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-rw-r--r--crypto/chacha.c260
1 files changed, 260 insertions, 0 deletions
diff --git a/crypto/chacha.c b/crypto/chacha.c
new file mode 100644
index 000000000000..c3a11f4e2d13
--- /dev/null
+++ b/crypto/chacha.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Crypto API wrappers for the ChaCha20, XChaCha20, and XChaCha12 stream ciphers
+ *
+ * Copyright (C) 2015 Martin Willi
+ * Copyright (C) 2018 Google LLC
+ */
+
+#include <linux/unaligned.h>
+#include <crypto/algapi.h>
+#include <crypto/chacha.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/module.h>
+
+struct chacha_ctx {
+ u32 key[8];
+ int nrounds;
+};
+
+static int chacha_setkey(struct crypto_skcipher *tfm,
+ const u8 *key, unsigned int keysize, int nrounds)
+{
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(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));
+
+ ctx->nrounds = nrounds;
+ return 0;
+}
+
+static int chacha20_setkey(struct crypto_skcipher *tfm,
+ const u8 *key, unsigned int keysize)
+{
+ return chacha_setkey(tfm, key, keysize, 20);
+}
+
+static int chacha12_setkey(struct crypto_skcipher *tfm,
+ const u8 *key, unsigned int keysize)
+{
+ return chacha_setkey(tfm, key, keysize, 12);
+}
+
+static int chacha_stream_xor(struct skcipher_request *req,
+ const struct chacha_ctx *ctx,
+ const u8 iv[CHACHA_IV_SIZE], bool arch)
+{
+ struct skcipher_walk walk;
+ struct chacha_state state;
+ int err;
+
+ err = skcipher_walk_virt(&walk, req, false);
+
+ chacha_init(&state, ctx->key, iv);
+
+ while (walk.nbytes > 0) {
+ unsigned int nbytes = walk.nbytes;
+
+ if (nbytes < walk.total)
+ nbytes = round_down(nbytes, CHACHA_BLOCK_SIZE);
+
+ if (arch)
+ chacha_crypt(&state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes, ctx->nrounds);
+ else
+ chacha_crypt_generic(&state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes,
+ ctx->nrounds);
+ err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+ }
+
+ return err;
+}
+
+static int crypto_chacha_crypt_generic(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ return chacha_stream_xor(req, ctx, req->iv, false);
+}
+
+static int crypto_chacha_crypt_arch(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ return chacha_stream_xor(req, ctx, req->iv, true);
+}
+
+static int crypto_xchacha_crypt(struct skcipher_request *req, bool arch)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx subctx;
+ struct chacha_state state;
+ u8 real_iv[16];
+
+ /* Compute the subkey given the original key and first 128 nonce bits */
+ chacha_init(&state, ctx->key, req->iv);
+ if (arch)
+ hchacha_block(&state, subctx.key, ctx->nrounds);
+ else
+ hchacha_block_generic(&state, subctx.key, ctx->nrounds);
+ subctx.nrounds = ctx->nrounds;
+
+ /* Build the real IV */
+ memcpy(&real_iv[0], req->iv + 24, 8); /* stream position */
+ memcpy(&real_iv[8], req->iv + 16, 8); /* remaining 64 nonce bits */
+
+ /* Generate the stream and XOR it with the data */
+ return chacha_stream_xor(req, &subctx, real_iv, arch);
+}
+
+static int crypto_xchacha_crypt_generic(struct skcipher_request *req)
+{
+ return crypto_xchacha_crypt(req, false);
+}
+
+static int crypto_xchacha_crypt_arch(struct skcipher_request *req)
+{
+ return crypto_xchacha_crypt(req, true);
+}
+
+static struct skcipher_alg algs[] = {
+ {
+ .base.cra_name = "chacha20",
+ .base.cra_driver_name = "chacha20-generic",
+ .base.cra_priority = 100,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha20_setkey,
+ .encrypt = crypto_chacha_crypt_generic,
+ .decrypt = crypto_chacha_crypt_generic,
+ },
+ {
+ .base.cra_name = "xchacha20",
+ .base.cra_driver_name = "xchacha20-generic",
+ .base.cra_priority = 100,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = XCHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha20_setkey,
+ .encrypt = crypto_xchacha_crypt_generic,
+ .decrypt = crypto_xchacha_crypt_generic,
+ },
+ {
+ .base.cra_name = "xchacha12",
+ .base.cra_driver_name = "xchacha12-generic",
+ .base.cra_priority = 100,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = XCHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha12_setkey,
+ .encrypt = crypto_xchacha_crypt_generic,
+ .decrypt = crypto_xchacha_crypt_generic,
+ },
+ {
+ .base.cra_name = "chacha20",
+ .base.cra_driver_name = "chacha20-" __stringify(ARCH),
+ .base.cra_priority = 300,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha20_setkey,
+ .encrypt = crypto_chacha_crypt_arch,
+ .decrypt = crypto_chacha_crypt_arch,
+ },
+ {
+ .base.cra_name = "xchacha20",
+ .base.cra_driver_name = "xchacha20-" __stringify(ARCH),
+ .base.cra_priority = 300,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = XCHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha20_setkey,
+ .encrypt = crypto_xchacha_crypt_arch,
+ .decrypt = crypto_xchacha_crypt_arch,
+ },
+ {
+ .base.cra_name = "xchacha12",
+ .base.cra_driver_name = "xchacha12-" __stringify(ARCH),
+ .base.cra_priority = 300,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = XCHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha12_setkey,
+ .encrypt = crypto_xchacha_crypt_arch,
+ .decrypt = crypto_xchacha_crypt_arch,
+ }
+};
+
+static unsigned int num_algs;
+
+static int __init crypto_chacha_mod_init(void)
+{
+ /* register the arch flavours only if they differ from generic */
+ num_algs = ARRAY_SIZE(algs);
+ BUILD_BUG_ON(ARRAY_SIZE(algs) % 2 != 0);
+ if (!chacha_is_arch_optimized())
+ num_algs /= 2;
+
+ return crypto_register_skciphers(algs, num_algs);
+}
+
+static void __exit crypto_chacha_mod_fini(void)
+{
+ crypto_unregister_skciphers(algs, num_algs);
+}
+
+module_init(crypto_chacha_mod_init);
+module_exit(crypto_chacha_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
+MODULE_DESCRIPTION("Crypto API wrappers for the ChaCha20, XChaCha20, and XChaCha12 stream ciphers");
+MODULE_ALIAS_CRYPTO("chacha20");
+MODULE_ALIAS_CRYPTO("chacha20-generic");
+MODULE_ALIAS_CRYPTO("chacha20-" __stringify(ARCH));
+MODULE_ALIAS_CRYPTO("xchacha20");
+MODULE_ALIAS_CRYPTO("xchacha20-generic");
+MODULE_ALIAS_CRYPTO("xchacha20-" __stringify(ARCH));
+MODULE_ALIAS_CRYPTO("xchacha12");
+MODULE_ALIAS_CRYPTO("xchacha12-generic");
+MODULE_ALIAS_CRYPTO("xchacha12-" __stringify(ARCH));
generated by cgit (git 2.34.1) at 2025-05-28 19:36:22 +0000