diff options
| -rw-r--r-- | src/method_aes128_gcm.c | 65 |
1 files changed, 34 insertions, 31 deletions
diff --git a/src/method_aes128_gcm.c b/src/method_aes128_gcm.c index ad4a5d2..b0c3232 100644 --- a/src/method_aes128_gcm.c +++ b/src/method_aes128_gcm.c @@ -25,7 +25,6 @@ #include "fastd.h" -#include <asm/byteorder.h> #include <crypto_stream_aes128ctr.h> @@ -34,12 +33,17 @@ #define BLOCKQWORDS (BLOCKBYTES/8) +typedef union _block_t { + uint8_t b[BLOCKBYTES]; + uint64_t qw[BLOCKQWORDS]; +} block_t; + struct _fastd_method_session_state { struct timespec valid_till; struct timespec refresh_after; uint8_t d[crypto_stream_aes128ctr_BEFORENMBYTES]; - uint64_t H[32*16*BLOCKQWORDS]; + block_t H[32][16]; uint8_t send_nonce[NONCEBYTES]; uint8_t receive_nonce[NONCEBYTES]; @@ -91,21 +95,19 @@ static size_t method_min_decrypt_head_space(fastd_context *ctx) { return 0; } -static const uint64_t r[BLOCKQWORDS] = { - __constant_cpu_to_le64(0x87), 0, -}; +static const block_t r = { .b = {0xe1} }; -static inline uint8_t shl(uint8_t out[BLOCKBYTES], const uint8_t in[BLOCKBYTES], int n) { +static inline uint8_t shr(block_t *out, const block_t *in, int n) { int i; uint8_t c = 0; for (i = 0; i < BLOCKBYTES; i++) { - uint8_t c2 = in[i] >> (8-n); - out[i] = (in[i] << n) | c; + uint8_t c2 = in->b[i] << (8-n); + out->b[i] = (in->b[i] >> n) | c; c = c2; } - return c; + return (c >> (8-n)); } static inline void xor(uint8_t *x, const uint8_t *a, const uint8_t *b, unsigned int l) { @@ -114,9 +116,9 @@ static inline void xor(uint8_t *x, const uint8_t *a, const uint8_t *b, unsigned x[i] = a[i] ^ b[i]; } -static inline void xor_block(uint64_t x[BLOCKQWORDS], const uint64_t a[BLOCKQWORDS]) { - x[0] ^= a[0]; - x[1] ^= a[1]; +static inline void xor_block(block_t *x, const block_t *a) { + x->qw[0] ^= a->qw[0]; + x->qw[1] ^= a->qw[1]; } static fastd_method_session_state* method_session_init(fastd_context *ctx, uint8_t *secret, size_t length, bool initiator) { @@ -137,30 +139,31 @@ static fastd_method_session_state* method_session_init(fastd_context *ctx, uint8 uint8_t zerononce[crypto_stream_aes128ctr_NONCEBYTES]; memset(zerononce, 0, crypto_stream_aes128ctr_NONCEBYTES); - uint64_t Hbase[4*BLOCKQWORDS]; - uint64_t Rbase[4*BLOCKQWORDS]; - crypto_stream_aes128ctr_afternm((uint8_t*)Hbase, BLOCKBYTES, zerononce, session->d); - memcpy(Rbase, r, BLOCKBYTES); + block_t Hbase[4]; + crypto_stream_aes128ctr_afternm(Hbase[0].b, BLOCKBYTES, zerononce, session->d); + + block_t Rbase[4]; + Rbase[0] = r; for (i = 1; i < 4; i++) { - uint8_t carry = shl((uint8_t*)(Hbase + i*BLOCKQWORDS), (uint8_t*)(Hbase + (i-1)*BLOCKQWORDS), 1); + uint8_t carry = shr(&Hbase[i], &Hbase[i-1], 1); if (carry) - xor_block(Hbase + i*BLOCKQWORDS, r); + xor_block(&Hbase[i], &r); - shl((uint8_t*)(Rbase + i*BLOCKQWORDS), (uint8_t*)(Rbase + (i-1)*BLOCKQWORDS), 1); + shr(&Rbase[i], &Rbase[i-1], 1); } - uint64_t R[16*BLOCKQWORDS]; + block_t R[16]; memset(session->H, 0, sizeof(session->H)); memset(R, 0, sizeof(R)); for (i = 0; i < 16; i++) { int j; for (j = 0; j < 4; j++) { - if (i & (1 << j)) { - xor_block(session->H + i*BLOCKQWORDS, Hbase + j*BLOCKQWORDS); - xor_block(R + i*BLOCKQWORDS, Rbase + j*BLOCKQWORDS); + if (i & (8 >> j)) { + xor_block(&session->H[0][i], &Hbase[j]); + xor_block(&R[i], &Rbase[j]); } } } @@ -169,8 +172,8 @@ static fastd_method_session_state* method_session_init(fastd_context *ctx, uint8 int j; for (j = 0; j < 16; j++) { - uint8_t carry = shl((uint8_t*)(session->H + (16*i + j)*BLOCKQWORDS), (uint8_t*)(session->H + (16*(i-1) + j)*BLOCKQWORDS), 4); - xor_block(session->H + (16*i + j)*BLOCKQWORDS, R + carry*BLOCKQWORDS); + uint8_t carry = shr(&session->H[i][j], &session->H[i-1][j], 4); + xor_block(&session->H[i][j], &R[carry]); } } @@ -205,19 +208,19 @@ static void method_session_free(fastd_context *ctx, fastd_method_session_state * } static void mulH(uint8_t out[BLOCKBYTES], const uint8_t in[BLOCKBYTES], fastd_method_session_state *session) { - uint64_t out2[BLOCKQWORDS]; - memset(out2, 0, BLOCKBYTES); + block_t out2; + memset(&out2, 0, BLOCKBYTES); int i; for (i = 0; i < 16; i++) { - xor_block(out2, session->H + (32*i + (in[i]&0xf))*BLOCKQWORDS); - xor_block(out2, session->H + (32*i+16 + (in[i]>>4))*BLOCKQWORDS); + xor_block(&out2, &session->H[2*i][in[i]>>4]); + xor_block(&out2, &session->H[2*i+1][in[i]&0xf]); } - memcpy(out, out2, BLOCKBYTES); + memcpy(out, &out2, BLOCKBYTES); } -#define BLOCKPTR(buf, i) (((uint8_t*)(buf))+i*BLOCKBYTES) +#define BLOCKPTR(buf, i) (((uint8_t*)(buf))+(i)*BLOCKBYTES) static bool method_encrypt(fastd_context *ctx, fastd_peer *peer, fastd_method_session_state *session, fastd_buffer *out, fastd_buffer in) { *out = fastd_buffer_alloc(in.len, NONCEBYTES+BLOCKBYTES, 0); |