summaryrefslogtreecommitdiffstats
path: root/crypto/dsa
diff options
context:
space:
mode:
Diffstat (limited to 'crypto/dsa')
-rw-r--r--crypto/dsa/dsa.h32
-rw-r--r--crypto/dsa/dsa_err.c3
-rw-r--r--crypto/dsa/dsa_ossl.c29
-rw-r--r--crypto/dsa/dsa_sign.c9
4 files changed, 58 insertions, 15 deletions
diff --git a/crypto/dsa/dsa.h b/crypto/dsa/dsa.h
index 408ee11b72..28aa8a3073 100644
--- a/crypto/dsa/dsa.h
+++ b/crypto/dsa/dsa.h
@@ -91,13 +91,27 @@
#define OPENSSL_DSA_FIPS_MIN_MODULUS_BITS 1024
#define DSA_FLAG_CACHE_MONT_P 0x01
-#define DSA_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DSA
- * implementation now uses constant time
- * modular exponentiation for secret exponents
- * by default. This flag causes the
- * faster variable sliding window method to
- * be used for all exponents.
+#define DSA_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the
+ * built-in DSA
+ * implementation now
+ * uses constant time
+ * modular exponentiation
+ * for secret exponents
+ * by default. This flag
+ * causes the faster
+ * variable sliding
+ * window method to be
+ * used for all
+ * exponents.
*/
+#define DSA_FLAG_NONCE_FROM_HASH 0x04 /* Causes the DSA nonce
+ * to be calculated from
+ * SHA512(private_key +
+ * H(message) +
+ * random). This
+ * strengthens DSA
+ * against a weak
+ * PRNG. */
/* If this flag is set the DSA method is FIPS compliant and can be used
* in FIPS mode. This is set in the validated module method. If an
@@ -133,8 +147,9 @@ struct dsa_method
{
const char *name;
DSA_SIG * (*dsa_do_sign)(const unsigned char *dgst, int dlen, DSA *dsa);
- int (*dsa_sign_setup)(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp,
- BIGNUM **rp);
+ int (*dsa_sign_setup)(DSA *dsa, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp,
+ const unsigned char *dgst, int dlen);
int (*dsa_do_verify)(const unsigned char *dgst, int dgst_len,
DSA_SIG *sig, DSA *dsa);
int (*dsa_mod_exp)(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1,
@@ -338,6 +353,7 @@ void ERR_load_DSA_strings(void);
#define DSA_R_MISSING_PARAMETERS 101
#define DSA_R_MODULUS_TOO_LARGE 103
#define DSA_R_NEED_NEW_SETUP_VALUES 110
+#define DSA_R_NONCE_CANNOT_BE_PRECOMPUTED 114
#define DSA_R_NO_PARAMETERS_SET 107
#define DSA_R_PARAMETER_ENCODING_ERROR 105
#define DSA_R_Q_NOT_PRIME 113
diff --git a/crypto/dsa/dsa_err.c b/crypto/dsa/dsa_err.c
index a46fade4c6..353d81aa7c 100644
--- a/crypto/dsa/dsa_err.c
+++ b/crypto/dsa/dsa_err.c
@@ -1,6 +1,6 @@
/* crypto/dsa/dsa_err.c */
/* ====================================================================
- * Copyright (c) 1999-2010 The OpenSSL Project. All rights reserved.
+ * Copyright (c) 1999-2013 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -112,6 +112,7 @@ static ERR_STRING_DATA DSA_str_reasons[]=
{ERR_REASON(DSA_R_MISSING_PARAMETERS) ,"missing parameters"},
{ERR_REASON(DSA_R_MODULUS_TOO_LARGE) ,"modulus too large"},
{ERR_REASON(DSA_R_NEED_NEW_SETUP_VALUES) ,"need new setup values"},
+{ERR_REASON(DSA_R_NONCE_CANNOT_BE_PRECOMPUTED),"nonce cannot be precomputed"},
{ERR_REASON(DSA_R_NO_PARAMETERS_SET) ,"no parameters set"},
{ERR_REASON(DSA_R_PARAMETER_ENCODING_ERROR),"parameter encoding error"},
{ERR_REASON(DSA_R_Q_NOT_PRIME) ,"q not prime"},
diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index 485cff0b19..d1f80609b1 100644
--- a/crypto/dsa/dsa_ossl.c
+++ b/crypto/dsa/dsa_ossl.c
@@ -72,7 +72,9 @@
#endif
static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
-static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp);
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp,
+ const unsigned char *dgst, int dlen);
static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
DSA *dsa);
static int dsa_init(DSA *dsa);
@@ -176,7 +178,8 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
redo:
if ((dsa->kinv == NULL) || (dsa->r == NULL))
{
- if (!dsa->meth->dsa_sign_setup(dsa,ctx,&kinv,&r)) goto err;
+ if (!dsa->meth->dsa_sign_setup(dsa,ctx,&kinv,&r,dgst,dlen))
+ goto err;
}
else
{
@@ -235,7 +238,9 @@ err:
return(ret);
}
-static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp,
+ const unsigned char *dgst, int dlen)
{
BN_CTX *ctx;
BIGNUM k,kq,*K,*kinv=NULL,*r=NULL;
@@ -261,8 +266,22 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
/* Get random k */
do
- if (!BN_rand_range(&k, dsa->q)) goto err;
- while (BN_is_zero(&k));
+ {
+#ifndef OPENSSL_NO_SHA512
+ if (dsa->flags & DSA_FLAG_NONCE_FROM_HASH)
+ {
+ /* If DSA_FLAG_NONCE_FROM_HASH is set then we calculate k from
+ * SHA512(private_key + H(message) + random). This protects the
+ * private key from a weak PRNG. */
+ if (!BN_generate_dsa_nonce(&k, dsa->q, dsa->priv_key, dgst,
+ dlen, ctx))
+ goto err;
+ }
+ else
+#endif
+ if (!BN_rand_range(&k, dsa->q)) goto err;
+ } while (BN_is_zero(&k));
+
if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
{
BN_set_flags(&k, BN_FLG_CONSTTIME);
diff --git a/crypto/dsa/dsa_sign.c b/crypto/dsa/dsa_sign.c
index 599093a4a8..b7e4caab2a 100644
--- a/crypto/dsa/dsa_sign.c
+++ b/crypto/dsa/dsa_sign.c
@@ -72,5 +72,12 @@ DSA_SIG * DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
int DSA_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
{
- return dsa->meth->dsa_sign_setup(dsa, ctx_in, kinvp, rp);
+ if (dsa->flags & DSA_FLAG_NONCE_FROM_HASH)
+ {
+ /* One cannot precompute the DSA nonce if it is required to
+ * depend on the message. */
+ DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_NONCE_CANNOT_BE_PRECOMPUTED);
+ return 0;
+ }
+ return dsa->meth->dsa_sign_setup(dsa, ctx_in, kinvp, rp, NULL, 0);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-07 04:25:39 +0000