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f9c9bdb513
Passing atomic=true to skcipher_walk_virt() only makes the later
skcipher_walk_done() calls use atomic memory allocations, not
skcipher_walk_virt() itself. Thus, we have to move it outside of the
preemption-disabled region (kernel_fpu_begin()/kernel_fpu_end()).
(skcipher_walk_virt() only allocates memory for certain layouts of the
input scatterlist, hence why I didn't notice this earlier...)
Reported-by: syzbot+9bf843c33f782d73ae7d@syzkaller.appspotmail.com
Fixes: 4af7826187 ("crypto: x86/chacha20 - add XChaCha20 support")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
305 lines
8.5 KiB
C
305 lines
8.5 KiB
C
/*
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* x64 SIMD accelerated ChaCha and XChaCha stream ciphers,
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* including ChaCha20 (RFC7539)
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*
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* Copyright (C) 2015 Martin Willi
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <crypto/algapi.h>
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#include <crypto/chacha.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <asm/fpu/api.h>
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#include <asm/simd.h>
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#define CHACHA_STATE_ALIGN 16
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asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
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#ifdef CONFIG_AS_AVX2
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asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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static bool chacha_use_avx2;
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#ifdef CONFIG_AS_AVX512
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asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
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unsigned int len, int nrounds);
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static bool chacha_use_avx512vl;
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#endif
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#endif
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static unsigned int chacha_advance(unsigned int len, unsigned int maxblocks)
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{
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len = min(len, maxblocks * CHACHA_BLOCK_SIZE);
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return round_up(len, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
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}
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static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes, int nrounds)
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{
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#ifdef CONFIG_AS_AVX2
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#ifdef CONFIG_AS_AVX512
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if (chacha_use_avx512vl) {
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while (bytes >= CHACHA_BLOCK_SIZE * 8) {
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chacha_8block_xor_avx512vl(state, dst, src, bytes,
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nrounds);
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bytes -= CHACHA_BLOCK_SIZE * 8;
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src += CHACHA_BLOCK_SIZE * 8;
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dst += CHACHA_BLOCK_SIZE * 8;
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state[12] += 8;
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}
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if (bytes > CHACHA_BLOCK_SIZE * 4) {
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chacha_8block_xor_avx512vl(state, dst, src, bytes,
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nrounds);
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state[12] += chacha_advance(bytes, 8);
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return;
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}
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if (bytes > CHACHA_BLOCK_SIZE * 2) {
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chacha_4block_xor_avx512vl(state, dst, src, bytes,
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nrounds);
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state[12] += chacha_advance(bytes, 4);
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return;
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}
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if (bytes) {
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chacha_2block_xor_avx512vl(state, dst, src, bytes,
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nrounds);
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state[12] += chacha_advance(bytes, 2);
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return;
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}
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}
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#endif
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if (chacha_use_avx2) {
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while (bytes >= CHACHA_BLOCK_SIZE * 8) {
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chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
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bytes -= CHACHA_BLOCK_SIZE * 8;
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src += CHACHA_BLOCK_SIZE * 8;
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dst += CHACHA_BLOCK_SIZE * 8;
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state[12] += 8;
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}
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if (bytes > CHACHA_BLOCK_SIZE * 4) {
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chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
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state[12] += chacha_advance(bytes, 8);
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return;
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}
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if (bytes > CHACHA_BLOCK_SIZE * 2) {
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chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
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state[12] += chacha_advance(bytes, 4);
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return;
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}
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if (bytes > CHACHA_BLOCK_SIZE) {
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chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
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state[12] += chacha_advance(bytes, 2);
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return;
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}
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}
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#endif
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while (bytes >= CHACHA_BLOCK_SIZE * 4) {
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chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
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bytes -= CHACHA_BLOCK_SIZE * 4;
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src += CHACHA_BLOCK_SIZE * 4;
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dst += CHACHA_BLOCK_SIZE * 4;
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state[12] += 4;
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}
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if (bytes > CHACHA_BLOCK_SIZE) {
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chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
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state[12] += chacha_advance(bytes, 4);
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return;
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}
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if (bytes) {
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chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
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state[12]++;
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}
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}
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static int chacha_simd_stream_xor(struct skcipher_walk *walk,
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struct chacha_ctx *ctx, u8 *iv)
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{
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u32 *state, state_buf[16 + 2] __aligned(8);
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int next_yield = 4096; /* bytes until next FPU yield */
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int err = 0;
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BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
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state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
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crypto_chacha_init(state, ctx, iv);
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while (walk->nbytes > 0) {
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unsigned int nbytes = walk->nbytes;
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if (nbytes < walk->total) {
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nbytes = round_down(nbytes, walk->stride);
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next_yield -= nbytes;
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}
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chacha_dosimd(state, walk->dst.virt.addr, walk->src.virt.addr,
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nbytes, ctx->nrounds);
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if (next_yield <= 0) {
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/* temporarily allow preemption */
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kernel_fpu_end();
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kernel_fpu_begin();
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next_yield = 4096;
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}
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err = skcipher_walk_done(walk, walk->nbytes - nbytes);
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}
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return err;
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}
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static int chacha_simd(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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int err;
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !irq_fpu_usable())
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return crypto_chacha_crypt(req);
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err = skcipher_walk_virt(&walk, req, true);
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if (err)
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return err;
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kernel_fpu_begin();
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err = chacha_simd_stream_xor(&walk, ctx, req->iv);
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kernel_fpu_end();
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return err;
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}
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static int xchacha_simd(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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struct chacha_ctx subctx;
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u32 *state, state_buf[16 + 2] __aligned(8);
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u8 real_iv[16];
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int err;
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !irq_fpu_usable())
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return crypto_xchacha_crypt(req);
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err = skcipher_walk_virt(&walk, req, true);
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if (err)
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return err;
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BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
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state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
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crypto_chacha_init(state, ctx, req->iv);
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kernel_fpu_begin();
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hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
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subctx.nrounds = ctx->nrounds;
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memcpy(&real_iv[0], req->iv + 24, 8);
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memcpy(&real_iv[8], req->iv + 16, 8);
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err = chacha_simd_stream_xor(&walk, &subctx, real_iv);
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kernel_fpu_end();
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return err;
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}
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static struct skcipher_alg algs[] = {
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{
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-simd",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = chacha_simd,
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.decrypt = chacha_simd,
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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-simd",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = xchacha_simd,
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.decrypt = xchacha_simd,
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}, {
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.base.cra_name = "xchacha12",
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.base.cra_driver_name = "xchacha12-simd",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha12_setkey,
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.encrypt = xchacha_simd,
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.decrypt = xchacha_simd,
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},
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};
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static int __init chacha_simd_mod_init(void)
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{
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if (!boot_cpu_has(X86_FEATURE_SSSE3))
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return -ENODEV;
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#ifdef CONFIG_AS_AVX2
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chacha_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
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boot_cpu_has(X86_FEATURE_AVX2) &&
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cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
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#ifdef CONFIG_AS_AVX512
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chacha_use_avx512vl = chacha_use_avx2 &&
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boot_cpu_has(X86_FEATURE_AVX512VL) &&
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boot_cpu_has(X86_FEATURE_AVX512BW); /* kmovq */
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#endif
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#endif
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return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
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}
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static void __exit chacha_simd_mod_fini(void)
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{
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crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
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}
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module_init(chacha_simd_mod_init);
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module_exit(chacha_simd_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
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MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
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MODULE_ALIAS_CRYPTO("chacha20");
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MODULE_ALIAS_CRYPTO("chacha20-simd");
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MODULE_ALIAS_CRYPTO("xchacha20");
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MODULE_ALIAS_CRYPTO("xchacha20-simd");
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MODULE_ALIAS_CRYPTO("xchacha12");
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MODULE_ALIAS_CRYPTO("xchacha12-simd");
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