diff options
Diffstat (limited to 'security/nss/lib/freebl/ec.c')
| -rw-r--r-- | security/nss/lib/freebl/ec.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/security/nss/lib/freebl/ec.c b/security/nss/lib/freebl/ec.c index b28815ade..6468a10d6 100644 --- a/security/nss/lib/freebl/ec.c +++ b/security/nss/lib/freebl/ec.c @@ -653,6 +653,7 @@ ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature, mp_int r, s; /* tuple (r, s) is the signature */ mp_int t; /* holding tmp values */ mp_int n; + mp_int ar; /* blinding value */ mp_err err = MP_OKAY; ECParams *ecParams = NULL; SECItem kGpoint = { siBuffer, NULL, 0 }; @@ -674,6 +675,7 @@ ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature, MP_DIGITS(&s) = 0; MP_DIGITS(&n) = 0; MP_DIGITS(&t) = 0; + MP_DIGITS(&ar) = 0; /* Check args */ if (!key || !signature || !digest || !kb || (kblen < 0)) { @@ -700,6 +702,7 @@ ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature, CHECK_MPI_OK(mp_init(&s)); CHECK_MPI_OK(mp_init(&n)); CHECK_MPI_OK(mp_init(&t)); + CHECK_MPI_OK(mp_init(&ar)); SECITEM_TO_MPINT(ecParams->order, &n); SECITEM_TO_MPINT(key->privateValue, &d); @@ -815,12 +818,25 @@ ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature, goto cleanup; } CHECK_MPI_OK(mp_read_unsigned_octets(&t, t2, 2 * ecParams->order.len)); /* t <-$ Zn */ - CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */ - CHECK_MPI_OK(mp_invmod(&k, &n, &k)); /* k = k**-1 mod n */ - CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */ - CHECK_MPI_OK(mp_mulmod(&d, &r, &n, &d)); /* d = d * r mod n */ - CHECK_MPI_OK(mp_addmod(&s, &d, &n, &s)); /* s = s + d mod n */ - CHECK_MPI_OK(mp_mulmod(&s, &k, &n, &s)); /* s = s * k mod n */ + PORT_Memset(t2, 0, 2 * ecParams->order.len); + if (RNG_GenerateGlobalRandomBytes(t2, 2 * ecParams->order.len) != SECSuccess) { + PORT_SetError(SEC_ERROR_NEED_RANDOM); + rv = SECFailure; + goto cleanup; + } + CHECK_MPI_OK(mp_read_unsigned_octets(&ar, t2, 2 * ecParams->order.len)); /* ar <-$ Zn */ + + /* Using mp_invmod on k directly would leak bits from k. */ + CHECK_MPI_OK(mp_mul(&k, &ar, &k)); /* k = k * ar */ + CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */ + CHECK_MPI_OK(mp_invmod(&k, &n, &k)); /* k = k**-1 mod n */ + CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */ + /* To avoid leaking secret bits here the addition is blinded. */ + CHECK_MPI_OK(mp_mul(&d, &ar, &t)); /* t = d * ar */ + CHECK_MPI_OK(mp_mulmod(&t, &r, &n, &d)); /* d = t * r mod n */ + CHECK_MPI_OK(mp_mulmod(&s, &ar, &n, &t)); /* t = s * ar mod n */ + CHECK_MPI_OK(mp_add(&t, &d, &s)); /* s = t + d */ + CHECK_MPI_OK(mp_mulmod(&s, &k, &n, &s)); /* s = s * k mod n */ #if EC_DEBUG mp_todecimal(&s, mpstr); @@ -858,6 +874,7 @@ cleanup: mp_clear(&s); mp_clear(&n); mp_clear(&t); + mp_clear(&ar); if (t2) { PORT_Free(t2); |