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-rw-r--r--lib/crypto/chacha20poly1305.c219
1 files changed, 219 insertions, 0 deletions
diff --git a/lib/crypto/chacha20poly1305.c b/lib/crypto/chacha20poly1305.c
new file mode 100644
index 000000000000..c12ddbe9eb92
--- /dev/null
+++ b/lib/crypto/chacha20poly1305.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is an implementation of the ChaCha20Poly1305 AEAD construction.
+ *
+ * Information: https://tools.ietf.org/html/rfc8439
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/chacha20poly1305.h>
+#include <crypto/chacha.h>
+#include <crypto/poly1305.h>
+
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#define CHACHA_KEY_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
+
+bool __init chacha20poly1305_selftest(void);
+
+static void chacha_load_key(u32 *k, const u8 *in)
+{
+ k[0] = get_unaligned_le32(in);
+ k[1] = get_unaligned_le32(in + 4);
+ k[2] = get_unaligned_le32(in + 8);
+ k[3] = get_unaligned_le32(in + 12);
+ k[4] = get_unaligned_le32(in + 16);
+ k[5] = get_unaligned_le32(in + 20);
+ k[6] = get_unaligned_le32(in + 24);
+ k[7] = get_unaligned_le32(in + 28);
+}
+
+static void xchacha_init(u32 *chacha_state, const u8 *key, const u8 *nonce)
+{
+ u32 k[CHACHA_KEY_WORDS];
+ u8 iv[CHACHA_IV_SIZE];
+
+ memset(iv, 0, 8);
+ memcpy(iv + 8, nonce + 16, 8);
+
+ chacha_load_key(k, key);
+
+ /* Compute the subkey given the original key and first 128 nonce bits */
+ chacha_init(chacha_state, k, nonce);
+ hchacha_block(chacha_state, k, 20);
+
+ chacha_init(chacha_state, k, iv);
+
+ memzero_explicit(k, sizeof(k));
+ memzero_explicit(iv, sizeof(iv));
+}
+
+static void
+__chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len, u32 *chacha_state)
+{
+ const u8 *pad0 = page_address(ZERO_PAGE(0));
+ struct poly1305_desc_ctx poly1305_state;
+ union {
+ u8 block0[POLY1305_KEY_SIZE];
+ __le64 lens[2];
+ } b;
+
+ chacha_crypt(chacha_state, b.block0, pad0, sizeof(b.block0), 20);
+ poly1305_init(&poly1305_state, b.block0);
+
+ poly1305_update(&poly1305_state, ad, ad_len);
+ if (ad_len & 0xf)
+ poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
+
+ chacha_crypt(chacha_state, dst, src, src_len, 20);
+
+ poly1305_update(&poly1305_state, dst, src_len);
+ if (src_len & 0xf)
+ poly1305_update(&poly1305_state, pad0, 0x10 - (src_len & 0xf));
+
+ b.lens[0] = cpu_to_le64(ad_len);
+ b.lens[1] = cpu_to_le64(src_len);
+ poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens));
+
+ poly1305_final(&poly1305_state, dst + src_len);
+
+ memzero_explicit(chacha_state, CHACHA_STATE_WORDS * sizeof(u32));
+ memzero_explicit(&b, sizeof(b));
+}
+
+void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ u32 chacha_state[CHACHA_STATE_WORDS];
+ u32 k[CHACHA_KEY_WORDS];
+ __le64 iv[2];
+
+ chacha_load_key(k, key);
+
+ iv[0] = 0;
+ iv[1] = cpu_to_le64(nonce);
+
+ chacha_init(chacha_state, k, (u8 *)iv);
+ __chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
+
+ memzero_explicit(iv, sizeof(iv));
+ memzero_explicit(k, sizeof(k));
+}
+EXPORT_SYMBOL(chacha20poly1305_encrypt);
+
+void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ u32 chacha_state[CHACHA_STATE_WORDS];
+
+ xchacha_init(chacha_state, key, nonce);
+ __chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
+}
+EXPORT_SYMBOL(xchacha20poly1305_encrypt);
+
+static bool
+__chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len, u32 *chacha_state)
+{
+ const u8 *pad0 = page_address(ZERO_PAGE(0));
+ struct poly1305_desc_ctx poly1305_state;
+ size_t dst_len;
+ int ret;
+ union {
+ u8 block0[POLY1305_KEY_SIZE];
+ u8 mac[POLY1305_DIGEST_SIZE];
+ __le64 lens[2];
+ } b;
+
+ if (unlikely(src_len < POLY1305_DIGEST_SIZE))
+ return false;
+
+ chacha_crypt(chacha_state, b.block0, pad0, sizeof(b.block0), 20);
+ poly1305_init(&poly1305_state, b.block0);
+
+ poly1305_update(&poly1305_state, ad, ad_len);
+ if (ad_len & 0xf)
+ poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
+
+ dst_len = src_len - POLY1305_DIGEST_SIZE;
+ poly1305_update(&poly1305_state, src, dst_len);
+ if (dst_len & 0xf)
+ poly1305_update(&poly1305_state, pad0, 0x10 - (dst_len & 0xf));
+
+ b.lens[0] = cpu_to_le64(ad_len);
+ b.lens[1] = cpu_to_le64(dst_len);
+ poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens));
+
+ poly1305_final(&poly1305_state, b.mac);
+
+ ret = crypto_memneq(b.mac, src + dst_len, POLY1305_DIGEST_SIZE);
+ if (likely(!ret))
+ chacha_crypt(chacha_state, dst, src, dst_len, 20);
+
+ memzero_explicit(&b, sizeof(b));
+
+ return !ret;
+}
+
+bool chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ u32 chacha_state[CHACHA_STATE_WORDS];
+ u32 k[CHACHA_KEY_WORDS];
+ __le64 iv[2];
+ bool ret;
+
+ chacha_load_key(k, key);
+
+ iv[0] = 0;
+ iv[1] = cpu_to_le64(nonce);
+
+ chacha_init(chacha_state, k, (u8 *)iv);
+ ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
+ chacha_state);
+
+ memzero_explicit(chacha_state, sizeof(chacha_state));
+ memzero_explicit(iv, sizeof(iv));
+ memzero_explicit(k, sizeof(k));
+ return ret;
+}
+EXPORT_SYMBOL(chacha20poly1305_decrypt);
+
+bool xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ u32 chacha_state[CHACHA_STATE_WORDS];
+
+ xchacha_init(chacha_state, key, nonce);
+ return __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
+ chacha_state);
+}
+EXPORT_SYMBOL(xchacha20poly1305_decrypt);
+
+static int __init mod_init(void)
+{
+ if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&
+ WARN_ON(!chacha20poly1305_selftest()))
+ return -ENODEV;
+ return 0;
+}
+
+module_init(mod_init);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChaCha20Poly1305 AEAD construction");
+MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-16 07:20:40 +0000