LibCrypto: Add support for raw EC keys and SECPxxxr1 signatures

Author: https://github.com/alimpfard
Commit: 3dd246a8e1
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4709
Reviewed-by: https://github.com/ADKaster ✅

Libraries/LibCrypto/Curves/SECPxxxr1.h

@@ -112,6 +112,29 @@ struct SECPxxxr1Signature {
         return SECPxxxr1Signature { r_big_int, s_big_int, scalar_size };
     }
 
+    static ErrorOr<SECPxxxr1Signature> from_raw(Span<int const> curve_oid, ReadonlyBytes signature)
+    {
+        size_t scalar_size;
+        if (curve_oid == ASN1::secp256r1_oid) {
+            scalar_size = ceil_div(256, 8);
+        } else if (curve_oid == ASN1::secp384r1_oid) {
+            scalar_size = ceil_div(384, 8);
+        } else if (curve_oid == ASN1::secp521r1_oid) {
+            scalar_size = ceil_div(521, 8);
+        } else {
+            return Error::from_string_literal("Unknown SECPxxxr1 curve");
+        }
+
+        if (signature.size() != scalar_size * 2)
+            return Error::from_string_literal("Invalid SECPxxxr1 signature");
+
+        return SECPxxxr1Signature {
+            UnsignedBigInteger::import_data(signature.slice(0, scalar_size)),
+            UnsignedBigInteger::import_data(signature.slice(scalar_size, scalar_size)),
+            scalar_size,
+        };
+    }
+
     ErrorOr<ByteBuffer> r_bytes() const
     {
         return SECPxxxr1Point::scalar_to_bytes(r, size);

Libraries/LibCrypto/PK/EC.cpp

@@ -61,9 +61,19 @@ static ErrorOr<ECPublicKey<>> read_ec_public_key(ReadonlyBytes bytes, Vector<Str
             UnsignedBigInteger::import_data(bytes.slice(1 + half_size, half_size)),
             half_size,
         };
-    } else {
-        ERROR_WITH_SCOPE("Unsupported public key format");
     }
+
+    if (bytes.size() % 2 == 0) {
+        // Raw public key, without the 0x04 prefix
+        auto half_size = bytes.size() / 2;
+        return ::Crypto::PK::ECPublicKey<> {
+            UnsignedBigInteger::import_data(bytes.slice(0, half_size)),
+            UnsignedBigInteger::import_data(bytes.slice(half_size, half_size)),
+            half_size,
+        };
+    }
+
+    ERROR_WITH_SCOPE("Unsupported public key format");
 }
 
 // https://www.rfc-editor.org/rfc/rfc5915#section-3