diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/crypto/chacha20poly1305.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/lib/crypto/chacha20poly1305.c b/lib/crypto/chacha20poly1305.c index c12ddbe9eb92..821e5cc9b14e 100644 --- a/lib/crypto/chacha20poly1305.c +++ b/lib/crypto/chacha20poly1305.c @@ -11,6 +11,7 @@ #include <crypto/chacha20poly1305.h> #include <crypto/chacha.h> #include <crypto/poly1305.h> +#include <crypto/scatterwalk.h> #include <asm/unaligned.h> #include <linux/kernel.h> @@ -205,6 +206,155 @@ bool xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len, } 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); + + 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); + chacha_crypt(chacha_state, b.block0, pad0, sizeof(b.block0), 20); + 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; + if (!preemptible()) + flags |= 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); + chacha_crypt(chacha_state, addr, addr, l, 20); + addr += l; + length -= l; + } + + if (unlikely(length > 0)) { + chacha_crypt(chacha_state, b.chacha_stream, pad0, + CHACHA_BLOCK_SIZE, 20); + 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) && |