[CRYPTO] aead: Add aead_geniv_alloc/aead_geniv_free

This patch creates the infrastructure to help the construction of IV
generator templates that wrap around AEAD algorithms by adding an IV
generator to them.  This is useful for AEAD algorithms with no built-in
IV generator or to replace their built-in generator.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 211 insertions, 5 deletions

diff --git a/crypto/aead.c b/crypto/aead.c
index 15335ed..9f7aca8 100644
--- a/crypto/aead.c
+++ b/crypto/aead.c
@@ -12,14 +12,16 @@
  *
  */
 
-#include <crypto/algapi.h>
-#include <linux/errno.h>
+#include <crypto/internal/aead.h>
+#include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 
+#include "internal.h"
+
 static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
 			    unsigned int keylen)
 {
@@ -55,18 +57,20 @@ static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
 
 int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
 {
+	struct aead_tfm *crt = crypto_aead_crt(tfm);
 	int err;
 
 	if (authsize > crypto_aead_alg(tfm)->maxauthsize)
 		return -EINVAL;
 
 	if (crypto_aead_alg(tfm)->setauthsize) {
-		err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
+		err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
 		if (err)
 			return err;
 	}
 
-	crypto_aead_crt(tfm)->authsize = authsize;
+	crypto_aead_crt(crt->base)->authsize = authsize;
+	crt->authsize = authsize;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
@@ -90,11 +94,13 @@ static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 	if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
 		return -EINVAL;
 
-	crt->setkey = setkey;
+	crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
+		      alg->setkey : setkey;
 	crt->encrypt = alg->encrypt;
 	crt->decrypt = alg->decrypt;
 	crt->givencrypt = alg->givencrypt ?: no_givcrypt;
 	crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
+	crt->base = __crypto_aead_cast(tfm);
 	crt->ivsize = alg->ivsize;
 	crt->authsize = alg->maxauthsize;
 
@@ -111,6 +117,7 @@ static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
+	seq_printf(m, "geniv        : %s\n", aead->geniv ?: "<built-in>");
 }
 
 const struct crypto_type crypto_aead_type = {
@@ -122,5 +129,204 @@ const struct crypto_type crypto_aead_type = {
 };
 EXPORT_SYMBOL_GPL(crypto_aead_type);
 
+static int aead_null_givencrypt(struct aead_givcrypt_request *req)
+{
+	return crypto_aead_encrypt(&req->areq);
+}
+
+static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
+{
+	return crypto_aead_decrypt(&req->areq);
+}
+
+static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
+{
+	struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
+	struct aead_tfm *crt = &tfm->crt_aead;
+
+	if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
+		return -EINVAL;
+
+	crt->setkey = setkey;
+	crt->encrypt = alg->encrypt;
+	crt->decrypt = alg->decrypt;
+	if (!alg->ivsize) {
+		crt->givencrypt = aead_null_givencrypt;
+		crt->givdecrypt = aead_null_givdecrypt;
+	}
+	crt->base = __crypto_aead_cast(tfm);
+	crt->ivsize = alg->ivsize;
+	crt->authsize = alg->maxauthsize;
+
+	return 0;
+}
+
+static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
+	__attribute__ ((unused));
+static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
+{
+	struct aead_alg *aead = &alg->cra_aead;
+
+	seq_printf(m, "type         : nivaead\n");
+	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
+	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
+	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
+	seq_printf(m, "geniv        : %s\n", aead->geniv);
+}
+
+const struct crypto_type crypto_nivaead_type = {
+	.ctxsize = crypto_aead_ctxsize,
+	.init = crypto_init_nivaead_ops,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_nivaead_show,
+#endif
+};
+EXPORT_SYMBOL_GPL(crypto_nivaead_type);
+
+static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
+			       const char *name, u32 type, u32 mask)
+{
+	struct crypto_alg *alg;
+	int err;
+
+	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
+	type |= CRYPTO_ALG_TYPE_AEAD;
+	mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;
+
+	alg = crypto_alg_mod_lookup(name, type, mask);
+	if (IS_ERR(alg))
+		return PTR_ERR(alg);
+
+	err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
+	crypto_mod_put(alg);
+	return err;
+}
+
+struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
+					 struct rtattr **tb, u32 type,
+					 u32 mask)
+{
+	const char *name;
+	struct crypto_aead_spawn *spawn;
+	struct crypto_attr_type *algt;
+	struct crypto_instance *inst;
+	struct crypto_alg *alg;
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	err = PTR_ERR(algt);
+	if (IS_ERR(algt))
+		return ERR_PTR(err);
+
+	if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
+	    algt->mask)
+		return ERR_PTR(-EINVAL);
+
+	name = crypto_attr_alg_name(tb[1]);
+	err = PTR_ERR(name);
+	if (IS_ERR(name))
+		return ERR_PTR(err);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return ERR_PTR(-ENOMEM);
+
+	spawn = crypto_instance_ctx(inst);
+
+	/* Ignore async algorithms if necessary. */
+	mask |= crypto_requires_sync(algt->type, algt->mask);
+
+	crypto_set_aead_spawn(spawn, inst);
+	err = crypto_grab_nivaead(spawn, name, type, mask);
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_aead_spawn_alg(spawn);
+
+	err = -EINVAL;
+	if (!alg->cra_aead.ivsize)
+		goto err_drop_alg;
+
+	/*
+	 * This is only true if we're constructing an algorithm with its
+	 * default IV generator.  For the default generator we elide the
+	 * template name and double-check the IV generator.
+	 */
+	if (algt->mask & CRYPTO_ALG_GENIV) {
+		if (strcmp(tmpl->name, alg->cra_aead.geniv))
+			goto err_drop_alg;
+
+		memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
+		memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
+		       CRYPTO_MAX_ALG_NAME);
+	} else {
+		err = -ENAMETOOLONG;
+		if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
+			     "%s(%s)", tmpl->name, alg->cra_name) >=
+		    CRYPTO_MAX_ALG_NAME)
+			goto err_drop_alg;
+		if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+			     "%s(%s)", tmpl->name, alg->cra_driver_name) >=
+		    CRYPTO_MAX_ALG_NAME)
+			goto err_drop_alg;
+	}
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
+	inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
+	inst->alg.cra_priority = alg->cra_priority;
+	inst->alg.cra_blocksize = alg->cra_blocksize;
+	inst->alg.cra_alignmask = alg->cra_alignmask;
+	inst->alg.cra_type = &crypto_aead_type;
+
+	inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
+	inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
+	inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
+
+	inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
+	inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
+	inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
+	inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;
+
+out:
+	return inst;
+
+err_drop_alg:
+	crypto_drop_aead(spawn);
+err_free_inst:
+	kfree(inst);
+	inst = ERR_PTR(err);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(aead_geniv_alloc);
+
+void aead_geniv_free(struct crypto_instance *inst)
+{
+	crypto_drop_aead(crypto_instance_ctx(inst));
+	kfree(inst);
+}
+EXPORT_SYMBOL_GPL(aead_geniv_free);
+
+int aead_geniv_init(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_aead *aead;
+
+	aead = crypto_spawn_aead(crypto_instance_ctx(inst));
+	if (IS_ERR(aead))
+		return PTR_ERR(aead);
+
+	tfm->crt_aead.base = aead;
+	tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(aead_geniv_init);
+
+void aead_geniv_exit(struct crypto_tfm *tfm)
+{
+	crypto_free_aead(tfm->crt_aead.base);
+}
+EXPORT_SYMBOL_GPL(aead_geniv_exit);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");