diff --git a/ChangeLog b/ChangeLog index 771632c99eb005e115973cd2ae316b2556875cee..84710c46f97a6b27a2cf5497785227776b44b89b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2016-08-04 Niels Möller <nisse@lysator.liu.se> + * dsa-sign.c (dsa_sign): Return failure if p is even, so that an + invalid key doesn't result in a crash inside mpz_powm_sec. + * rsa-sign-tr.c (rsa_compute_root_tr): Return failure if any of p, q or n is even, to avoid crashing inside mpz_powm_sec. Invalid keys with even modulo are rejected by rsa_public_key_prepare and diff --git a/dsa-sign.c b/dsa-sign.c index 9d6bb1849de248604b9e3c8403167e85b060b116..b713743e9df58b556888653e0ff6a0b2e155bd2b 100644 --- a/dsa-sign.c +++ b/dsa-sign.c @@ -56,6 +56,11 @@ dsa_sign(const struct dsa_params *params, mpz_t tmp; int res; + /* Check that p is odd, so that invalid keys don't result in a crash + inside mpz_powm_sec. */ + if (mpz_even_p (params->p)) + return 0; + /* Select k, 0<k<q, randomly */ mpz_init_set(tmp, params->q); mpz_sub_ui(tmp, tmp, 1);