diff options
| author | Andy Polyakov <appro@openssl.org> | 2017-12-23 15:15:30 +0100 |
|---|---|---|
| committer | Andy Polyakov <appro@openssl.org> | 2017-12-27 12:27:01 +0100 |
| commit | 8af7e94d7b720224547efa7e3364857f7f666dd4 (patch) | |
| tree | ee39d26916d2daec875bcc79f8b84d269efa3bc0 /crypto/ec/ecp_nistp521.c | |
| parent | b78eb0b697f3ba680c5c6e8576ece82ee680068b (diff) | |
ec/ecp_nistp*.c: sanitize for undefined/implmentation-specific behaviour.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/4974)
Diffstat (limited to 'crypto/ec/ecp_nistp521.c')
| -rw-r--r-- | crypto/ec/ecp_nistp521.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/crypto/ec/ecp_nistp521.c b/crypto/ec/ecp_nistp521.c index 9d264f63d4..dcb5415c69 100644 --- a/crypto/ec/ecp_nistp521.c +++ b/crypto/ec/ecp_nistp521.c @@ -50,7 +50,6 @@ typedef __uint128_t uint128_t; /* nonstandard; implemented by gcc on 64-bit typedef uint8_t u8; typedef uint64_t u64; -typedef int64_t s64; /* * The underlying field. P521 operates over GF(2^521-1). We can serialise an @@ -867,7 +866,7 @@ static limb felem_is_zero(const felem in) * We know that ftmp[i] < 2^63, therefore the only way that the top bit * can be set is if is_zero was 0 before the decrement. */ - is_zero = ((s64) is_zero) >> 63; + is_zero = 0 - (is_zero >> 63); is_p = ftmp[0] ^ kPrime[0]; is_p |= ftmp[1] ^ kPrime[1]; @@ -880,7 +879,7 @@ static limb felem_is_zero(const felem in) is_p |= ftmp[8] ^ kPrime[8]; is_p--; - is_p = ((s64) is_p) >> 63; + is_p = 0 - (is_p >> 63); is_zero |= is_p; return is_zero; @@ -951,7 +950,7 @@ static void felem_contract(felem out, const felem in) is_p &= is_p << 4; is_p &= is_p << 2; is_p &= is_p << 1; - is_p = ((s64) is_p) >> 63; + is_p = 0 - (is_p >> 63); is_p = ~is_p; /* is_p is 0 iff |out| == 2^521-1 and all ones otherwise */ @@ -977,7 +976,7 @@ static void felem_contract(felem out, const felem in) is_greater |= is_greater << 4; is_greater |= is_greater << 2; is_greater |= is_greater << 1; - is_greater = ((s64) is_greater) >> 63; + is_greater = 0 - (is_greater >> 63); out[0] -= kPrime[0] & is_greater; out[1] -= kPrime[1] & is_greater; |