diff options
| author | David Benjamin <davidben@google.com> | 2017-04-21 12:07:03 -0400 |
|---|---|---|
| committer | Rich Salz <rsalz@openssl.org> | 2017-04-22 08:38:59 -0400 |
| commit | bbe056fd676379067588cf823a7a7422c2077f6b (patch) | |
| tree | 04a698d0a72a8339a4f313f052abe69ee0039796 | |
| parent | 48e017b9ca6876f709197de22b986e8238868ce4 (diff) | |
Numbers greater than 1 are usually non-negative.
BN_is_prime_fasttest_ex begins by rejecting if a <= 1. Then it goes to
set A := abs(a), but a cannot be negative at this point.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3275)
(cherry picked from commit 8b24f94209676bbe9933affd2879a686b1ed044d)
| -rw-r--r-- | crypto/bn/bn_prime.c | 24 |
1 files changed, 6 insertions, 18 deletions
diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c index 7103acfe0b..616389cfa6 100644 --- a/crypto/bn/bn_prime.c +++ b/crypto/bn/bn_prime.c @@ -205,7 +205,6 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, BN_CTX *ctx = NULL; BIGNUM *A1, *A1_odd, *check; /* taken from ctx */ BN_MONT_CTX *mont = NULL; - const BIGNUM *A = NULL; if (BN_cmp(a, BN_value_one()) <= 0) return 0; @@ -235,25 +234,14 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, goto err; BN_CTX_start(ctx); - /* A := abs(a) */ - if (a->neg) { - BIGNUM *t; - if ((t = BN_CTX_get(ctx)) == NULL) - goto err; - if (BN_copy(t, a) == NULL) - goto err; - t->neg = 0; - A = t; - } else - A = a; A1 = BN_CTX_get(ctx); A1_odd = BN_CTX_get(ctx); check = BN_CTX_get(ctx); if (check == NULL) goto err; - /* compute A1 := A - 1 */ - if (!BN_copy(A1, A)) + /* compute A1 := a - 1 */ + if (!BN_copy(A1, a)) goto err; if (!BN_sub_word(A1, 1)) goto err; @@ -269,11 +257,11 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, if (!BN_rshift(A1_odd, A1, k)) goto err; - /* Montgomery setup for computations mod A */ + /* Montgomery setup for computations mod a */ mont = BN_MONT_CTX_new(); if (mont == NULL) goto err; - if (!BN_MONT_CTX_set(mont, A, ctx)) + if (!BN_MONT_CTX_set(mont, a, ctx)) goto err; for (i = 0; i < checks; i++) { @@ -281,9 +269,9 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, goto err; if (!BN_add_word(check, 1)) goto err; - /* now 1 <= check < A */ + /* now 1 <= check < a */ - j = witness(check, A, A1, A1_odd, k, ctx, mont); + j = witness(check, a, A1, A1_odd, k, ctx, mont); if (j == -1) goto err; if (j) { |