From 0a5dff9882e56f80ff021e039aee93e167f16b9e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 2 Jul 2019 21:41:40 +0200 Subject: [PATCH] crypto: arm/ghash - provide a synchronous version GHASH is used by the GCM mode, which is often used in contexts where only synchronous ciphers are permitted. So provide a synchronous version of GHASH based on the existing code. This requires a non-SIMD fallback to deal with invocations occurring from a context where SIMD instructions may not be used. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm/crypto/ghash-ce-glue.c | 78 ++++++++++++++++++++++----------- 1 file changed, 52 insertions(+), 26 deletions(-) diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c index 52d472a050e6..bb906b5f1eb3 100644 --- a/arch/arm/crypto/ghash-ce-glue.c +++ b/arch/arm/crypto/ghash-ce-glue.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -30,6 +31,8 @@ struct ghash_key { u64 h2[2]; u64 h3[2]; u64 h4[2]; + + be128 k; }; struct ghash_desc_ctx { @@ -62,6 +65,36 @@ static int ghash_init(struct shash_desc *desc) return 0; } +static void ghash_do_update(int blocks, u64 dg[], const char *src, + struct ghash_key *key, const char *head) +{ + if (likely(crypto_simd_usable())) { + kernel_neon_begin(); + pmull_ghash_update(blocks, dg, src, key, head); + kernel_neon_end(); + } else { + be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) }; + + do { + const u8 *in = src; + + if (head) { + in = head; + blocks++; + head = NULL; + } else { + src += GHASH_BLOCK_SIZE; + } + + crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE); + gf128mul_lle(&dst, &key->k); + } while (--blocks); + + dg[0] = be64_to_cpu(dst.b); + dg[1] = be64_to_cpu(dst.a); + } +} + static int ghash_update(struct shash_desc *desc, const u8 *src, unsigned int len) { @@ -85,10 +118,8 @@ static int ghash_update(struct shash_desc *desc, const u8 *src, blocks = len / GHASH_BLOCK_SIZE; len %= GHASH_BLOCK_SIZE; - kernel_neon_begin(); - pmull_ghash_update(blocks, ctx->digest, src, key, - partial ? ctx->buf : NULL); - kernel_neon_end(); + ghash_do_update(blocks, ctx->digest, src, key, + partial ? ctx->buf : NULL); src += blocks * GHASH_BLOCK_SIZE; partial = 0; } @@ -106,9 +137,7 @@ static int ghash_final(struct shash_desc *desc, u8 *dst) struct ghash_key *key = crypto_shash_ctx(desc->tfm); memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial); - kernel_neon_begin(); - pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL); - kernel_neon_end(); + ghash_do_update(1, ctx->digest, ctx->buf, key, NULL); } put_unaligned_be64(ctx->digest[1], dst); put_unaligned_be64(ctx->digest[0], dst + 8); @@ -132,24 +161,25 @@ static int ghash_setkey(struct crypto_shash *tfm, const u8 *inkey, unsigned int keylen) { struct ghash_key *key = crypto_shash_ctx(tfm); - be128 h, k; + be128 h; if (keylen != GHASH_BLOCK_SIZE) { crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); return -EINVAL; } - memcpy(&k, inkey, GHASH_BLOCK_SIZE); - ghash_reflect(key->h, &k); + /* needed for the fallback */ + memcpy(&key->k, inkey, GHASH_BLOCK_SIZE); + ghash_reflect(key->h, &key->k); - h = k; - gf128mul_lle(&h, &k); + h = key->k; + gf128mul_lle(&h, &key->k); ghash_reflect(key->h2, &h); - gf128mul_lle(&h, &k); + gf128mul_lle(&h, &key->k); ghash_reflect(key->h3, &h); - gf128mul_lle(&h, &k); + gf128mul_lle(&h, &key->k); ghash_reflect(key->h4, &h); return 0; @@ -162,15 +192,13 @@ static struct shash_alg ghash_alg = { .final = ghash_final, .setkey = ghash_setkey, .descsize = sizeof(struct ghash_desc_ctx), - .base = { - .cra_name = "__ghash", - .cra_driver_name = "__driver-ghash-ce", - .cra_priority = 0, - .cra_flags = CRYPTO_ALG_INTERNAL, - .cra_blocksize = GHASH_BLOCK_SIZE, - .cra_ctxsize = sizeof(struct ghash_key), - .cra_module = THIS_MODULE, - }, + + .base.cra_name = "ghash", + .base.cra_driver_name = "ghash-ce-sync", + .base.cra_priority = 300 - 1, + .base.cra_blocksize = GHASH_BLOCK_SIZE, + .base.cra_ctxsize = sizeof(struct ghash_key), + .base.cra_module = THIS_MODULE, }; static int ghash_async_init(struct ahash_request *req) @@ -285,9 +313,7 @@ static int ghash_async_init_tfm(struct crypto_tfm *tfm) struct cryptd_ahash *cryptd_tfm; struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm); - cryptd_tfm = cryptd_alloc_ahash("__driver-ghash-ce", - CRYPTO_ALG_INTERNAL, - CRYPTO_ALG_INTERNAL); + cryptd_tfm = cryptd_alloc_ahash("ghash-ce-sync", 0, 0); if (IS_ERR(cryptd_tfm)) return PTR_ERR(cryptd_tfm); ctx->cryptd_tfm = cryptd_tfm; -- 2.30.2