diff options
| author | Brian Smith <brian@briansmith.org> | 2015-10-13 00:46:18 +0300 |
|---|---|---|
| committer | Adam Langley <alangley@gmail.com> | 2015-10-27 00:37:00 +0300 |
| commit | eca509c8daf998a6eb84f32a85c2f3137d692e55 (patch) | |
| tree | 1b91a096b74ac206ff2af4f862677a8f32352ea8 /crypto/modes | |
| parent | 9383eab5e9b0b0a59dee752c2eb9bb85d25b07b5 (diff) | |
Clarify confusing conditionals in crypto/gcm/gcm.c.
MSVC was warning about the assignment in the |if| condition. Also, the
formatting of the negative number made it look like a subtraction.
Finally, what was being calculated was unclear.
Change-Id: If56c672302c638aac6a87f715e8dcbb87ecb56ed
Reviewed-on: https://boringssl-review.googlesource.com/6212
Reviewed-by: Adam Langley <alangley@gmail.com>
Diffstat (limited to 'crypto/modes')
| -rw-r--r-- | crypto/modes/gcm.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/crypto/modes/gcm.c b/crypto/modes/gcm.c index b597f45b..218032f6 100644 --- a/crypto/modes/gcm.c +++ b/crypto/modes/gcm.c @@ -86,6 +86,9 @@ } \ } while (0) +// kSizeTWithoutLower4Bits is a mask that can be used to zero the lower four +// bits of a |size_t|. +static const size_t kSizeTWithoutLower4Bits = (size_t) -16; static void gcm_init_4bit(u128 Htable[16], uint64_t H[2]) { u128 V; @@ -963,7 +966,6 @@ int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx, const uint8_t *in, char little; } is_endian = {1}; unsigned int n, ctr; - size_t i; uint64_t mlen = ctx->len.u[1]; void *key = ctx->key; #ifdef GCM_FUNCREF_4BIT @@ -1022,7 +1024,8 @@ int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx, const uint8_t *in, len -= GHASH_CHUNK; } #endif - if ((i = (len & (size_t) - 16))) { + size_t i = len & kSizeTWithoutLower4Bits; + if (i != 0) { size_t j = i / 16; (*stream)(in, out, j, key, ctx->Yi.c); @@ -1073,7 +1076,6 @@ int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx, const uint8_t *in, char little; } is_endian = {1}; unsigned int n, ctr; - size_t i; uint64_t mlen = ctx->len.u[1]; void *key = ctx->key; #ifdef GCM_FUNCREF_4BIT @@ -1134,7 +1136,8 @@ int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx, const uint8_t *in, len -= GHASH_CHUNK; } #endif - if ((i = (len & (size_t) - 16))) { + size_t i = len & kSizeTWithoutLower4Bits; + if (i != 0) { size_t j = i / 16; #if defined(GHASH) |