diff options
| -rw-r--r-- | CHANGES | 14 | ||||
| -rw-r--r-- | crypto/rsa/rsa.h | 7 | ||||
| -rw-r--r-- | crypto/rsa/rsa_eay.c | 14 | ||||
| -rw-r--r-- | crypto/rsa/rsa_lib.c | 21 |
4 files changed, 38 insertions, 18 deletions
@@ -10,12 +10,18 @@ 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. + *) Turn on RSA blinding by default in the default implementation + to avoid a timing attack. Applications that don't want it can call + RSA_blinding_off() or use the new flag RSA_FLAG_NO_BLINDING. + They would be ill-advised to do so in most cases. [Ben Laurie, Steve Henson, Geoff Thorpe] + *) Change RSA blinding code so that it works when the PRNG is not + seeded (in this case, the secret RSA exponent is abused as + an unpredictable seed -- if it is not unpredictable, there + is no point in blinding anyway). + [Bodo Moeller] + 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.h b/crypto/rsa/rsa.h index 76aed3cb38..6844ee9d28 100644 --- a/crypto/rsa/rsa.h +++ b/crypto/rsa/rsa.h @@ -152,6 +152,11 @@ struct rsa_st #define RSA_FLAG_CACHE_PUBLIC 0x02 #define RSA_FLAG_CACHE_PRIVATE 0x04 #define RSA_FLAG_BLINDING 0x08 +#define RSA_FLAG_NO_BLINDING 0x80 /* new with 0.9.6j and 0.9.7b; the built-in + * RSA implementation now uses blinding by + * default (ignoring RSA_FLAG_BLINDING), + * but other engines might not need it + */ #define RSA_FLAG_THREAD_SAFE 0x10 /* This flag means the private key operations will be handled by rsa_mod_exp * and that they do not depend on the private key components being present: @@ -164,6 +169,8 @@ struct rsa_st */ #define RSA_FLAG_SIGN_VER 0x40 +#define RSA_FLAG_NO_BLINDING 0x80 + #define RSA_PKCS1_PADDING 1 #define RSA_SSLV23_PADDING 2 #define RSA_NO_PADDING 3 diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c index 444111fc39..e5f23fd684 100644 --- a/crypto/rsa/rsa_eay.c +++ b/crypto/rsa/rsa_eay.c @@ -203,9 +203,9 @@ static int rsa_eay_blinding(RSA *rsa, BN_CTX *ctx) #define BLINDING_HELPER(rsa, ctx, err_instr) \ do { \ - if(((rsa)->flags & RSA_FLAG_BLINDING) && \ - ((rsa)->blinding == NULL) && \ - !rsa_eay_blinding(rsa, ctx)) \ + if((!((rsa)->flags & RSA_FLAG_NO_BLINDING)) && \ + ((rsa)->blinding == NULL) && \ + !rsa_eay_blinding(rsa, ctx)) \ err_instr \ } while(0) @@ -255,7 +255,7 @@ static int RSA_eay_private_encrypt(int flen, unsigned char *from, BLINDING_HELPER(rsa, ctx, goto err;); - if (rsa->flags & RSA_FLAG_BLINDING) + if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err; if ( (rsa->flags & RSA_FLAG_EXT_PKEY) || @@ -270,7 +270,7 @@ static int RSA_eay_private_encrypt(int flen, unsigned char *from, if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,NULL)) goto err; } - if (rsa->flags & RSA_FLAG_BLINDING) + if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) goto err; /* put in leading 0 bytes if the number is less than the @@ -334,7 +334,7 @@ static int RSA_eay_private_decrypt(int flen, unsigned char *from, BLINDING_HELPER(rsa, ctx, goto err;); - if (rsa->flags & RSA_FLAG_BLINDING) + if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err; /* do the decrypt */ @@ -351,7 +351,7 @@ static int RSA_eay_private_decrypt(int flen, unsigned char *from, goto err; } - if (rsa->flags & RSA_FLAG_BLINDING) + if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) goto err; p=buf; diff --git a/crypto/rsa/rsa_lib.c b/crypto/rsa/rsa_lib.c index 0aeefae7db..d6854591f6 100644 --- a/crypto/rsa/rsa_lib.c +++ b/crypto/rsa/rsa_lib.c @@ -73,10 +73,6 @@ RSA *RSA_new(void) { RSA *r=RSA_new_method(NULL); -#ifndef OPENSSL_NO_FORCE_RSA_BLINDING - r->flags|=RSA_FLAG_BLINDING; -#endif - return r; } @@ -257,7 +253,8 @@ void RSA_blinding_off(RSA *rsa) BN_BLINDING_free(rsa->blinding); rsa->blinding=NULL; } - rsa->flags&= ~RSA_FLAG_BLINDING; + rsa->flags &= ~RSA_FLAG_BLINDING; + rsa->flags |= RSA_FLAG_NO_BLINDING; } int RSA_blinding_on(RSA *rsa, BN_CTX *p_ctx) @@ -278,13 +275,23 @@ int RSA_blinding_on(RSA *rsa, BN_CTX *p_ctx) BN_CTX_start(ctx); A = BN_CTX_get(ctx); - if (!BN_rand_range(A,rsa->n)) goto err; + if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL) + { + /* if PRNG is not properly seeded, resort to secret exponent as unpredictable seed */ + RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0); + if (!BN_pseudo_rand_range(A,rsa->n)) goto err; + } + else + { + if (!BN_rand_range(A,rsa->n)) goto err; + } if ((Ai=BN_mod_inverse(NULL,A,rsa->n,ctx)) == NULL) goto err; if (!rsa->meth->bn_mod_exp(A,A,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err; rsa->blinding=BN_BLINDING_new(A,Ai,rsa->n); - rsa->flags|=RSA_FLAG_BLINDING; + rsa->flags |= RSA_FLAG_BLINDING; + rsa->flags &= ~RSA_FLAG_NO_BLINDING; BN_free(Ai); ret=1; err: |