[PATCH 4/8] crypto: geniv - use memcpy_sglist() instead of null skcipher

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

For copying data between two scatterlists, just use memcpy_sglist()
instead of the so-called "null skcipher".  This is much simpler.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 crypto/Kconfig                  |  1 -
 crypto/echainiv.c               | 18 +++---------------
 crypto/geniv.c                  | 13 +------------
 crypto/seqiv.c                  | 17 +++--------------
 include/crypto/internal/geniv.h |  1 -
 5 files changed, 7 insertions(+), 43 deletions(-)

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 231791703594..f0c8cc5e30ae 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -813,11 +813,10 @@ config CRYPTO_GCM
 	  This is required for IPSec ESP (XFRM_ESP).
 
 config CRYPTO_GENIV
 	tristate
 	select CRYPTO_AEAD
-	select CRYPTO_NULL
 	select CRYPTO_MANAGER
 	select CRYPTO_RNG_DEFAULT
 
 config CRYPTO_SEQIV
 	tristate "Sequence Number IV Generator"
diff --git a/crypto/echainiv.c b/crypto/echainiv.c
index 1913be8dfbba..e0a2d3209938 100644
--- a/crypto/echainiv.c
+++ b/crypto/echainiv.c
@@ -30,33 +30,21 @@ static int echainiv_encrypt(struct aead_request *req)
 	struct aead_request *subreq = aead_request_ctx(req);
 	__be64 nseqno;
 	u64 seqno;
 	u8 *info;
 	unsigned int ivsize = crypto_aead_ivsize(geniv);
-	int err;
 
 	if (req->cryptlen < ivsize)
 		return -EINVAL;
 
 	aead_request_set_tfm(subreq, ctx->child);
 
 	info = req->iv;
 
-	if (req->src != req->dst) {
-		SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
-
-		skcipher_request_set_sync_tfm(nreq, ctx->sknull);
-		skcipher_request_set_callback(nreq, req->base.flags,
-					      NULL, NULL);
-		skcipher_request_set_crypt(nreq, req->src, req->dst,
-					   req->assoclen + req->cryptlen,
-					   NULL);
-
-		err = crypto_skcipher_encrypt(nreq);
-		if (err)
-			return err;
-	}
+	if (req->src != req->dst)
+		memcpy_sglist(req->dst, req->src,
+			      req->assoclen + req->cryptlen);
 
 	aead_request_set_callback(subreq, req->base.flags,
 				  req->base.complete, req->base.data);
 	aead_request_set_crypt(subreq, req->dst, req->dst,
 			       req->cryptlen, info);
diff --git a/crypto/geniv.c b/crypto/geniv.c
index bee4621b4f12..42eff6a7387c 100644
--- a/crypto/geniv.c
+++ b/crypto/geniv.c
@@ -7,11 +7,10 @@
  * Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
  */
 
 #include <crypto/internal/geniv.h>
 #include <crypto/internal/rng.h>
-#include <crypto/null.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/rtnetlink.h>
 #include <linux/slab.h>
@@ -123,41 +122,31 @@ int aead_init_geniv(struct crypto_aead *aead)
 				   crypto_aead_ivsize(aead));
 	crypto_put_default_rng();
 	if (err)
 		goto out;
 
-	ctx->sknull = crypto_get_default_null_skcipher();
-	err = PTR_ERR(ctx->sknull);
-	if (IS_ERR(ctx->sknull))
-		goto out;
-
 	child = crypto_spawn_aead(aead_instance_ctx(inst));
 	err = PTR_ERR(child);
 	if (IS_ERR(child))
-		goto drop_null;
+		goto out;
 
 	ctx->child = child;
 	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
 				      sizeof(struct aead_request));
 
 	err = 0;
 
 out:
 	return err;
-
-drop_null:
-	crypto_put_default_null_skcipher();
-	goto out;
 }
 EXPORT_SYMBOL_GPL(aead_init_geniv);
 
 void aead_exit_geniv(struct crypto_aead *tfm)
 {
 	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 
 	crypto_free_aead(ctx->child);
-	crypto_put_default_null_skcipher();
 }
 EXPORT_SYMBOL_GPL(aead_exit_geniv);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Shared IV generator code");
diff --git a/crypto/seqiv.c b/crypto/seqiv.c
index a17ef5184398..2bae99e33526 100644
--- a/crypto/seqiv.c
+++ b/crypto/seqiv.c
@@ -62,24 +62,13 @@ static int seqiv_aead_encrypt(struct aead_request *req)
 
 	compl = req->base.complete;
 	data = req->base.data;
 	info = req->iv;
 
-	if (req->src != req->dst) {
-		SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
-
-		skcipher_request_set_sync_tfm(nreq, ctx->sknull);
-		skcipher_request_set_callback(nreq, req->base.flags,
-					      NULL, NULL);
-		skcipher_request_set_crypt(nreq, req->src, req->dst,
-					   req->assoclen + req->cryptlen,
-					   NULL);
-
-		err = crypto_skcipher_encrypt(nreq);
-		if (err)
-			return err;
-	}
+	if (req->src != req->dst)
+		memcpy_sglist(req->dst, req->src,
+			      req->assoclen + req->cryptlen);
 
 	if (unlikely(!IS_ALIGNED((unsigned long)info,
 				 crypto_aead_alignmask(geniv) + 1))) {
 		info = kmemdup(req->iv, ivsize, req->base.flags &
 			       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
diff --git a/include/crypto/internal/geniv.h b/include/crypto/internal/geniv.h
index 7fd7126f593a..012f5fb22d43 100644
--- a/include/crypto/internal/geniv.h
+++ b/include/crypto/internal/geniv.h
@@ -13,11 +13,10 @@
 #include <linux/types.h>
 
 struct aead_geniv_ctx {
 	spinlock_t lock;
 	struct crypto_aead *child;
-	struct crypto_sync_skcipher *sknull;
 	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
 };
 
 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
 				       struct rtattr **tb);
-- 
2.49.0