check CRT

diff --git a/CHANGES b/CHANGES
index 22558b88f7d79b4fc01ee7fb98bd5cbe5c2abfc1..8cd5cf57b863aeedef99317bbfde3d60d1e77008 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,7 +4,13 @@
 
  Changes between 0.9.6 and 0.9.7  [xx XXX 2000]
 
-  *) MIPS assembler BIGNUM division bug fix.
+  *) 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]
 
   *) Fix bug in PKCS#12 key generation routines. This was triggered

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 41b968d3bf2cdca7cb28bc9cdb87456df5384062..ba530b8f00a63825244d9731365ca97b377c6345 100644 (file)
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -453,7 +453,7 @@ err:
 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
        {
        const RSA_METHOD *meth;
-       BIGNUM r1,m1;
+       BIGNUM r1,m1,vrfy;
        int ret=0;
        BN_CTX *ctx;
 
@@ -461,6 +461,7 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
        if ((ctx=BN_CTX_new()) == NULL) goto err;
        BN_init(&m1);
        BN_init(&r1);
+       BN_init(&vrfy);
 
        if (rsa->flags & RSA_FLAG_CACHE_PRIVATE)
                {
@@ -541,10 +542,19 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const 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);
        }