diff options
| author | Matt Caswell <matt@openssl.org> | 2018-05-24 16:12:52 +0100 |
|---|---|---|
| committer | Matt Caswell <matt@openssl.org> | 2018-05-29 16:51:52 +0100 |
| commit | 235119f015e46a74040b78b10fd6e954f7f07774 (patch) | |
| tree | 6ef53ac39ab74506560a84018ce08b39f1f63bc1 /crypto | |
| parent | d8908c3310240bb0efd9b17c663a8b9e47bf31dc (diff) | |
The result of a ^ 0 mod -1 is 0 not 1
Thanks to Guido Vranken and OSSFuzz for finding this issue.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6355)
(cherry picked from commit 4aa5b725d549b3ebc3a4f2f1c44e44a11f68752b)
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/bn/bn_exp.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 40115fc720..2eb393d5b2 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -290,8 +290,8 @@ int BN_mod_exp_recp(BIGNUM *r, 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)) { + /* x**0 mod 1, or x**0 mod -1 is still zero. */ + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(r); } else { @@ -432,8 +432,8 @@ int BN_mod_exp_mont(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)) { + /* x**0 mod 1, or x**0 mod -1 is still zero. */ + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else { @@ -733,8 +733,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, */ bits = p->top * BN_BITS2; if (bits == 0) { - /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + /* x**0 mod 1, or x**0 mod -1 is still zero. */ + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else { @@ -1247,8 +1247,8 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, bits = BN_num_bits(p); if (bits == 0) { - /* x**0 mod 1 is still zero. */ - if (BN_is_one(m)) { + /* x**0 mod 1, or x**0 mod -1 is still zero. */ + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(rr); } else { @@ -1369,9 +1369,9 @@ int BN_mod_exp_simple(BIGNUM *r, 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 (bits == 0) { + /* x**0 mod 1, or x**0 mod -1 is still zero. */ + if (BN_abs_is_word(m, 1)) { ret = 1; BN_zero(r); } else { |