Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/crypto/ofb.c b/crypto/ofb.c
new file mode 100644
index 0000000..133ff4c
--- /dev/null
+++ b/crypto/ofb.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * OFB: Output FeedBack mode
+ *
+ * Copyright (C) 2018 ARM Limited or its affiliates.
+ * All rights reserved.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static int crypto_ofb_crypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
+ const unsigned int bsize = crypto_cipher_blocksize(cipher);
+ struct skcipher_walk walk;
+ int err;
+
+ err = skcipher_walk_virt(&walk, req, false);
+
+ while (walk.nbytes >= bsize) {
+ const u8 *src = walk.src.virt.addr;
+ u8 *dst = walk.dst.virt.addr;
+ u8 * const iv = walk.iv;
+ unsigned int nbytes = walk.nbytes;
+
+ do {
+ crypto_cipher_encrypt_one(cipher, iv, iv);
+ crypto_xor_cpy(dst, src, iv, bsize);
+ dst += bsize;
+ src += bsize;
+ } while ((nbytes -= bsize) >= bsize);
+
+ err = skcipher_walk_done(&walk, nbytes);
+ }
+
+ if (walk.nbytes) {
+ crypto_cipher_encrypt_one(cipher, walk.iv, walk.iv);
+ crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, walk.iv,
+ walk.nbytes);
+ err = skcipher_walk_done(&walk, 0);
+ }
+ return err;
+}
+
+static int crypto_ofb_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ struct skcipher_instance *inst;
+ struct crypto_alg *alg;
+ int err;
+
+ inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
+ if (IS_ERR(inst))
+ return PTR_ERR(inst);
+
+ /* OFB mode is a stream cipher. */
+ inst->alg.base.cra_blocksize = 1;
+
+ /*
+ * To simplify the implementation, configure the skcipher walk to only
+ * give a partial block at the very end, never earlier.
+ */
+ inst->alg.chunksize = alg->cra_blocksize;
+
+ inst->alg.encrypt = crypto_ofb_crypt;
+ inst->alg.decrypt = crypto_ofb_crypt;
+
+ err = skcipher_register_instance(tmpl, inst);
+ if (err)
+ inst->free(inst);
+
+ crypto_mod_put(alg);
+ return err;
+}
+
+static struct crypto_template crypto_ofb_tmpl = {
+ .name = "ofb",
+ .create = crypto_ofb_create,
+ .module = THIS_MODULE,
+};
+
+static int __init crypto_ofb_module_init(void)
+{
+ return crypto_register_template(&crypto_ofb_tmpl);
+}
+
+static void __exit crypto_ofb_module_exit(void)
+{
+ crypto_unregister_template(&crypto_ofb_tmpl);
+}
+
+subsys_initcall(crypto_ofb_module_init);
+module_exit(crypto_ofb_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("OFB block cipher mode of operation");
+MODULE_ALIAS_CRYPTO("ofb");