crypto: poly1305 - add new 32 and 64-bit generic versions

These two C implementations from Zinc -- a 32x32 one and a 64x64 one,
depending on the platform -- come from Andrew Moon's public domain
poly1305-donna portable code, modified for usage in the kernel. The
precomputation in the 32-bit version and the use of 64x64 multiplies in
the 64-bit version make these perform better than the code it replaces.
Moon's code is also very widespread and has received many eyeballs of
scrutiny.

There's a bit of interference between the x86 implementation, which
relies on internal details of the old scalar implementation. In the next
commit, the x86 implementation will be replaced with a faster one that
doesn't rely on this, so none of this matters much. But for now, to keep
this passing the tests, we inline the bits of the old implementation
that the x86 implementation relied on. Also, since we now support a
slightly larger key space, via the union, some offsets had to be fixed
up.

Nonce calculation was folded in with the emit function, to take
advantage of 64x64 arithmetic. However, Adiantum appeared to rely on no
nonce handling in emit, so this path was conditionalized. We also
introduced a new struct, poly1305_core_key, to represent the precise
amount of space that particular implementation uses.

Testing with kbench9000, depending on the CPU, the update function for
the 32x32 version has been improved by 4%-7%, and for the 64x64 by
19%-30%. The 32x32 gains are small, but I think there's great value in
having a parallel implementation to the 64x64 one so that the two can be
compared side-by-side as nice stand-alone units.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 27 insertions, 4 deletions

diff --git a/crypto/adiantum.c b/crypto/adiantum.c
index 4d7a6cac..53d5e705 100644
--- a/crypto/adiantum.c
+++ b/crypto/adiantum.c
@@ -70,7 +70,7 @@ struct adiantum_tfm_ctx {
 	struct crypto_skcipher *streamcipher;
 	struct crypto_cipher *blockcipher;
 	struct crypto_shash *hash;
-	struct poly1305_key header_hash_key;
+	struct poly1305_core_key header_hash_key;
 };
 
 struct adiantum_request_ctx {
@@ -239,7 +239,7 @@ static void adiantum_hash_header(struct skcipher_request *req)
 	poly1305_core_blocks(&state, &tctx->header_hash_key, req->iv,
 			     TWEAK_SIZE / POLY1305_BLOCK_SIZE, 1);
 
-	poly1305_core_emit(&state, &rctx->header_hash);
+	poly1305_core_emit(&state, NULL, &rctx->header_hash);
 }
 
 /* Hash the left-hand part (the "bulk") of the message using NHPoly1305 */
diff --git a/crypto/nhpoly1305.c b/crypto/nhpoly1305.c
index f6b6a520..8a3006c3 100644
--- a/crypto/nhpoly1305.c
+++ b/crypto/nhpoly1305.c
@@ -210,7 +210,7 @@ int crypto_nhpoly1305_final_helper(struct shash_desc *desc, u8 *dst, nh_t nh_fn)
 	if (state->nh_remaining)
 		process_nh_hash_value(state, key);
 
-	poly1305_core_emit(&state->poly_state, dst);
+	poly1305_core_emit(&state->poly_state, NULL, dst);
 	return 0;
 }
 EXPORT_SYMBOL(crypto_nhpoly1305_final_helper);
diff --git a/crypto/poly1305_generic.c b/crypto/poly1305_generic.c
index 21edbd8c..94af47eb 100644
--- a/crypto/poly1305_generic.c
+++ b/crypto/poly1305_generic.c
@@ -31,6 +31,29 @@ static int crypto_poly1305_init(struct shash_desc *desc)
 	return 0;
 }
 
+static unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
+					       const u8 *src, unsigned int srclen)
+{
+	if (!dctx->sset) {
+		if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) {
+			poly1305_core_setkey(&dctx->core_r, src);
+			src += POLY1305_BLOCK_SIZE;
+			srclen -= POLY1305_BLOCK_SIZE;
+			dctx->rset = 2;
+		}
+		if (srclen >= POLY1305_BLOCK_SIZE) {
+			dctx->s[0] = get_unaligned_le32(src +  0);
+			dctx->s[1] = get_unaligned_le32(src +  4);
+			dctx->s[2] = get_unaligned_le32(src +  8);
+			dctx->s[3] = get_unaligned_le32(src + 12);
+			src += POLY1305_BLOCK_SIZE;
+			srclen -= POLY1305_BLOCK_SIZE;
+			dctx->sset = true;
+		}
+	}
+	return srclen;
+}
+
 static void poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src,
 			    unsigned int srclen)
 {
@@ -42,7 +65,7 @@ static void poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src,
 		srclen = datalen;
 	}
 
-	poly1305_core_blocks(&dctx->h, dctx->r, src,
+	poly1305_core_blocks(&dctx->h, &dctx->core_r, src,
 			     srclen / POLY1305_BLOCK_SIZE, 1);
 }