[PATCH v4 10/14] crypto: poly1305 - use structures for key and accumulator

Eric Biggers
2018-11-17T01:29:37Z

In preparation for exposing a low-level Poly1305 API which implements
the ε-almost-∆-universal (εA∆U) hash function underlying the Poly1305
MAC and supports block-aligned inputs only, create structures
poly1305_key and poly1305_state which hold the limbs of the Poly1305
"r" key and accumulator, respectively.

These structures could actually have the same type (e.g. poly1305_val),
but different types are preferable, to prevent misuse.

Acked-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
arch/x86/crypto/poly1305_glue.c | 20 +++++++------
crypto/poly1305_generic.c | 52 ++++++++++++++++-----------------
include/crypto/poly1305.h | 12 ++++++--
3 files changed, 47 insertions(+), 37 deletions(-)

diff --git a/arch/x86/crypto/poly1305_glue.c b/arch/x86/crypto/poly1305_glue.c
index f012b7e28ad1..88cc01506c84 100644
--- a/arch/x86/crypto/poly1305_glue.c
+++ b/arch/x86/crypto/poly1305_glue.c
@@ -83,35 +83,37 @@ static unsigned int poly1305_simd_blocks(struct poly1305_desc_ctx *dctx,
if (poly1305_use_avx2 && srclen >= POLY1305_BLOCK_SIZE * 4) {
if (unlikely(!sctx->wset)) {
if (!sctx->uset) {
- memcpy(sctx->u, dctx->r, sizeof(sctx->u));
- poly1305_simd_mult(sctx->u, dctx->r);
+ memcpy(sctx->u, dctx->r.r, sizeof(sctx->u));
+ poly1305_simd_mult(sctx->u, dctx->r.r);
sctx->uset = true;
}
memcpy(sctx->u + 5, sctx->u, sizeof(sctx->u));
- poly1305_simd_mult(sctx->u + 5, dctx->r);
+ poly1305_simd_mult(sctx->u + 5, dctx->r.r);
memcpy(sctx->u + 10, sctx->u + 5, sizeof(sctx->u));
- poly1305_simd_mult(sctx->u + 10, dctx->r);
+ poly1305_simd_mult(sctx->u + 10, dctx->r.r);
sctx->wset = true;
}
blocks = srclen / (POLY1305_BLOCK_SIZE * 4);
- poly1305_4block_avx2(dctx->h, src, dctx->r, blocks, sctx->u);
+ poly1305_4block_avx2(dctx->h.h, src, dctx->r.r, blocks,
+ sctx->u);
src += POLY1305_BLOCK_SIZE * 4 * blocks;
srclen -= POLY1305_BLOCK_SIZE * 4 * blocks;
}
#endif
if (likely(srclen >= POLY1305_BLOCK_SIZE * 2)) {
if (unlikely(!sctx->uset)) {
- memcpy(sctx->u, dctx->r, sizeof(sctx->u));
- poly1305_simd_mult(sctx->u, dctx->r);
+ memcpy(sctx->u, dctx->r.r, sizeof(sctx->u));
+ poly1305_simd_mult(sctx->u, dctx->r.r);
sctx->uset = true;
}
blocks = srclen / (POLY1305_BLOCK_SIZE * 2);
- poly1305_2block_sse2(dctx->h, src, dctx->r, blocks, sctx->u);
+ poly1305_2block_sse2(dctx->h.h, src, dctx->r.r, blocks,
+ sctx->u);
src += POLY1305_BLOCK_SIZE * 2 * blocks;
srclen -= POLY1305_BLOCK_SIZE * 2 * blocks;
}
if (srclen >= POLY1305_BLOCK_SIZE) {
- poly1305_block_sse2(dctx->h, src, dctx->r, 1);
+ poly1305_block_sse2(dctx->h.h, src, dctx->r.r, 1);
srclen -= POLY1305_BLOCK_SIZE;
}
return srclen;
diff --git a/crypto/poly1305_generic.c b/crypto/poly1305_generic.c
index 47d3a6b83931..a23173f351b7 100644
--- a/crypto/poly1305_generic.c
+++ b/crypto/poly1305_generic.c
@@ -38,7 +38,7 @@ int crypto_poly1305_init(struct shash_desc *desc)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);

- memset(dctx->h, 0, sizeof(dctx->h));
+ memset(dctx->h.h, 0, sizeof(dctx->h.h));
dctx->buflen = 0;
dctx->rset = false;
dctx->sset = false;
@@ -50,11 +50,11 @@ EXPORT_SYMBOL_GPL(crypto_poly1305_init);
static void poly1305_setrkey(struct poly1305_desc_ctx *dctx, const u8 *key)
{
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
- dctx->r[0] = (get_unaligned_le32(key + 0) >> 0) & 0x3ffffff;
- dctx->r[1] = (get_unaligned_le32(key + 3) >> 2) & 0x3ffff03;
- dctx->r[2] = (get_unaligned_le32(key + 6) >> 4) & 0x3ffc0ff;
- dctx->r[3] = (get_unaligned_le32(key + 9) >> 6) & 0x3f03fff;
- dctx->r[4] = (get_unaligned_le32(key + 12) >> 8) & 0x00fffff;
+ dctx->r.r[0] = (get_unaligned_le32(key + 0) >> 0) & 0x3ffffff;
+ dctx->r.r[1] = (get_unaligned_le32(key + 3) >> 2) & 0x3ffff03;
+ dctx->r.r[2] = (get_unaligned_le32(key + 6) >> 4) & 0x3ffc0ff;
+ dctx->r.r[3] = (get_unaligned_le32(key + 9) >> 6) & 0x3f03fff;
+ dctx->r.r[4] = (get_unaligned_le32(key + 12) >> 8) & 0x00fffff;
}

static void poly1305_setskey(struct poly1305_desc_ctx *dctx, const u8 *key)
@@ -107,22 +107,22 @@ static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
srclen = datalen;
}

- r0 = dctx->r[0];
- r1 = dctx->r[1];
- r2 = dctx->r[2];
- r3 = dctx->r[3];
- r4 = dctx->r[4];
+ r0 = dctx->r.r[0];
+ r1 = dctx->r.r[1];
+ r2 = dctx->r.r[2];
+ r3 = dctx->r.r[3];
+ r4 = dctx->r.r[4];

s1 = r1 * 5;
s2 = r2 * 5;
s3 = r3 * 5;
s4 = r4 * 5;

- h0 = dctx->h[0];
- h1 = dctx->h[1];
- h2 = dctx->h[2];
- h3 = dctx->h[3];
- h4 = dctx->h[4];
+ h0 = dctx->h.h[0];
+ h1 = dctx->h.h[1];
+ h2 = dctx->h.h[2];
+ h3 = dctx->h.h[3];
+ h4 = dctx->h.h[4];

while (likely(srclen >= POLY1305_BLOCK_SIZE)) {

@@ -157,11 +157,11 @@ static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
srclen -= POLY1305_BLOCK_SIZE;
}

- dctx->h[0] = h0;
- dctx->h[1] = h1;
- dctx->h[2] = h2;
- dctx->h[3] = h3;
- dctx->h[4] = h4;
+ dctx->h.h[0] = h0;
+ dctx->h.h[1] = h1;
+ dctx->h.h[2] = h2;
+ dctx->h.h[3] = h3;
+ dctx->h.h[4] = h4;

return srclen;
}
@@ -220,11 +220,11 @@ int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
}

/* fully carry h */
- h0 = dctx->h[0];
- h1 = dctx->h[1];
- h2 = dctx->h[2];
- h3 = dctx->h[3];
- h4 = dctx->h[4];
+ h0 = dctx->h.h[0];
+ h1 = dctx->h.h[1];
+ h2 = dctx->h.h[2];
+ h3 = dctx->h.h[3];
+ h4 = dctx->h.h[4];

h2 += (h1 >> 26); h1 = h1 & 0x3ffffff;
h3 += (h2 >> 26); h2 = h2 & 0x3ffffff;
diff --git a/include/crypto/poly1305.h b/include/crypto/poly1305.h
index f718a19da82f..493244c46664 100644
--- a/include/crypto/poly1305.h
+++ b/include/crypto/poly1305.h
@@ -13,13 +13,21 @@
#define POLY1305_KEY_SIZE 32
#define POLY1305_DIGEST_SIZE 16

+struct poly1305_key {
+ u32 r[5]; /* key, base 2^26 */
+};
+
+struct poly1305_state {
+ u32 h[5]; /* accumulator, base 2^26 */
+};
+
struct poly1305_desc_ctx {
/* key */
- u32 r[5];
+ struct poly1305_key r;
/* finalize key */
u32 s[4];
/* accumulator */
- u32 h[5];
+ struct poly1305_state h;
/* partial buffer */
u8 buf[POLY1305_BLOCK_SIZE];
/* bytes used in partial buffer */
--
2.19.1.1215.g8438c0b245-goog