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crypto: skcipher - Add low-level skcipher interface
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This patch allows skcipher algorithms and instances to be created
and registered with the crypto API.  They are accessible through
the top-level skcipher interface, along with ablkcipher/blkcipher
algorithms and instances.

This patch also introduces a new parameter called chunk size
which is meant for ciphers such as CTR and CTS which ostensibly
can handle arbitrary lengths, but still behave like block ciphers
in that you can only process a partial block at the very end.

For these ciphers the block size will continue to be set to 1
as it is now while the chunk size will be set to the underlying
block size.

Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
herbertx committed Jul 18, 2016
1 parent eb9bc8e commit 4e6c3df
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196 changes: 189 additions & 7 deletions crypto/skcipher.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,11 @@

#include <crypto/internal/skcipher.h>
#include <linux/bug.h>
#include <linux/cryptouser.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/seq_file.h>
#include <net/netlink.h>

#include "internal.h"

Expand All @@ -25,10 +29,11 @@ static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
if (alg->cra_type == &crypto_blkcipher_type)
return sizeof(struct crypto_blkcipher *);

BUG_ON(alg->cra_type != &crypto_ablkcipher_type &&
alg->cra_type != &crypto_givcipher_type);
if (alg->cra_type == &crypto_ablkcipher_type ||
alg->cra_type == &crypto_givcipher_type)
return sizeof(struct crypto_ablkcipher *);

return sizeof(struct crypto_ablkcipher *);
return crypto_alg_extsize(alg);
}

static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
Expand Down Expand Up @@ -216,32 +221,209 @@ static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
return 0;
}

static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);

alg->exit(skcipher);
}

static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);

if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
return crypto_init_skcipher_ops_blkcipher(tfm);

BUG_ON(tfm->__crt_alg->cra_type != &crypto_ablkcipher_type &&
tfm->__crt_alg->cra_type != &crypto_givcipher_type);
if (tfm->__crt_alg->cra_type == &crypto_ablkcipher_type ||
tfm->__crt_alg->cra_type == &crypto_givcipher_type)
return crypto_init_skcipher_ops_ablkcipher(tfm);

skcipher->setkey = alg->setkey;
skcipher->encrypt = alg->encrypt;
skcipher->decrypt = alg->decrypt;
skcipher->ivsize = alg->ivsize;
skcipher->keysize = alg->max_keysize;

if (alg->exit)
skcipher->base.exit = crypto_skcipher_exit_tfm;

return crypto_init_skcipher_ops_ablkcipher(tfm);
if (alg->init)
return alg->init(skcipher);

return 0;
}

static void crypto_skcipher_free_instance(struct crypto_instance *inst)
{
struct skcipher_instance *skcipher =
container_of(inst, struct skcipher_instance, s.base);

skcipher->free(skcipher);
}

static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
base);

seq_printf(m, "type : skcipher\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, "min keysize : %u\n", skcipher->min_keysize);
seq_printf(m, "max keysize : %u\n", skcipher->max_keysize);
seq_printf(m, "ivsize : %u\n", skcipher->ivsize);
seq_printf(m, "chunksize : %u\n", skcipher->chunksize);
}

#ifdef CONFIG_NET
static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_blkcipher rblkcipher;
struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
base);

strncpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
strncpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));

rblkcipher.blocksize = alg->cra_blocksize;
rblkcipher.min_keysize = skcipher->min_keysize;
rblkcipher.max_keysize = skcipher->max_keysize;
rblkcipher.ivsize = skcipher->ivsize;

if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
sizeof(struct crypto_report_blkcipher), &rblkcipher))
goto nla_put_failure;
return 0;

nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif

static const struct crypto_type crypto_skcipher_type2 = {
.extsize = crypto_skcipher_extsize,
.init_tfm = crypto_skcipher_init_tfm,
.free = crypto_skcipher_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_skcipher_show,
#endif
.report = crypto_skcipher_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
.type = CRYPTO_ALG_TYPE_BLKCIPHER,
.type = CRYPTO_ALG_TYPE_SKCIPHER,
.tfmsize = offsetof(struct crypto_skcipher, base),
};

int crypto_grab_skcipher2(struct crypto_skcipher_spawn *spawn,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_skcipher_type2;
return crypto_grab_spawn(&spawn->base, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_skcipher2);

struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);

int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask)
{
return crypto_type_has_alg(alg_name, &crypto_skcipher_type2,
type, mask);
}
EXPORT_SYMBOL_GPL(crypto_has_skcipher2);

static int skcipher_prepare_alg(struct skcipher_alg *alg)
{
struct crypto_alg *base = &alg->base;

if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
return -EINVAL;

if (!alg->chunksize)
alg->chunksize = base->cra_blocksize;

base->cra_type = &crypto_skcipher_type2;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;

return 0;
}

int crypto_register_skcipher(struct skcipher_alg *alg)
{
struct crypto_alg *base = &alg->base;
int err;

err = skcipher_prepare_alg(alg);
if (err)
return err;

return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_skcipher);

void crypto_unregister_skcipher(struct skcipher_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);

int crypto_register_skciphers(struct skcipher_alg *algs, int count)
{
int i, ret;

for (i = 0; i < count; i++) {
ret = crypto_register_skcipher(&algs[i]);
if (ret)
goto err;
}

return 0;

err:
for (--i; i >= 0; --i)
crypto_unregister_skcipher(&algs[i]);

return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_skciphers);

void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
{
int i;

for (i = count - 1; i >= 0; --i)
crypto_unregister_skcipher(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);

int skcipher_register_instance(struct crypto_template *tmpl,
struct skcipher_instance *inst)
{
int err;

err = skcipher_prepare_alg(&inst->alg);
if (err)
return err;

return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(skcipher_register_instance);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Symmetric key cipher type");
87 changes: 87 additions & 0 deletions include/crypto/internal/skcipher.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,46 @@

struct rtattr;

struct skcipher_instance {
void (*free)(struct skcipher_instance *inst);
union {
struct {
char head[offsetof(struct skcipher_alg, base)];
struct crypto_instance base;
} s;
struct skcipher_alg alg;
};
};

struct crypto_skcipher_spawn {
struct crypto_spawn base;
};

extern const struct crypto_type crypto_givcipher_type;

static inline struct crypto_instance *skcipher_crypto_instance(
struct skcipher_instance *inst)
{
return &inst->s.base;
}

static inline struct skcipher_instance *skcipher_alg_instance(
struct crypto_skcipher *skcipher)
{
return container_of(crypto_skcipher_alg(skcipher),
struct skcipher_instance, alg);
}

static inline void *skcipher_instance_ctx(struct skcipher_instance *inst)
{
return crypto_instance_ctx(skcipher_crypto_instance(inst));
}

static inline void skcipher_request_complete(struct skcipher_request *req, int err)
{
req->base.complete(&req->base, err);
}

static inline void crypto_set_skcipher_spawn(
struct crypto_skcipher_spawn *spawn, struct crypto_instance *inst)
{
Expand All @@ -33,6 +67,8 @@ static inline void crypto_set_skcipher_spawn(

int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
u32 type, u32 mask);
int crypto_grab_skcipher2(struct crypto_skcipher_spawn *spawn,
const char *name, u32 type, u32 mask);

struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type, u32 mask);

Expand All @@ -47,6 +83,12 @@ static inline struct crypto_alg *crypto_skcipher_spawn_alg(
return spawn->base.alg;
}

static inline struct skcipher_alg *crypto_spawn_skcipher_alg(
struct crypto_skcipher_spawn *spawn)
{
return container_of(spawn->base.alg, struct skcipher_alg, base);
}

static inline struct crypto_ablkcipher *crypto_spawn_skcipher(
struct crypto_skcipher_spawn *spawn)
{
Expand All @@ -55,6 +97,25 @@ static inline struct crypto_ablkcipher *crypto_spawn_skcipher(
crypto_skcipher_mask(0)));
}

static inline struct crypto_skcipher *crypto_spawn_skcipher2(
struct crypto_skcipher_spawn *spawn)
{
return crypto_spawn_tfm2(&spawn->base);
}

static inline void crypto_skcipher_set_reqsize(
struct crypto_skcipher *skcipher, unsigned int reqsize)
{
skcipher->reqsize = reqsize;
}

int crypto_register_skcipher(struct skcipher_alg *alg);
void crypto_unregister_skcipher(struct skcipher_alg *alg);
int crypto_register_skciphers(struct skcipher_alg *algs, int count);
void crypto_unregister_skciphers(struct skcipher_alg *algs, int count);
int skcipher_register_instance(struct crypto_template *tmpl,
struct skcipher_instance *inst);

int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req);
int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req);
const char *crypto_default_geniv(const struct crypto_alg *alg);
Expand Down Expand Up @@ -122,5 +183,31 @@ static inline u32 skcipher_request_flags(struct skcipher_request *req)
return req->base.flags;
}

static inline unsigned int crypto_skcipher_alg_min_keysize(
struct skcipher_alg *alg)
{
if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
return alg->base.cra_blkcipher.min_keysize;

if (alg->base.cra_ablkcipher.encrypt)
return alg->base.cra_ablkcipher.min_keysize;

return alg->min_keysize;
}

static inline unsigned int crypto_skcipher_alg_max_keysize(
struct skcipher_alg *alg)
{
if ((alg->base.cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
return alg->base.cra_blkcipher.max_keysize;

if (alg->base.cra_ablkcipher.encrypt)
return alg->base.cra_ablkcipher.max_keysize;

return alg->max_keysize;
}

#endif /* _CRYPTO_INTERNAL_SKCIPHER_H */

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