From: Ulf Möller <ulf@openssl.org>
Date: Wed, 28 Mar 2001 04:49:39 +0000 (+0000)
Subject: check the CRT result.
X-Git-Tag: OpenSSL_0_9_6a-beta3~16
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=1777e3fd5eac0e491bb16a0bb37f4b0f298e6486;p=oweals%2Fopenssl.git

check the CRT result.
---

diff --git a/CHANGES b/CHANGES
index 318e4aebcb..0c1f30e0b4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,12 @@
 
  Changes between 0.9.6 and 0.9.6a  [xx XXX 2001]
 
+  *) Check the result of RSA-CRT (see D. Boneh, R. DeMillo, R. Lipton:
+     On the Importance of Eliminating Errors in Cryptographic
+	 Computations, J. Cryptology 14 (2001) 2, 101-119,
+	 http://theory.stanford.edu/~dabo/papers/faults.ps.gz).
+	 [Ulf Moeller]
+  
   *) MIPS assembler BIGNUM division bug fix. 
      [Andy Polyakov]
 
diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 62618fe5a9..3e38320257 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -443,13 +443,14 @@ err:
 
 static int RSA_eay_mod_exp(BIGNUM *r0, BIGNUM *I, RSA *rsa)
 	{
-	BIGNUM r1,m1;
+	BIGNUM r1,m1,vrfy;
 	int ret=0;
 	BN_CTX *ctx;
 
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
 	BN_init(&m1);
 	BN_init(&r1);
+	BN_init(&vrfy);
 
 	if (rsa->flags & RSA_FLAG_CACHE_PRIVATE)
 		{
@@ -530,10 +531,19 @@ static int RSA_eay_mod_exp(BIGNUM *r0, BIGNUM *I, RSA *rsa)
 	if (!BN_mul(&r1,r0,rsa->q,ctx)) goto err;
 	if (!BN_add(r0,&r1,&m1)) goto err;
 
+	if (rsa->e && rsa->n)
+		{
+		if (!rsa->meth->bn_mod_exp(&vrfy,r0,rsa->e,rsa->n,ctx,NULL)) goto err;
+		if (BN_cmp(I, &vrfy) != 0)
+			{
+			if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,NULL)) goto err;
+			}
+		}
 	ret=1;
 err:
 	BN_clear_free(&m1);
 	BN_clear_free(&r1);
+	BN_clear_free(&vrfy);
 	BN_CTX_free(ctx);
 	return(ret);
 	}