From 31904ecdf3f1c613d1377dfe79c0413672de7762 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Mon, 8 Mar 2010 18:10:35 +0000
Subject: RSA PSS verification support including certificates and certificate
 requests. Add new ASN1 signature initialisation function to handle this case.

---
 crypto/rsa/rsa_ameth.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 105 insertions(+), 1 deletion(-)

(limited to 'crypto/rsa/rsa_ameth.c')

diff --git a/crypto/rsa/rsa_ameth.c b/crypto/rsa/rsa_ameth.c
index 2ec302c560..4e1dcfb3c3 100644
--- a/crypto/rsa/rsa_ameth.c
+++ b/crypto/rsa/rsa_ameth.c
@@ -449,6 +449,109 @@ static int rsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 
 	}
 
+/* Customised RSA item verification routine. This is called 
+ * when a signature is encountered requiring special handling. We 
+ * currently only handle PSS.
+ */
+
+
+static int rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
+			X509_ALGOR *sigalg, ASN1_BIT_STRING *sig,
+			EVP_PKEY *pkey)
+	{
+	int rv = -1;
+	int saltlen;
+	const EVP_MD *mgf1md = NULL, *md = NULL;
+	RSA_PSS_PARAMS *pss;
+	X509_ALGOR *maskHash;
+	EVP_PKEY_CTX *pkctx;
+	/* Sanity check: make sure it is PSS */
+	if (OBJ_obj2nid(sigalg->algorithm) != NID_rsassaPss)
+		{
+		RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
+		return -1;
+		}
+	/* Decode PSS parameters */
+	pss = rsa_pss_decode(sigalg, &maskHash);
+
+	if (pss == NULL)
+		{
+		RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_INVALID_PSS_PARAMETERS);
+		goto err;
+		}
+	/* Check mask and lookup mask hash algorithm */
+	if (pss->maskGenAlgorithm)
+		{
+		if (OBJ_obj2nid(pss->maskGenAlgorithm->algorithm) != NID_mgf1)
+			{
+			RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNSUPPORTED_MASK_ALGORITHM);
+			goto err;
+			}
+		if (!maskHash)
+			{
+			RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNSUPPORTED_MASK_PARAMETER);
+			goto err;
+			}
+		mgf1md = EVP_get_digestbyobj(maskHash->algorithm);
+		if (mgf1md == NULL)
+			{
+			RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNKNOWN_MASK_DIGEST);
+			goto err;
+			}
+		}
+	else
+		mgf1md = EVP_sha1();
+
+	if (pss->hashAlgorithm)
+		{
+		md = EVP_get_digestbyobj(maskHash->algorithm);
+		if (md == NULL)
+			{
+			RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_UNKNOWN_PSS_DIGEST);
+			goto err;
+			}
+		}
+	else
+		md = EVP_sha1();
+
+	if (pss->saltLength)
+		{
+		saltlen = ASN1_INTEGER_get(pss->saltLength);
+
+		/* Could perform more salt length sanity checks but the main
+		 * RSA routines will trap other invalid values anyway.
+		 */
+		if (saltlen < 0)
+			{
+			RSAerr(RSA_F_RSA_ITEM_VERIFY, RSA_R_INVALID_SALT_LENGTH);
+			goto err;
+			}
+		}
+	else
+		saltlen = 20;
+
+	/* We have all parameters now set up context */
+
+	if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))
+		goto err;
+
+	if (!EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING))
+		goto err;
+
+	if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen))
+		goto err;
+
+	if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md))
+		goto err;
+	/* Carry on */
+	rv = 2;
+
+	err:
+	RSA_PSS_PARAMS_free(pss);
+	if (maskHash)
+		X509_ALGOR_free(maskHash);
+	return rv;
+	}
 
 const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[] = 
 	{
@@ -478,7 +581,8 @@ const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[] =
 		int_rsa_free,
 		rsa_pkey_ctrl,
 		old_rsa_priv_decode,
-		old_rsa_priv_encode
+		old_rsa_priv_encode,
+		rsa_item_verify
 		},
 
 		{
-- 
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