RSA PSS ASN1 signing method

CHANGES

@@ -4,6 +4,11 @@
 
  Changes between 1.0.0 and 1.1.0  [xx XXX xxxx]
 
+  *) Add RSA PSS signing function. This will generated and set the
+     appropriate AlgorithmIdentifiers for PSS based on those in the
+     corresponding EVP_MD_CTX structure. No application support yet.
+     [Steve Henson]
+
   *) Support for companion algorithm specific ASN1 signing routines.
      New function ASN1_item_sign_ctx() signs a pre-initialised
      EVP_MD_CTX structure and sets AlgorithmIdentifiers based on

crypto/rsa/rsa_ameth.c

@@ -535,13 +535,13 @@ static int rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
 	if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))
 		goto err;
 
-	if (!EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING))
+	if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING) <= 0)
 		goto err;
 
-	if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen))
+	if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen) <= 0)
 		goto err;
 
-	if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md))
+	if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
 		goto err;
 	/* Carry on */
 	rv = 2;
@@ -553,6 +553,92 @@ static int rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
 	return rv;
 	}
 
+static int rsa_item_sign(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
+				X509_ALGOR *alg1, X509_ALGOR *alg2, 
+				ASN1_BIT_STRING *sig)
+	{
+	int pad_mode;
+	EVP_PKEY_CTX *pkctx = ctx->pctx;
+	if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)
+		return 0;
+	if (pad_mode == RSA_PKCS1_PADDING)
+		return 2;
+	if (pad_mode == RSA_PKCS1_PSS_PADDING)
+		{
+		const EVP_MD *sigmd, *mgf1md;
+		RSA_PSS_PARAMS *pss = NULL;
+		X509_ALGOR *mgf1alg = NULL;
+		ASN1_STRING *os1 = NULL, *os2 = NULL;
+		EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkctx);
+		int saltlen, rv = 0;
+		sigmd = EVP_MD_CTX_md(ctx);
+		if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) <= 0)
+			goto err;
+		if (!EVP_PKEY_CTX_get_rsa_pss_saltlen(pkctx, &saltlen))
+			goto err;
+		if (saltlen == -1)
+			saltlen = EVP_MD_size(sigmd);
+		else if (saltlen == -2)
+			saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
+		pss = RSA_PSS_PARAMS_new();
+		if (!pss)
+			goto err;
+		if (saltlen != 20)
+			{
+			pss->saltLength = ASN1_INTEGER_new();
+			if (!pss->saltLength)
+				goto err;
+			if (!ASN1_INTEGER_set(pss->saltLength, saltlen))
+				goto err;
+			}
+		if (EVP_MD_type(sigmd) != NID_sha1)
+			{
+			pss->hashAlgorithm = X509_ALGOR_new();
+			if (!pss->hashAlgorithm)
+				goto err;
+			X509_ALGOR_set_md(pss->hashAlgorithm, sigmd);
+			}
+		if (EVP_MD_type(mgf1md) != NID_sha1)
+			{
+			ASN1_STRING *stmp = NULL;
+			/* need to embed algorithm ID inside another */
+			mgf1alg = X509_ALGOR_new();
+			X509_ALGOR_set_md(mgf1alg, mgf1md);
+			if (!ASN1_item_pack(mgf1alg, ASN1_ITEM_rptr(X509_ALGOR),
+									&stmp))
+					goto err;
+			pss->maskGenAlgorithm = X509_ALGOR_new();
+			if (!pss->maskGenAlgorithm)
+				goto err;
+			X509_ALGOR_set0(pss->maskGenAlgorithm,
+					OBJ_nid2obj(NID_mgf1),
+					V_ASN1_SEQUENCE, stmp);
+			}
+		/* Finally create string with pss parameter encoding. */
+		if (!ASN1_item_pack(pss, ASN1_ITEM_rptr(RSA_PSS_PARAMS), &os1))
+			goto err;
+		os2 = ASN1_STRING_dup(os1);
+		if (!os2)
+			goto err;
+		X509_ALGOR_set0(alg1, OBJ_nid2obj(NID_rsassaPss),
+					V_ASN1_SEQUENCE, os1);
+		X509_ALGOR_set0(alg2, OBJ_nid2obj(NID_rsassaPss),
+					V_ASN1_SEQUENCE, os2);
+		os1 = os2 = NULL;
+		rv = 3;
+		err:
+		if (mgf1alg)
+			X509_ALGOR_free(mgf1alg);
+		if (pss)
+			RSA_PSS_PARAMS_free(pss);
+		if (os1)
+			ASN1_STRING_free(os1);
+		return rv;
+		
+		}
+	return 2;
+	}
+
 const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[] = 
 	{
 		{
@@ -582,7 +668,8 @@ const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[] =
 		rsa_pkey_ctrl,
 		old_rsa_priv_decode,
 		old_rsa_priv_encode,
-		rsa_item_verify
+		rsa_item_verify,
+		rsa_item_sign
 		},
 
 		{

crypto/x509/x509.h

@@ -897,6 +897,9 @@ int ASN1_item_verify(const ASN1_ITEM *it, X509_ALGOR *algor1,
 int ASN1_item_sign(const ASN1_ITEM *it, X509_ALGOR *algor1, X509_ALGOR *algor2,
 	ASN1_BIT_STRING *signature,
 	void *data, EVP_PKEY *pkey, const EVP_MD *type);
+int ASN1_item_sign_ctx(EVP_MD_CTX *ctx,
+		const ASN1_ITEM *it, X509_ALGOR *algor1, X509_ALGOR *algor2,
+	     	ASN1_BIT_STRING *signature, void *asn);
 #endif
 
 int 		X509_set_version(X509 *x,long version);