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crypto: skcipher - Make use of internal state
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This patch adds code to the skcipher/lskcipher API to make use
of the internal state if present.  In particular, the skcipher
lskcipher wrapper will allocate a buffer for the IV/state and
feed that to the underlying lskcipher algorithm.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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@herbertx
herbertx committed Dec 8, 2023
1 parent 0ae4dcc commit 662ea18
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Showing 3 changed files with 139 additions and 8 deletions.
34 changes: 28 additions & 6 deletions crypto/lskcipher.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,7 @@ static int crypto_lskcipher_crypt_unaligned(
u8 *iv, int (*crypt)(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv, u32 flags))
{
unsigned statesize = crypto_lskcipher_statesize(tfm);
unsigned ivsize = crypto_lskcipher_ivsize(tfm);
unsigned bs = crypto_lskcipher_blocksize(tfm);
unsigned cs = crypto_lskcipher_chunksize(tfm);
Expand All @@ -104,7 +105,7 @@ static int crypto_lskcipher_crypt_unaligned(
if (!tiv)
return -ENOMEM;

memcpy(tiv, iv, ivsize);
memcpy(tiv, iv, ivsize + statesize);

p = kmalloc(PAGE_SIZE, GFP_ATOMIC);
err = -ENOMEM;
Expand Down Expand Up @@ -132,7 +133,7 @@ static int crypto_lskcipher_crypt_unaligned(
err = len ? -EINVAL : 0;

out:
memcpy(iv, tiv, ivsize);
memcpy(iv, tiv, ivsize + statesize);
kfree_sensitive(p);
kfree_sensitive(tiv);
return err;
Expand Down Expand Up @@ -197,25 +198,45 @@ EXPORT_SYMBOL_GPL(crypto_lskcipher_decrypt);
static int crypto_lskcipher_crypt_sg(struct skcipher_request *req,
int (*crypt)(struct crypto_lskcipher *tfm,
const u8 *src, u8 *dst,
unsigned len, u8 *iv,
unsigned len, u8 *ivs,
u32 flags))
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
u8 *ivs = skcipher_request_ctx(req);
struct crypto_lskcipher *tfm = *ctx;
struct skcipher_walk walk;
unsigned ivsize;
u32 flags;
int err;

ivsize = crypto_lskcipher_ivsize(tfm);
ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(skcipher) + 1);

flags = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP;

if (req->base.flags & CRYPTO_SKCIPHER_REQ_CONT)
flags |= CRYPTO_LSKCIPHER_FLAG_CONT;
else
memcpy(ivs, req->iv, ivsize);

if (!(req->base.flags & CRYPTO_SKCIPHER_REQ_NOTFINAL))
flags |= CRYPTO_LSKCIPHER_FLAG_FINAL;

err = skcipher_walk_virt(&walk, req, false);

while (walk.nbytes) {
err = crypt(tfm, walk.src.virt.addr, walk.dst.virt.addr,
walk.nbytes, walk.iv,
walk.nbytes == walk.total ?
CRYPTO_LSKCIPHER_FLAG_FINAL : 0);
walk.nbytes, ivs,
flags & ~(walk.nbytes == walk.total ?
0 : CRYPTO_LSKCIPHER_FLAG_FINAL));
err = skcipher_walk_done(&walk, err);
flags |= CRYPTO_LSKCIPHER_FLAG_CONT;
}

if (flags & CRYPTO_LSKCIPHER_FLAG_FINAL)
memcpy(req->iv, ivs, ivsize);

return err;
}

Expand Down Expand Up @@ -278,6 +299,7 @@ static void __maybe_unused crypto_lskcipher_show(
seq_printf(m, "max keysize : %u\n", skcipher->co.max_keysize);
seq_printf(m, "ivsize : %u\n", skcipher->co.ivsize);
seq_printf(m, "chunksize : %u\n", skcipher->co.chunksize);
seq_printf(m, "statesize : %u\n", skcipher->co.statesize);
}

static int __maybe_unused crypto_lskcipher_report(
Expand Down
80 changes: 78 additions & 2 deletions crypto/skcipher.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -698,6 +698,64 @@ int crypto_skcipher_decrypt(struct skcipher_request *req)
}
EXPORT_SYMBOL_GPL(crypto_skcipher_decrypt);

static int crypto_lskcipher_export(struct skcipher_request *req, void *out)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
u8 *ivs = skcipher_request_ctx(req);

ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1);

memcpy(out, ivs + crypto_skcipher_ivsize(tfm),
crypto_skcipher_statesize(tfm));

return 0;
}

static int crypto_lskcipher_import(struct skcipher_request *req, const void *in)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
u8 *ivs = skcipher_request_ctx(req);

ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1);

memcpy(ivs + crypto_skcipher_ivsize(tfm), in,
crypto_skcipher_statesize(tfm));

return 0;
}

static int skcipher_noexport(struct skcipher_request *req, void *out)
{
return 0;
}

static int skcipher_noimport(struct skcipher_request *req, const void *in)
{
return 0;
}

int crypto_skcipher_export(struct skcipher_request *req, void *out)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct skcipher_alg *alg = crypto_skcipher_alg(tfm);

if (alg->co.base.cra_type != &crypto_skcipher_type)
return crypto_lskcipher_export(req, out);
return alg->export(req, out);
}
EXPORT_SYMBOL_GPL(crypto_skcipher_export);

int crypto_skcipher_import(struct skcipher_request *req, const void *in)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct skcipher_alg *alg = crypto_skcipher_alg(tfm);

if (alg->co.base.cra_type != &crypto_skcipher_type)
return crypto_lskcipher_import(req, in);
return alg->import(req, in);
}
EXPORT_SYMBOL_GPL(crypto_skcipher_import);

static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
Expand All @@ -713,8 +771,17 @@ static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)

skcipher_set_needkey(skcipher);

if (tfm->__crt_alg->cra_type != &crypto_skcipher_type)
if (tfm->__crt_alg->cra_type != &crypto_skcipher_type) {
unsigned am = crypto_skcipher_alignmask(skcipher);
unsigned reqsize;

reqsize = am & ~(crypto_tfm_ctx_alignment() - 1);
reqsize += crypto_skcipher_ivsize(skcipher);
reqsize += crypto_skcipher_statesize(skcipher);
crypto_skcipher_set_reqsize(skcipher, reqsize);

return crypto_init_lskcipher_ops_sg(tfm);
}

if (alg->exit)
skcipher->base.exit = crypto_skcipher_exit_tfm;
Expand Down Expand Up @@ -756,6 +823,7 @@ static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
seq_printf(m, "ivsize : %u\n", skcipher->ivsize);
seq_printf(m, "chunksize : %u\n", skcipher->chunksize);
seq_printf(m, "walksize : %u\n", skcipher->walksize);
seq_printf(m, "statesize : %u\n", skcipher->statesize);
}

static int __maybe_unused crypto_skcipher_report(
Expand Down Expand Up @@ -870,7 +938,9 @@ int skcipher_prepare_alg_common(struct skcipher_alg_common *alg)
struct crypto_istat_cipher *istat = skcipher_get_stat_common(alg);
struct crypto_alg *base = &alg->base;

if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
alg->statesize > PAGE_SIZE / 2 ||
(alg->ivsize + alg->statesize) > PAGE_SIZE / 2)
return -EINVAL;

if (!alg->chunksize)
Expand Down Expand Up @@ -899,6 +969,12 @@ static int skcipher_prepare_alg(struct skcipher_alg *alg)
if (!alg->walksize)
alg->walksize = alg->chunksize;

if (!alg->statesize) {
alg->import = skcipher_noimport;
alg->export = skcipher_noexport;
} else if (!(alg->import && alg->export))
return -EINVAL;

base->cra_type = &crypto_skcipher_type;
base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;

Expand Down
33 changes: 33 additions & 0 deletions include/crypto/skcipher.h
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Original file line number Diff line number Diff line change
Expand Up @@ -746,6 +746,39 @@ int crypto_skcipher_encrypt(struct skcipher_request *req);
*/
int crypto_skcipher_decrypt(struct skcipher_request *req);

/**
* crypto_skcipher_export() - export partial state
* @req: reference to the skcipher_request handle that holds all information
* needed to perform the operation
* @out: output buffer of sufficient size that can hold the state
*
* Export partial state of the transformation. This function dumps the
* entire state of the ongoing transformation into a provided block of
* data so it can be @import 'ed back later on. This is useful in case
* you want to save partial result of the transformation after
* processing certain amount of data and reload this partial result
* multiple times later on for multiple re-use. No data processing
* happens at this point.
*
* Return: 0 if the cipher operation was successful; < 0 if an error occurred
*/
int crypto_skcipher_export(struct skcipher_request *req, void *out);

/**
* crypto_skcipher_import() - import partial state
* @req: reference to the skcipher_request handle that holds all information
* needed to perform the operation
* @in: buffer holding the state
*
* Import partial state of the transformation. This function loads the
* entire state of the ongoing transformation from a provided block of
* data so the transformation can continue from this point onward. No
* data processing happens at this point.
*
* Return: 0 if the cipher operation was successful; < 0 if an error occurred
*/
int crypto_skcipher_import(struct skcipher_request *req, const void *in);

/**
* crypto_lskcipher_encrypt() - encrypt plaintext
* @tfm: lskcipher handle
Expand Down

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