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/*
* Cryptographic API.
*
* Support for OMAP AES GCM HW acceleration.
*
* Copyright (c) 2016 Texas Instruments Incorporated
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <linux/errno.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/omap-dma.h>
#include <linux/interrupt.h>
#include <crypto/aes.h>
#include <crypto/gcm.h>
#include <crypto/scatterwalk.h>
#include <crypto/skcipher.h>
#include <crypto/internal/aead.h>
#include "omap-crypto.h"
#include "omap-aes.h"
static int omap_aes_gcm_handle_queue(struct omap_aes_dev *dd,
struct aead_request *req);
static void omap_aes_gcm_finish_req(struct omap_aes_dev *dd, int ret)
{
struct aead_request *req = dd->aead_req;
dd->flags &= ~FLAGS_BUSY;
dd->in_sg = NULL;
dd->out_sg = NULL;
req->base.complete(&req->base, ret);
}
static void omap_aes_gcm_done_task(struct omap_aes_dev *dd)
{
u8 *tag;
int alen, clen, i, ret = 0, nsg;
struct omap_aes_reqctx *rctx;
alen = ALIGN(dd->assoc_len, AES_BLOCK_SIZE);
clen = ALIGN(dd->total, AES_BLOCK_SIZE);
rctx = aead_request_ctx(dd->aead_req);
nsg = !!(dd->assoc_len && dd->total);
dma_sync_sg_for_device(dd->dev, dd->out_sg, dd->out_sg_len,
DMA_FROM_DEVICE);
dma_unmap_sg(dd->dev, dd->in_sg, dd->in_sg_len, DMA_TO_DEVICE);
dma_unmap_sg(dd->dev, dd->out_sg, dd->out_sg_len, DMA_FROM_DEVICE);
omap_aes_crypt_dma_stop(dd);
omap_crypto_cleanup(dd->out_sg, dd->orig_out,
dd->aead_req->assoclen, dd->total,
FLAGS_OUT_DATA_ST_SHIFT, dd->flags);
if (dd->flags & FLAGS_ENCRYPT)
scatterwalk_map_and_copy(rctx->auth_tag,
dd->aead_req->dst,
dd->total + dd->aead_req->assoclen,
dd->authsize, 1);
omap_crypto_cleanup(&dd->in_sgl[0], NULL, 0, alen,
FLAGS_ASSOC_DATA_ST_SHIFT, dd->flags);
omap_crypto_cleanup(&dd->in_sgl[nsg], NULL, 0, clen,
FLAGS_IN_DATA_ST_SHIFT, dd->flags);
if (!(dd->flags & FLAGS_ENCRYPT)) {
tag = (u8 *)rctx->auth_tag;
for (i = 0; i < dd->authsize; i++) {
if (tag[i]) {
dev_err(dd->dev, "GCM decryption: Tag Message is wrong\n");
ret = -EBADMSG;
}
}
}
omap_aes_gcm_finish_req(dd, ret);
omap_aes_gcm_handle_queue(dd, NULL);
}
static int omap_aes_gcm_copy_buffers(struct omap_aes_dev *dd,
struct aead_request *req)
{
int alen, clen, cryptlen, assoclen, ret;
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int authlen = crypto_aead_authsize(aead);
struct scatterlist *tmp, sg_arr[2];
int nsg;
u16 flags;
assoclen = req->assoclen;
cryptlen = req->cryptlen;
if (dd->flags & FLAGS_RFC4106_GCM)
assoclen -= 8;
if (!(dd->flags & FLAGS_ENCRYPT))
cryptlen -= authlen;
alen = ALIGN(assoclen, AES_BLOCK_SIZE);
clen = ALIGN(cryptlen, AES_BLOCK_SIZE);
nsg = !!(assoclen && cryptlen);
omap_aes_clear_copy_flags(dd);
sg_init_table(dd->in_sgl, nsg + 1);
if (assoclen) {
tmp = req->src;
ret = omap_crypto_align_sg(&tmp, assoclen,
AES_BLOCK_SIZE, dd->in_sgl,
OMAP_CRYPTO_COPY_DATA |
OMAP_CRYPTO_ZERO_BUF |
OMAP_CRYPTO_FORCE_SINGLE_ENTRY,
FLAGS_ASSOC_DATA_ST_SHIFT,
&dd->flags);
}
if (cryptlen) {
tmp = scatterwalk_ffwd(sg_arr, req->src, req->assoclen);
ret = omap_crypto_align_sg(&tmp, cryptlen,
AES_BLOCK_SIZE, &dd->in_sgl[nsg],
OMAP_CRYPTO_COPY_DATA |
OMAP_CRYPTO_ZERO_BUF |
OMAP_CRYPTO_FORCE_SINGLE_ENTRY,
FLAGS_IN_DATA_ST_SHIFT,
&dd->flags);
}
dd->in_sg = dd->in_sgl;
dd->total = cryptlen;
dd->assoc_len = assoclen;
dd->authsize = authlen;
dd->out_sg = req->dst;
dd->orig_out = req->dst;
dd->out_sg = scatterwalk_ffwd(sg_arr, req->dst, assoclen);
flags = 0;
if (req->src == req->dst || dd->out_sg == sg_arr)
flags |= OMAP_CRYPTO_FORCE_COPY;
ret = omap_crypto_align_sg(&dd->out_sg, cryptlen,
AES_BLOCK_SIZE, &dd->out_sgl,
flags,
FLAGS_OUT_DATA_ST_SHIFT, &dd->flags);
if (ret)
return ret;
dd->in_sg_len = sg_nents_for_len(dd->in_sg, alen + clen);
dd->out_sg_len = sg_nents_for_len(dd->out_sg, clen);
return 0;
}
static void omap_aes_gcm_complete(struct crypto_async_request *req, int err)
{
struct omap_aes_gcm_result *res = req->data;
if (err == -EINPROGRESS)
return;
res->err = err;
complete(&res->completion);
}
static int do_encrypt_iv(struct aead_request *req, u32 *tag, u32 *iv)
{
struct scatterlist iv_sg, tag_sg;
struct skcipher_request *sk_req;
struct omap_aes_gcm_result result;
struct omap_aes_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
int ret = 0;
sk_req = skcipher_request_alloc(ctx->ctr, GFP_KERNEL);
if (!sk_req) {
pr_err("skcipher: Failed to allocate request\n");
return -ENOMEM;
}
init_completion(&result.completion);
sg_init_one(&iv_sg, iv, AES_BLOCK_SIZE);
sg_init_one(&tag_sg, tag, AES_BLOCK_SIZE);
skcipher_request_set_callback(sk_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
omap_aes_gcm_complete, &result);
ret = crypto_skcipher_setkey(ctx->ctr, (u8 *)ctx->key, ctx->keylen);
skcipher_request_set_crypt(sk_req, &iv_sg, &tag_sg, AES_BLOCK_SIZE,
NULL);
ret = crypto_skcipher_encrypt(sk_req);
switch (ret) {
case 0:
break;
case -EINPROGRESS:
case -EBUSY:
ret = wait_for_completion_interruptible(&result.completion);
if (!ret) {
ret = result.err;
if (!ret) {
reinit_completion(&result.completion);
break;
}
}
/* fall through */
default:
pr_err("Encryption of IV failed for GCM mode\n");
break;
}
skcipher_request_free(sk_req);
return ret;
}
void omap_aes_gcm_dma_out_callback(void *data)
{
struct omap_aes_dev *dd = data;
struct omap_aes_reqctx *rctx;
int i, val;
u32 *auth_tag, tag[4];
if (!(dd->flags & FLAGS_ENCRYPT))
scatterwalk_map_and_copy(tag, dd->aead_req->src,
dd->total + dd->aead_req->assoclen,
dd->authsize, 0);
rctx = aead_request_ctx(dd->aead_req);
auth_tag = (u32 *)rctx->auth_tag;
for (i = 0; i < 4; i++) {
val = omap_aes_read(dd, AES_REG_TAG_N(dd, i));
auth_tag[i] = val ^ auth_tag[i];
if (!(dd->flags & FLAGS_ENCRYPT))
auth_tag[i] = auth_tag[i] ^ tag[i];
}
omap_aes_gcm_done_task(dd);
}
static int omap_aes_gcm_handle_queue(struct omap_aes_dev *dd,
struct aead_request *req)
{
struct omap_aes_ctx *ctx;
struct aead_request *backlog;
struct omap_aes_reqctx *rctx;
unsigned long flags;
int err, ret = 0;
spin_lock_irqsave(&dd->lock, flags);
if (req)
ret = aead_enqueue_request(&dd->aead_queue, req);
if (dd->flags & FLAGS_BUSY) {
spin_unlock_irqrestore(&dd->lock, flags);
return ret;
}
backlog = aead_get_backlog(&dd->aead_queue);
req = aead_dequeue_request(&dd->aead_queue);
if (req)
dd->flags |= FLAGS_BUSY;
spin_unlock_irqrestore(&dd->lock, flags);
if (!req)
return ret;
if (backlog)
backlog->base.complete(&backlog->base, -EINPROGRESS);
ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
rctx = aead_request_ctx(req);
dd->ctx = ctx;
rctx->dd = dd;
dd->aead_req = req;
rctx->mode &= FLAGS_MODE_MASK;
dd->flags = (dd->flags & ~FLAGS_MODE_MASK) | rctx->mode;
err = omap_aes_gcm_copy_buffers(dd, req);
if (err)
return err;
err = omap_aes_write_ctrl(dd);
if (!err)
err = omap_aes_crypt_dma_start(dd);
if (err) {
omap_aes_gcm_finish_req(dd, err);
omap_aes_gcm_handle_queue(dd, NULL);
}
return ret;
}
static int omap_aes_gcm_crypt(struct aead_request *req, unsigned long mode)
{
struct omap_aes_reqctx *rctx = aead_request_ctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int authlen = crypto_aead_authsize(aead);
struct omap_aes_dev *dd;
__be32 counter = cpu_to_be32(1);
int err, assoclen;
memset(rctx->auth_tag, 0, sizeof(rctx->auth_tag));
memcpy(rctx->iv + GCM_AES_IV_SIZE, &counter, 4);
err = do_encrypt_iv(req, (u32 *)rctx->auth_tag, (u32 *)rctx->iv);
if (err)
return err;
if (mode & FLAGS_RFC4106_GCM)
assoclen = req->assoclen - 8;
else
assoclen = req->assoclen;
if (assoclen + req->cryptlen == 0) {
scatterwalk_map_and_copy(rctx->auth_tag, req->dst, 0, authlen,
1);
return 0;
}
dd = omap_aes_find_dev(rctx);
if (!dd)
return -ENODEV;
rctx->mode = mode;
return omap_aes_gcm_handle_queue(dd, req);
}
int omap_aes_gcm_encrypt(struct aead_request *req)
{
struct omap_aes_reqctx *rctx = aead_request_ctx(req);
memcpy(rctx->iv, req->iv, GCM_AES_IV_SIZE);
return omap_aes_gcm_crypt(req, FLAGS_ENCRYPT | FLAGS_GCM);
}
int omap_aes_gcm_decrypt(struct aead_request *req)
{
struct omap_aes_reqctx *rctx = aead_request_ctx(req);
memcpy(rctx->iv, req->iv, GCM_AES_IV_SIZE);
return omap_aes_gcm_crypt(req, FLAGS_GCM);
}
int omap_aes_4106gcm_encrypt(struct aead_request *req)
{
struct omap_aes_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct omap_aes_reqctx *rctx = aead_request_ctx(req);
memcpy(rctx->iv, ctx->nonce, 4);
memcpy(rctx->iv + 4, req->iv, 8);
return omap_aes_gcm_crypt(req, FLAGS_ENCRYPT | FLAGS_GCM |
FLAGS_RFC4106_GCM);
}
int omap_aes_4106gcm_decrypt(struct aead_request *req)
{
struct omap_aes_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct omap_aes_reqctx *rctx = aead_request_ctx(req);
memcpy(rctx->iv, ctx->nonce, 4);
memcpy(rctx->iv + 4, req->iv, 8);
return omap_aes_gcm_crypt(req, FLAGS_GCM | FLAGS_RFC4106_GCM);
}
int omap_aes_gcm_setkey(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen)
{
struct omap_aes_ctx *ctx = crypto_aead_ctx(tfm);
if (keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_192 &&
keylen != AES_KEYSIZE_256)
return -EINVAL;
memcpy(ctx->key, key, keylen);
ctx->keylen = keylen;
return 0;
}
int omap_aes_4106gcm_setkey(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen)
{
struct omap_aes_ctx *ctx = crypto_aead_ctx(tfm);
if (keylen < 4)
return -EINVAL;
keylen -= 4;
if (keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_192 &&
keylen != AES_KEYSIZE_256)
return -EINVAL;
memcpy(ctx->key, key, keylen);
memcpy(ctx->nonce, key + keylen, 4);
ctx->keylen = keylen;
return 0;
}