Blinding fix.

diff --git a/CHANGES b/CHANGES
index 46916103b98a27f3315704b31d7ef50e0df4978a..ab440fc46dc6d9aa4653123d26b2e6a8f26a3b4f 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -10,6 +10,12 @@
      in ssl3_get_client_key_exchange (ssl/s3_srvr.c).
      [Bodo Moeller]
 
+  *) Turn on RSA blinding by default, to avoid a timing attack. Applications
+     that don't want it can call RSA_blinding_off(). They would be ill-advised
+     to do so in most cases. The automatic enabling can also be turned off
+     by defining OPENSSL_FORCE_NO_RSA_BLINDING at compile-time.
+     [Ben Laurie, Steve Henson, Geoff Thorpe]
+
  Changes between 0.9.6h and 0.9.6i  [19 Feb 2003]
 
   *) In ssl3_get_record (ssl/s3_pkt.c), minimize information leaked

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index c49abe6e3eedfb802c4d48725cdfb95e37c000ce..444111fc394e2a914a5dd6fd8915c77b867af6b5 100644 (file)
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -190,6 +190,25 @@ err:
        return(r);
        }
 
+static int rsa_eay_blinding(RSA *rsa, BN_CTX *ctx)
+       {
+       int ret = 1;
+       CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+       /* Check again inside the lock - the macro's check is racey */
+       if(rsa->blinding == NULL)
+               ret = RSA_blinding_on(rsa, ctx);
+       CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
+       return ret;
+       }
+
+#define BLINDING_HELPER(rsa, ctx, err_instr) \
+       do { \
+               if(((rsa)->flags & RSA_FLAG_BLINDING) && \
+                               ((rsa)->blinding == NULL) && \
+                               !rsa_eay_blinding(rsa, ctx)) \
+                       err_instr \
+       } while(0)
+
 /* signing */
 static int RSA_eay_private_encrypt(int flen, unsigned char *from,
             unsigned char *to, RSA *rsa, int padding)
@@ -234,8 +253,8 @@ static int RSA_eay_private_encrypt(int flen, unsigned char *from,
                goto err;
                }
 
-       if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
-               RSA_blinding_on(rsa,ctx);
+       BLINDING_HELPER(rsa, ctx, goto err;);
+
        if (rsa->flags & RSA_FLAG_BLINDING)
                if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err;
 
@@ -313,8 +332,8 @@ static int RSA_eay_private_decrypt(int flen, unsigned char *from,
                goto err;
                }
 
-       if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
-               RSA_blinding_on(rsa,ctx);
+       BLINDING_HELPER(rsa, ctx, goto err;);
+
        if (rsa->flags & RSA_FLAG_BLINDING)
                if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err;
 

diff --git a/crypto/rsa/rsa_lib.c b/crypto/rsa/rsa_lib.c
index 422643e9f2e8a364dd80e3b09e60168447f6627e..0aeefae7db9d34fc75def0b339dccccfeae38762 100644 (file)
--- a/crypto/rsa/rsa_lib.c
+++ b/crypto/rsa/rsa_lib.c
@@ -71,7 +71,13 @@ static STACK_OF(CRYPTO_EX_DATA_FUNCS) *rsa_meth=NULL;
 
 RSA *RSA_new(void)
        {
-       return(RSA_new_method(NULL));
+       RSA *r=RSA_new_method(NULL);
+
+#ifndef OPENSSL_NO_FORCE_RSA_BLINDING
+       r->flags|=RSA_FLAG_BLINDING;
+#endif
+
+       return r;
        }
 
 void RSA_set_default_method(RSA_METHOD *meth)