1 files changed, 87 insertions, 0 deletions
diff --git a/crypto/arc4.c b/crypto/arc4.c
new file mode 100644
index 000000000..3254dcc34
--- /dev/null
+++ b/crypto/arc4.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cryptographic API
+ *
+ * ARC4 Cipher Algorithm
+ *
+ * Jon Oberheide <jon@oberheide.org>
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/arc4.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+
+static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			      unsigned int key_len)
+{
+	struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	return arc4_setkey(ctx, in_key, key_len);
+}
+
+static int crypto_arc4_crypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, false);
+
+	while (walk.nbytes > 0) {
+		arc4_crypt(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+			   walk.nbytes);
+		err = skcipher_walk_done(&walk, 0);
+	}
+
+	return err;
+}
+
+static int crypto_arc4_init(struct crypto_skcipher *tfm)
+{
+	pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
+			    current->comm, (unsigned long)current->pid);
+
+	return 0;
+}
+
+static struct skcipher_alg arc4_alg = {
+	/*
+	 * For legacy reasons, this is named "ecb(arc4)", not "arc4".
+	 * Nevertheless it's actually a stream cipher, not a block cipher.
+	 */
+	.base.cra_name		=	"ecb(arc4)",
+	.base.cra_driver_name	=	"ecb(arc4)-generic",
+	.base.cra_priority	=	100,
+	.base.cra_blocksize	=	ARC4_BLOCK_SIZE,
+	.base.cra_ctxsize	=	sizeof(struct arc4_ctx),
+	.base.cra_module	=	THIS_MODULE,
+	.min_keysize		=	ARC4_MIN_KEY_SIZE,
+	.max_keysize		=	ARC4_MAX_KEY_SIZE,
+	.setkey			=	crypto_arc4_setkey,
+	.encrypt		=	crypto_arc4_crypt,
+	.decrypt		=	crypto_arc4_crypt,
+	.init			=	crypto_arc4_init,
+};
+
+static int __init arc4_init(void)
+{
+	return crypto_register_skcipher(&arc4_alg);
+}
+
+static void __exit arc4_exit(void)
+{
+	crypto_unregister_skcipher(&arc4_alg);
+}
+
+subsys_initcall(arc4_init);
+module_exit(arc4_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
+MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
+MODULE_ALIAS_CRYPTO("ecb(arc4)");