diff options
Diffstat (limited to 'crypto/openssl/crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/openssl/crypto/bn/bn_exp.c | 41 |
1 files changed, 32 insertions, 9 deletions
diff --git a/crypto/openssl/crypto/bn/bn_exp.c b/crypto/openssl/crypto/bn/bn_exp.c index 7e33ba9..4839625 100644 --- a/crypto/openssl/crypto/bn/bn_exp.c +++ b/crypto/openssl/crypto/bn/bn_exp.c @@ -271,9 +271,14 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, } bits = BN_num_bits(p); - if (bits == 0) { - ret = BN_one(r); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(r); + } else { + ret = BN_one(r); + } return ret; } @@ -407,7 +412,13 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, } bits = BN_num_bits(p); if (bits == 0) { - ret = BN_one(rr); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(rr); + } else { + ret = BN_one(rr); + } return ret; } @@ -579,7 +590,7 @@ static int MOD_EXP_CTIME_COPY_FROM_PREBUF(BIGNUM *b, int top, * precomputation memory layout to limit data-dependency to a minimum to * protect secret exponents (cf. the hyper-threading timing attacks pointed * out by Colin Percival, - * http://www.daemong-consideredperthreading-considered-harmful/) + * http://www.daemonology.net/hyperthreading-considered-harmful/) */ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, @@ -608,7 +619,13 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, bits = BN_num_bits(p); if (bits == 0) { - ret = BN_one(rr); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(rr); + } else { + ret = BN_one(rr); + } return ret; } @@ -908,8 +925,9 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, if (BN_is_one(m)) { ret = 1; BN_zero(rr); - } else + } else { ret = BN_one(rr); + } return ret; } if (a == 0) { @@ -1023,9 +1041,14 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, } bits = BN_num_bits(p); - - if (bits == 0) { - ret = BN_one(r); + if (bits == 0) { + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(r); + } else { + ret = BN_one(r); + } return ret; } |
