308 lines
7.1 KiB
C
308 lines
7.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* SM4-CCM AEAD Algorithm using ARMv8 Crypto Extensions
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* as specified in rfc8998
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* https://datatracker.ietf.org/doc/html/rfc8998
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*
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* Copyright (C) 2022 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
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*/
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#include <linux/module.h>
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#include <linux/crypto.h>
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#include <linux/kernel.h>
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#include <linux/cpufeature.h>
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#include <asm/neon.h>
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#include <crypto/scatterwalk.h>
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#include <crypto/internal/aead.h>
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#include <crypto/internal/skcipher.h>
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#include <crypto/sm4.h>
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#include "sm4-ce.h"
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asmlinkage void sm4_ce_cbcmac_update(const u32 *rkey_enc, u8 *mac,
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const u8 *src, unsigned int nblocks);
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asmlinkage void sm4_ce_ccm_enc(const u32 *rkey_enc, u8 *dst, const u8 *src,
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u8 *iv, unsigned int nbytes, u8 *mac);
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asmlinkage void sm4_ce_ccm_dec(const u32 *rkey_enc, u8 *dst, const u8 *src,
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u8 *iv, unsigned int nbytes, u8 *mac);
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asmlinkage void sm4_ce_ccm_final(const u32 *rkey_enc, u8 *iv, u8 *mac);
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static int ccm_setkey(struct crypto_aead *tfm, const u8 *key,
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unsigned int key_len)
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{
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struct sm4_ctx *ctx = crypto_aead_ctx(tfm);
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if (key_len != SM4_KEY_SIZE)
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return -EINVAL;
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kernel_neon_begin();
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sm4_ce_expand_key(key, ctx->rkey_enc, ctx->rkey_dec,
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crypto_sm4_fk, crypto_sm4_ck);
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kernel_neon_end();
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return 0;
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}
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static int ccm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
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{
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if ((authsize & 1) || authsize < 4)
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return -EINVAL;
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return 0;
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}
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static int ccm_format_input(u8 info[], struct aead_request *req,
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unsigned int msglen)
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{
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struct crypto_aead *aead = crypto_aead_reqtfm(req);
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unsigned int l = req->iv[0] + 1;
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unsigned int m;
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__be32 len;
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/* verify that CCM dimension 'L': 2 <= L <= 8 */
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if (l < 2 || l > 8)
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return -EINVAL;
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if (l < 4 && msglen >> (8 * l))
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return -EOVERFLOW;
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memset(&req->iv[SM4_BLOCK_SIZE - l], 0, l);
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memcpy(info, req->iv, SM4_BLOCK_SIZE);
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m = crypto_aead_authsize(aead);
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/* format flags field per RFC 3610/NIST 800-38C */
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*info |= ((m - 2) / 2) << 3;
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if (req->assoclen)
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*info |= (1 << 6);
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/*
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* format message length field,
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* Linux uses a u32 type to represent msglen
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*/
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if (l >= 4)
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l = 4;
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len = cpu_to_be32(msglen);
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memcpy(&info[SM4_BLOCK_SIZE - l], (u8 *)&len + 4 - l, l);
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return 0;
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}
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static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
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{
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struct crypto_aead *aead = crypto_aead_reqtfm(req);
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struct sm4_ctx *ctx = crypto_aead_ctx(aead);
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struct __packed { __be16 l; __be32 h; } aadlen;
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u32 assoclen = req->assoclen;
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struct scatter_walk walk;
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unsigned int len;
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if (assoclen < 0xff00) {
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aadlen.l = cpu_to_be16(assoclen);
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len = 2;
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} else {
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aadlen.l = cpu_to_be16(0xfffe);
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put_unaligned_be32(assoclen, &aadlen.h);
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len = 6;
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}
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sm4_ce_crypt_block(ctx->rkey_enc, mac, mac);
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crypto_xor(mac, (const u8 *)&aadlen, len);
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scatterwalk_start(&walk, req->src);
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do {
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u32 n = scatterwalk_clamp(&walk, assoclen);
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u8 *p, *ptr;
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if (!n) {
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scatterwalk_start(&walk, sg_next(walk.sg));
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n = scatterwalk_clamp(&walk, assoclen);
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}
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p = ptr = scatterwalk_map(&walk);
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assoclen -= n;
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scatterwalk_advance(&walk, n);
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while (n > 0) {
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unsigned int l, nblocks;
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if (len == SM4_BLOCK_SIZE) {
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if (n < SM4_BLOCK_SIZE) {
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sm4_ce_crypt_block(ctx->rkey_enc,
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mac, mac);
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len = 0;
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} else {
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nblocks = n / SM4_BLOCK_SIZE;
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sm4_ce_cbcmac_update(ctx->rkey_enc,
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mac, ptr, nblocks);
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ptr += nblocks * SM4_BLOCK_SIZE;
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n %= SM4_BLOCK_SIZE;
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continue;
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}
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}
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l = min(n, SM4_BLOCK_SIZE - len);
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if (l) {
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crypto_xor(mac + len, ptr, l);
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len += l;
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ptr += l;
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n -= l;
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}
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}
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scatterwalk_unmap(p);
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scatterwalk_done(&walk, 0, assoclen);
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} while (assoclen);
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}
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static int ccm_crypt(struct aead_request *req, struct skcipher_walk *walk,
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u32 *rkey_enc, u8 mac[],
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void (*sm4_ce_ccm_crypt)(const u32 *rkey_enc, u8 *dst,
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const u8 *src, u8 *iv,
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unsigned int nbytes, u8 *mac))
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{
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u8 __aligned(8) ctr0[SM4_BLOCK_SIZE];
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int err = 0;
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/* preserve the initial ctr0 for the TAG */
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memcpy(ctr0, walk->iv, SM4_BLOCK_SIZE);
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crypto_inc(walk->iv, SM4_BLOCK_SIZE);
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kernel_neon_begin();
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if (req->assoclen)
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ccm_calculate_auth_mac(req, mac);
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while (walk->nbytes && walk->nbytes != walk->total) {
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unsigned int tail = walk->nbytes % SM4_BLOCK_SIZE;
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sm4_ce_ccm_crypt(rkey_enc, walk->dst.virt.addr,
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walk->src.virt.addr, walk->iv,
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walk->nbytes - tail, mac);
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kernel_neon_end();
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err = skcipher_walk_done(walk, tail);
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kernel_neon_begin();
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}
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if (walk->nbytes) {
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sm4_ce_ccm_crypt(rkey_enc, walk->dst.virt.addr,
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walk->src.virt.addr, walk->iv,
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walk->nbytes, mac);
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sm4_ce_ccm_final(rkey_enc, ctr0, mac);
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kernel_neon_end();
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err = skcipher_walk_done(walk, 0);
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} else {
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sm4_ce_ccm_final(rkey_enc, ctr0, mac);
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kernel_neon_end();
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}
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return err;
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}
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static int ccm_encrypt(struct aead_request *req)
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{
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struct crypto_aead *aead = crypto_aead_reqtfm(req);
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struct sm4_ctx *ctx = crypto_aead_ctx(aead);
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u8 __aligned(8) mac[SM4_BLOCK_SIZE];
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struct skcipher_walk walk;
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int err;
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err = ccm_format_input(mac, req, req->cryptlen);
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if (err)
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return err;
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err = skcipher_walk_aead_encrypt(&walk, req, false);
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if (err)
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return err;
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err = ccm_crypt(req, &walk, ctx->rkey_enc, mac, sm4_ce_ccm_enc);
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if (err)
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return err;
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/* copy authtag to end of dst */
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scatterwalk_map_and_copy(mac, req->dst, req->assoclen + req->cryptlen,
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crypto_aead_authsize(aead), 1);
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return 0;
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}
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static int ccm_decrypt(struct aead_request *req)
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{
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struct crypto_aead *aead = crypto_aead_reqtfm(req);
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unsigned int authsize = crypto_aead_authsize(aead);
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struct sm4_ctx *ctx = crypto_aead_ctx(aead);
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u8 __aligned(8) mac[SM4_BLOCK_SIZE];
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u8 authtag[SM4_BLOCK_SIZE];
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struct skcipher_walk walk;
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int err;
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err = ccm_format_input(mac, req, req->cryptlen - authsize);
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if (err)
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return err;
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err = skcipher_walk_aead_decrypt(&walk, req, false);
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if (err)
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return err;
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err = ccm_crypt(req, &walk, ctx->rkey_enc, mac, sm4_ce_ccm_dec);
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if (err)
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return err;
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/* compare calculated auth tag with the stored one */
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scatterwalk_map_and_copy(authtag, req->src,
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req->assoclen + req->cryptlen - authsize,
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authsize, 0);
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if (crypto_memneq(authtag, mac, authsize))
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return -EBADMSG;
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return 0;
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}
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static struct aead_alg sm4_ccm_alg = {
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.base = {
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.cra_name = "ccm(sm4)",
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.cra_driver_name = "ccm-sm4-ce",
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.cra_priority = 400,
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.cra_blocksize = 1,
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.cra_ctxsize = sizeof(struct sm4_ctx),
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.cra_module = THIS_MODULE,
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},
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.ivsize = SM4_BLOCK_SIZE,
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.chunksize = SM4_BLOCK_SIZE,
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.maxauthsize = SM4_BLOCK_SIZE,
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.setkey = ccm_setkey,
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.setauthsize = ccm_setauthsize,
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.encrypt = ccm_encrypt,
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.decrypt = ccm_decrypt,
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};
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static int __init sm4_ce_ccm_init(void)
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{
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return crypto_register_aead(&sm4_ccm_alg);
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}
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static void __exit sm4_ce_ccm_exit(void)
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{
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crypto_unregister_aead(&sm4_ccm_alg);
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}
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module_cpu_feature_match(SM4, sm4_ce_ccm_init);
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module_exit(sm4_ce_ccm_exit);
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MODULE_DESCRIPTION("Synchronous SM4 in CCM mode using ARMv8 Crypto Extensions");
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MODULE_ALIAS_CRYPTO("ccm(sm4)");
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MODULE_AUTHOR("Tianjia Zhang <tianjia.zhang@linux.alibaba.com>");
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MODULE_LICENSE("GPL v2");
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