linux/crypto/ahash.c
Eric Biggers 2f1f34c1bf crypto: ahash - optimize performance when wrapping shash
The "ahash" API provides access to both CPU-based and hardware offload-
based implementations of hash algorithms.  Typically the former are
implemented as "shash" algorithms under the hood, while the latter are
implemented as "ahash" algorithms.  The "ahash" API provides access to
both.  Various kernel subsystems use the ahash API because they want to
support hashing hardware offload without using a separate API for it.

Yet, the common case is that a crypto accelerator is not actually being
used, and ahash is just wrapping a CPU-based shash algorithm.

This patch optimizes the ahash API for that common case by eliminating
the extra indirect call for each ahash operation on top of shash.

It also fixes the double-counting of crypto stats in this scenario
(though CONFIG_CRYPTO_STATS should *not* be enabled by anyone interested
in performance anyway...), and it eliminates redundant checking of
CRYPTO_TFM_NEED_KEY.  As a bonus, it also shrinks struct crypto_ahash.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-27 18:04:30 +08:00

775 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Asynchronous Cryptographic Hash operations.
*
* This is the implementation of the ahash (asynchronous hash) API. It differs
* from shash (synchronous hash) in that ahash supports asynchronous operations,
* and it hashes data from scatterlists instead of virtually addressed buffers.
*
* The ahash API provides access to both ahash and shash algorithms. The shash
* API only provides access to shash algorithms.
*
* Copyright (c) 2008 Loc Ho <lho@amcc.com>
*/
#include <crypto/scatterwalk.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "hash.h"
#define CRYPTO_ALG_TYPE_AHASH_MASK 0x0000000e
static inline struct crypto_istat_hash *ahash_get_stat(struct ahash_alg *alg)
{
return hash_get_stat(&alg->halg);
}
static inline int crypto_ahash_errstat(struct ahash_alg *alg, int err)
{
if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
return err;
if (err && err != -EINPROGRESS && err != -EBUSY)
atomic64_inc(&ahash_get_stat(alg)->err_cnt);
return err;
}
/*
* For an ahash tfm that is using an shash algorithm (instead of an ahash
* algorithm), this returns the underlying shash tfm.
*/
static inline struct crypto_shash *ahash_to_shash(struct crypto_ahash *tfm)
{
return *(struct crypto_shash **)crypto_ahash_ctx(tfm);
}
static inline struct shash_desc *prepare_shash_desc(struct ahash_request *req,
struct crypto_ahash *tfm)
{
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = ahash_to_shash(tfm);
return desc;
}
int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
{
struct crypto_hash_walk walk;
int nbytes;
for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
nbytes = crypto_hash_walk_done(&walk, nbytes))
nbytes = crypto_shash_update(desc, walk.data, nbytes);
return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_update);
int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
{
struct crypto_hash_walk walk;
int nbytes;
nbytes = crypto_hash_walk_first(req, &walk);
if (!nbytes)
return crypto_shash_final(desc, req->result);
do {
nbytes = crypto_hash_walk_last(&walk) ?
crypto_shash_finup(desc, walk.data, nbytes,
req->result) :
crypto_shash_update(desc, walk.data, nbytes);
nbytes = crypto_hash_walk_done(&walk, nbytes);
} while (nbytes > 0);
return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_finup);
int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
{
unsigned int nbytes = req->nbytes;
struct scatterlist *sg;
unsigned int offset;
int err;
if (nbytes &&
(sg = req->src, offset = sg->offset,
nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
void *data;
data = kmap_local_page(sg_page(sg));
err = crypto_shash_digest(desc, data + offset, nbytes,
req->result);
kunmap_local(data);
} else
err = crypto_shash_init(desc) ?:
shash_ahash_finup(req, desc);
return err;
}
EXPORT_SYMBOL_GPL(shash_ahash_digest);
static void crypto_exit_ahash_using_shash(struct crypto_tfm *tfm)
{
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
crypto_free_shash(*ctx);
}
static int crypto_init_ahash_using_shash(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
struct crypto_shash *shash;
if (!crypto_mod_get(calg))
return -EAGAIN;
shash = crypto_create_tfm(calg, &crypto_shash_type);
if (IS_ERR(shash)) {
crypto_mod_put(calg);
return PTR_ERR(shash);
}
crt->using_shash = true;
*ctx = shash;
tfm->exit = crypto_exit_ahash_using_shash;
crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
CRYPTO_TFM_NEED_KEY);
crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
return 0;
}
static int hash_walk_next(struct crypto_hash_walk *walk)
{
unsigned int offset = walk->offset;
unsigned int nbytes = min(walk->entrylen,
((unsigned int)(PAGE_SIZE)) - offset);
walk->data = kmap_local_page(walk->pg);
walk->data += offset;
walk->entrylen -= nbytes;
return nbytes;
}
static int hash_walk_new_entry(struct crypto_hash_walk *walk)
{
struct scatterlist *sg;
sg = walk->sg;
walk->offset = sg->offset;
walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
walk->offset = offset_in_page(walk->offset);
walk->entrylen = sg->length;
if (walk->entrylen > walk->total)
walk->entrylen = walk->total;
walk->total -= walk->entrylen;
return hash_walk_next(walk);
}
int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
{
walk->data -= walk->offset;
kunmap_local(walk->data);
crypto_yield(walk->flags);
if (err)
return err;
if (walk->entrylen) {
walk->offset = 0;
walk->pg++;
return hash_walk_next(walk);
}
if (!walk->total)
return 0;
walk->sg = sg_next(walk->sg);
return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
int crypto_hash_walk_first(struct ahash_request *req,
struct crypto_hash_walk *walk)
{
walk->total = req->nbytes;
if (!walk->total) {
walk->entrylen = 0;
return 0;
}
walk->sg = req->src;
walk->flags = req->base.flags;
return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
return -ENOSYS;
}
static void ahash_set_needkey(struct crypto_ahash *tfm, struct ahash_alg *alg)
{
if (alg->setkey != ahash_nosetkey &&
!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
}
int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
if (likely(tfm->using_shash)) {
struct crypto_shash *shash = ahash_to_shash(tfm);
int err;
err = crypto_shash_setkey(shash, key, keylen);
if (unlikely(err)) {
crypto_ahash_set_flags(tfm,
crypto_shash_get_flags(shash) &
CRYPTO_TFM_NEED_KEY);
return err;
}
} else {
struct ahash_alg *alg = crypto_ahash_alg(tfm);
int err;
err = alg->setkey(tfm, key, keylen);
if (unlikely(err)) {
ahash_set_needkey(tfm, alg);
return err;
}
}
crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
int crypto_ahash_init(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
if (likely(tfm->using_shash))
return crypto_shash_init(prepare_shash_desc(req, tfm));
if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
return crypto_ahash_alg(tfm)->init(req);
}
EXPORT_SYMBOL_GPL(crypto_ahash_init);
static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt,
bool has_state)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
unsigned int ds = crypto_ahash_digestsize(tfm);
struct ahash_request *subreq;
unsigned int subreq_size;
unsigned int reqsize;
u8 *result;
gfp_t gfp;
u32 flags;
subreq_size = sizeof(*subreq);
reqsize = crypto_ahash_reqsize(tfm);
reqsize = ALIGN(reqsize, crypto_tfm_ctx_alignment());
subreq_size += reqsize;
subreq_size += ds;
flags = ahash_request_flags(req);
gfp = (flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? GFP_KERNEL : GFP_ATOMIC;
subreq = kmalloc(subreq_size, gfp);
if (!subreq)
return -ENOMEM;
ahash_request_set_tfm(subreq, tfm);
ahash_request_set_callback(subreq, flags, cplt, req);
result = (u8 *)(subreq + 1) + reqsize;
ahash_request_set_crypt(subreq, req->src, result, req->nbytes);
if (has_state) {
void *state;
state = kmalloc(crypto_ahash_statesize(tfm), gfp);
if (!state) {
kfree(subreq);
return -ENOMEM;
}
crypto_ahash_export(req, state);
crypto_ahash_import(subreq, state);
kfree_sensitive(state);
}
req->priv = subreq;
return 0;
}
static void ahash_restore_req(struct ahash_request *req, int err)
{
struct ahash_request *subreq = req->priv;
if (!err)
memcpy(req->result, subreq->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
req->priv = NULL;
kfree_sensitive(subreq);
}
int crypto_ahash_update(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
struct ahash_alg *alg;
if (likely(tfm->using_shash))
return shash_ahash_update(req, ahash_request_ctx(req));
alg = crypto_ahash_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
atomic64_add(req->nbytes, &ahash_get_stat(alg)->hash_tlen);
return crypto_ahash_errstat(alg, alg->update(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_update);
int crypto_ahash_final(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
struct ahash_alg *alg;
if (likely(tfm->using_shash))
return crypto_shash_final(ahash_request_ctx(req), req->result);
alg = crypto_ahash_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
atomic64_inc(&ahash_get_stat(alg)->hash_cnt);
return crypto_ahash_errstat(alg, alg->final(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_final);
int crypto_ahash_finup(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
struct ahash_alg *alg;
if (likely(tfm->using_shash))
return shash_ahash_finup(req, ahash_request_ctx(req));
alg = crypto_ahash_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_hash *istat = ahash_get_stat(alg);
atomic64_inc(&istat->hash_cnt);
atomic64_add(req->nbytes, &istat->hash_tlen);
}
return crypto_ahash_errstat(alg, alg->finup(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_finup);
int crypto_ahash_digest(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
struct ahash_alg *alg;
int err;
if (likely(tfm->using_shash))
return shash_ahash_digest(req, prepare_shash_desc(req, tfm));
alg = crypto_ahash_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_hash *istat = ahash_get_stat(alg);
atomic64_inc(&istat->hash_cnt);
atomic64_add(req->nbytes, &istat->hash_tlen);
}
if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
err = -ENOKEY;
else
err = alg->digest(req);
return crypto_ahash_errstat(alg, err);
}
EXPORT_SYMBOL_GPL(crypto_ahash_digest);
static void ahash_def_finup_done2(void *data, int err)
{
struct ahash_request *areq = data;
if (err == -EINPROGRESS)
return;
ahash_restore_req(areq, err);
ahash_request_complete(areq, err);
}
static int ahash_def_finup_finish1(struct ahash_request *req, int err)
{
struct ahash_request *subreq = req->priv;
if (err)
goto out;
subreq->base.complete = ahash_def_finup_done2;
err = crypto_ahash_alg(crypto_ahash_reqtfm(req))->final(subreq);
if (err == -EINPROGRESS || err == -EBUSY)
return err;
out:
ahash_restore_req(req, err);
return err;
}
static void ahash_def_finup_done1(void *data, int err)
{
struct ahash_request *areq = data;
struct ahash_request *subreq;
if (err == -EINPROGRESS)
goto out;
subreq = areq->priv;
subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
err = ahash_def_finup_finish1(areq, err);
if (err == -EINPROGRESS || err == -EBUSY)
return;
out:
ahash_request_complete(areq, err);
}
static int ahash_def_finup(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
int err;
err = ahash_save_req(req, ahash_def_finup_done1, true);
if (err)
return err;
err = crypto_ahash_alg(tfm)->update(req->priv);
if (err == -EINPROGRESS || err == -EBUSY)
return err;
return ahash_def_finup_finish1(req, err);
}
int crypto_ahash_export(struct ahash_request *req, void *out)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
if (likely(tfm->using_shash))
return crypto_shash_export(ahash_request_ctx(req), out);
return crypto_ahash_alg(tfm)->export(req, out);
}
EXPORT_SYMBOL_GPL(crypto_ahash_export);
int crypto_ahash_import(struct ahash_request *req, const void *in)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
if (likely(tfm->using_shash))
return crypto_shash_import(prepare_shash_desc(req, tfm), in);
if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
return crypto_ahash_alg(tfm)->import(req, in);
}
EXPORT_SYMBOL_GPL(crypto_ahash_import);
static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
struct ahash_alg *alg = crypto_ahash_alg(hash);
alg->exit_tfm(hash);
}
static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
struct ahash_alg *alg = crypto_ahash_alg(hash);
crypto_ahash_set_statesize(hash, alg->halg.statesize);
if (tfm->__crt_alg->cra_type == &crypto_shash_type)
return crypto_init_ahash_using_shash(tfm);
ahash_set_needkey(hash, alg);
if (alg->exit_tfm)
tfm->exit = crypto_ahash_exit_tfm;
return alg->init_tfm ? alg->init_tfm(hash) : 0;
}
static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
{
if (alg->cra_type == &crypto_shash_type)
return sizeof(struct crypto_shash *);
return crypto_alg_extsize(alg);
}
static void crypto_ahash_free_instance(struct crypto_instance *inst)
{
struct ahash_instance *ahash = ahash_instance(inst);
ahash->free(ahash);
}
static int __maybe_unused crypto_ahash_report(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_hash rhash;
memset(&rhash, 0, sizeof(rhash));
strscpy(rhash.type, "ahash", sizeof(rhash.type));
rhash.blocksize = alg->cra_blocksize;
rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
}
static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_printf(m, "type : ahash\n");
seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
"yes" : "no");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "digestsize : %u\n",
__crypto_hash_alg_common(alg)->digestsize);
}
static int __maybe_unused crypto_ahash_report_stat(
struct sk_buff *skb, struct crypto_alg *alg)
{
return crypto_hash_report_stat(skb, alg, "ahash");
}
static const struct crypto_type crypto_ahash_type = {
.extsize = crypto_ahash_extsize,
.init_tfm = crypto_ahash_init_tfm,
.free = crypto_ahash_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_ahash_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
.report = crypto_ahash_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
.report_stat = crypto_ahash_report_stat,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
.type = CRYPTO_ALG_TYPE_AHASH,
.tfmsize = offsetof(struct crypto_ahash, base),
};
int crypto_grab_ahash(struct crypto_ahash_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_ahash_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_ahash);
struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
{
return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_has_ahash);
struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
{
struct hash_alg_common *halg = crypto_hash_alg_common(hash);
struct crypto_tfm *tfm = crypto_ahash_tfm(hash);
struct crypto_ahash *nhash;
struct ahash_alg *alg;
int err;
if (!crypto_hash_alg_has_setkey(halg)) {
tfm = crypto_tfm_get(tfm);
if (IS_ERR(tfm))
return ERR_CAST(tfm);
return hash;
}
nhash = crypto_clone_tfm(&crypto_ahash_type, tfm);
if (IS_ERR(nhash))
return nhash;
nhash->reqsize = hash->reqsize;
nhash->statesize = hash->statesize;
if (likely(hash->using_shash)) {
struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
struct crypto_shash *shash;
shash = crypto_clone_shash(ahash_to_shash(hash));
if (IS_ERR(shash)) {
err = PTR_ERR(shash);
goto out_free_nhash;
}
*nctx = shash;
return nhash;
}
err = -ENOSYS;
alg = crypto_ahash_alg(hash);
if (!alg->clone_tfm)
goto out_free_nhash;
err = alg->clone_tfm(nhash, hash);
if (err)
goto out_free_nhash;
return nhash;
out_free_nhash:
crypto_free_ahash(nhash);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_clone_ahash);
static int ahash_prepare_alg(struct ahash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
int err;
if (alg->halg.statesize == 0)
return -EINVAL;
err = hash_prepare_alg(&alg->halg);
if (err)
return err;
base->cra_type = &crypto_ahash_type;
base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
if (!alg->finup)
alg->finup = ahash_def_finup;
if (!alg->setkey)
alg->setkey = ahash_nosetkey;
return 0;
}
int crypto_register_ahash(struct ahash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
int err;
err = ahash_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_ahash);
void crypto_unregister_ahash(struct ahash_alg *alg)
{
crypto_unregister_alg(&alg->halg.base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
int crypto_register_ahashes(struct ahash_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_ahash(&algs[i]);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_ahash(&algs[i]);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_ahashes);
void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_ahash(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
int ahash_register_instance(struct crypto_template *tmpl,
struct ahash_instance *inst)
{
int err;
if (WARN_ON(!inst->free))
return -EINVAL;
err = ahash_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(ahash_register_instance);
bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
{
struct crypto_alg *alg = &halg->base;
if (alg->cra_type == &crypto_shash_type)
return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
return __crypto_ahash_alg(alg)->setkey != ahash_nosetkey;
}
EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Asynchronous cryptographic hash type");