summaryrefslogtreecommitdiffstats
path: root/lib/crypto/chacha20poly1305.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/crypto/chacha20poly1305.c')
-rw-r--r--lib/crypto/chacha20poly1305.c368
1 files changed, 368 insertions, 0 deletions
diff --git a/lib/crypto/chacha20poly1305.c b/lib/crypto/chacha20poly1305.c
new file mode 100644
index 000000000..5850f3b87
--- /dev/null
+++ b/lib/crypto/chacha20poly1305.c
@@ -0,0 +1,368 @@
+// 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 <crypto/scatterwalk.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))
+
+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;
+
+ chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
+ 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));
+
+ chacha20_crypt(chacha_state, dst, src, src_len);
+
+ 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;
+
+ chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
+ 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))
+ chacha20_crypt(chacha_state, dst, src, dst_len);
+
+ 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
+bool chacha20poly1305_crypt_sg_inplace(struct scatterlist *src,
+ const size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE],
+ int encrypt)
+{
+ const u8 *pad0 = page_address(ZERO_PAGE(0));
+ struct poly1305_desc_ctx poly1305_state;
+ u32 chacha_state[CHACHA_STATE_WORDS];
+ struct sg_mapping_iter miter;
+ size_t partial = 0;
+ unsigned int flags;
+ bool ret = true;
+ int sl;
+ union {
+ struct {
+ u32 k[CHACHA_KEY_WORDS];
+ __le64 iv[2];
+ };
+ u8 block0[POLY1305_KEY_SIZE];
+ u8 chacha_stream[CHACHA_BLOCK_SIZE];
+ struct {
+ u8 mac[2][POLY1305_DIGEST_SIZE];
+ };
+ __le64 lens[2];
+ } b __aligned(16);
+
+ if (WARN_ON(src_len > INT_MAX))
+ return false;
+
+ chacha_load_key(b.k, key);
+
+ b.iv[0] = 0;
+ b.iv[1] = cpu_to_le64(nonce);
+
+ chacha_init(chacha_state, b.k, (u8 *)b.iv);
+ chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
+ poly1305_init(&poly1305_state, b.block0);
+
+ if (unlikely(ad_len)) {
+ poly1305_update(&poly1305_state, ad, ad_len);
+ if (ad_len & 0xf)
+ poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
+ }
+
+ flags = SG_MITER_TO_SG | SG_MITER_ATOMIC;
+
+ sg_miter_start(&miter, src, sg_nents(src), flags);
+
+ for (sl = src_len; sl > 0 && sg_miter_next(&miter); sl -= miter.length) {
+ u8 *addr = miter.addr;
+ size_t length = min_t(size_t, sl, miter.length);
+
+ if (!encrypt)
+ poly1305_update(&poly1305_state, addr, length);
+
+ if (unlikely(partial)) {
+ size_t l = min(length, CHACHA_BLOCK_SIZE - partial);
+
+ crypto_xor(addr, b.chacha_stream + partial, l);
+ partial = (partial + l) & (CHACHA_BLOCK_SIZE - 1);
+
+ addr += l;
+ length -= l;
+ }
+
+ if (likely(length >= CHACHA_BLOCK_SIZE || length == sl)) {
+ size_t l = length;
+
+ if (unlikely(length < sl))
+ l &= ~(CHACHA_BLOCK_SIZE - 1);
+ chacha20_crypt(chacha_state, addr, addr, l);
+ addr += l;
+ length -= l;
+ }
+
+ if (unlikely(length > 0)) {
+ chacha20_crypt(chacha_state, b.chacha_stream, pad0,
+ CHACHA_BLOCK_SIZE);
+ crypto_xor(addr, b.chacha_stream, length);
+ partial = length;
+ }
+
+ if (encrypt)
+ poly1305_update(&poly1305_state, miter.addr,
+ min_t(size_t, sl, miter.length));
+ }
+
+ 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));
+
+ if (likely(sl <= -POLY1305_DIGEST_SIZE)) {
+ if (encrypt) {
+ poly1305_final(&poly1305_state,
+ miter.addr + miter.length + sl);
+ ret = true;
+ } else {
+ poly1305_final(&poly1305_state, b.mac[0]);
+ ret = !crypto_memneq(b.mac[0],
+ miter.addr + miter.length + sl,
+ POLY1305_DIGEST_SIZE);
+ }
+ }
+
+ sg_miter_stop(&miter);
+
+ if (unlikely(sl > -POLY1305_DIGEST_SIZE)) {
+ poly1305_final(&poly1305_state, b.mac[1]);
+ scatterwalk_map_and_copy(b.mac[encrypt], src, src_len,
+ sizeof(b.mac[1]), encrypt);
+ ret = encrypt ||
+ !crypto_memneq(b.mac[0], b.mac[1], POLY1305_DIGEST_SIZE);
+ }
+
+ memzero_explicit(chacha_state, sizeof(chacha_state));
+ memzero_explicit(&b, sizeof(b));
+
+ return ret;
+}
+
+bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ return chacha20poly1305_crypt_sg_inplace(src, src_len, ad, ad_len,
+ nonce, key, 1);
+}
+EXPORT_SYMBOL(chacha20poly1305_encrypt_sg_inplace);
+
+bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+ const u8 *ad, const size_t ad_len,
+ const u64 nonce,
+ const u8 key[CHACHA20POLY1305_KEY_SIZE])
+{
+ if (unlikely(src_len < POLY1305_DIGEST_SIZE))
+ return false;
+
+ return chacha20poly1305_crypt_sg_inplace(src,
+ src_len - POLY1305_DIGEST_SIZE,
+ ad, ad_len, nonce, key, 0);
+}
+EXPORT_SYMBOL(chacha20poly1305_decrypt_sg_inplace);
+
+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 2024-10-31 21:03:54 +0000