[CRYPTO] salsa20_i586: Salsa20 stream cipher algorithm (i586 version)
This patch contains the salsa20-i586 implementation. The original
assembly code came from
<http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s>. I have reformatted
it (added indents) so that it matches the other algorithms in
arch/x86/crypto.
Signed-off-by: Tan Swee Heng <thesweeheng@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/arch/x86/crypto/salsa20_glue.c b/arch/x86/crypto/salsa20_glue.c
new file mode 100644
index 0000000..3be4439
--- /dev/null
+++ b/arch/x86/crypto/salsa20_glue.c
@@ -0,0 +1,127 @@
+/*
+ * Glue code for optimized assembly version of Salsa20.
+ *
+ * Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com>
+ *
+ * The assembly codes are public domain assembly codes written by Daniel. J.
+ * Bernstein <djb@cr.yp.to>. The codes are modified to include indentation
+ * and to remove extraneous comments and functions that are not needed.
+ * - i586 version, renamed as salsa20-i586-asm_32.S
+ * available from <http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/algapi.h>
+#include <linux/module.h>
+#include <linux/crypto.h>
+
+#define SALSA20_IV_SIZE 8U
+#define SALSA20_MIN_KEY_SIZE 16U
+#define SALSA20_MAX_KEY_SIZE 32U
+
+// use the ECRYPT_* function names
+#define salsa20_keysetup ECRYPT_keysetup
+#define salsa20_ivsetup ECRYPT_ivsetup
+#define salsa20_encrypt_bytes ECRYPT_encrypt_bytes
+
+struct salsa20_ctx
+{
+ u32 input[16];
+};
+
+asmlinkage void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k,
+ u32 keysize, u32 ivsize);
+asmlinkage void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv);
+asmlinkage void salsa20_encrypt_bytes(struct salsa20_ctx *ctx,
+ const u8 *src, u8 *dst, u32 bytes);
+
+static int setkey(struct crypto_tfm *tfm, const u8 *key,
+ unsigned int keysize)
+{
+ struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm);
+ salsa20_keysetup(ctx, key, keysize*8, SALSA20_IV_SIZE*8);
+ return 0;
+}
+
+static int encrypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst, struct scatterlist *src,
+ unsigned int nbytes)
+{
+ struct blkcipher_walk walk;
+ struct crypto_blkcipher *tfm = desc->tfm;
+ struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ int err;
+
+ blkcipher_walk_init(&walk, dst, src, nbytes);
+ err = blkcipher_walk_virt_block(desc, &walk, 64);
+
+ salsa20_ivsetup(ctx, walk.iv);
+
+ if (likely(walk.nbytes == nbytes))
+ {
+ salsa20_encrypt_bytes(ctx, walk.src.virt.addr,
+ walk.dst.virt.addr, nbytes);
+ return blkcipher_walk_done(desc, &walk, 0);
+ }
+
+ while (walk.nbytes >= 64) {
+ salsa20_encrypt_bytes(ctx, walk.src.virt.addr,
+ walk.dst.virt.addr,
+ walk.nbytes - (walk.nbytes % 64));
+ err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64);
+ }
+
+ if (walk.nbytes) {
+ salsa20_encrypt_bytes(ctx, walk.src.virt.addr,
+ walk.dst.virt.addr, walk.nbytes);
+ err = blkcipher_walk_done(desc, &walk, 0);
+ }
+
+ return err;
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "salsa20",
+ .cra_driver_name = "salsa20-asm",
+ .cra_priority = 200,
+ .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
+ .cra_type = &crypto_blkcipher_type,
+ .cra_blocksize = 1,
+ .cra_ctxsize = sizeof(struct salsa20_ctx),
+ .cra_alignmask = 3,
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_u = {
+ .blkcipher = {
+ .setkey = setkey,
+ .encrypt = encrypt,
+ .decrypt = encrypt,
+ .min_keysize = SALSA20_MIN_KEY_SIZE,
+ .max_keysize = SALSA20_MAX_KEY_SIZE,
+ .ivsize = SALSA20_IV_SIZE,
+ }
+ }
+};
+
+static int __init init(void)
+{
+ return crypto_register_alg(&alg);
+}
+
+static void __exit fini(void)
+{
+ crypto_unregister_alg(&alg);
+}
+
+module_init(init);
+module_exit(fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)");
+MODULE_ALIAS("salsa20");
+MODULE_ALIAS("salsa20-asm");