[CRYPTO] skcipher: Add skcipher_geniv_alloc/skcipher_geniv_free
This patch creates the infrastructure to help the construction of givcipher
templates that wrap around existing blkcipher/ablkcipher algorithms by adding
an IV generator to them.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 7a3e1a3..ca6ef06 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -14,8 +14,8 @@
*
*/
+#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
-#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
@@ -450,6 +450,7 @@
crt->setkey = async_setkey;
crt->encrypt = async_encrypt;
crt->decrypt = async_decrypt;
+ crt->base = __crypto_ablkcipher_cast(tfm);
crt->ivsize = alg->ivsize;
return 0;
@@ -509,5 +510,187 @@
};
EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
+static int crypto_grab_nivcipher(struct crypto_skcipher_spawn *spawn,
+ const char *name, u32 type, u32 mask)
+{
+ struct crypto_alg *alg;
+ int err;
+
+ type = crypto_skcipher_type(type);
+ mask = crypto_skcipher_mask(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 *skcipher_geniv_alloc(struct crypto_template *tmpl,
+ struct rtattr **tb, u32 type,
+ u32 mask)
+{
+ struct {
+ int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
+ unsigned int keylen);
+ int (*encrypt)(struct ablkcipher_request *req);
+ int (*decrypt)(struct ablkcipher_request *req);
+
+ unsigned int min_keysize;
+ unsigned int max_keysize;
+ unsigned int ivsize;
+
+ const char *geniv;
+ } balg;
+ const char *name;
+ struct crypto_skcipher_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_GIVCIPHER | 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_skcipher_spawn(spawn, inst);
+ err = crypto_grab_nivcipher(spawn, name, type, mask);
+ if (err)
+ goto err_free_inst;
+
+ alg = crypto_skcipher_spawn_alg(spawn);
+
+ if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+ CRYPTO_ALG_TYPE_BLKCIPHER) {
+ balg.ivsize = alg->cra_blkcipher.ivsize;
+ balg.min_keysize = alg->cra_blkcipher.min_keysize;
+ balg.max_keysize = alg->cra_blkcipher.max_keysize;
+
+ balg.setkey = async_setkey;
+ balg.encrypt = async_encrypt;
+ balg.decrypt = async_decrypt;
+
+ balg.geniv = alg->cra_blkcipher.geniv;
+ } else {
+ balg.ivsize = alg->cra_ablkcipher.ivsize;
+ balg.min_keysize = alg->cra_ablkcipher.min_keysize;
+ balg.max_keysize = alg->cra_ablkcipher.max_keysize;
+
+ balg.setkey = alg->cra_ablkcipher.setkey;
+ balg.encrypt = alg->cra_ablkcipher.encrypt;
+ balg.decrypt = alg->cra_ablkcipher.decrypt;
+
+ balg.geniv = alg->cra_ablkcipher.geniv;
+ }
+
+ err = -EINVAL;
+ if (!balg.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 (!balg.geniv)
+ balg.geniv = crypto_default_geniv(alg);
+ err = -EAGAIN;
+ if (strcmp(tmpl->name, balg.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_GIVCIPHER | 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_givcipher_type;
+
+ inst->alg.cra_ablkcipher.ivsize = balg.ivsize;
+ inst->alg.cra_ablkcipher.min_keysize = balg.min_keysize;
+ inst->alg.cra_ablkcipher.max_keysize = balg.max_keysize;
+ inst->alg.cra_ablkcipher.geniv = balg.geniv;
+
+ inst->alg.cra_ablkcipher.setkey = balg.setkey;
+ inst->alg.cra_ablkcipher.encrypt = balg.encrypt;
+ inst->alg.cra_ablkcipher.decrypt = balg.decrypt;
+
+out:
+ return inst;
+
+err_drop_alg:
+ crypto_drop_skcipher(spawn);
+err_free_inst:
+ kfree(inst);
+ inst = ERR_PTR(err);
+ goto out;
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_alloc);
+
+void skcipher_geniv_free(struct crypto_instance *inst)
+{
+ crypto_drop_skcipher(crypto_instance_ctx(inst));
+ kfree(inst);
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_free);
+
+int skcipher_geniv_init(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_ablkcipher *cipher;
+
+ cipher = crypto_spawn_skcipher(crypto_instance_ctx(inst));
+ if (IS_ERR(cipher))
+ return PTR_ERR(cipher);
+
+ tfm->crt_ablkcipher.base = cipher;
+ tfm->crt_ablkcipher.reqsize += crypto_ablkcipher_reqsize(cipher);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_init);
+
+void skcipher_geniv_exit(struct crypto_tfm *tfm)
+{
+ crypto_free_ablkcipher(tfm->crt_ablkcipher.base);
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_exit);
+
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic block chaining cipher type");