diff options
Diffstat (limited to 'crypto/openssl/crypto/bn/bn_word.c')
| -rw-r--r-- | crypto/openssl/crypto/bn/bn_word.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/crypto/openssl/crypto/bn/bn_word.c b/crypto/openssl/crypto/bn/bn_word.c index b031a60..9b5f9cb 100644 --- a/crypto/openssl/crypto/bn/bn_word.c +++ b/crypto/openssl/crypto/bn/bn_word.c @@ -72,10 +72,32 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) if (w == 0) return (BN_ULONG)-1; +#ifndef BN_LLONG + /* + * If |w| is too long and we don't have BN_ULLONG then we need to fall + * back to using BN_div_word + */ + if (w > ((BN_ULONG)1 << BN_BITS4)) { + BIGNUM *tmp = BN_dup(a); + if (tmp == NULL) + return (BN_ULONG)-1; + + ret = BN_div_word(tmp, w); + BN_free(tmp); + + return ret; + } +#endif + bn_check_top(a); w &= BN_MASK2; for (i = a->top - 1; i >= 0; i--) { #ifndef BN_LLONG + /* + * We can assume here that | w <= ((BN_ULONG)1 << BN_BITS4) | and so + * | ret < ((BN_ULONG)1 << BN_BITS4) | and therefore the shifts here are + * safe and will not overflow + */ ret = ((ret << BN_BITS4) | ((a->d[i] >> BN_BITS4) & BN_MASK2l)) % w; ret = ((ret << BN_BITS4) | (a->d[i] & BN_MASK2l)) % w; #else |
