[RFC] [PATCH 5/5] authenc: Add support for the pcrypt aead wrapper

[Steffen Klassert]

This adds support for aead wrapper templates. An aead wrapper
can be coosen via a module parameter. For the moment only
pcrypt is supported.

Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com>
---
 crypto/authenc.c |   33 +++++++++++++++++++++++++++++++--
 1 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/crypto/authenc.c b/crypto/authenc.c
index 5793b64..aaa0fcc 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -13,6 +13,7 @@
 #include <crypto/aead.h>
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
+#include <crypto/internal/aead.h>
 #include <crypto/authenc.h>
 #include <crypto/scatterwalk.h>
 #include <linux/err.h>
@@ -23,6 +24,10 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
+static char *wrapper = NULL;
+module_param(wrapper, charp, 0);
+MODULE_PARM_DESC(wrapper, "Wrapper template for AEAD algorithms");
+
 struct authenc_instance_ctx {
        struct crypto_spawn auth;
        struct crypto_skcipher_spawn enc;
@@ -157,15 +162,16 @@ static int crypto_authenc_genicv(struct aead_request 
*req, u8 *iv,
 
        dstp = sg_page(dst);
        vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset;
+       cryptlen = req->cryptlen;
 
-       if (ivsize) {
+       if (ivsize && !(aead_request_flags(req) & CRYPTO_TFM_REQ_SG_HAS_IV)) {
                sg_init_table(cipher, 2);
                sg_set_buf(cipher, iv, ivsize);
                authenc_chain(cipher, dst, vdst == iv + ivsize);
                dst = cipher;
+               cryptlen += ivsize;
        }
 
-       cryptlen = req->cryptlen + ivsize;
        hash = crypto_authenc_hash(req, flags, dst, cryptlen);
        if (IS_ERR(hash))
                return PTR_ERR(hash);
@@ -369,6 +375,26 @@ static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm)
        crypto_free_ablkcipher(ctx->enc);
 }
 
+static int crypto_authenc_set_wrapper(struct crypto_instance *inst)
+{
+       int err = 0;
+
+       if (!wrapper)
+               goto out;
+
+       if (!strcmp(wrapper, "pcrypt")) {
+               inst->alg.cra_type = &crypto_nivaead_type;
+               inst->alg.cra_aead.geniv = "eseqiv";
+               inst->alg.cra_aead.wrapper = "pcrypt";
+
+               goto out;
+       }
+
+       err = -EINVAL;
+out:
+       return err;
+}
+
 static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
 {
        struct crypto_attr_type *algt;
@@ -452,6 +478,9 @@ static struct crypto_instance *crypto_authenc_alloc(struct 
rtattr **tb)
        inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
        inst->alg.cra_aead.givencrypt = crypto_authenc_givencrypt;
 
+       if (crypto_authenc_set_wrapper(inst))
+               goto err_drop_enc;
+
 out:
        crypto_mod_put(auth);
        return inst;
-- 
1.5.4.2

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