Move c_src dirs back to toplevel

[bcachefs-tools-debian] / linux / crypto / chacha20_generic.c

diff --git a/linux/crypto/chacha20_generic.c b/linux/crypto/chacha20_generic.c
new file mode 100644 (file)
index 0000000..914189e
--- /dev/null
+++ b/linux/crypto/chacha20_generic.c
@@ -0,0 +1,111 @@
+/*
+ * ChaCha20 256-bit cipher algorithm, RFC7539
+ *
+ * Copyright (C) 2015 Martin Willi
+ *
+ * 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 <linux/byteorder.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/scatterlist.h>
+#include <asm/unaligned.h>
+
+#include <linux/crypto.h>
+#include <crypto/algapi.h>
+#include <crypto/chacha.h>
+#include <crypto/skcipher.h>
+
+#include <sodium/crypto_stream_chacha20.h>
+
+static struct skcipher_alg alg;
+
+struct chacha20_tfm {
+       struct crypto_skcipher  tfm;
+       u32                     key[8];
+};
+
+static int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+                                 unsigned int keysize)
+{
+       struct chacha20_tfm *ctx =
+               container_of(tfm, struct chacha20_tfm, tfm);
+       int i;
+
+       if (keysize != CHACHA_KEY_SIZE)
+               return -EINVAL;
+
+       for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
+               ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));
+
+       return 0;
+}
+
+static int crypto_chacha20_crypt(struct skcipher_request *req)
+{
+       struct chacha20_tfm *ctx =
+               container_of(req->tfm, struct chacha20_tfm, tfm.base);
+       struct scatterlist *sg = req->src;
+       unsigned nbytes = req->cryptlen;
+       u32 iv[4];
+       int ret;
+
+       BUG_ON(req->src != req->dst);
+
+       memcpy(iv, req->iv, sizeof(iv));
+
+       while (1) {
+               ret = crypto_stream_chacha20_xor_ic(sg_virt(sg),
+                                                   sg_virt(sg),
+                                                   sg->length,
+                                                   (void *) &iv[2],
+                                                   iv[0] | ((u64) iv[1] << 32),
+                                                   (void *) ctx->key);
+               BUG_ON(ret);
+
+               nbytes -= sg->length;
+
+               if (sg_is_last(sg))
+                       break;
+
+               BUG_ON(sg->length % CHACHA_BLOCK_SIZE);
+               iv[0] += sg->length / CHACHA_BLOCK_SIZE;
+               sg = sg_next(sg);
+       };
+
+       BUG_ON(nbytes);
+
+       return 0;
+}
+
+static void *crypto_chacha20_alloc_tfm(void)
+{
+       struct chacha20_tfm *tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+
+       if (!tfm)
+               return NULL;
+
+       tfm->tfm.base.alg       = &alg.base;
+       tfm->tfm.setkey         = crypto_chacha20_setkey;
+       tfm->tfm.encrypt        = crypto_chacha20_crypt;
+       tfm->tfm.decrypt        = crypto_chacha20_crypt;
+       tfm->tfm.ivsize         = CHACHA_IV_SIZE;
+       tfm->tfm.keysize        = CHACHA_KEY_SIZE;
+
+       return tfm;
+}
+
+static struct skcipher_alg alg = {
+       .base.cra_name          = "chacha20",
+       .base.alloc_tfm         = crypto_chacha20_alloc_tfm,
+};
+
+__attribute__((constructor(110)))
+static int chacha20_generic_mod_init(void)
+{
+       return crypto_register_skcipher(&alg);
+}