poly1305_glue.c
// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <crypto/algapi.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/poly1305.h>
#include <crypto/internal/simd.h>
#include <linux/crypto.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sizes.h>
#include <asm/intel-family.h>
#include <asm/simd.h>
asmlinkage void poly1305_init_x86_64(void *ctx,
const u8 key[POLY1305_BLOCK_SIZE]);
asmlinkage void poly1305_blocks_x86_64(void *ctx, const u8 *inp,
const size_t len, const u32 padbit);
asmlinkage void poly1305_emit_x86_64(void *ctx, u8 mac[POLY1305_DIGEST_SIZE],
const u32 nonce[4]);
asmlinkage void poly1305_emit_avx(void *ctx, u8 mac[POLY1305_DIGEST_SIZE],
const u32 nonce[4]);
asmlinkage void poly1305_blocks_avx(void *ctx, const u8 *inp, const size_t len,
const u32 padbit);
asmlinkage void poly1305_blocks_avx2(void *ctx, const u8 *inp, const size_t len,
const u32 padbit);
asmlinkage void poly1305_blocks_avx512(void *ctx, const u8 *inp,
const size_t len, const u32 padbit);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx2);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx512);
struct poly1305_arch_internal {
union {
struct {
u32 h[5];
u32 is_base2_26;
};
u64 hs[3];
};
u64 r[2];
u64 pad;
struct { u32 r2, r1, r4, r3; } rn[9];
};
/* The AVX code uses base 2^26, while the scalar code uses base 2^64. If we hit
* the unfortunate situation of using AVX and then having to go back to scalar
* -- because the user is silly and has called the update function from two
* separate contexts -- then we need to convert back to the original base before
* proceeding. It is possible to reason that the initial reduction below is
* sufficient given the implementation invariants. However, for an avoidance of
* doubt and because this is not performance critical, we do the full reduction
* anyway. Z3 proof of below function: https://xn--4db.cc/ltPtHCKN/py
*/
static void convert_to_base2_64(void *ctx)
{
struct poly1305_arch_internal *state = ctx;
u32 cy;
if (!state->is_base2_26)
return;
cy = state->h[0] >> 26; state->h[0] &= 0x3ffffff; state->h[1] += cy;
cy = state->h[1] >> 26; state->h[1] &= 0x3ffffff; state->h[2] += cy;
cy = state->h[2] >> 26; state->h[2] &= 0x3ffffff; state->h[3] += cy;
cy = state->h[3] >> 26; state->h[3] &= 0x3ffffff; state->h[4] += cy;
state->hs[0] = ((u64)state->h[2] << 52) | ((u64)state->h[1] << 26) | state->h[0];
state->hs[1] = ((u64)state->h[4] << 40) | ((u64)state->h[3] << 14) | (state->h[2] >> 12);
state->hs[2] = state->h[4] >> 24;
#define ULT(a, b) ((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1))
cy = (state->hs[2] >> 2) + (state->hs[2] & ~3ULL);
state->hs[2] &= 3;
state->hs[0] += cy;
state->hs[1] += (cy = ULT(state->hs[0], cy));
state->hs[2] += ULT(state->hs[1], cy);
#undef ULT
state->is_base2_26 = 0;
}
static void poly1305_simd_init(void *ctx, const u8 key[POLY1305_BLOCK_SIZE])
{
poly1305_init_x86_64(ctx, key);
}
static void poly1305_simd_blocks(void *ctx, const u8 *inp, size_t len,
const u32 padbit)
{
struct poly1305_arch_internal *state = ctx;
/* SIMD disables preemption, so relax after processing each page. */
BUILD_BUG_ON(SZ_4K < POLY1305_BLOCK_SIZE ||
SZ_4K % POLY1305_BLOCK_SIZE);
if (!static_branch_likely(&poly1305_use_avx) ||
(len < (POLY1305_BLOCK_SIZE * 18) && !state->is_base2_26) ||
!crypto_simd_usable()) {
convert_to_base2_64(ctx);
poly1305_blocks_x86_64(ctx, inp, len, padbit);
return;
}
do {
const size_t bytes = min_t(size_t, len, SZ_4K);
kernel_fpu_begin();
if (IS_ENABLED(CONFIG_AS_AVX512) && static_branch_likely(&poly1305_use_avx512))
poly1305_blocks_avx512(ctx, inp, bytes, padbit);
else if (static_branch_likely(&poly1305_use_avx2))
poly1305_blocks_avx2(ctx, inp, bytes, padbit);
else
poly1305_blocks_avx(ctx, inp, bytes, padbit);
kernel_fpu_end();
len -= bytes;
inp += bytes;
} while (len);
}
static void poly1305_simd_emit(void *ctx, u8 mac[POLY1305_DIGEST_SIZE],
const u32 nonce[4])
{
if (!static_branch_likely(&poly1305_use_avx))
poly1305_emit_x86_64(ctx, mac, nonce);
else
poly1305_emit_avx(ctx, mac, nonce);
}
void poly1305_init_arch(struct poly1305_desc_ctx *dctx, const u8 key[POLY1305_KEY_SIZE])
{
poly1305_simd_init(&dctx->h, key);
dctx->s[0] = get_unaligned_le32(&key[16]);
dctx->s[1] = get_unaligned_le32(&key[20]);
dctx->s[2] = get_unaligned_le32(&key[24]);
dctx->s[3] = get_unaligned_le32(&key[28]);
dctx->buflen = 0;
dctx->sset = true;
}
EXPORT_SYMBOL(poly1305_init_arch);
static unsigned int crypto_poly1305_setdctxkey(struct poly1305_desc_ctx *dctx,
const u8 *inp, unsigned int len)
{
unsigned int acc = 0;
if (unlikely(!dctx->sset)) {
if (!dctx->rset && len >= POLY1305_BLOCK_SIZE) {
poly1305_simd_init(&dctx->h, inp);
inp += POLY1305_BLOCK_SIZE;
len -= POLY1305_BLOCK_SIZE;
acc += POLY1305_BLOCK_SIZE;
dctx->rset = 1;
}
if (len >= POLY1305_BLOCK_SIZE) {
dctx->s[0] = get_unaligned_le32(&inp[0]);
dctx->s[1] = get_unaligned_le32(&inp[4]);
dctx->s[2] = get_unaligned_le32(&inp[8]);
dctx->s[3] = get_unaligned_le32(&inp[12]);
acc += POLY1305_BLOCK_SIZE;
dctx->sset = true;
}
}
return acc;
}
void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
unsigned int srclen)
{
unsigned int bytes, used;
if (unlikely(dctx->buflen)) {
bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
memcpy(dctx->buf + dctx->buflen, src, bytes);
src += bytes;
srclen -= bytes;
dctx->buflen += bytes;
if (dctx->buflen == POLY1305_BLOCK_SIZE) {
if (likely(!crypto_poly1305_setdctxkey(dctx, dctx->buf, POLY1305_BLOCK_SIZE)))
poly1305_simd_blocks(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 1);
dctx->buflen = 0;
}
}
if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
bytes = round_down(srclen, POLY1305_BLOCK_SIZE);
srclen -= bytes;
used = crypto_poly1305_setdctxkey(dctx, src, bytes);
if (likely(bytes - used))
poly1305_simd_blocks(&dctx->h, src + used, bytes - used, 1);
src += bytes;
}
if (unlikely(srclen)) {
dctx->buflen = srclen;
memcpy(dctx->buf, src, srclen);
}
}
EXPORT_SYMBOL(poly1305_update_arch);
void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
{
if (unlikely(dctx->buflen)) {
dctx->buf[dctx->buflen++] = 1;
memset(dctx->buf + dctx->buflen, 0,
POLY1305_BLOCK_SIZE - dctx->buflen);
poly1305_simd_blocks(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
}
poly1305_simd_emit(&dctx->h, dst, dctx->s);
memzero_explicit(dctx, sizeof(*dctx));
}
EXPORT_SYMBOL(poly1305_final_arch);
static int crypto_poly1305_init(struct shash_desc *desc)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
*dctx = (struct poly1305_desc_ctx){};
return 0;
}
static int crypto_poly1305_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
poly1305_update_arch(dctx, src, srclen);
return 0;
}
static int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
if (unlikely(!dctx->sset))
return -ENOKEY;
poly1305_final_arch(dctx, dst);
return 0;
}
static struct shash_alg alg = {
.digestsize = POLY1305_DIGEST_SIZE,
.init = crypto_poly1305_init,
.update = crypto_poly1305_update,
.final = crypto_poly1305_final,
.descsize = sizeof(struct poly1305_desc_ctx),
.base = {
.cra_name = "poly1305",
.cra_driver_name = "poly1305-simd",
.cra_priority = 300,
.cra_blocksize = POLY1305_BLOCK_SIZE,
.cra_module = THIS_MODULE,
},
};
static int __init poly1305_simd_mod_init(void)
{
if (boot_cpu_has(X86_FEATURE_AVX) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL))
static_branch_enable(&poly1305_use_avx);
if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL))
static_branch_enable(&poly1305_use_avx2);
if (IS_ENABLED(CONFIG_AS_AVX512) && boot_cpu_has(X86_FEATURE_AVX) &&
boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_AVX512F) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM | XFEATURE_MASK_AVX512, NULL) &&
/* Skylake downclocks unacceptably much when using zmm, but later generations are fast. */
boot_cpu_data.x86_model != INTEL_FAM6_SKYLAKE_X)
static_branch_enable(&poly1305_use_avx512);
return IS_REACHABLE(CONFIG_CRYPTO_HASH) ? crypto_register_shash(&alg) : 0;
}
static void __exit poly1305_simd_mod_exit(void)
{
if (IS_REACHABLE(CONFIG_CRYPTO_HASH))
crypto_unregister_shash(&alg);
}
module_init(poly1305_simd_mod_init);
module_exit(poly1305_simd_mod_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
MODULE_DESCRIPTION("Poly1305 authenticator");
MODULE_ALIAS_CRYPTO("poly1305");
MODULE_ALIAS_CRYPTO("poly1305-simd");