crypto: skcipher - Make use of internal state

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>

1 files changed, 78 insertions, 2 deletions

diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index ac8b8c042654..bc70e159d27d 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -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);
@@ -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;
@@ -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(
@@ -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)
@@ -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;