![Eric Biggers](/assets/img/avatar_default.png)
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
368 lines
9.6 KiB
C
368 lines
9.6 KiB
C
/*
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* Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
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*
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* Copyright (C) 2015 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*/
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#include <asm/hwcap.h>
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#include <asm/neon.h>
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#include <asm/simd.h>
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#include <asm/unaligned.h>
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#include <crypto/cryptd.h>
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#include <crypto/internal/hash.h>
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#include <crypto/internal/simd.h>
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#include <crypto/gf128mul.h>
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#include <linux/cpufeature.h>
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#include <linux/crypto.h>
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#include <linux/module.h>
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MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("ghash");
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#define GHASH_BLOCK_SIZE 16
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#define GHASH_DIGEST_SIZE 16
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struct ghash_key {
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u64 h[2];
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u64 h2[2];
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u64 h3[2];
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u64 h4[2];
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};
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struct ghash_desc_ctx {
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u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
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u8 buf[GHASH_BLOCK_SIZE];
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u32 count;
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};
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struct ghash_async_ctx {
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struct cryptd_ahash *cryptd_tfm;
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};
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asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
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struct ghash_key const *k,
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const char *head);
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asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
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struct ghash_key const *k,
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const char *head);
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static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
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struct ghash_key const *k,
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const char *head);
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static int ghash_init(struct shash_desc *desc)
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{
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struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
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*ctx = (struct ghash_desc_ctx){};
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return 0;
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}
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static int ghash_update(struct shash_desc *desc, const u8 *src,
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unsigned int len)
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{
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struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
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unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
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ctx->count += len;
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if ((partial + len) >= GHASH_BLOCK_SIZE) {
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struct ghash_key *key = crypto_shash_ctx(desc->tfm);
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int blocks;
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if (partial) {
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int p = GHASH_BLOCK_SIZE - partial;
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memcpy(ctx->buf + partial, src, p);
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src += p;
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len -= p;
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}
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blocks = len / GHASH_BLOCK_SIZE;
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len %= GHASH_BLOCK_SIZE;
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kernel_neon_begin();
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pmull_ghash_update(blocks, ctx->digest, src, key,
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partial ? ctx->buf : NULL);
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kernel_neon_end();
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src += blocks * GHASH_BLOCK_SIZE;
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partial = 0;
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}
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if (len)
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memcpy(ctx->buf + partial, src, len);
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return 0;
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}
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static int ghash_final(struct shash_desc *desc, u8 *dst)
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{
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struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
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unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
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if (partial) {
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struct ghash_key *key = crypto_shash_ctx(desc->tfm);
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memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
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kernel_neon_begin();
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pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
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kernel_neon_end();
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}
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put_unaligned_be64(ctx->digest[1], dst);
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put_unaligned_be64(ctx->digest[0], dst + 8);
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*ctx = (struct ghash_desc_ctx){};
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return 0;
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}
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static void ghash_reflect(u64 h[], const be128 *k)
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{
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u64 carry = be64_to_cpu(k->a) >> 63;
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h[0] = (be64_to_cpu(k->b) << 1) | carry;
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h[1] = (be64_to_cpu(k->a) << 1) | (be64_to_cpu(k->b) >> 63);
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if (carry)
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h[1] ^= 0xc200000000000000UL;
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}
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static int ghash_setkey(struct crypto_shash *tfm,
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const u8 *inkey, unsigned int keylen)
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{
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struct ghash_key *key = crypto_shash_ctx(tfm);
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be128 h, k;
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if (keylen != GHASH_BLOCK_SIZE) {
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crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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memcpy(&k, inkey, GHASH_BLOCK_SIZE);
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ghash_reflect(key->h, &k);
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h = k;
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gf128mul_lle(&h, &k);
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ghash_reflect(key->h2, &h);
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gf128mul_lle(&h, &k);
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ghash_reflect(key->h3, &h);
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gf128mul_lle(&h, &k);
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ghash_reflect(key->h4, &h);
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return 0;
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}
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static struct shash_alg ghash_alg = {
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.digestsize = GHASH_DIGEST_SIZE,
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.init = ghash_init,
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.update = ghash_update,
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.final = ghash_final,
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.setkey = ghash_setkey,
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.descsize = sizeof(struct ghash_desc_ctx),
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.base = {
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.cra_name = "__ghash",
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.cra_driver_name = "__driver-ghash-ce",
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.cra_priority = 0,
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.cra_flags = CRYPTO_ALG_INTERNAL,
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.cra_blocksize = GHASH_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct ghash_key),
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.cra_module = THIS_MODULE,
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},
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};
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static int ghash_async_init(struct ahash_request *req)
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{
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struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
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desc->tfm = child;
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return crypto_shash_init(desc);
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}
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static int ghash_async_update(struct ahash_request *req)
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{
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
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if (!crypto_simd_usable() ||
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(in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
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memcpy(cryptd_req, req, sizeof(*req));
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ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
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return crypto_ahash_update(cryptd_req);
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} else {
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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return shash_ahash_update(req, desc);
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}
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}
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static int ghash_async_final(struct ahash_request *req)
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{
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
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if (!crypto_simd_usable() ||
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(in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
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memcpy(cryptd_req, req, sizeof(*req));
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ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
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return crypto_ahash_final(cryptd_req);
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} else {
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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return crypto_shash_final(desc, req->result);
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}
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}
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static int ghash_async_digest(struct ahash_request *req)
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{
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struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
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if (!crypto_simd_usable() ||
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(in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
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memcpy(cryptd_req, req, sizeof(*req));
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ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
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return crypto_ahash_digest(cryptd_req);
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} else {
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
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desc->tfm = child;
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return shash_ahash_digest(req, desc);
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}
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}
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static int ghash_async_import(struct ahash_request *req, const void *in)
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{
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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desc->tfm = cryptd_ahash_child(ctx->cryptd_tfm);
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return crypto_shash_import(desc, in);
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}
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static int ghash_async_export(struct ahash_request *req, void *out)
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{
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struct ahash_request *cryptd_req = ahash_request_ctx(req);
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struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
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return crypto_shash_export(desc, out);
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}
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static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
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struct crypto_ahash *child = &ctx->cryptd_tfm->base;
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int err;
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crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
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crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
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& CRYPTO_TFM_REQ_MASK);
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err = crypto_ahash_setkey(child, key, keylen);
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crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
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& CRYPTO_TFM_RES_MASK);
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return err;
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}
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static int ghash_async_init_tfm(struct crypto_tfm *tfm)
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{
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struct cryptd_ahash *cryptd_tfm;
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struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
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cryptd_tfm = cryptd_alloc_ahash("__driver-ghash-ce",
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CRYPTO_ALG_INTERNAL,
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CRYPTO_ALG_INTERNAL);
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if (IS_ERR(cryptd_tfm))
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return PTR_ERR(cryptd_tfm);
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ctx->cryptd_tfm = cryptd_tfm;
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crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
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sizeof(struct ahash_request) +
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crypto_ahash_reqsize(&cryptd_tfm->base));
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return 0;
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}
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static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
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{
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struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
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cryptd_free_ahash(ctx->cryptd_tfm);
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}
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static struct ahash_alg ghash_async_alg = {
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.init = ghash_async_init,
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.update = ghash_async_update,
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.final = ghash_async_final,
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.setkey = ghash_async_setkey,
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.digest = ghash_async_digest,
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.import = ghash_async_import,
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.export = ghash_async_export,
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.halg.digestsize = GHASH_DIGEST_SIZE,
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.halg.statesize = sizeof(struct ghash_desc_ctx),
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.halg.base = {
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.cra_name = "ghash",
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.cra_driver_name = "ghash-ce",
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.cra_priority = 300,
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.cra_flags = CRYPTO_ALG_ASYNC,
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.cra_blocksize = GHASH_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct ghash_async_ctx),
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.cra_module = THIS_MODULE,
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.cra_init = ghash_async_init_tfm,
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.cra_exit = ghash_async_exit_tfm,
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},
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};
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static int __init ghash_ce_mod_init(void)
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{
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int err;
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if (!(elf_hwcap & HWCAP_NEON))
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return -ENODEV;
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if (elf_hwcap2 & HWCAP2_PMULL)
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pmull_ghash_update = pmull_ghash_update_p64;
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else
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pmull_ghash_update = pmull_ghash_update_p8;
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err = crypto_register_shash(&ghash_alg);
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if (err)
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return err;
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err = crypto_register_ahash(&ghash_async_alg);
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if (err)
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goto err_shash;
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return 0;
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err_shash:
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crypto_unregister_shash(&ghash_alg);
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return err;
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}
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static void __exit ghash_ce_mod_exit(void)
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{
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crypto_unregister_ahash(&ghash_async_alg);
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crypto_unregister_shash(&ghash_alg);
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}
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module_init(ghash_ce_mod_init);
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module_exit(ghash_ce_mod_exit);
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