linux/crypto/geniv.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

164 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* geniv: Shared IV generator code
*
* This file provides common code to IV generators such as seqiv.
*
* Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/internal/geniv.h>
#include <crypto/internal/rng.h>
#include <crypto/null.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
static int aead_geniv_setkey(struct crypto_aead *tfm,
const u8 *key, unsigned int keylen)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
return crypto_aead_setkey(ctx->child, key, keylen);
}
static int aead_geniv_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
return crypto_aead_setauthsize(ctx->child, authsize);
}
static void aead_geniv_free(struct aead_instance *inst)
{
crypto_drop_aead(aead_instance_ctx(inst));
kfree(inst);
}
struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
struct rtattr **tb)
{
struct crypto_aead_spawn *spawn;
struct aead_instance *inst;
struct aead_alg *alg;
unsigned int ivsize;
unsigned int maxauthsize;
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
if (err)
return ERR_PTR(err);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-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);
ivsize = crypto_aead_alg_ivsize(alg);
maxauthsize = crypto_aead_alg_maxauthsize(alg);
err = -EINVAL;
if (ivsize < sizeof(u64))
goto err_free_inst;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"%s(%s)", tmpl->name, alg->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)", tmpl->name, alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
inst->alg.setkey = aead_geniv_setkey;
inst->alg.setauthsize = aead_geniv_setauthsize;
inst->alg.ivsize = ivsize;
inst->alg.maxauthsize = maxauthsize;
inst->free = aead_geniv_free;
out:
return inst;
err_free_inst:
aead_geniv_free(inst);
inst = ERR_PTR(err);
goto out;
}
EXPORT_SYMBOL_GPL(aead_geniv_alloc);
int aead_init_geniv(struct crypto_aead *aead)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
struct aead_instance *inst = aead_alg_instance(aead);
struct crypto_aead *child;
int err;
spin_lock_init(&ctx->lock);
err = crypto_get_default_rng();
if (err)
goto out;
err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
crypto_aead_ivsize(aead));
crypto_put_default_rng();
if (err)
goto out;
ctx->sknull = crypto_get_default_null_skcipher();
err = PTR_ERR(ctx->sknull);
if (IS_ERR(ctx->sknull))
goto out;
child = crypto_spawn_aead(aead_instance_ctx(inst));
err = PTR_ERR(child);
if (IS_ERR(child))
goto drop_null;
ctx->child = child;
crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
sizeof(struct aead_request));
err = 0;
out:
return err;
drop_null:
crypto_put_default_null_skcipher();
goto out;
}
EXPORT_SYMBOL_GPL(aead_init_geniv);
void aead_exit_geniv(struct crypto_aead *tfm)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_aead(ctx->child);
crypto_put_default_null_skcipher();
}
EXPORT_SYMBOL_GPL(aead_exit_geniv);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Shared IV generator code");