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gcm.c
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gcm.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* GCM: Galois/Counter Mode.
*
* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <[email protected]>
*/
#include <crypto/gf128mul.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/internal/hash.h>
#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <crypto/gcm.h>
#include <crypto/hash.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
struct gcm_instance_ctx {
struct crypto_skcipher_spawn ctr;
struct crypto_ahash_spawn ghash;
};
struct crypto_gcm_ctx {
struct crypto_skcipher *ctr;
struct crypto_ahash *ghash;
};
struct crypto_rfc4106_ctx {
struct crypto_aead *child;
u8 nonce[4];
};
struct crypto_rfc4106_req_ctx {
struct scatterlist src[3];
struct scatterlist dst[3];
struct aead_request subreq;
};
struct crypto_rfc4543_instance_ctx {
struct crypto_aead_spawn aead;
};
struct crypto_rfc4543_ctx {
struct crypto_aead *child;
struct crypto_sync_skcipher *null;
u8 nonce[4];
};
struct crypto_rfc4543_req_ctx {
struct aead_request subreq;
};
struct crypto_gcm_ghash_ctx {
unsigned int cryptlen;
struct scatterlist *src;
int (*complete)(struct aead_request *req, u32 flags);
};
struct crypto_gcm_req_priv_ctx {
u8 iv[16];
u8 auth_tag[16];
u8 iauth_tag[16];
struct scatterlist src[3];
struct scatterlist dst[3];
struct scatterlist sg;
struct crypto_gcm_ghash_ctx ghash_ctx;
union {
struct ahash_request ahreq;
struct skcipher_request skreq;
} u;
};
static struct {
u8 buf[16];
struct scatterlist sg;
} *gcm_zeroes;
static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc);
static inline struct crypto_gcm_req_priv_ctx *crypto_gcm_reqctx(
struct aead_request *req)
{
unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
}
static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ahash *ghash = ctx->ghash;
struct crypto_skcipher *ctr = ctx->ctr;
struct {
be128 hash;
u8 iv[16];
struct crypto_wait wait;
struct scatterlist sg[1];
struct skcipher_request req;
} *data;
int err;
crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(ctr, key, keylen);
if (err)
return err;
data = kzalloc(sizeof(*data) + crypto_skcipher_reqsize(ctr),
GFP_KERNEL);
if (!data)
return -ENOMEM;
crypto_init_wait(&data->wait);
sg_init_one(data->sg, &data->hash, sizeof(data->hash));
skcipher_request_set_tfm(&data->req, ctr);
skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
CRYPTO_TFM_REQ_MAY_BACKLOG,
crypto_req_done,
&data->wait);
skcipher_request_set_crypt(&data->req, data->sg, data->sg,
sizeof(data->hash), data->iv);
err = crypto_wait_req(crypto_skcipher_encrypt(&data->req),
&data->wait);
if (err)
goto out;
crypto_ahash_clear_flags(ghash, CRYPTO_TFM_REQ_MASK);
crypto_ahash_set_flags(ghash, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ahash_setkey(ghash, (u8 *)&data->hash, sizeof(be128));
out:
kzfree(data);
return err;
}
static int crypto_gcm_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
return crypto_gcm_check_authsize(authsize);
}
static void crypto_gcm_init_common(struct aead_request *req)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
__be32 counter = cpu_to_be32(1);
struct scatterlist *sg;
memset(pctx->auth_tag, 0, sizeof(pctx->auth_tag));
memcpy(pctx->iv, req->iv, GCM_AES_IV_SIZE);
memcpy(pctx->iv + GCM_AES_IV_SIZE, &counter, 4);
sg_init_table(pctx->src, 3);
sg_set_buf(pctx->src, pctx->auth_tag, sizeof(pctx->auth_tag));
sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
if (sg != pctx->src + 1)
sg_chain(pctx->src, 2, sg);
if (req->src != req->dst) {
sg_init_table(pctx->dst, 3);
sg_set_buf(pctx->dst, pctx->auth_tag, sizeof(pctx->auth_tag));
sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
if (sg != pctx->dst + 1)
sg_chain(pctx->dst, 2, sg);
}
}
static void crypto_gcm_init_crypt(struct aead_request *req,
unsigned int cryptlen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct skcipher_request *skreq = &pctx->u.skreq;
struct scatterlist *dst;
dst = req->src == req->dst ? pctx->src : pctx->dst;
skcipher_request_set_tfm(skreq, ctx->ctr);
skcipher_request_set_crypt(skreq, pctx->src, dst,
cryptlen + sizeof(pctx->auth_tag),
pctx->iv);
}
static inline unsigned int gcm_remain(unsigned int len)
{
len &= 0xfU;
return len ? 16 - len : 0;
}
static void gcm_hash_len_done(struct crypto_async_request *areq, int err);
static int gcm_hash_update(struct aead_request *req,
crypto_completion_t compl,
struct scatterlist *src,
unsigned int len, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct ahash_request *ahreq = &pctx->u.ahreq;
ahash_request_set_callback(ahreq, flags, compl, req);
ahash_request_set_crypt(ahreq, src, NULL, len);
return crypto_ahash_update(ahreq);
}
static int gcm_hash_remain(struct aead_request *req,
unsigned int remain,
crypto_completion_t compl, u32 flags)
{
return gcm_hash_update(req, compl, &gcm_zeroes->sg, remain, flags);
}
static int gcm_hash_len(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct ahash_request *ahreq = &pctx->u.ahreq;
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
be128 lengths;
lengths.a = cpu_to_be64(req->assoclen * 8);
lengths.b = cpu_to_be64(gctx->cryptlen * 8);
memcpy(pctx->iauth_tag, &lengths, 16);
sg_init_one(&pctx->sg, pctx->iauth_tag, 16);
ahash_request_set_callback(ahreq, flags, gcm_hash_len_done, req);
ahash_request_set_crypt(ahreq, &pctx->sg,
pctx->iauth_tag, sizeof(lengths));
return crypto_ahash_finup(ahreq);
}
static int gcm_hash_len_continue(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
return gctx->complete(req, flags);
}
static void gcm_hash_len_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_len_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash_crypt_remain_continue(struct aead_request *req, u32 flags)
{
return gcm_hash_len(req, flags) ?:
gcm_hash_len_continue(req, flags);
}
static void gcm_hash_crypt_remain_done(struct crypto_async_request *areq,
int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_crypt_remain_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash_crypt_continue(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
unsigned int remain;
remain = gcm_remain(gctx->cryptlen);
if (remain)
return gcm_hash_remain(req, remain,
gcm_hash_crypt_remain_done, flags) ?:
gcm_hash_crypt_remain_continue(req, flags);
return gcm_hash_crypt_remain_continue(req, flags);
}
static void gcm_hash_crypt_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_crypt_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash_assoc_remain_continue(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
if (gctx->cryptlen)
return gcm_hash_update(req, gcm_hash_crypt_done,
gctx->src, gctx->cryptlen, flags) ?:
gcm_hash_crypt_continue(req, flags);
return gcm_hash_crypt_remain_continue(req, flags);
}
static void gcm_hash_assoc_remain_done(struct crypto_async_request *areq,
int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_assoc_remain_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash_assoc_continue(struct aead_request *req, u32 flags)
{
unsigned int remain;
remain = gcm_remain(req->assoclen);
if (remain)
return gcm_hash_remain(req, remain,
gcm_hash_assoc_remain_done, flags) ?:
gcm_hash_assoc_remain_continue(req, flags);
return gcm_hash_assoc_remain_continue(req, flags);
}
static void gcm_hash_assoc_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_assoc_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash_init_continue(struct aead_request *req, u32 flags)
{
if (req->assoclen)
return gcm_hash_update(req, gcm_hash_assoc_done,
req->src, req->assoclen, flags) ?:
gcm_hash_assoc_continue(req, flags);
return gcm_hash_assoc_remain_continue(req, flags);
}
static void gcm_hash_init_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_hash_init_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int gcm_hash(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct ahash_request *ahreq = &pctx->u.ahreq;
struct crypto_gcm_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
ahash_request_set_tfm(ahreq, ctx->ghash);
ahash_request_set_callback(ahreq, flags, gcm_hash_init_done, req);
return crypto_ahash_init(ahreq) ?:
gcm_hash_init_continue(req, flags);
}
static int gcm_enc_copy_hash(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
u8 *auth_tag = pctx->auth_tag;
crypto_xor(auth_tag, pctx->iauth_tag, 16);
scatterwalk_map_and_copy(auth_tag, req->dst,
req->assoclen + req->cryptlen,
crypto_aead_authsize(aead), 1);
return 0;
}
static int gcm_encrypt_continue(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
gctx->src = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
gctx->cryptlen = req->cryptlen;
gctx->complete = gcm_enc_copy_hash;
return gcm_hash(req, flags);
}
static void gcm_encrypt_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (err)
goto out;
err = gcm_encrypt_continue(req, 0);
if (err == -EINPROGRESS)
return;
out:
aead_request_complete(req, err);
}
static int crypto_gcm_encrypt(struct aead_request *req)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct skcipher_request *skreq = &pctx->u.skreq;
u32 flags = aead_request_flags(req);
crypto_gcm_init_common(req);
crypto_gcm_init_crypt(req, req->cryptlen);
skcipher_request_set_callback(skreq, flags, gcm_encrypt_done, req);
return crypto_skcipher_encrypt(skreq) ?:
gcm_encrypt_continue(req, flags);
}
static int crypto_gcm_verify(struct aead_request *req)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
u8 *auth_tag = pctx->auth_tag;
u8 *iauth_tag = pctx->iauth_tag;
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen - authsize;
crypto_xor(auth_tag, iauth_tag, 16);
scatterwalk_map_and_copy(iauth_tag, req->src,
req->assoclen + cryptlen, authsize, 0);
return crypto_memneq(iauth_tag, auth_tag, authsize) ? -EBADMSG : 0;
}
static void gcm_decrypt_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
if (!err)
err = crypto_gcm_verify(req);
aead_request_complete(req, err);
}
static int gcm_dec_hash_continue(struct aead_request *req, u32 flags)
{
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct skcipher_request *skreq = &pctx->u.skreq;
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
crypto_gcm_init_crypt(req, gctx->cryptlen);
skcipher_request_set_callback(skreq, flags, gcm_decrypt_done, req);
return crypto_skcipher_decrypt(skreq) ?: crypto_gcm_verify(req);
}
static int crypto_gcm_decrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen;
u32 flags = aead_request_flags(req);
cryptlen -= authsize;
crypto_gcm_init_common(req);
gctx->src = sg_next(pctx->src);
gctx->cryptlen = cryptlen;
gctx->complete = gcm_dec_hash_continue;
return gcm_hash(req, flags);
}
static int crypto_gcm_init_tfm(struct crypto_aead *tfm)
{
struct aead_instance *inst = aead_alg_instance(tfm);
struct gcm_instance_ctx *ictx = aead_instance_ctx(inst);
struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_skcipher *ctr;
struct crypto_ahash *ghash;
unsigned long align;
int err;
ghash = crypto_spawn_ahash(&ictx->ghash);
if (IS_ERR(ghash))
return PTR_ERR(ghash);
ctr = crypto_spawn_skcipher(&ictx->ctr);
err = PTR_ERR(ctr);
if (IS_ERR(ctr))
goto err_free_hash;
ctx->ctr = ctr;
ctx->ghash = ghash;
align = crypto_aead_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(tfm,
align + offsetof(struct crypto_gcm_req_priv_ctx, u) +
max(sizeof(struct skcipher_request) +
crypto_skcipher_reqsize(ctr),
sizeof(struct ahash_request) +
crypto_ahash_reqsize(ghash)));
return 0;
err_free_hash:
crypto_free_ahash(ghash);
return err;
}
static void crypto_gcm_exit_tfm(struct crypto_aead *tfm)
{
struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_ahash(ctx->ghash);
crypto_free_skcipher(ctx->ctr);
}
static void crypto_gcm_free(struct aead_instance *inst)
{
struct gcm_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_skcipher(&ctx->ctr);
crypto_drop_ahash(&ctx->ghash);
kfree(inst);
}
static int crypto_gcm_create_common(struct crypto_template *tmpl,
struct rtattr **tb,
const char *ctr_name,
const char *ghash_name)
{
struct crypto_attr_type *algt;
u32 mask;
struct aead_instance *inst;
struct gcm_instance_ctx *ctx;
struct skcipher_alg *ctr;
struct hash_alg_common *ghash;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;
mask = crypto_requires_sync(algt->type, algt->mask);
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
ctx = aead_instance_ctx(inst);
err = crypto_grab_ahash(&ctx->ghash, aead_crypto_instance(inst),
ghash_name, 0, mask);
if (err)
goto err_free_inst;
ghash = crypto_spawn_ahash_alg(&ctx->ghash);
err = -EINVAL;
if (strcmp(ghash->base.cra_name, "ghash") != 0 ||
ghash->digestsize != 16)
goto err_free_inst;
err = crypto_grab_skcipher(&ctx->ctr, aead_crypto_instance(inst),
ctr_name, 0, mask);
if (err)
goto err_free_inst;
ctr = crypto_spawn_skcipher_alg(&ctx->ctr);
/* The skcipher algorithm must be CTR mode, using 16-byte blocks. */
err = -EINVAL;
if (strncmp(ctr->base.cra_name, "ctr(", 4) != 0 ||
crypto_skcipher_alg_ivsize(ctr) != 16 ||
ctr->base.cra_blocksize != 1)
goto err_free_inst;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"gcm(%s", ctr->base.cra_name + 4) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"gcm_base(%s,%s)", ctr->base.cra_driver_name,
ghash->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_flags = (ghash->base.cra_flags |
ctr->base.cra_flags) & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = (ghash->base.cra_priority +
ctr->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = ghash->base.cra_alignmask |
ctr->base.cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
inst->alg.ivsize = GCM_AES_IV_SIZE;
inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
inst->alg.maxauthsize = 16;
inst->alg.init = crypto_gcm_init_tfm;
inst->alg.exit = crypto_gcm_exit_tfm;
inst->alg.setkey = crypto_gcm_setkey;
inst->alg.setauthsize = crypto_gcm_setauthsize;
inst->alg.encrypt = crypto_gcm_encrypt;
inst->alg.decrypt = crypto_gcm_decrypt;
inst->free = crypto_gcm_free;
err = aead_register_instance(tmpl, inst);
if (err) {
err_free_inst:
crypto_gcm_free(inst);
}
return err;
}
static int crypto_gcm_create(struct crypto_template *tmpl, struct rtattr **tb)
{
const char *cipher_name;
char ctr_name[CRYPTO_MAX_ALG_NAME];
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return PTR_ERR(cipher_name);
if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", cipher_name) >=
CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
return crypto_gcm_create_common(tmpl, tb, ctr_name, "ghash");
}
static int crypto_gcm_base_create(struct crypto_template *tmpl,
struct rtattr **tb)
{
const char *ctr_name;
const char *ghash_name;
ctr_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(ctr_name))
return PTR_ERR(ctr_name);
ghash_name = crypto_attr_alg_name(tb[2]);
if (IS_ERR(ghash_name))
return PTR_ERR(ghash_name);
return crypto_gcm_create_common(tmpl, tb, ctr_name, ghash_name);
}
static int crypto_rfc4106_setkey(struct crypto_aead *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
struct crypto_aead *child = ctx->child;
if (keylen < 4)
return -EINVAL;
keylen -= 4;
memcpy(ctx->nonce, key + keylen, 4);
crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
return crypto_aead_setkey(child, key, keylen);
}
static int crypto_rfc4106_setauthsize(struct crypto_aead *parent,
unsigned int authsize)
{
struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
int err;
err = crypto_rfc4106_check_authsize(authsize);
if (err)
return err;
return crypto_aead_setauthsize(ctx->child, authsize);
}
static struct aead_request *crypto_rfc4106_crypt(struct aead_request *req)
{
struct crypto_rfc4106_req_ctx *rctx = aead_request_ctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(aead);
struct aead_request *subreq = &rctx->subreq;
struct crypto_aead *child = ctx->child;
struct scatterlist *sg;
u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
crypto_aead_alignmask(child) + 1);
scatterwalk_map_and_copy(iv + GCM_AES_IV_SIZE, req->src, 0, req->assoclen - 8, 0);
memcpy(iv, ctx->nonce, 4);
memcpy(iv + 4, req->iv, 8);
sg_init_table(rctx->src, 3);
sg_set_buf(rctx->src, iv + GCM_AES_IV_SIZE, req->assoclen - 8);
sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
if (sg != rctx->src + 1)
sg_chain(rctx->src, 2, sg);
if (req->src != req->dst) {
sg_init_table(rctx->dst, 3);
sg_set_buf(rctx->dst, iv + GCM_AES_IV_SIZE, req->assoclen - 8);
sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
if (sg != rctx->dst + 1)
sg_chain(rctx->dst, 2, sg);
}
aead_request_set_tfm(subreq, child);
aead_request_set_callback(subreq, req->base.flags, req->base.complete,
req->base.data);
aead_request_set_crypt(subreq, rctx->src,
req->src == req->dst ? rctx->src : rctx->dst,
req->cryptlen, iv);
aead_request_set_ad(subreq, req->assoclen - 8);
return subreq;
}
static int crypto_rfc4106_encrypt(struct aead_request *req)
{
int err;
err = crypto_ipsec_check_assoclen(req->assoclen);
if (err)
return err;
req = crypto_rfc4106_crypt(req);
return crypto_aead_encrypt(req);
}
static int crypto_rfc4106_decrypt(struct aead_request *req)
{
int err;
err = crypto_ipsec_check_assoclen(req->assoclen);
if (err)
return err;
req = crypto_rfc4106_crypt(req);
return crypto_aead_decrypt(req);
}
static int crypto_rfc4106_init_tfm(struct crypto_aead *tfm)
{
struct aead_instance *inst = aead_alg_instance(tfm);
struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_aead *aead;
unsigned long align;
aead = crypto_spawn_aead(spawn);
if (IS_ERR(aead))
return PTR_ERR(aead);
ctx->child = aead;
align = crypto_aead_alignmask(aead);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(
tfm,
sizeof(struct crypto_rfc4106_req_ctx) +
ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
align + 24);
return 0;
}
static void crypto_rfc4106_exit_tfm(struct crypto_aead *tfm)
{
struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_aead(ctx->child);
}
static void crypto_rfc4106_free(struct aead_instance *inst)
{
crypto_drop_aead(aead_instance_ctx(inst));
kfree(inst);
}
static int crypto_rfc4106_create(struct crypto_template *tmpl,
struct rtattr **tb)
{
struct crypto_attr_type *algt;
u32 mask;
struct aead_instance *inst;
struct crypto_aead_spawn *spawn;
struct aead_alg *alg;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;
mask = crypto_requires_sync(algt->type, algt->mask);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
spawn = aead_instance_ctx(inst);
err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
alg = crypto_spawn_aead_alg(spawn);
err = -EINVAL;
/* Underlying IV size must be 12. */
if (crypto_aead_alg_ivsize(alg) != GCM_AES_IV_SIZE)
goto err_free_inst;
/* Not a stream cipher? */
if (alg->base.cra_blocksize != 1)
goto err_free_inst;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"rfc4106(%s)", alg->base.cra_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"rfc4106(%s)", alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4106_ctx);
inst->alg.ivsize = GCM_RFC4106_IV_SIZE;
inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
inst->alg.init = crypto_rfc4106_init_tfm;
inst->alg.exit = crypto_rfc4106_exit_tfm;
inst->alg.setkey = crypto_rfc4106_setkey;
inst->alg.setauthsize = crypto_rfc4106_setauthsize;
inst->alg.encrypt = crypto_rfc4106_encrypt;
inst->alg.decrypt = crypto_rfc4106_decrypt;
inst->free = crypto_rfc4106_free;
err = aead_register_instance(tmpl, inst);
if (err) {
err_free_inst:
crypto_rfc4106_free(inst);
}
return err;
}
static int crypto_rfc4543_setkey(struct crypto_aead *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);
struct crypto_aead *child = ctx->child;
if (keylen < 4)
return -EINVAL;
keylen -= 4;
memcpy(ctx->nonce, key + keylen, 4);
crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
return crypto_aead_setkey(child, key, keylen);
}
static int crypto_rfc4543_setauthsize(struct crypto_aead *parent,
unsigned int authsize)
{
struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);
if (authsize != 16)
return -EINVAL;
return crypto_aead_setauthsize(ctx->child, authsize);
}
static int crypto_rfc4543_crypt(struct aead_request *req, bool enc)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_rfc4543_req_ctx *rctx = aead_request_ctx(req);
struct aead_request *subreq = &rctx->subreq;
unsigned int authsize = crypto_aead_authsize(aead);
u8 *iv = PTR_ALIGN((u8 *)(rctx + 1) + crypto_aead_reqsize(ctx->child),
crypto_aead_alignmask(ctx->child) + 1);
int err;
if (req->src != req->dst) {
err = crypto_rfc4543_copy_src_to_dst(req, enc);
if (err)
return err;
}
memcpy(iv, ctx->nonce, 4);
memcpy(iv + 4, req->iv, 8);
aead_request_set_tfm(subreq, ctx->child);
aead_request_set_callback(subreq, req->base.flags,
req->base.complete, req->base.data);
aead_request_set_crypt(subreq, req->src, req->dst,
enc ? 0 : authsize, iv);
aead_request_set_ad(subreq, req->assoclen + req->cryptlen -
subreq->cryptlen);
return enc ? crypto_aead_encrypt(subreq) : crypto_aead_decrypt(subreq);
}
static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead);
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int nbytes = req->assoclen + req->cryptlen -
(enc ? 0 : authsize);
SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);
skcipher_request_set_sync_tfm(nreq, ctx->null);
skcipher_request_set_callback(nreq, req->base.flags, NULL, NULL);
skcipher_request_set_crypt(nreq, req->src, req->dst, nbytes, NULL);
return crypto_skcipher_encrypt(nreq);
}
static int crypto_rfc4543_encrypt(struct aead_request *req)
{
return crypto_ipsec_check_assoclen(req->assoclen) ?:
crypto_rfc4543_crypt(req, true);
}
static int crypto_rfc4543_decrypt(struct aead_request *req)
{
return crypto_ipsec_check_assoclen(req->assoclen) ?:
crypto_rfc4543_crypt(req, false);
}