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linux-next/crypto/xcbc.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

275 lines
6.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C)2006 USAGI/WIDE Project
*
* Author:
* Kazunori Miyazawa <miyazawa@linux-ipv6.org>
*/
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
0x02020202, 0x02020202, 0x02020202, 0x02020202,
0x03030303, 0x03030303, 0x03030303, 0x03030303};
/*
* +------------------------
* | <parent tfm>
* +------------------------
* | xcbc_tfm_ctx
* +------------------------
* | consts (block size * 2)
* +------------------------
*/
struct xcbc_tfm_ctx {
struct crypto_cipher *child;
u8 ctx[];
};
/*
* +------------------------
* | <shash desc>
* +------------------------
* | xcbc_desc_ctx
* +------------------------
* | odds (block size)
* +------------------------
* | prev (block size)
* +------------------------
*/
struct xcbc_desc_ctx {
unsigned int len;
u8 ctx[];
};
#define XCBC_BLOCKSIZE 16
static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
const u8 *inkey, unsigned int keylen)
{
unsigned long alignmask = crypto_shash_alignmask(parent);
struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
int err = 0;
u8 key1[XCBC_BLOCKSIZE];
int bs = sizeof(key1);
if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
return err;
crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
return crypto_cipher_setkey(ctx->child, key1, bs);
}
static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
{
unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
int bs = crypto_shash_blocksize(pdesc->tfm);
u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
ctx->len = 0;
memset(prev, 0, bs);
return 0;
}
static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
unsigned int len)
{
struct crypto_shash *parent = pdesc->tfm;
unsigned long alignmask = crypto_shash_alignmask(parent);
struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
struct crypto_cipher *tfm = tctx->child;
int bs = crypto_shash_blocksize(parent);
u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
u8 *prev = odds + bs;
/* checking the data can fill the block */
if ((ctx->len + len) <= bs) {
memcpy(odds + ctx->len, p, len);
ctx->len += len;
return 0;
}
/* filling odds with new data and encrypting it */
memcpy(odds + ctx->len, p, bs - ctx->len);
len -= bs - ctx->len;
p += bs - ctx->len;
crypto_xor(prev, odds, bs);
crypto_cipher_encrypt_one(tfm, prev, prev);
/* clearing the length */
ctx->len = 0;
/* encrypting the rest of data */
while (len > bs) {
crypto_xor(prev, p, bs);
crypto_cipher_encrypt_one(tfm, prev, prev);
p += bs;
len -= bs;
}
/* keeping the surplus of blocksize */
if (len) {
memcpy(odds, p, len);
ctx->len = len;
}
return 0;
}
static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
{
struct crypto_shash *parent = pdesc->tfm;
unsigned long alignmask = crypto_shash_alignmask(parent);
struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
struct crypto_cipher *tfm = tctx->child;
int bs = crypto_shash_blocksize(parent);
u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
u8 *prev = odds + bs;
unsigned int offset = 0;
if (ctx->len != bs) {
unsigned int rlen;
u8 *p = odds + ctx->len;
*p = 0x80;
p++;
rlen = bs - ctx->len -1;
if (rlen)
memset(p, 0, rlen);
offset += bs;
}
crypto_xor(prev, odds, bs);
crypto_xor(prev, consts + offset, bs);
crypto_cipher_encrypt_one(tfm, out, prev);
return 0;
}
static int xcbc_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_cipher *cipher;
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
};
static void xcbc_exit_tfm(struct crypto_tfm *tfm)
{
struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->child);
}
static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct shash_instance *inst;
struct crypto_cipher_spawn *spawn;
struct crypto_alg *alg;
unsigned long alignmask;
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
if (err)
return err;
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
spawn = shash_instance_ctx(inst);
err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
alg = crypto_spawn_cipher_alg(spawn);
err = -EINVAL;
if (alg->cra_blocksize != XCBC_BLOCKSIZE)
goto err_free_inst;
err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
if (err)
goto err_free_inst;
alignmask = alg->cra_alignmask | 3;
inst->alg.base.cra_alignmask = alignmask;
inst->alg.base.cra_priority = alg->cra_priority;
inst->alg.base.cra_blocksize = alg->cra_blocksize;
inst->alg.digestsize = alg->cra_blocksize;
inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
crypto_tfm_ctx_alignment()) +
(alignmask &
~(crypto_tfm_ctx_alignment() - 1)) +
alg->cra_blocksize * 2;
inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
alignmask + 1) +
alg->cra_blocksize * 2;
inst->alg.base.cra_init = xcbc_init_tfm;
inst->alg.base.cra_exit = xcbc_exit_tfm;
inst->alg.init = crypto_xcbc_digest_init;
inst->alg.update = crypto_xcbc_digest_update;
inst->alg.final = crypto_xcbc_digest_final;
inst->alg.setkey = crypto_xcbc_digest_setkey;
inst->free = shash_free_singlespawn_instance;
err = shash_register_instance(tmpl, inst);
if (err) {
err_free_inst:
shash_free_singlespawn_instance(inst);
}
return err;
}
static struct crypto_template crypto_xcbc_tmpl = {
.name = "xcbc",
.create = xcbc_create,
.module = THIS_MODULE,
};
static int __init crypto_xcbc_module_init(void)
{
return crypto_register_template(&crypto_xcbc_tmpl);
}
static void __exit crypto_xcbc_module_exit(void)
{
crypto_unregister_template(&crypto_xcbc_tmpl);
}
subsys_initcall(crypto_xcbc_module_init);
module_exit(crypto_xcbc_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XCBC keyed hash algorithm");
MODULE_ALIAS_CRYPTO("xcbc");