linux-stable/crypto/shash.c
Waiman Long 453431a549 mm, treewide: rename kzfree() to kfree_sensitive()
As said by Linus:

  A symmetric naming is only helpful if it implies symmetries in use.
  Otherwise it's actively misleading.

  In "kzalloc()", the z is meaningful and an important part of what the
  caller wants.

  In "kzfree()", the z is actively detrimental, because maybe in the
  future we really _might_ want to use that "memfill(0xdeadbeef)" or
  something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

  git grep -w --name-only kzfree |\
  xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:22 -07:00

615 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Synchronous Cryptographic Hash operations.
*
* Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/scatterwalk.h>
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>
#include <linux/compiler.h>
#include "internal.h"
static const struct crypto_type crypto_shash_type;
int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(shash_no_setkey);
static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned long absize;
u8 *buffer, *alignbuffer;
int err;
absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
buffer = kmalloc(absize, GFP_ATOMIC);
if (!buffer)
return -ENOMEM;
alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
memcpy(alignbuffer, key, keylen);
err = shash->setkey(tfm, alignbuffer, keylen);
kfree_sensitive(buffer);
return err;
}
static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg)
{
if (crypto_shash_alg_needs_key(alg))
crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
}
int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
int err;
if ((unsigned long)key & alignmask)
err = shash_setkey_unaligned(tfm, key, keylen);
else
err = shash->setkey(tfm, key, keylen);
if (unlikely(err)) {
shash_set_needkey(tfm, shash);
return err;
}
crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_shash_setkey);
static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned int unaligned_len = alignmask + 1 -
((unsigned long)data & alignmask);
/*
* We cannot count on __aligned() working for large values:
* https://patchwork.kernel.org/patch/9507697/
*/
u8 ubuf[MAX_ALGAPI_ALIGNMASK * 2];
u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
int err;
if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf)))
return -EINVAL;
if (unaligned_len > len)
unaligned_len = len;
memcpy(buf, data, unaligned_len);
err = shash->update(desc, buf, unaligned_len);
memset(buf, 0, unaligned_len);
return err ?:
shash->update(desc, data + unaligned_len, len - unaligned_len);
}
int crypto_shash_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if ((unsigned long)data & alignmask)
return shash_update_unaligned(desc, data, len);
return shash->update(desc, data, len);
}
EXPORT_SYMBOL_GPL(crypto_shash_update);
static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
unsigned long alignmask = crypto_shash_alignmask(tfm);
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned int ds = crypto_shash_digestsize(tfm);
/*
* We cannot count on __aligned() working for large values:
* https://patchwork.kernel.org/patch/9507697/
*/
u8 ubuf[MAX_ALGAPI_ALIGNMASK + HASH_MAX_DIGESTSIZE];
u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
int err;
if (WARN_ON(buf + ds > ubuf + sizeof(ubuf)))
return -EINVAL;
err = shash->final(desc, buf);
if (err)
goto out;
memcpy(out, buf, ds);
out:
memset(buf, 0, ds);
return err;
}
int crypto_shash_final(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if ((unsigned long)out & alignmask)
return shash_final_unaligned(desc, out);
return shash->final(desc, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_final);
static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return crypto_shash_update(desc, data, len) ?:
crypto_shash_final(desc, out);
}
int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if (((unsigned long)data | (unsigned long)out) & alignmask)
return shash_finup_unaligned(desc, data, len, out);
return shash->finup(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_finup);
static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return crypto_shash_init(desc) ?:
crypto_shash_finup(desc, data, len, out);
}
int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
if (((unsigned long)data | (unsigned long)out) & alignmask)
return shash_digest_unaligned(desc, data, len, out);
return shash->digest(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_digest);
int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
unsigned int len, u8 *out)
{
SHASH_DESC_ON_STACK(desc, tfm);
int err;
desc->tfm = tfm;
err = crypto_shash_digest(desc, data, len, out);
shash_desc_zero(desc);
return err;
}
EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);
static int shash_default_export(struct shash_desc *desc, void *out)
{
memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
return 0;
}
static int shash_default_import(struct shash_desc *desc, const void *in)
{
memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
return 0;
}
static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
return crypto_shash_setkey(*ctx, key, keylen);
}
static int shash_async_init(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return crypto_shash_init(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);
static int shash_async_update(struct ahash_request *req)
{
return shash_ahash_update(req, ahash_request_ctx(req));
}
static int shash_async_final(struct ahash_request *req)
{
return crypto_shash_final(ahash_request_ctx(req), req->result);
}
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);
static int shash_async_finup(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return shash_ahash_finup(req, desc);
}
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_atomic(sg_page(sg));
err = crypto_shash_digest(desc, data + offset, nbytes,
req->result);
kunmap_atomic(data);
} else
err = crypto_shash_init(desc) ?:
shash_ahash_finup(req, desc);
return err;
}
EXPORT_SYMBOL_GPL(shash_ahash_digest);
static int shash_async_digest(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return shash_ahash_digest(req, desc);
}
static int shash_async_export(struct ahash_request *req, void *out)
{
return crypto_shash_export(ahash_request_ctx(req), out);
}
static int shash_async_import(struct ahash_request *req, const void *in)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return crypto_shash_import(desc, in);
}
static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
crypto_free_shash(*ctx);
}
int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct shash_alg *alg = __crypto_shash_alg(calg);
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);
}
*ctx = shash;
tfm->exit = crypto_exit_shash_ops_async;
crt->init = shash_async_init;
crt->update = shash_async_update;
crt->final = shash_async_final;
crt->finup = shash_async_finup;
crt->digest = shash_async_digest;
if (crypto_shash_alg_has_setkey(alg))
crt->setkey = shash_async_setkey;
crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
CRYPTO_TFM_NEED_KEY);
crt->export = shash_async_export;
crt->import = shash_async_import;
crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
return 0;
}
static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_shash *hash = __crypto_shash_cast(tfm);
struct shash_alg *alg = crypto_shash_alg(hash);
alg->exit_tfm(hash);
}
static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_shash *hash = __crypto_shash_cast(tfm);
struct shash_alg *alg = crypto_shash_alg(hash);
int err;
hash->descsize = alg->descsize;
shash_set_needkey(hash, alg);
if (alg->exit_tfm)
tfm->exit = crypto_shash_exit_tfm;
if (!alg->init_tfm)
return 0;
err = alg->init_tfm(hash);
if (err)
return err;
/* ->init_tfm() may have increased the descsize. */
if (WARN_ON_ONCE(hash->descsize > HASH_MAX_DESCSIZE)) {
if (alg->exit_tfm)
alg->exit_tfm(hash);
return -EINVAL;
}
return 0;
}
static void crypto_shash_free_instance(struct crypto_instance *inst)
{
struct shash_instance *shash = shash_instance(inst);
shash->free(shash);
}
#ifdef CONFIG_NET
static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_hash rhash;
struct shash_alg *salg = __crypto_shash_alg(alg);
memset(&rhash, 0, sizeof(rhash));
strscpy(rhash.type, "shash", sizeof(rhash.type));
rhash.blocksize = alg->cra_blocksize;
rhash.digestsize = salg->digestsize;
return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
}
#else
static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
{
struct shash_alg *salg = __crypto_shash_alg(alg);
seq_printf(m, "type : shash\n");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "digestsize : %u\n", salg->digestsize);
}
static const struct crypto_type crypto_shash_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_shash_init_tfm,
.free = crypto_shash_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_shash_show,
#endif
.report = crypto_shash_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_SHASH,
.tfmsize = offsetof(struct crypto_shash, base),
};
int crypto_grab_shash(struct crypto_shash_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_shash_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_shash);
struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_shash);
static int shash_prepare_alg(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->base;
if (alg->digestsize > HASH_MAX_DIGESTSIZE ||
alg->descsize > HASH_MAX_DESCSIZE ||
alg->statesize > HASH_MAX_STATESIZE)
return -EINVAL;
if ((alg->export && !alg->import) || (alg->import && !alg->export))
return -EINVAL;
base->cra_type = &crypto_shash_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
if (!alg->finup)
alg->finup = shash_finup_unaligned;
if (!alg->digest)
alg->digest = shash_digest_unaligned;
if (!alg->export) {
alg->export = shash_default_export;
alg->import = shash_default_import;
alg->statesize = alg->descsize;
}
if (!alg->setkey)
alg->setkey = shash_no_setkey;
return 0;
}
int crypto_register_shash(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->base;
int err;
err = shash_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_shash);
void crypto_unregister_shash(struct shash_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shash);
int crypto_register_shashes(struct shash_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_shash(&algs[i]);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_shash(&algs[i]);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_shashes);
void crypto_unregister_shashes(struct shash_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_shash(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shashes);
int shash_register_instance(struct crypto_template *tmpl,
struct shash_instance *inst)
{
int err;
if (WARN_ON(!inst->free))
return -EINVAL;
err = shash_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, shash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(shash_register_instance);
void shash_free_singlespawn_instance(struct shash_instance *inst)
{
crypto_drop_spawn(shash_instance_ctx(inst));
kfree(inst);
}
EXPORT_SYMBOL_GPL(shash_free_singlespawn_instance);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synchronous cryptographic hash type");