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crypto: chacha20poly1305 - Use skcipher
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This patch converts chacha20poly1305 to use the new skcipher
interface as opposed to ablkcipher.

It also fixes a buglet where we may end up with an async poly1305
when the user asks for a async algorithm.  This shouldn't be a
problem yet as there aren't any async implementations of poly1305
out there.

Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
herbertx committed Jul 18, 2016
1 parent 16f37ec commit 1e1f006
Showing 1 changed file with 46 additions and 43 deletions.
89 changes: 46 additions & 43 deletions crypto/chacha20poly1305.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ struct chachapoly_instance_ctx {
};

struct chachapoly_ctx {
struct crypto_ablkcipher *chacha;
struct crypto_skcipher *chacha;
struct crypto_ahash *poly;
/* key bytes we use for the ChaCha20 IV */
unsigned int saltlen;
Expand All @@ -53,7 +53,7 @@ struct poly_req {
struct chacha_req {
u8 iv[CHACHA20_IV_SIZE];
struct scatterlist src[1];
struct ablkcipher_request req; /* must be last member */
struct skcipher_request req; /* must be last member */
};

struct chachapoly_req_ctx {
Expand Down Expand Up @@ -144,12 +144,12 @@ static int chacha_decrypt(struct aead_request *req)
dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
}

ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_decrypt_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, src, dst,
rctx->cryptlen, creq->iv);
err = crypto_ablkcipher_decrypt(&creq->req);
skcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_decrypt_done, req);
skcipher_request_set_tfm(&creq->req, ctx->chacha);
skcipher_request_set_crypt(&creq->req, src, dst,
rctx->cryptlen, creq->iv);
err = crypto_skcipher_decrypt(&creq->req);
if (err)
return err;

Expand Down Expand Up @@ -393,13 +393,13 @@ static int poly_genkey(struct aead_request *req)

chacha_iv(creq->iv, req, 0);

ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
poly_genkey_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, creq->src, creq->src,
POLY1305_KEY_SIZE, creq->iv);
skcipher_request_set_callback(&creq->req, aead_request_flags(req),
poly_genkey_done, req);
skcipher_request_set_tfm(&creq->req, ctx->chacha);
skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
POLY1305_KEY_SIZE, creq->iv);

err = crypto_ablkcipher_decrypt(&creq->req);
err = crypto_skcipher_decrypt(&creq->req);
if (err)
return err;

Expand Down Expand Up @@ -433,12 +433,12 @@ static int chacha_encrypt(struct aead_request *req)
dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
}

ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_encrypt_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, src, dst,
req->cryptlen, creq->iv);
err = crypto_ablkcipher_encrypt(&creq->req);
skcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_encrypt_done, req);
skcipher_request_set_tfm(&creq->req, ctx->chacha);
skcipher_request_set_crypt(&creq->req, src, dst,
req->cryptlen, creq->iv);
err = crypto_skcipher_encrypt(&creq->req);
if (err)
return err;

Expand Down Expand Up @@ -500,13 +500,13 @@ static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
keylen -= ctx->saltlen;
memcpy(ctx->salt, key + keylen, ctx->saltlen);

crypto_ablkcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
crypto_ablkcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);

err = crypto_ablkcipher_setkey(ctx->chacha, key, keylen);
crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctx->chacha) &
CRYPTO_TFM_RES_MASK);
err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
CRYPTO_TFM_RES_MASK);
return err;
}

Expand All @@ -524,15 +524,15 @@ static int chachapoly_init(struct crypto_aead *tfm)
struct aead_instance *inst = aead_alg_instance(tfm);
struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_ablkcipher *chacha;
struct crypto_skcipher *chacha;
struct crypto_ahash *poly;
unsigned long align;

poly = crypto_spawn_ahash(&ictx->poly);
if (IS_ERR(poly))
return PTR_ERR(poly);

chacha = crypto_spawn_skcipher(&ictx->chacha);
chacha = crypto_spawn_skcipher2(&ictx->chacha);
if (IS_ERR(chacha)) {
crypto_free_ahash(poly);
return PTR_ERR(chacha);
Expand All @@ -548,8 +548,8 @@ static int chachapoly_init(struct crypto_aead *tfm)
tfm,
align + offsetof(struct chachapoly_req_ctx, u) +
max(offsetof(struct chacha_req, req) +
sizeof(struct ablkcipher_request) +
crypto_ablkcipher_reqsize(chacha),
sizeof(struct skcipher_request) +
crypto_skcipher_reqsize(chacha),
offsetof(struct poly_req, req) +
sizeof(struct ahash_request) +
crypto_ahash_reqsize(poly)));
Expand All @@ -562,7 +562,7 @@ static void chachapoly_exit(struct crypto_aead *tfm)
struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);

crypto_free_ahash(ctx->poly);
crypto_free_ablkcipher(ctx->chacha);
crypto_free_skcipher(ctx->chacha);
}

static void chachapoly_free(struct aead_instance *inst)
Expand All @@ -579,7 +579,7 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
{
struct crypto_attr_type *algt;
struct aead_instance *inst;
struct crypto_alg *chacha;
struct skcipher_alg *chacha;
struct crypto_alg *poly;
struct hash_alg_common *poly_hash;
struct chachapoly_instance_ctx *ctx;
Expand All @@ -605,7 +605,9 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,

poly = crypto_find_alg(poly_name, &crypto_ahash_type,
CRYPTO_ALG_TYPE_HASH,
CRYPTO_ALG_TYPE_AHASH_MASK);
CRYPTO_ALG_TYPE_AHASH_MASK |
crypto_requires_sync(algt->type,
algt->mask));
if (IS_ERR(poly))
return PTR_ERR(poly);

Expand All @@ -623,20 +625,20 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
goto err_free_inst;

crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
err = crypto_grab_skcipher2(&ctx->chacha, chacha_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err)
goto err_drop_poly;

chacha = crypto_skcipher_spawn_alg(&ctx->chacha);
chacha = crypto_spawn_skcipher_alg(&ctx->chacha);

err = -EINVAL;
/* Need 16-byte IV size, including Initial Block Counter value */
if (chacha->cra_ablkcipher.ivsize != CHACHA20_IV_SIZE)
if (crypto_skcipher_alg_ivsize(chacha) != CHACHA20_IV_SIZE)
goto out_drop_chacha;
/* Not a stream cipher? */
if (chacha->cra_blocksize != 1)
if (chacha->base.cra_blocksize != 1)
goto out_drop_chacha;

err = -ENAMETOOLONG;
Expand All @@ -645,20 +647,21 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
poly_name) >= CRYPTO_MAX_ALG_NAME)
goto out_drop_chacha;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"%s(%s,%s)", name, chacha->cra_driver_name,
"%s(%s,%s)", name, chacha->base.cra_driver_name,
poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto out_drop_chacha;

inst->alg.base.cra_flags = (chacha->cra_flags | poly->cra_flags) &
inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = (chacha->cra_priority +
inst->alg.base.cra_priority = (chacha->base.cra_priority +
poly->cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = chacha->cra_alignmask |
inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
poly->cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
ctx->saltlen;
inst->alg.ivsize = ivsize;
inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
inst->alg.init = chachapoly_init;
inst->alg.exit = chachapoly_exit;
Expand Down

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