| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * aes-ccm-glue.c - AES-CCM transform for ARMv8 with Crypto Extensions |
| * |
| * Copyright (C) 2013 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org> |
| */ |
| |
| #include <asm/neon.h> |
| #include <asm/simd.h> |
| #include <asm/unaligned.h> |
| #include <crypto/aes.h> |
| #include <crypto/scatterwalk.h> |
| #include <crypto/internal/aead.h> |
| #include <crypto/internal/simd.h> |
| #include <crypto/internal/skcipher.h> |
| #include <linux/module.h> |
| |
| #include "aes-ce-setkey.h" |
| |
| static int num_rounds(struct crypto_aes_ctx *ctx) |
| { |
| /* |
| * # of rounds specified by AES: |
| * 128 bit key 10 rounds |
| * 192 bit key 12 rounds |
| * 256 bit key 14 rounds |
| * => n byte key => 6 + (n/4) rounds |
| */ |
| return 6 + ctx->key_length / 4; |
| } |
| |
| asmlinkage void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes, |
| u32 *macp, u32 const rk[], u32 rounds); |
| |
| asmlinkage void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes, |
| u32 const rk[], u32 rounds, u8 mac[], |
| u8 ctr[]); |
| |
| asmlinkage void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes, |
| u32 const rk[], u32 rounds, u8 mac[], |
| u8 ctr[]); |
| |
| asmlinkage void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u32 const rk[], |
| u32 rounds); |
| |
| static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key, |
| unsigned int key_len) |
| { |
| struct crypto_aes_ctx *ctx = crypto_aead_ctx(tfm); |
| |
| return ce_aes_expandkey(ctx, in_key, key_len); |
| } |
| |
| static int ccm_setauthsize(struct crypto_aead *tfm, unsigned int authsize) |
| { |
| if ((authsize & 1) || authsize < 4) |
| return -EINVAL; |
| return 0; |
| } |
| |
| static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| __be32 *n = (__be32 *)&maciv[AES_BLOCK_SIZE - 8]; |
| u32 l = req->iv[0] + 1; |
| |
| /* verify that CCM dimension 'L' is set correctly in the IV */ |
| if (l < 2 || l > 8) |
| return -EINVAL; |
| |
| /* verify that msglen can in fact be represented in L bytes */ |
| if (l < 4 && msglen >> (8 * l)) |
| return -EOVERFLOW; |
| |
| /* |
| * Even if the CCM spec allows L values of up to 8, the Linux cryptoapi |
| * uses a u32 type to represent msglen so the top 4 bytes are always 0. |
| */ |
| n[0] = 0; |
| n[1] = cpu_to_be32(msglen); |
| |
| memcpy(maciv, req->iv, AES_BLOCK_SIZE - l); |
| |
| /* |
| * Meaning of byte 0 according to CCM spec (RFC 3610/NIST 800-38C) |
| * - bits 0..2 : max # of bytes required to represent msglen, minus 1 |
| * (already set by caller) |
| * - bits 3..5 : size of auth tag (1 => 4 bytes, 2 => 6 bytes, etc) |
| * - bit 6 : indicates presence of authenticate-only data |
| */ |
| maciv[0] |= (crypto_aead_authsize(aead) - 2) << 2; |
| if (req->assoclen) |
| maciv[0] |= 0x40; |
| |
| memset(&req->iv[AES_BLOCK_SIZE - l], 0, l); |
| return 0; |
| } |
| |
| static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[], |
| u32 abytes, u32 *macp) |
| { |
| if (crypto_simd_usable()) { |
| kernel_neon_begin(); |
| ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc, |
| num_rounds(key)); |
| kernel_neon_end(); |
| } else { |
| if (*macp > 0 && *macp < AES_BLOCK_SIZE) { |
| int added = min(abytes, AES_BLOCK_SIZE - *macp); |
| |
| crypto_xor(&mac[*macp], in, added); |
| |
| *macp += added; |
| in += added; |
| abytes -= added; |
| } |
| |
| while (abytes >= AES_BLOCK_SIZE) { |
| aes_encrypt(key, mac, mac); |
| crypto_xor(mac, in, AES_BLOCK_SIZE); |
| |
| in += AES_BLOCK_SIZE; |
| abytes -= AES_BLOCK_SIZE; |
| } |
| |
| if (abytes > 0) { |
| aes_encrypt(key, mac, mac); |
| crypto_xor(mac, in, abytes); |
| *macp = abytes; |
| } |
| } |
| } |
| |
| static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[]) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead); |
| struct __packed { __be16 l; __be32 h; u16 len; } ltag; |
| struct scatter_walk walk; |
| u32 len = req->assoclen; |
| u32 macp = 0; |
| |
| /* prepend the AAD with a length tag */ |
| if (len < 0xff00) { |
| ltag.l = cpu_to_be16(len); |
| ltag.len = 2; |
| } else { |
| ltag.l = cpu_to_be16(0xfffe); |
| put_unaligned_be32(len, <ag.h); |
| ltag.len = 6; |
| } |
| |
| ccm_update_mac(ctx, mac, (u8 *)<ag, ltag.len, &macp); |
| scatterwalk_start(&walk, req->src); |
| |
| do { |
| u32 n = scatterwalk_clamp(&walk, len); |
| u8 *p; |
| |
| if (!n) { |
| scatterwalk_start(&walk, sg_next(walk.sg)); |
| n = scatterwalk_clamp(&walk, len); |
| } |
| p = scatterwalk_map(&walk); |
| ccm_update_mac(ctx, mac, p, n, &macp); |
| len -= n; |
| |
| scatterwalk_unmap(p); |
| scatterwalk_advance(&walk, n); |
| scatterwalk_done(&walk, 0, len); |
| } while (len); |
| } |
| |
| static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[], |
| struct crypto_aes_ctx *ctx, bool enc) |
| { |
| u8 buf[AES_BLOCK_SIZE]; |
| int err = 0; |
| |
| while (walk->nbytes) { |
| int blocks = walk->nbytes / AES_BLOCK_SIZE; |
| u32 tail = walk->nbytes % AES_BLOCK_SIZE; |
| u8 *dst = walk->dst.virt.addr; |
| u8 *src = walk->src.virt.addr; |
| u32 nbytes = walk->nbytes; |
| |
| if (nbytes == walk->total && tail > 0) { |
| blocks++; |
| tail = 0; |
| } |
| |
| do { |
| u32 bsize = AES_BLOCK_SIZE; |
| |
| if (nbytes < AES_BLOCK_SIZE) |
| bsize = nbytes; |
| |
| crypto_inc(walk->iv, AES_BLOCK_SIZE); |
| aes_encrypt(ctx, buf, walk->iv); |
| aes_encrypt(ctx, mac, mac); |
| if (enc) |
| crypto_xor(mac, src, bsize); |
| crypto_xor_cpy(dst, src, buf, bsize); |
| if (!enc) |
| crypto_xor(mac, dst, bsize); |
| dst += bsize; |
| src += bsize; |
| nbytes -= bsize; |
| } while (--blocks); |
| |
| err = skcipher_walk_done(walk, tail); |
| } |
| |
| if (!err) { |
| aes_encrypt(ctx, buf, iv0); |
| aes_encrypt(ctx, mac, mac); |
| crypto_xor(mac, buf, AES_BLOCK_SIZE); |
| } |
| return err; |
| } |
| |
| static int ccm_encrypt(struct aead_request *req) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead); |
| struct skcipher_walk walk; |
| u8 __aligned(8) mac[AES_BLOCK_SIZE]; |
| u8 buf[AES_BLOCK_SIZE]; |
| u32 len = req->cryptlen; |
| int err; |
| |
| err = ccm_init_mac(req, mac, len); |
| if (err) |
| return err; |
| |
| if (req->assoclen) |
| ccm_calculate_auth_mac(req, mac); |
| |
| /* preserve the original iv for the final round */ |
| memcpy(buf, req->iv, AES_BLOCK_SIZE); |
| |
| err = skcipher_walk_aead_encrypt(&walk, req, false); |
| |
| if (crypto_simd_usable()) { |
| while (walk.nbytes) { |
| u32 tail = walk.nbytes % AES_BLOCK_SIZE; |
| |
| if (walk.nbytes == walk.total) |
| tail = 0; |
| |
| kernel_neon_begin(); |
| ce_aes_ccm_encrypt(walk.dst.virt.addr, |
| walk.src.virt.addr, |
| walk.nbytes - tail, ctx->key_enc, |
| num_rounds(ctx), mac, walk.iv); |
| kernel_neon_end(); |
| |
| err = skcipher_walk_done(&walk, tail); |
| } |
| if (!err) { |
| kernel_neon_begin(); |
| ce_aes_ccm_final(mac, buf, ctx->key_enc, |
| num_rounds(ctx)); |
| kernel_neon_end(); |
| } |
| } else { |
| err = ccm_crypt_fallback(&walk, mac, buf, ctx, true); |
| } |
| if (err) |
| return err; |
| |
| /* copy authtag to end of dst */ |
| scatterwalk_map_and_copy(mac, req->dst, req->assoclen + req->cryptlen, |
| crypto_aead_authsize(aead), 1); |
| |
| return 0; |
| } |
| |
| static int ccm_decrypt(struct aead_request *req) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead); |
| unsigned int authsize = crypto_aead_authsize(aead); |
| struct skcipher_walk walk; |
| u8 __aligned(8) mac[AES_BLOCK_SIZE]; |
| u8 buf[AES_BLOCK_SIZE]; |
| u32 len = req->cryptlen - authsize; |
| int err; |
| |
| err = ccm_init_mac(req, mac, len); |
| if (err) |
| return err; |
| |
| if (req->assoclen) |
| ccm_calculate_auth_mac(req, mac); |
| |
| /* preserve the original iv for the final round */ |
| memcpy(buf, req->iv, AES_BLOCK_SIZE); |
| |
| err = skcipher_walk_aead_decrypt(&walk, req, false); |
| |
| if (crypto_simd_usable()) { |
| while (walk.nbytes) { |
| u32 tail = walk.nbytes % AES_BLOCK_SIZE; |
| |
| if (walk.nbytes == walk.total) |
| tail = 0; |
| |
| kernel_neon_begin(); |
| ce_aes_ccm_decrypt(walk.dst.virt.addr, |
| walk.src.virt.addr, |
| walk.nbytes - tail, ctx->key_enc, |
| num_rounds(ctx), mac, walk.iv); |
| kernel_neon_end(); |
| |
| err = skcipher_walk_done(&walk, tail); |
| } |
| if (!err) { |
| kernel_neon_begin(); |
| ce_aes_ccm_final(mac, buf, ctx->key_enc, |
| num_rounds(ctx)); |
| kernel_neon_end(); |
| } |
| } else { |
| err = ccm_crypt_fallback(&walk, mac, buf, ctx, false); |
| } |
| |
| if (err) |
| return err; |
| |
| /* compare calculated auth tag with the stored one */ |
| scatterwalk_map_and_copy(buf, req->src, |
| req->assoclen + req->cryptlen - authsize, |
| authsize, 0); |
| |
| if (crypto_memneq(mac, buf, authsize)) |
| return -EBADMSG; |
| return 0; |
| } |
| |
| static struct aead_alg ccm_aes_alg = { |
| .base = { |
| .cra_name = "ccm(aes)", |
| .cra_driver_name = "ccm-aes-ce", |
| .cra_priority = 300, |
| .cra_blocksize = 1, |
| .cra_ctxsize = sizeof(struct crypto_aes_ctx), |
| .cra_module = THIS_MODULE, |
| }, |
| .ivsize = AES_BLOCK_SIZE, |
| .chunksize = AES_BLOCK_SIZE, |
| .maxauthsize = AES_BLOCK_SIZE, |
| .setkey = ccm_setkey, |
| .setauthsize = ccm_setauthsize, |
| .encrypt = ccm_encrypt, |
| .decrypt = ccm_decrypt, |
| }; |
| |
| static int __init aes_mod_init(void) |
| { |
| if (!cpu_have_named_feature(AES)) |
| return -ENODEV; |
| return crypto_register_aead(&ccm_aes_alg); |
| } |
| |
| static void __exit aes_mod_exit(void) |
| { |
| crypto_unregister_aead(&ccm_aes_alg); |
| } |
| |
| module_init(aes_mod_init); |
| module_exit(aes_mod_exit); |
| |
| MODULE_DESCRIPTION("Synchronous AES in CCM mode using ARMv8 Crypto Extensions"); |
| MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); |
| MODULE_LICENSE("GPL v2"); |
| MODULE_ALIAS_CRYPTO("ccm(aes)"); |