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linux-next/crypto/chacha20poly1305.c
Eric Biggers 7bcb2c99f8 crypto: algapi - use common mechanism for inheriting flags 
The flag CRYPTO_ALG_ASYNC is "inherited" in the sense that when a
template is instantiated, the template will have CRYPTO_ALG_ASYNC set if
any of the algorithms it uses has CRYPTO_ALG_ASYNC set.

We'd like to add a second flag (CRYPTO_ALG_ALLOCATES_MEMORY) that gets
"inherited" in the same way.  This is difficult because the handling of
CRYPTO_ALG_ASYNC is hardcoded everywhere.  Address this by:

  - Add CRYPTO_ALG_INHERITED_FLAGS, which contains the set of flags that
    have these inheritance semantics.

  - Add crypto_algt_inherited_mask(), for use by template ->create()
    methods.  It returns any of these flags that the user asked to be
    unset and thus must be passed in the 'mask' to crypto_grab_*().

  - Also modify crypto_check_attr_type() to handle computing the 'mask'
    so that most templates can just use this.

  - Make crypto_grab_*() propagate these flags to the template instance
    being created so that templates don't have to do this themselves.

Make crypto/simd.c propagate these flags too, since it "wraps" another
algorithm, similar to a template.

Based on a patch by Mikulas Patocka <mpatocka@redhat.com>
(https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com).

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-07-16 21:49:08 +10:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ChaCha20-Poly1305 AEAD, RFC7539
*
* Copyright (C) 2015 Martin Willi
*/
#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <crypto/chacha.h>
#include <crypto/poly1305.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
struct chachapoly_instance_ctx {
struct crypto_skcipher_spawn chacha;
struct crypto_ahash_spawn poly;
unsigned int saltlen;
};
struct chachapoly_ctx {
struct crypto_skcipher *chacha;
struct crypto_ahash *poly;
/* key bytes we use for the ChaCha20 IV */
unsigned int saltlen;
u8 salt[];
};
struct poly_req {
/* zero byte padding for AD/ciphertext, as needed */
u8 pad[POLY1305_BLOCK_SIZE];
/* tail data with AD/ciphertext lengths */
struct {
__le64 assoclen;
__le64 cryptlen;
} tail;
struct scatterlist src[1];
struct ahash_request req; /* must be last member */
};
struct chacha_req {
u8 iv[CHACHA_IV_SIZE];
struct scatterlist src[1];
struct skcipher_request req; /* must be last member */
};
struct chachapoly_req_ctx {
struct scatterlist src[2];
struct scatterlist dst[2];
/* the key we generate for Poly1305 using Chacha20 */
u8 key[POLY1305_KEY_SIZE];
/* calculated Poly1305 tag */
u8 tag[POLY1305_DIGEST_SIZE];
/* length of data to en/decrypt, without ICV */
unsigned int cryptlen;
/* Actual AD, excluding IV */
unsigned int assoclen;
/* request flags, with MAY_SLEEP cleared if needed */
u32 flags;
union {
struct poly_req poly;
struct chacha_req chacha;
} u;
};
static inline void async_done_continue(struct aead_request *req, int err,
int (*cont)(struct aead_request *))
{
if (!err) {
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
rctx->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
err = cont(req);
}
if (err != -EINPROGRESS && err != -EBUSY)
aead_request_complete(req, err);
}
static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
__le32 leicb = cpu_to_le32(icb);
memcpy(iv, &leicb, sizeof(leicb));
memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
CHACHA_IV_SIZE - sizeof(leicb) - ctx->saltlen);
}
static int poly_verify_tag(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
u8 tag[sizeof(rctx->tag)];
scatterwalk_map_and_copy(tag, req->src,
req->assoclen + rctx->cryptlen,
sizeof(tag), 0);
if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
return -EBADMSG;
return 0;
}
static int poly_copy_tag(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
scatterwalk_map_and_copy(rctx->tag, req->dst,
req->assoclen + rctx->cryptlen,
sizeof(rctx->tag), 1);
return 0;
}
static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_verify_tag);
}
static int chacha_decrypt(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
struct scatterlist *src, *dst;
int err;
if (rctx->cryptlen == 0)
goto skip;
chacha_iv(creq->iv, req, 1);
src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
dst = src;
if (req->src != req->dst)
dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
skcipher_request_set_callback(&creq->req, rctx->flags,
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;
skip:
return poly_verify_tag(req);
}
static int poly_tail_continue(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
if (rctx->cryptlen == req->cryptlen) /* encrypting */
return poly_copy_tag(req);
return chacha_decrypt(req);
}
static void poly_tail_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_tail_continue);
}
static int poly_tail(struct aead_request *req)
{
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
preq->tail.assoclen = cpu_to_le64(rctx->assoclen);
preq->tail.cryptlen = cpu_to_le64(rctx->cryptlen);
sg_init_one(preq->src, &preq->tail, sizeof(preq->tail));
ahash_request_set_callback(&preq->req, rctx->flags,
poly_tail_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src,
rctx->tag, sizeof(preq->tail));
err = crypto_ahash_finup(&preq->req);
if (err)
return err;
return poly_tail_continue(req);
}
static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_tail);
}
static int poly_cipherpad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
unsigned int padlen;
int err;
padlen = -rctx->cryptlen % POLY1305_BLOCK_SIZE;
memset(preq->pad, 0, sizeof(preq->pad));
sg_init_one(preq->src, preq->pad, padlen);
ahash_request_set_callback(&preq->req, rctx->flags,
poly_cipherpad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_tail(req);
}
static void poly_cipher_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_cipherpad);
}
static int poly_cipher(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
struct scatterlist *crypt = req->src;
int err;
if (rctx->cryptlen == req->cryptlen) /* encrypting */
crypt = req->dst;
crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
ahash_request_set_callback(&preq->req, rctx->flags,
poly_cipher_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_cipherpad(req);
}
static void poly_adpad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_cipher);
}
static int poly_adpad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
unsigned int padlen;
int err;
padlen = -rctx->assoclen % POLY1305_BLOCK_SIZE;
memset(preq->pad, 0, sizeof(preq->pad));
sg_init_one(preq->src, preq->pad, padlen);
ahash_request_set_callback(&preq->req, rctx->flags,
poly_adpad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_cipher(req);
}
static void poly_ad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_adpad);
}
static int poly_ad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
ahash_request_set_callback(&preq->req, rctx->flags,
poly_ad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_adpad(req);
}
static void poly_setkey_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_ad);
}
static int poly_setkey(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
sg_init_one(preq->src, rctx->key, sizeof(rctx->key));
ahash_request_set_callback(&preq->req, rctx->flags,
poly_setkey_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_ad(req);
}
static void poly_init_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_setkey);
}
static int poly_init(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
ahash_request_set_callback(&preq->req, rctx->flags,
poly_init_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
err = crypto_ahash_init(&preq->req);
if (err)
return err;
return poly_setkey(req);
}
static void poly_genkey_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_init);
}
static int poly_genkey(struct aead_request *req)
{
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
int err;
rctx->assoclen = req->assoclen;
if (crypto_aead_ivsize(tfm) == 8) {
if (rctx->assoclen < 8)
return -EINVAL;
rctx->assoclen -= 8;
}
memset(rctx->key, 0, sizeof(rctx->key));
sg_init_one(creq->src, rctx->key, sizeof(rctx->key));
chacha_iv(creq->iv, req, 0);
skcipher_request_set_callback(&creq->req, rctx->flags,
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_skcipher_decrypt(&creq->req);
if (err)
return err;
return poly_init(req);
}
static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_genkey);
}
static int chacha_encrypt(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
struct scatterlist *src, *dst;
int err;
if (req->cryptlen == 0)
goto skip;
chacha_iv(creq->iv, req, 1);
src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
dst = src;
if (req->src != req->dst)
dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
skcipher_request_set_callback(&creq->req, rctx->flags,
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;
skip:
return poly_genkey(req);
}
static int chachapoly_encrypt(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
rctx->cryptlen = req->cryptlen;
rctx->flags = aead_request_flags(req);
/* encrypt call chain:
* - chacha_encrypt/done()
* - poly_genkey/done()
* - poly_init/done()
* - poly_setkey/done()
* - poly_ad/done()
* - poly_adpad/done()
* - poly_cipher/done()
* - poly_cipherpad/done()
* - poly_tail/done/continue()
* - poly_copy_tag()
*/
return chacha_encrypt(req);
}
static int chachapoly_decrypt(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
rctx->flags = aead_request_flags(req);
/* decrypt call chain:
* - poly_genkey/done()
* - poly_init/done()
* - poly_setkey/done()
* - poly_ad/done()
* - poly_adpad/done()
* - poly_cipher/done()
* - poly_cipherpad/done()
* - poly_tail/done/continue()
* - chacha_decrypt/done()
* - poly_verify_tag()
*/
return poly_genkey(req);
}
static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
if (keylen != ctx->saltlen + CHACHA_KEY_SIZE)
return -EINVAL;
keylen -= ctx->saltlen;
memcpy(ctx->salt, key + keylen, ctx->saltlen);
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);
return crypto_skcipher_setkey(ctx->chacha, key, keylen);
}
static int chachapoly_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
if (authsize != POLY1305_DIGEST_SIZE)
return -EINVAL;
return 0;
}
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_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);
if (IS_ERR(chacha)) {
crypto_free_ahash(poly);
return PTR_ERR(chacha);
}
ctx->chacha = chacha;
ctx->poly = poly;
ctx->saltlen = ictx->saltlen;
align = crypto_aead_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(
tfm,
align + offsetof(struct chachapoly_req_ctx, u) +
max(offsetof(struct chacha_req, req) +
sizeof(struct skcipher_request) +
crypto_skcipher_reqsize(chacha),
offsetof(struct poly_req, req) +
sizeof(struct ahash_request) +
crypto_ahash_reqsize(poly)));
return 0;
}
static void chachapoly_exit(struct crypto_aead *tfm)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_ahash(ctx->poly);
crypto_free_skcipher(ctx->chacha);
}
static void chachapoly_free(struct aead_instance *inst)
{
struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_skcipher(&ctx->chacha);
crypto_drop_ahash(&ctx->poly);
kfree(inst);
}
static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
const char *name, unsigned int ivsize)
{
u32 mask;
struct aead_instance *inst;
struct chachapoly_instance_ctx *ctx;
struct skcipher_alg *chacha;
struct hash_alg_common *poly;
int err;
if (ivsize > CHACHAPOLY_IV_SIZE)
return -EINVAL;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
if (err)
return err;
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
ctx = aead_instance_ctx(inst);
ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
err = crypto_grab_skcipher(&ctx->chacha, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
err = crypto_grab_ahash(&ctx->poly, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[2]), 0, mask);
if (err)
goto err_free_inst;
poly = crypto_spawn_ahash_alg(&ctx->poly);
err = -EINVAL;
if (poly->digestsize != POLY1305_DIGEST_SIZE)
goto err_free_inst;
/* Need 16-byte IV size, including Initial Block Counter value */
if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
goto err_free_inst;
/* Not a stream cipher? */
if (chacha->base.cra_blocksize != 1)
goto err_free_inst;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"%s(%s,%s)", name, chacha->base.cra_name,
poly->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"%s(%s,%s)", name, chacha->base.cra_driver_name,
poly->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_priority = (chacha->base.cra_priority +
poly->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
poly->base.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;
inst->alg.encrypt = chachapoly_encrypt;
inst->alg.decrypt = chachapoly_decrypt;
inst->alg.setkey = chachapoly_setkey;
inst->alg.setauthsize = chachapoly_setauthsize;
inst->free = chachapoly_free;
err = aead_register_instance(tmpl, inst);
if (err) {
err_free_inst:
chachapoly_free(inst);
}
return err;
}
static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
{
return chachapoly_create(tmpl, tb, "rfc7539", 12);
}
static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
{
return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
}
static struct crypto_template rfc7539_tmpls[] = {
{
.name = "rfc7539",
.create = rfc7539_create,
.module = THIS_MODULE,
}, {
.name = "rfc7539esp",
.create = rfc7539esp_create,
.module = THIS_MODULE,
},
};
static int __init chacha20poly1305_module_init(void)
{
return crypto_register_templates(rfc7539_tmpls,
ARRAY_SIZE(rfc7539_tmpls));
}
static void __exit chacha20poly1305_module_exit(void)
{
crypto_unregister_templates(rfc7539_tmpls,
ARRAY_SIZE(rfc7539_tmpls));
}
subsys_initcall(chacha20poly1305_module_init);
module_exit(chacha20poly1305_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
MODULE_ALIAS_CRYPTO("rfc7539");
MODULE_ALIAS_CRYPTO("rfc7539esp");
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