Commit a3fd8210 authored by Ard Biesheuvel's avatar Ard Biesheuvel

arm64/crypto: AES in CCM mode using ARMv8 Crypto Extensions

This patch adds support for the AES-CCM encryption algorithm for CPUs that
have support for the AES part of the ARM v8 Crypto Extensions.
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 317f2f75
......@@ -29,4 +29,11 @@ config CRYPTO_AES_ARM64_CE
select CRYPTO_ALGAPI
select CRYPTO_AES
config CRYPTO_AES_ARM64_CE_CCM
tristate "AES in CCM mode using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_ALGAPI
select CRYPTO_AES
select CRYPTO_AEAD
endif
......@@ -19,3 +19,6 @@ ghash-ce-y := ghash-ce-glue.o ghash-ce-core.o
obj-$(CONFIG_CRYPTO_AES_ARM64_CE) += aes-ce-cipher.o
CFLAGS_aes-ce-cipher.o += -march=armv8-a+crypto
obj-$(CONFIG_CRYPTO_AES_ARM64_CE_CCM) += aes-ce-ccm.o
aes-ce-ccm-y := aes-ce-ccm-glue.o aes-ce-ccm-core.o
/*
* aesce-ccm-core.S - AES-CCM transform for ARMv8 with Crypto Extensions
*
* Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
.text
.arch armv8-a+crypto
/*
* void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
* u32 *macp, u8 const rk[], u32 rounds);
*/
ENTRY(ce_aes_ccm_auth_data)
ldr w8, [x3] /* leftover from prev round? */
ld1 {v0.2d}, [x0] /* load mac */
cbz w8, 1f
sub w8, w8, #16
eor v1.16b, v1.16b, v1.16b
0: ldrb w7, [x1], #1 /* get 1 byte of input */
subs w2, w2, #1
add w8, w8, #1
ins v1.b[0], w7
ext v1.16b, v1.16b, v1.16b, #1 /* rotate in the input bytes */
beq 8f /* out of input? */
cbnz w8, 0b
eor v0.16b, v0.16b, v1.16b
1: ld1 {v3.2d}, [x4] /* load first round key */
prfm pldl1strm, [x1]
cmp w5, #12 /* which key size? */
add x6, x4, #16
sub w7, w5, #2 /* modified # of rounds */
bmi 2f
bne 5f
mov v5.16b, v3.16b
b 4f
2: mov v4.16b, v3.16b
ld1 {v5.2d}, [x6], #16 /* load 2nd round key */
3: aese v0.16b, v4.16b
aesmc v0.16b, v0.16b
4: ld1 {v3.2d}, [x6], #16 /* load next round key */
aese v0.16b, v5.16b
aesmc v0.16b, v0.16b
5: ld1 {v4.2d}, [x6], #16 /* load next round key */
subs w7, w7, #3
aese v0.16b, v3.16b
aesmc v0.16b, v0.16b
ld1 {v5.2d}, [x6], #16 /* load next round key */
bpl 3b
aese v0.16b, v4.16b
subs w2, w2, #16 /* last data? */
eor v0.16b, v0.16b, v5.16b /* final round */
bmi 6f
ld1 {v1.16b}, [x1], #16 /* load next input block */
eor v0.16b, v0.16b, v1.16b /* xor with mac */
bne 1b
6: st1 {v0.2d}, [x0] /* store mac */
beq 10f
adds w2, w2, #16
beq 10f
mov w8, w2
7: ldrb w7, [x1], #1
umov w6, v0.b[0]
eor w6, w6, w7
strb w6, [x0], #1
subs w2, w2, #1
beq 10f
ext v0.16b, v0.16b, v0.16b, #1 /* rotate out the mac bytes */
b 7b
8: mov w7, w8
add w8, w8, #16
9: ext v1.16b, v1.16b, v1.16b, #1
adds w7, w7, #1
bne 9b
eor v0.16b, v0.16b, v1.16b
st1 {v0.2d}, [x0]
10: str w8, [x3]
ret
ENDPROC(ce_aes_ccm_auth_data)
/*
* void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u8 const rk[],
* u32 rounds);
*/
ENTRY(ce_aes_ccm_final)
ld1 {v3.2d}, [x2], #16 /* load first round key */
ld1 {v0.2d}, [x0] /* load mac */
cmp w3, #12 /* which key size? */
sub w3, w3, #2 /* modified # of rounds */
ld1 {v1.2d}, [x1] /* load 1st ctriv */
bmi 0f
bne 3f
mov v5.16b, v3.16b
b 2f
0: mov v4.16b, v3.16b
1: ld1 {v5.2d}, [x2], #16 /* load next round key */
aese v0.16b, v4.16b
aese v1.16b, v4.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
2: ld1 {v3.2d}, [x2], #16 /* load next round key */
aese v0.16b, v5.16b
aese v1.16b, v5.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
3: ld1 {v4.2d}, [x2], #16 /* load next round key */
subs w3, w3, #3
aese v0.16b, v3.16b
aese v1.16b, v3.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
bpl 1b
aese v0.16b, v4.16b
aese v1.16b, v4.16b
/* final round key cancels out */
eor v0.16b, v0.16b, v1.16b /* en-/decrypt the mac */
st1 {v0.2d}, [x0] /* store result */
ret
ENDPROC(ce_aes_ccm_final)
.macro aes_ccm_do_crypt,enc
ldr x8, [x6, #8] /* load lower ctr */
ld1 {v0.2d}, [x5] /* load mac */
rev x8, x8 /* keep swabbed ctr in reg */
0: /* outer loop */
ld1 {v1.1d}, [x6] /* load upper ctr */
prfm pldl1strm, [x1]
add x8, x8, #1
rev x9, x8
cmp w4, #12 /* which key size? */
sub w7, w4, #2 /* get modified # of rounds */
ins v1.d[1], x9 /* no carry in lower ctr */
ld1 {v3.2d}, [x3] /* load first round key */
add x10, x3, #16
bmi 1f
bne 4f
mov v5.16b, v3.16b
b 3f
1: mov v4.16b, v3.16b
ld1 {v5.2d}, [x10], #16 /* load 2nd round key */
2: /* inner loop: 3 rounds, 2x interleaved */
aese v0.16b, v4.16b
aese v1.16b, v4.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
3: ld1 {v3.2d}, [x10], #16 /* load next round key */
aese v0.16b, v5.16b
aese v1.16b, v5.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
4: ld1 {v4.2d}, [x10], #16 /* load next round key */
subs w7, w7, #3
aese v0.16b, v3.16b
aese v1.16b, v3.16b
aesmc v0.16b, v0.16b
aesmc v1.16b, v1.16b
ld1 {v5.2d}, [x10], #16 /* load next round key */
bpl 2b
aese v0.16b, v4.16b
aese v1.16b, v4.16b
subs w2, w2, #16
bmi 6f /* partial block? */
ld1 {v2.16b}, [x1], #16 /* load next input block */
.if \enc == 1
eor v2.16b, v2.16b, v5.16b /* final round enc+mac */
eor v1.16b, v1.16b, v2.16b /* xor with crypted ctr */
.else
eor v2.16b, v2.16b, v1.16b /* xor with crypted ctr */
eor v1.16b, v2.16b, v5.16b /* final round enc */
.endif
eor v0.16b, v0.16b, v2.16b /* xor mac with pt ^ rk[last] */
st1 {v1.16b}, [x0], #16 /* write output block */
bne 0b
rev x8, x8
st1 {v0.2d}, [x5] /* store mac */
str x8, [x6, #8] /* store lsb end of ctr (BE) */
5: ret
6: eor v0.16b, v0.16b, v5.16b /* final round mac */
eor v1.16b, v1.16b, v5.16b /* final round enc */
st1 {v0.2d}, [x5] /* store mac */
add w2, w2, #16 /* process partial tail block */
7: ldrb w9, [x1], #1 /* get 1 byte of input */
umov w6, v1.b[0] /* get top crypted ctr byte */
umov w7, v0.b[0] /* get top mac byte */
.if \enc == 1
eor w7, w7, w9
eor w9, w9, w6
.else
eor w9, w9, w6
eor w7, w7, w9
.endif
strb w9, [x0], #1 /* store out byte */
strb w7, [x5], #1 /* store mac byte */
subs w2, w2, #1
beq 5b
ext v0.16b, v0.16b, v0.16b, #1 /* shift out mac byte */
ext v1.16b, v1.16b, v1.16b, #1 /* shift out ctr byte */
b 7b
.endm
/*
* void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes,
* u8 const rk[], u32 rounds, u8 mac[],
* u8 ctr[]);
* void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes,
* u8 const rk[], u32 rounds, u8 mac[],
* u8 ctr[]);
*/
ENTRY(ce_aes_ccm_encrypt)
aes_ccm_do_crypt 1
ENDPROC(ce_aes_ccm_encrypt)
ENTRY(ce_aes_ccm_decrypt)
aes_ccm_do_crypt 0
ENDPROC(ce_aes_ccm_decrypt)
/*
* aes-ccm-glue.c - AES-CCM transform for ARMv8 with Crypto Extensions
*
* Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <asm/neon.h>
#include <asm/unaligned.h>
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/scatterwalk.h>
#include <linux/crypto.h>
#include <linux/module.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);
int ret;
ret = crypto_aes_expand_key(ctx, in_key, key_len);
if (!ret)
return 0;
tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
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_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, &ltag.h);
ltag.len = 6;
}
ce_aes_ccm_auth_data(mac, (u8 *)&ltag, ltag.len, &macp, ctx->key_enc,
num_rounds(ctx));
scatterwalk_start(&walk, req->assoc);
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);
ce_aes_ccm_auth_data(mac, p, n, &macp, ctx->key_enc,
num_rounds(ctx));
len -= n;
scatterwalk_unmap(p);
scatterwalk_advance(&walk, n);
scatterwalk_done(&walk, 0, len);
} while (len);
}
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 blkcipher_desc desc = { .info = req->iv };
struct blkcipher_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;
kernel_neon_begin_partial(6);
if (req->assoclen)
ccm_calculate_auth_mac(req, mac);
/* preserve the original iv for the final round */
memcpy(buf, req->iv, AES_BLOCK_SIZE);
blkcipher_walk_init(&walk, req->dst, req->src, len);
err = blkcipher_aead_walk_virt_block(&desc, &walk, aead,
AES_BLOCK_SIZE);
while (walk.nbytes) {
u32 tail = walk.nbytes % AES_BLOCK_SIZE;
if (walk.nbytes == len)
tail = 0;
ce_aes_ccm_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
walk.nbytes - tail, ctx->key_enc,
num_rounds(ctx), mac, walk.iv);
len -= walk.nbytes - tail;
err = blkcipher_walk_done(&desc, &walk, tail);
}
if (!err)
ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx));
kernel_neon_end();
if (err)
return err;
/* copy authtag to end of dst */
scatterwalk_map_and_copy(mac, req->dst, 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 blkcipher_desc desc = { .info = req->iv };
struct blkcipher_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;
kernel_neon_begin_partial(6);
if (req->assoclen)
ccm_calculate_auth_mac(req, mac);
/* preserve the original iv for the final round */
memcpy(buf, req->iv, AES_BLOCK_SIZE);
blkcipher_walk_init(&walk, req->dst, req->src, len);
err = blkcipher_aead_walk_virt_block(&desc, &walk, aead,
AES_BLOCK_SIZE);
while (walk.nbytes) {
u32 tail = walk.nbytes % AES_BLOCK_SIZE;
if (walk.nbytes == len)
tail = 0;
ce_aes_ccm_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
walk.nbytes - tail, ctx->key_enc,
num_rounds(ctx), mac, walk.iv);
len -= walk.nbytes - tail;
err = blkcipher_walk_done(&desc, &walk, tail);
}
if (!err)
ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx));
kernel_neon_end();
if (err)
return err;
/* compare calculated auth tag with the stored one */
scatterwalk_map_and_copy(buf, req->src, req->cryptlen - authsize,
authsize, 0);
if (memcmp(mac, buf, authsize))
return -EBADMSG;
return 0;
}
static struct crypto_alg ccm_aes_alg = {
.cra_name = "ccm(aes)",
.cra_driver_name = "ccm-aes-ce",
.cra_priority = 300,
.cra_flags = CRYPTO_ALG_TYPE_AEAD,
.cra_blocksize = 1,
.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.cra_alignmask = 7,
.cra_type = &crypto_aead_type,
.cra_module = THIS_MODULE,
.cra_aead = {
.ivsize = 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 (!(elf_hwcap & HWCAP_AES))
return -ENODEV;
return crypto_register_alg(&ccm_aes_alg);
}
static void __exit aes_mod_exit(void)
{
crypto_unregister_alg(&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("ccm(aes)");
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment