diff options
| author | Emilia Kasper <emilia@openssl.org> | 2014-12-15 14:52:22 +0100 |
|---|---|---|
| committer | Emilia Kasper <emilia@openssl.org> | 2014-12-17 10:01:13 +0100 |
| commit | bfd19df6d06918c98a52a90e53712a8883d18db0 (patch) | |
| tree | 7544185de048c30ced77fe6496a152dd3d55aa7a | |
| parent | 7f9edfd23a9b9cd0827cc381e8fbd8cd0c9e5035 (diff) | |
Check for invalid divisors in BN_div.
Invalid zero-padding in the divisor could cause a division by 0.
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit a43bcd9e96c5180e5c6c82164ece643c0097485e)
| -rw-r--r-- | crypto/bn/bn_div.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c index 7b2403185e..0ec90e805c 100644 --- a/crypto/bn/bn_div.c +++ b/crypto/bn/bn_div.c @@ -189,15 +189,17 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor, int no_branch=0; /* Invalid zero-padding would have particularly bad consequences - * in the case of 'num', so don't just rely on bn_check_top() for this one + * so don't just rely on bn_check_top() here * (bn_check_top() works only for BN_DEBUG builds) */ - if (num->top > 0 && num->d[num->top - 1] == 0) + if ((num->top > 0 && num->d[num->top - 1] == 0) || + (divisor->top > 0 && divisor->d[divisor->top - 1] == 0)) { BNerr(BN_F_BN_DIV,BN_R_NOT_INITIALIZED); return 0; } bn_check_top(num); + bn_check_top(divisor); if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) { @@ -207,7 +209,7 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor, bn_check_top(dv); bn_check_top(rm); /* bn_check_top(num); */ /* 'num' has been checked already */ - bn_check_top(divisor); + /* bn_check_top(divisor); */ /* 'divisor' has been checked already */ if (BN_is_zero(divisor)) { |