static int setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct priv *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
int err, i;
be128 tmp = { 0 };
int bsize = crypto_cipher_blocksize(child);
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
if ((err = crypto_cipher_setkey(child, key, keylen - bsize)))
return err;
crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
if (ctx->table)
gf128mul_free_64k(ctx->table);
/* initialize multiplication table for Key2 */
ctx->table = gf128mul_init_64k_bbe((be128 *)(key + keylen - bsize));
if (!ctx->table)
return -ENOMEM;
/* initialize optimization table */
for (i = 0; i < 128; i++) {
setbit128_bbe(&tmp, i);
ctx->mulinc[i] = tmp;
gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
}
return 0;
}
static void exit_tfm(struct crypto_skcipher *tfm)
{
struct priv *ctx = crypto_skcipher_ctx(tfm);
if (ctx->table)
gf128mul_free_64k(ctx->table);
crypto_free_skcipher(ctx->child);
}
int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
{
be128 tmp = { 0 };
int i;
if (ctx->table)
gf128mul_free_64k(ctx->table);
/* initialize multiplication table for Key2 */
ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
if (!ctx->table)
return -ENOMEM;
/* initialize optimization table */
for (i = 0; i < 128; i++) {
setbit128_bbe(&tmp, i);
ctx->mulinc[i] = tmp;
gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
}
return 0;
}
void lrw_free_table(struct lrw_table_ctx *ctx)
{
if (ctx->table)
gf128mul_free_64k(ctx->table);
}
static int crypt(struct blkcipher_desc *d,
struct blkcipher_walk *w, struct priv *ctx,
void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
{
int err;
unsigned int avail;
const int bs = crypto_cipher_blocksize(ctx->child);
struct sinfo s = {
.tfm = crypto_cipher_tfm(ctx->child),
.fn = fn
};
be128 *iv;
u8 *wsrc;
u8 *wdst;
err = blkcipher_walk_virt(d, w);
if (!(avail = w->nbytes))
return err;
wsrc = w->src.virt.addr;
wdst = w->dst.virt.addr;
/* calculate first value of T */
iv = (be128 *)w->iv;
s.t = *iv;
/* T <- I*Key2 */
gf128mul_64k_bbe(&s.t, ctx->table);
goto first;
for (;;) {
do {
/* T <- I*Key2, using the optimization
* discussed in the specification */
be128_xor(&s.t, &s.t, &ctx->mulinc[get_index128(iv)]);
inc(iv);
first:
lrw_round(&s, wdst, wsrc);
wsrc += bs;
wdst += bs;
} while ((avail -= bs) >= bs);
err = blkcipher_walk_done(d, w, avail);
if (!(avail = w->nbytes))
break;
wsrc = w->src.virt.addr;
wdst = w->dst.virt.addr;
}
return err;
}
static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk w;
blkcipher_walk_init(&w, dst, src, nbytes);
return crypt(desc, &w, ctx,
crypto_cipher_alg(ctx->child)->cia_encrypt);
}
static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk w;
blkcipher_walk_init(&w, dst, src, nbytes);
return crypt(desc, &w, ctx,
crypto_cipher_alg(ctx->child)->cia_decrypt);
}
static int init_tfm(struct crypto_tfm *tfm)
{
struct crypto_cipher *cipher;
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct priv *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
if (crypto_cipher_blocksize(cipher) != 16) {
*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return -EINVAL;
}
ctx->child = cipher;
return 0;
}
static void exit_tfm(struct crypto_tfm *tfm)
{
struct priv *ctx = crypto_tfm_ctx(tfm);
if (ctx->table)
gf128mul_free_64k(ctx->table);
crypto_free_cipher(ctx->child);
}
static struct crypto_instance *alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
return ERR_CAST(alg);
inst = crypto_alloc_instance("lrw", alg);
if (IS_ERR(inst))
goto out_put_alg;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = alg->cra_blocksize;
if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
else inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_blkcipher_type;
if (!(alg->cra_blocksize % 4))
inst->alg.cra_alignmask |= 3;
inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
inst->alg.cra_blkcipher.min_keysize =
alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
inst->alg.cra_blkcipher.max_keysize =
alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;
inst->alg.cra_ctxsize = sizeof(struct priv);
inst->alg.cra_init = init_tfm;
inst->alg.cra_exit = exit_tfm;
inst->alg.cra_blkcipher.setkey = setkey;
inst->alg.cra_blkcipher.encrypt = encrypt;
inst->alg.cra_blkcipher.decrypt = decrypt;
out_put_alg:
crypto_mod_put(alg);
return inst;
}
static void free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
