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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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ba89b4eaa6
The ChaCha20-Poly1305 library code uses the sg_miter API to process input presented via scatterlists, except for the special case where the digest buffer is not covered entirely by the same scatterlist entry as the last byte of input. In that case, it uses scatterwalk_map_and_copy() to access the memory in the input scatterlist where the digest is stored. This results in a dependency on crypto/scatterwalk.c and therefore on CONFIG_CRYPTO_ALGAPI, which is unnecessary, as the sg_miter API already provides this functionality via sg_copy_to_buffer(). So use that instead, and drop the dependencies on CONFIG_CRYPTO_ALGAPI and CONFIG_CRYPTO. Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
372 lines
9.9 KiB
C
372 lines
9.9 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR MIT
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* This is an implementation of the ChaCha20Poly1305 AEAD construction.
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*
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* Information: https://tools.ietf.org/html/rfc8439
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*/
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#include <crypto/chacha20poly1305.h>
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#include <crypto/chacha.h>
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#include <crypto/poly1305.h>
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#include <crypto/utils.h>
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#include <linux/unaligned.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#define CHACHA_KEY_WORDS (CHACHA_KEY_SIZE / sizeof(u32))
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static void chacha_load_key(u32 *k, const u8 *in)
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{
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k[0] = get_unaligned_le32(in);
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k[1] = get_unaligned_le32(in + 4);
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k[2] = get_unaligned_le32(in + 8);
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k[3] = get_unaligned_le32(in + 12);
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k[4] = get_unaligned_le32(in + 16);
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k[5] = get_unaligned_le32(in + 20);
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k[6] = get_unaligned_le32(in + 24);
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k[7] = get_unaligned_le32(in + 28);
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}
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static void xchacha_init(u32 *chacha_state, const u8 *key, const u8 *nonce)
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{
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u32 k[CHACHA_KEY_WORDS];
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u8 iv[CHACHA_IV_SIZE];
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memset(iv, 0, 8);
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memcpy(iv + 8, nonce + 16, 8);
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chacha_load_key(k, key);
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/* Compute the subkey given the original key and first 128 nonce bits */
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chacha_init(chacha_state, k, nonce);
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hchacha_block(chacha_state, k, 20);
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chacha_init(chacha_state, k, iv);
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memzero_explicit(k, sizeof(k));
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memzero_explicit(iv, sizeof(iv));
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}
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static void
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__chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len, u32 *chacha_state)
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{
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const u8 *pad0 = page_address(ZERO_PAGE(0));
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struct poly1305_desc_ctx poly1305_state;
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union {
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u8 block0[POLY1305_KEY_SIZE];
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__le64 lens[2];
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} b;
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chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
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poly1305_init(&poly1305_state, b.block0);
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poly1305_update(&poly1305_state, ad, ad_len);
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if (ad_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
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chacha20_crypt(chacha_state, dst, src, src_len);
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poly1305_update(&poly1305_state, dst, src_len);
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if (src_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (src_len & 0xf));
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b.lens[0] = cpu_to_le64(ad_len);
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b.lens[1] = cpu_to_le64(src_len);
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poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens));
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poly1305_final(&poly1305_state, dst + src_len);
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memzero_explicit(chacha_state, CHACHA_STATE_WORDS * sizeof(u32));
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memzero_explicit(&b, sizeof(b));
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}
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void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u64 nonce,
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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u32 chacha_state[CHACHA_STATE_WORDS];
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u32 k[CHACHA_KEY_WORDS];
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__le64 iv[2];
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chacha_load_key(k, key);
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iv[0] = 0;
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iv[1] = cpu_to_le64(nonce);
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chacha_init(chacha_state, k, (u8 *)iv);
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__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
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memzero_explicit(iv, sizeof(iv));
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memzero_explicit(k, sizeof(k));
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}
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EXPORT_SYMBOL(chacha20poly1305_encrypt);
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void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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u32 chacha_state[CHACHA_STATE_WORDS];
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xchacha_init(chacha_state, key, nonce);
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__chacha20poly1305_encrypt(dst, src, src_len, ad, ad_len, chacha_state);
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}
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EXPORT_SYMBOL(xchacha20poly1305_encrypt);
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static bool
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__chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len, u32 *chacha_state)
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{
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const u8 *pad0 = page_address(ZERO_PAGE(0));
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struct poly1305_desc_ctx poly1305_state;
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size_t dst_len;
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int ret;
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union {
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u8 block0[POLY1305_KEY_SIZE];
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u8 mac[POLY1305_DIGEST_SIZE];
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__le64 lens[2];
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} b;
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if (unlikely(src_len < POLY1305_DIGEST_SIZE))
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return false;
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chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
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poly1305_init(&poly1305_state, b.block0);
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poly1305_update(&poly1305_state, ad, ad_len);
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if (ad_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
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dst_len = src_len - POLY1305_DIGEST_SIZE;
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poly1305_update(&poly1305_state, src, dst_len);
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if (dst_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (dst_len & 0xf));
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b.lens[0] = cpu_to_le64(ad_len);
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b.lens[1] = cpu_to_le64(dst_len);
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poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens));
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poly1305_final(&poly1305_state, b.mac);
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ret = crypto_memneq(b.mac, src + dst_len, POLY1305_DIGEST_SIZE);
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if (likely(!ret))
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chacha20_crypt(chacha_state, dst, src, dst_len);
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memzero_explicit(&b, sizeof(b));
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return !ret;
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}
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bool chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u64 nonce,
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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u32 chacha_state[CHACHA_STATE_WORDS];
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u32 k[CHACHA_KEY_WORDS];
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__le64 iv[2];
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bool ret;
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chacha_load_key(k, key);
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iv[0] = 0;
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iv[1] = cpu_to_le64(nonce);
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chacha_init(chacha_state, k, (u8 *)iv);
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ret = __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
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chacha_state);
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memzero_explicit(chacha_state, sizeof(chacha_state));
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memzero_explicit(iv, sizeof(iv));
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memzero_explicit(k, sizeof(k));
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return ret;
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}
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EXPORT_SYMBOL(chacha20poly1305_decrypt);
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bool xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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u32 chacha_state[CHACHA_STATE_WORDS];
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xchacha_init(chacha_state, key, nonce);
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return __chacha20poly1305_decrypt(dst, src, src_len, ad, ad_len,
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chacha_state);
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}
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EXPORT_SYMBOL(xchacha20poly1305_decrypt);
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static
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bool chacha20poly1305_crypt_sg_inplace(struct scatterlist *src,
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const size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u64 nonce,
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const u8 key[CHACHA20POLY1305_KEY_SIZE],
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int encrypt)
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{
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const u8 *pad0 = page_address(ZERO_PAGE(0));
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struct poly1305_desc_ctx poly1305_state;
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u32 chacha_state[CHACHA_STATE_WORDS];
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struct sg_mapping_iter miter;
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size_t partial = 0;
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unsigned int flags;
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bool ret = true;
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int sl;
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union {
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struct {
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u32 k[CHACHA_KEY_WORDS];
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__le64 iv[2];
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};
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u8 block0[POLY1305_KEY_SIZE];
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u8 chacha_stream[CHACHA_BLOCK_SIZE];
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struct {
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u8 mac[2][POLY1305_DIGEST_SIZE];
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};
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__le64 lens[2];
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} b __aligned(16);
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if (WARN_ON(src_len > INT_MAX))
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return false;
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chacha_load_key(b.k, key);
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b.iv[0] = 0;
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b.iv[1] = cpu_to_le64(nonce);
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chacha_init(chacha_state, b.k, (u8 *)b.iv);
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chacha20_crypt(chacha_state, b.block0, pad0, sizeof(b.block0));
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poly1305_init(&poly1305_state, b.block0);
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if (unlikely(ad_len)) {
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poly1305_update(&poly1305_state, ad, ad_len);
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if (ad_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (ad_len & 0xf));
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}
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flags = SG_MITER_TO_SG | SG_MITER_ATOMIC;
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sg_miter_start(&miter, src, sg_nents(src), flags);
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for (sl = src_len; sl > 0 && sg_miter_next(&miter); sl -= miter.length) {
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u8 *addr = miter.addr;
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size_t length = min_t(size_t, sl, miter.length);
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if (!encrypt)
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poly1305_update(&poly1305_state, addr, length);
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if (unlikely(partial)) {
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size_t l = min(length, CHACHA_BLOCK_SIZE - partial);
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crypto_xor(addr, b.chacha_stream + partial, l);
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partial = (partial + l) & (CHACHA_BLOCK_SIZE - 1);
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addr += l;
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length -= l;
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}
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if (likely(length >= CHACHA_BLOCK_SIZE || length == sl)) {
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size_t l = length;
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if (unlikely(length < sl))
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l &= ~(CHACHA_BLOCK_SIZE - 1);
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chacha20_crypt(chacha_state, addr, addr, l);
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addr += l;
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length -= l;
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}
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if (unlikely(length > 0)) {
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chacha20_crypt(chacha_state, b.chacha_stream, pad0,
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CHACHA_BLOCK_SIZE);
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crypto_xor(addr, b.chacha_stream, length);
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partial = length;
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}
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if (encrypt)
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poly1305_update(&poly1305_state, miter.addr,
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min_t(size_t, sl, miter.length));
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}
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if (src_len & 0xf)
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poly1305_update(&poly1305_state, pad0, 0x10 - (src_len & 0xf));
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b.lens[0] = cpu_to_le64(ad_len);
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b.lens[1] = cpu_to_le64(src_len);
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poly1305_update(&poly1305_state, (u8 *)b.lens, sizeof(b.lens));
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if (likely(sl <= -POLY1305_DIGEST_SIZE)) {
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if (encrypt) {
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poly1305_final(&poly1305_state,
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miter.addr + miter.length + sl);
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ret = true;
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} else {
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poly1305_final(&poly1305_state, b.mac[0]);
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ret = !crypto_memneq(b.mac[0],
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miter.addr + miter.length + sl,
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POLY1305_DIGEST_SIZE);
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}
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}
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sg_miter_stop(&miter);
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if (unlikely(sl > -POLY1305_DIGEST_SIZE)) {
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poly1305_final(&poly1305_state, b.mac[1]);
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sg_copy_buffer(src, sg_nents(src), b.mac[encrypt],
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sizeof(b.mac[1]), src_len, !encrypt);
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ret = encrypt ||
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!crypto_memneq(b.mac[0], b.mac[1], POLY1305_DIGEST_SIZE);
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}
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memzero_explicit(chacha_state, sizeof(chacha_state));
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memzero_explicit(&b, sizeof(b));
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return ret;
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}
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bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u64 nonce,
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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return chacha20poly1305_crypt_sg_inplace(src, src_len, ad, ad_len,
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nonce, key, 1);
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}
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EXPORT_SYMBOL(chacha20poly1305_encrypt_sg_inplace);
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bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
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const u8 *ad, const size_t ad_len,
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const u64 nonce,
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const u8 key[CHACHA20POLY1305_KEY_SIZE])
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{
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if (unlikely(src_len < POLY1305_DIGEST_SIZE))
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return false;
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return chacha20poly1305_crypt_sg_inplace(src,
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src_len - POLY1305_DIGEST_SIZE,
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ad, ad_len, nonce, key, 0);
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}
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EXPORT_SYMBOL(chacha20poly1305_decrypt_sg_inplace);
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static int __init chacha20poly1305_init(void)
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{
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if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&
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WARN_ON(!chacha20poly1305_selftest()))
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return -ENODEV;
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return 0;
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}
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static void __exit chacha20poly1305_exit(void)
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{
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}
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module_init(chacha20poly1305_init);
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module_exit(chacha20poly1305_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("ChaCha20Poly1305 AEAD construction");
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MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
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