X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Frsa%2Frsa_i32_pkcs1_sign.c;h=44b6e6d517640b5d871ef2715d484e9e4f30ee3b;hp=c901badaa899c8fc88f26c5c53ce08a4475b477f;hb=28e4e120b84dacdf53963639f1a8a6fec2793662;hpb=6dd8c51ba7e8ca106ede7ff58b5c507042bbf6eb

diff --git a/src/rsa/rsa_i32_pkcs1_sign.c b/src/rsa/rsa_i32_pkcs1_sign.c
index c901bad..44b6e6d 100644
--- a/src/rsa/rsa_i32_pkcs1_sign.c
+++ b/src/rsa/rsa_i32_pkcs1_sign.c
@@ -30,75 +30,8 @@ br_rsa_i32_pkcs1_sign(const unsigned char *hash_oid,
 	const unsigned char *hash, size_t hash_len,
 	const br_rsa_private_key *sk, unsigned char *x)
 {
-	size_t u, x3, xlen;
-
-	/*
-	 * Padded hash value has format:
-	 *  00 01 FF .. FF 00 30 x1 30 x2 06 x3 OID 05 00 04 x4 HASH
-	 *
-	 * with the following rules:
-	 *
-	 *  -- Total length is equal to the modulus length (unsigned
-	 *     encoding).
-	 *
-	 *  -- There must be at least eight bytes of value 0xFF.
-	 *
-	 *  -- x4 is equal to the hash length (hash_len).
-	 *
-	 *  -- x3 is equal to the encoded OID value length (hash_oid[0]).
-	 *
-	 *  -- x2 = x3 + 4.
-	 *
-	 *  -- x1 = x2 + x4 + 4 = x3 + x4 + 8.
-	 *
-	 * Note: the "05 00" is optional (signatures with and without
-	 * that sequence exist in practice), but notes in PKCS#1 seem to
-	 * indicate that the presence of that sequence (specifically,
-	 * an ASN.1 NULL value for the hash parameters) may be slightly
-	 * more "standard" than the opposite.
-	 */
-	xlen = (sk->n_bitlen + 7) >> 3;
-
-	if (hash_oid == NULL) {
-		if (xlen < hash_len + 11) {
-			return 0;
-		}
-		x[0] = 0x00;
-		x[1] = 0x01;
-		u = xlen - hash_len;
-		memset(x + 2, 0xFF, u - 3);
-		x[u - 1] = 0x00;
-	} else {
-		x3 = hash_oid[0];
-
-		/*
-		 * Check that there is enough room for all the elements,
-		 * including at least eight bytes of value 0xFF.
-		 */
-		if (xlen < (x3 + hash_len + 21)) {
-			return 0;
-		}
-		x[0] = 0x00;
-		x[1] = 0x01;
-		u = xlen - x3 - hash_len - 11;
-		memset(x + 2, 0xFF, u - 2);
-		x[u] = 0x00;
-		x[u + 1] = 0x30;
-		x[u + 2] = x3 + hash_len + 8;
-		x[u + 3] = 0x30;
-		x[u + 4] = x3 + 4;
-		x[u + 5] = 0x06;
-		memcpy(x + u + 6, hash_oid, x3 + 1);
-		u += x3 + 7;
-		x[u ++] = 0x05;
-		x[u ++] = 0x00;
-		x[u ++] = 0x04;
-		x[u ++] = hash_len;
+	if (!br_rsa_pkcs1_sig_pad(hash_oid, hash, hash_len, sk->n_bitlen, x)) {
+		return 0;
 	}
-	memcpy(x + u, hash, hash_len);
-
-	/*
-	 * Do the actual computation.
-	 */
 	return br_rsa_i32_private(x, sk);
 }