466 lines
11 KiB
C
466 lines
11 KiB
C
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/*
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* GCM: Galois/Counter Mode.
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*
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* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
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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 <crypto/algapi.h>
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#include <crypto/gf128mul.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "scatterwalk.h"
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struct gcm_instance_ctx {
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struct crypto_spawn ctr;
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};
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struct crypto_gcm_ctx {
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struct crypto_ablkcipher *ctr;
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struct gf128mul_4k *gf128;
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};
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struct crypto_gcm_ghash_ctx {
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u32 bytes;
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u32 flags;
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struct gf128mul_4k *gf128;
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u8 buffer[16];
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};
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struct crypto_gcm_req_priv_ctx {
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u8 auth_tag[16];
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u8 counter[16];
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struct crypto_gcm_ghash_ctx ghash;
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};
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static void crypto_gcm_ghash_init(struct crypto_gcm_ghash_ctx *ctx, u32 flags,
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struct gf128mul_4k *gf128)
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{
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ctx->bytes = 0;
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ctx->flags = flags;
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ctx->gf128 = gf128;
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memset(ctx->buffer, 0, 16);
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}
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static void crypto_gcm_ghash_update(struct crypto_gcm_ghash_ctx *ctx,
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const u8 *src, unsigned int srclen)
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{
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u8 *dst = ctx->buffer;
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if (ctx->bytes) {
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int n = min(srclen, ctx->bytes);
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u8 *pos = dst + (16 - ctx->bytes);
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ctx->bytes -= n;
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srclen -= n;
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while (n--)
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*pos++ ^= *src++;
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if (!ctx->bytes)
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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}
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while (srclen >= 16) {
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crypto_xor(dst, src, 16);
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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src += 16;
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srclen -= 16;
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}
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if (srclen) {
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ctx->bytes = 16 - srclen;
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while (srclen--)
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*dst++ ^= *src++;
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}
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}
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static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx *ctx,
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struct scatterlist *sg, int len)
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{
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struct scatter_walk walk;
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u8 *src;
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int n;
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scatterwalk_start(&walk, sg);
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while (len) {
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n = scatterwalk_clamp(&walk, len);
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if (!n) {
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scatterwalk_start(&walk, sg_next(walk.sg));
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n = scatterwalk_clamp(&walk, len);
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}
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src = scatterwalk_map(&walk, 0);
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crypto_gcm_ghash_update(ctx, src, n);
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len -= n;
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scatterwalk_unmap(src, 0);
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scatterwalk_advance(&walk, n);
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scatterwalk_done(&walk, 0, len);
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if (len)
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crypto_yield(ctx->flags);
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}
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}
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static void crypto_gcm_ghash_flush(struct crypto_gcm_ghash_ctx *ctx)
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{
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u8 *dst = ctx->buffer;
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if (ctx->bytes) {
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u8 *tmp = dst + (16 - ctx->bytes);
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while (ctx->bytes--)
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*tmp++ ^= 0;
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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}
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ctx->bytes = 0;
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}
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static void crypto_gcm_ghash_final_xor(struct crypto_gcm_ghash_ctx *ctx,
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unsigned int authlen,
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unsigned int cryptlen, u8 *dst)
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{
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u8 *buf = ctx->buffer;
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u128 lengths;
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lengths.a = cpu_to_be64(authlen * 8);
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lengths.b = cpu_to_be64(cryptlen * 8);
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crypto_gcm_ghash_flush(ctx);
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crypto_xor(buf, (u8 *)&lengths, 16);
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gf128mul_4k_lle((be128 *)buf, ctx->gf128);
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crypto_xor(dst, buf, 16);
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}
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static inline void crypto_gcm_set_counter(u8 *counterblock, u32 value)
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{
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*((u32 *)&counterblock[12]) = cpu_to_be32(value);
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}
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static int crypto_gcm_encrypt_counter(struct crypto_aead *aead, u8 *block,
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u32 value, const u8 *iv)
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{
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struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
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struct crypto_ablkcipher *ctr = ctx->ctr;
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struct ablkcipher_request req;
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struct scatterlist sg;
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u8 counterblock[16];
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if (iv == NULL)
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memset(counterblock, 0, 12);
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else
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memcpy(counterblock, iv, 12);
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crypto_gcm_set_counter(counterblock, value);
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sg_init_one(&sg, block, 16);
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ablkcipher_request_set_tfm(&req, ctr);
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ablkcipher_request_set_crypt(&req, &sg, &sg, 16, counterblock);
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ablkcipher_request_set_callback(&req, 0, NULL, NULL);
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memset(block, 0, 16);
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return crypto_ablkcipher_encrypt(&req);
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}
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static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
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unsigned int keylen)
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{
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struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
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struct crypto_ablkcipher *ctr = ctx->ctr;
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int alignmask = crypto_ablkcipher_alignmask(ctr);
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u8 alignbuf[16+alignmask];
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u8 *hash = (u8 *)ALIGN((unsigned long)alignbuf, alignmask+1);
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int err = 0;
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crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
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crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_ablkcipher_setkey(ctr, key, keylen);
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if (err)
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goto out;
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crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
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CRYPTO_TFM_RES_MASK);
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err = crypto_gcm_encrypt_counter(aead, hash, -1, NULL);
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if (err)
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goto out;
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if (ctx->gf128 != NULL)
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gf128mul_free_4k(ctx->gf128);
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ctx->gf128 = gf128mul_init_4k_lle((be128 *)hash);
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if (ctx->gf128 == NULL)
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err = -ENOMEM;
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out:
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return err;
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}
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static int crypto_gcm_init_crypt(struct ablkcipher_request *ablk_req,
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struct aead_request *req,
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void (*done)(struct crypto_async_request *,
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int))
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{
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struct crypto_aead *aead = crypto_aead_reqtfm(req);
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struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
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struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);
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u32 flags = req->base.tfm->crt_flags;
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u8 *auth_tag = pctx->auth_tag;
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u8 *counter = pctx->counter;
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struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
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int err = 0;
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ablkcipher_request_set_tfm(ablk_req, ctx->ctr);
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ablkcipher_request_set_callback(ablk_req, aead_request_flags(req),
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done, req);
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ablkcipher_request_set_crypt(ablk_req, req->src, req->dst,
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req->cryptlen, counter);
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err = crypto_gcm_encrypt_counter(aead, auth_tag, 0, req->iv);
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if (err)
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goto out;
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memcpy(counter, req->iv, 12);
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crypto_gcm_set_counter(counter, 1);
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crypto_gcm_ghash_init(ghash, flags, ctx->gf128);
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if (req->assoclen) {
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crypto_gcm_ghash_update_sg(ghash, req->assoc, req->assoclen);
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crypto_gcm_ghash_flush(ghash);
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}
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out:
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return err;
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}
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static void crypto_gcm_encrypt_done(struct crypto_async_request *areq, int err)
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{
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struct aead_request *req = areq->data;
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struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);
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u8 *auth_tag = pctx->auth_tag;
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struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
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crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen);
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crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,
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auth_tag);
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aead_request_complete(req, err);
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}
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static int crypto_gcm_encrypt(struct aead_request *req)
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{
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struct ablkcipher_request abreq;
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struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);
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u8 *auth_tag = pctx->auth_tag;
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struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
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int err = 0;
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err = crypto_gcm_init_crypt(&abreq, req, crypto_gcm_encrypt_done);
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if (err)
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return err;
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if (req->cryptlen) {
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err = crypto_ablkcipher_encrypt(&abreq);
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if (err)
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return err;
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crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen);
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}
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crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,
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auth_tag);
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return err;
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}
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static void crypto_gcm_decrypt_done(struct crypto_async_request *areq, int err)
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{
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aead_request_complete(areq->data, err);
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}
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static int crypto_gcm_decrypt(struct aead_request *req)
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{
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struct ablkcipher_request abreq;
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struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);
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u8 *auth_tag = pctx->auth_tag;
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struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
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u8 tag[16];
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int err;
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if (!req->cryptlen)
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return -EINVAL;
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memcpy(tag, auth_tag, 16);
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err = crypto_gcm_init_crypt(&abreq, req, crypto_gcm_decrypt_done);
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if (err)
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return err;
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crypto_gcm_ghash_update_sg(ghash, req->src, req->cryptlen);
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crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,
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auth_tag);
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if (memcmp(tag, auth_tag, 16))
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return -EINVAL;
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return crypto_ablkcipher_decrypt(&abreq);
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}
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static int crypto_gcm_init_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_instance *inst = (void *)tfm->__crt_alg;
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struct gcm_instance_ctx *ictx = crypto_instance_ctx(inst);
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struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
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struct crypto_ablkcipher *ctr;
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unsigned long align;
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int err;
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ctr = crypto_spawn_ablkcipher(&ictx->ctr);
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err = PTR_ERR(ctr);
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if (IS_ERR(ctr))
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return err;
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ctx->ctr = ctr;
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ctx->gf128 = NULL;
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align = max_t(unsigned long, crypto_ablkcipher_alignmask(ctr),
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__alignof__(u32) - 1);
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align &= ~(crypto_tfm_ctx_alignment() - 1);
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tfm->crt_aead.reqsize = align + sizeof(struct crypto_gcm_req_priv_ctx);
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return 0;
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}
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static void crypto_gcm_exit_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
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if (ctx->gf128 != NULL)
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gf128mul_free_4k(ctx->gf128);
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crypto_free_ablkcipher(ctx->ctr);
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}
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static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
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{
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struct crypto_instance *inst;
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struct crypto_alg *ctr;
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struct crypto_alg *cipher;
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struct gcm_instance_ctx *ctx;
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int err;
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char ctr_name[CRYPTO_MAX_ALG_NAME];
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);
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if (err)
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return ERR_PTR(err);
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cipher = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
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CRYPTO_ALG_TYPE_MASK);
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||
|
|
inst = ERR_PTR(PTR_ERR(cipher));
|
||
|
|
if (IS_ERR(cipher))
|
||
|
|
return inst;
|
||
|
|
|
||
|
|
inst = ERR_PTR(ENAMETOOLONG);
|
||
|
|
if (snprintf(
|
||
|
|
ctr_name, CRYPTO_MAX_ALG_NAME,
|
||
|
|
"ctr(%s,0,16,4)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME)
|
||
|
|
return inst;
|
||
|
|
|
||
|
|
ctr = crypto_alg_mod_lookup(ctr_name, CRYPTO_ALG_TYPE_BLKCIPHER,
|
||
|
|
CRYPTO_ALG_TYPE_MASK);
|
||
|
|
|
||
|
|
if (IS_ERR(ctr))
|
||
|
|
return ERR_PTR(PTR_ERR(ctr));
|
||
|
|
|
||
|
|
if (cipher->cra_blocksize != 16)
|
||
|
|
goto out_put_ctr;
|
||
|
|
|
||
|
|
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
|
||
|
|
err = -ENOMEM;
|
||
|
|
if (!inst)
|
||
|
|
goto out_put_ctr;
|
||
|
|
|
||
|
|
err = -ENAMETOOLONG;
|
||
|
|
if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
|
||
|
|
"gcm(%s)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME ||
|
||
|
|
snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
|
||
|
|
"gcm(%s)", cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
|
||
|
|
goto err_free_inst;
|
||
|
|
|
||
|
|
|
||
|
|
ctx = crypto_instance_ctx(inst);
|
||
|
|
err = crypto_init_spawn(&ctx->ctr, ctr, inst, CRYPTO_ALG_TYPE_MASK);
|
||
|
|
if (err)
|
||
|
|
goto err_free_inst;
|
||
|
|
|
||
|
|
inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
|
||
|
|
inst->alg.cra_priority = ctr->cra_priority;
|
||
|
|
inst->alg.cra_blocksize = 16;
|
||
|
|
inst->alg.cra_alignmask = __alignof__(u32) - 1;
|
||
|
|
inst->alg.cra_type = &crypto_aead_type;
|
||
|
|
inst->alg.cra_aead.ivsize = 12;
|
||
|
|
inst->alg.cra_aead.authsize = 16;
|
||
|
|
inst->alg.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
|
||
|
|
inst->alg.cra_init = crypto_gcm_init_tfm;
|
||
|
|
inst->alg.cra_exit = crypto_gcm_exit_tfm;
|
||
|
|
inst->alg.cra_aead.setkey = crypto_gcm_setkey;
|
||
|
|
inst->alg.cra_aead.encrypt = crypto_gcm_encrypt;
|
||
|
|
inst->alg.cra_aead.decrypt = crypto_gcm_decrypt;
|
||
|
|
|
||
|
|
out:
|
||
|
|
crypto_mod_put(ctr);
|
||
|
|
return inst;
|
||
|
|
err_free_inst:
|
||
|
|
kfree(inst);
|
||
|
|
out_put_ctr:
|
||
|
|
inst = ERR_PTR(err);
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void crypto_gcm_free(struct crypto_instance *inst)
|
||
|
|
{
|
||
|
|
struct gcm_instance_ctx *ctx = crypto_instance_ctx(inst);
|
||
|
|
|
||
|
|
crypto_drop_spawn(&ctx->ctr);
|
||
|
|
kfree(inst);
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct crypto_template crypto_gcm_tmpl = {
|
||
|
|
.name = "gcm",
|
||
|
|
.alloc = crypto_gcm_alloc,
|
||
|
|
.free = crypto_gcm_free,
|
||
|
|
.module = THIS_MODULE,
|
||
|
|
};
|
||
|
|
|
||
|
|
static int __init crypto_gcm_module_init(void)
|
||
|
|
{
|
||
|
|
return crypto_register_template(&crypto_gcm_tmpl);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit crypto_gcm_module_exit(void)
|
||
|
|
{
|
||
|
|
crypto_unregister_template(&crypto_gcm_tmpl);
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(crypto_gcm_module_init);
|
||
|
|
module_exit(crypto_gcm_module_exit);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL");
|
||
|
|
MODULE_DESCRIPTION("Galois/Counter Mode");
|
||
|
|
MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");
|