diff options
| author | Theo Buehler <tb@cvs.openbsd.org> | 2023-05-09 05:38:12 +0000 |
|---|---|---|
| committer | Theo Buehler <tb@cvs.openbsd.org> | 2023-05-09 05:38:12 +0000 |
| commit | 8e570acf08180c565e84a3b76068671b6b5f3196 (patch) | |
| tree | 053649920556dc7dafa5897030102ac5effdb62c /lib | |
| parent | ab6a0a8fc329e93aa45aa7c87256a4afb73a749b (diff) | |
bn_exp: also special case -1 modulus
Anything taken to the power of 0 is 1, and then reduced mod 1 or mod -1 it
will be 0. If "anything" includes 0 or not is a matter of convention, but
it should not depend on the sign of the modulus...
Reported by Guido Vranken
ok jsing (who had the same diff)
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/libcrypto/bn/bn_exp.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/lib/libcrypto/bn/bn_exp.c b/lib/libcrypto/bn/bn_exp.c index ff9933578ca..9e5d1fd26db 100644 --- a/lib/libcrypto/bn/bn_exp.c +++ b/lib/libcrypto/bn/bn_exp.c @@ -1,4 +1,4 @@ -/* $OpenBSD: bn_exp.c,v 1.45 2023/03/30 14:21:10 tb Exp $ */ +/* $OpenBSD: bn_exp.c,v 1.46 2023/05/09 05:38:11 tb Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * @@ -194,7 +194,7 @@ BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(r); } else @@ -402,7 +402,7 @@ BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else @@ -658,7 +658,7 @@ BN_mod_exp_mont_internal(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, const BIG bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else @@ -843,7 +843,7 @@ BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, const BIGNUM *m, bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else @@ -968,7 +968,7 @@ BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, bits = BN_num_bits(p); if (bits == 0) { /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(r); } else |