, sQ);
+       if (plen != sizeof P || qlen != sizeof P) {
+               fprintf(stderr, "KAT is incorrect\n");
+               exit(EXIT_FAILURE);
+       }
+       k[0] = 0x10;
+       if (impl->mul(P, plen, k, 1, BR_EC_secp256r1) != 1) {
+               fprintf(stderr, "P-256 multiplication failed\n");
+               exit(EXIT_FAILURE);
+       }
+       check_equals("P256_carry", P, Q, plen);
+       printf(".");
+       fflush(stdout);
+}
+
+static void
+test_EC_P256_carry(const br_ec_impl *impl)
+{
+       test_EC_P256_carry_inner(impl,
+               "0435BAA24B2B6E1B3C88E22A383BD88CC4B9A3166E7BCF94FF6591663AE066B33B821EBA1B4FC8EA609A87EB9A9C9A1CCD5C9F42FA1365306F64D7CAA718B8C978",
+               "0447752A76CA890328D34E675C4971EC629132D1FC4863EDB61219B72C4E58DC5E9D51E7B293488CFD913C3CF20E438BB65C2BA66A7D09EABB45B55E804260C5EB");
+       test_EC_P256_carry_inner(impl,
+               "04DCAE9D9CE211223602024A6933BD42F77B6BF4EAB9C8915F058C149419FADD2CC9FC0707B270A1B5362BA4D249AFC8AC3DA1EFCA8270176EEACA525B49EE19E6",
+               "048DAC7B0BE9B3206FCE8B24B6B4AEB122F2A67D13E536B390B6585CA193427E63F222388B5F51D744D6F5D47536D89EEEC89552BCB269E7828019C4410DFE980A");
+}
+
 static void
 test_EC_KAT(const char *name, const br_ec_impl *impl, uint32_t curve_mask)
 {
@@ -5074,6 +5107,7 @@ test_EC_KAT(const char *name, const br_ec_impl *impl, uint32_t curve_mask)
                        "C9AFA9D845BA75166B5C215767B1D6934E50C3DB36E89B127B8A622B120F6721",
                        "0460FED4BA255A9D31C961EB74C6356D68C049B8923B61FA6CE669622E60F29FB67903FE1008B8BC99A41AE9E95628BC64F2F1B20C2D7E9F5177A3C294D4462299",
                        impl, BR_EC_secp256r1);
+               test_EC_P256_carry(impl);
        }
        if (curve_mask & ((uint32_t)1 << BR_EC_secp384r1)) {
                test_EC_inner(