diff options
Diffstat (limited to 'crypto/bn/bn.h')
| -rw-r--r-- | crypto/bn/bn.h | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h index c056bba5f0..c84a1b5267 100644 --- a/crypto/bn/bn.h +++ b/crypto/bn/bn.h @@ -824,6 +824,16 @@ BIGNUM *bn_dup_expand(const BIGNUM *a, int words); /* unused */ /* We only need assert() when debugging */ # include <assert.h> +/* + * The new BN_FLG_FIXED_TOP flag marks vectors that were not treated with + * bn_correct_top, in other words such vectors are permitted to have zeros + * in most significant limbs. Such vectors are used internally to achieve + * execution time invariance for critical operations with private keys. + * It's BN_DEBUG-only flag, because user application is not supposed to + * observe it anyway. Moreover, optimizing compiler would actually remove + * all operations manipulating the bit in question in non-BN_DEBUG build. + */ +# define BN_FLG_FIXED_TOP 0x10000 # ifdef BN_DEBUG_RAND /* To avoid "make update" cvs wars due to BN_DEBUG, use some tricks */ # ifndef RAND_pseudo_bytes @@ -856,8 +866,10 @@ int RAND_pseudo_bytes(unsigned char *buf, int num); do { \ const BIGNUM *_bnum2 = (a); \ if (_bnum2 != NULL) { \ - assert((_bnum2->top == 0) || \ - (_bnum2->d[_bnum2->top - 1] != 0)); \ + int _top = _bnum2->top; \ + assert((_top == 0) || \ + (_bnum2->flags & BN_FLG_FIXED_TOP) || \ + (_bnum2->d[_top - 1] != 0)); \ bn_pollute(_bnum2); \ } \ } while(0) @@ -875,6 +887,7 @@ int RAND_pseudo_bytes(unsigned char *buf, int num); # else /* !BN_DEBUG */ +# define BN_FLG_FIXED_TOP 0 # define bn_pollute(a) # define bn_check_top(a) # define bn_fix_top(a) bn_correct_top(a) |