#include <crypto/aes.h>
#include <crypto/b128ops.h>
#include <crypto/gcm.h>
#include <crypto/ghash.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/cpufeature.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/unaligned.h>
#include <asm/simd.h>
MODULE_DESCRIPTION("AES-GCM using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("gcm(aes)");
MODULE_ALIAS_CRYPTO("rfc4106(gcm(aes))");
#define RFC4106_NONCE_SIZE 4
struct arm_ghash_key {
be128 k;
u64 h[4][2];
};
struct gcm_aes_ctx {
struct aes_enckey aes_key;
u8 nonce[RFC4106_NONCE_SIZE];
struct arm_ghash_key ghash_key;
};
asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
u64 const h[4][2], const char *head);
asmlinkage void pmull_gcm_encrypt(int bytes, u8 dst[], const u8 src[],
u64 const h[4][2], u64 dg[], u8 ctr[],
u32 const rk[], int rounds, u8 tag[]);
asmlinkage int pmull_gcm_decrypt(int bytes, u8 dst[], const u8 src[],
u64 const h[4][2], u64 dg[], u8 ctr[],
u32 const rk[], int rounds, const u8 l[],
const u8 tag[], u64 authsize);
static void ghash_do_simd_update(int blocks, u64 dg[], const char *src,
struct arm_ghash_key *key, const char *head)
{
scoped_ksimd()
pmull_ghash_update_p64(blocks, dg, src, key->h, head);
}
static void ghash_reflect(u64 h[], const be128 *k)
{
u64 carry = be64_to_cpu(k->a) & BIT(63) ? 1 : 0;
h[0] = (be64_to_cpu(k->b) << 1) | carry;
h[1] = (be64_to_cpu(k->a) << 1) | (be64_to_cpu(k->b) >> 63);
if (carry)
h[1] ^= 0xc200000000000000UL;
}
static int gcm_aes_setkey(struct crypto_aead *tfm, const u8 *inkey,
unsigned int keylen)
{
struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
u8 key[GHASH_BLOCK_SIZE];
be128 h;
int ret;
ret = aes_prepareenckey(&ctx->aes_key, inkey, keylen);
if (ret)
return -EINVAL;
aes_encrypt(&ctx->aes_key, key, (u8[AES_BLOCK_SIZE]){});
memcpy(&ctx->ghash_key.k, key, GHASH_BLOCK_SIZE);
ghash_reflect(ctx->ghash_key.h[0], &ctx->ghash_key.k);
h = ctx->ghash_key.k;
gf128mul_lle(&h, &ctx->ghash_key.k);
ghash_reflect(ctx->ghash_key.h[1], &h);
gf128mul_lle(&h, &ctx->ghash_key.k);
ghash_reflect(ctx->ghash_key.h[2], &h);
gf128mul_lle(&h, &ctx->ghash_key.k);
ghash_reflect(ctx->ghash_key.h[3], &h);
return 0;
}
static int gcm_aes_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
return crypto_gcm_check_authsize(authsize);
}
static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
int *buf_count, struct gcm_aes_ctx *ctx)
{
if (*buf_count > 0) {
int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);
memcpy(&buf[*buf_count], src, buf_added);
*buf_count += buf_added;
src += buf_added;
count -= buf_added;
}
if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
int blocks = count / GHASH_BLOCK_SIZE;
ghash_do_simd_update(blocks, dg, src, &ctx->ghash_key,
*buf_count ? buf : NULL);
src += blocks * GHASH_BLOCK_SIZE;
count %= GHASH_BLOCK_SIZE;
*buf_count = 0;
}
if (count > 0) {
memcpy(buf, src, count);
*buf_count = count;
}
}
static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[], u32 len)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
u8 buf[GHASH_BLOCK_SIZE];
struct scatter_walk walk;
int buf_count = 0;
scatterwalk_start(&walk, req->src);
do {
unsigned int n;
n = scatterwalk_next(&walk, len);
gcm_update_mac(dg, walk.addr, n, buf, &buf_count, ctx);
scatterwalk_done_src(&walk, n);
len -= n;
} while (len);
if (buf_count) {
memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
ghash_do_simd_update(1, dg, buf, &ctx->ghash_key, NULL);
}
}
static int gcm_encrypt(struct aead_request *req, char *iv, int assoclen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
struct skcipher_walk walk;
u8 buf[AES_BLOCK_SIZE];
u64 dg[2] = {};
be128 lengths;
u8 *tag;
int err;
lengths.a = cpu_to_be64(assoclen * 8);
lengths.b = cpu_to_be64(req->cryptlen * 8);
if (assoclen)
gcm_calculate_auth_mac(req, dg, assoclen);
put_unaligned_be32(2, iv + GCM_AES_IV_SIZE);
err = skcipher_walk_aead_encrypt(&walk, req, false);
do {
const u8 *src = walk.src.virt.addr;
u8 *dst = walk.dst.virt.addr;
int nbytes = walk.nbytes;
tag = (u8 *)&lengths;
if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
src = dst = memcpy(buf + sizeof(buf) - nbytes,
src, nbytes);
} else if (nbytes < walk.total) {
nbytes &= ~(AES_BLOCK_SIZE - 1);
tag = NULL;
}
scoped_ksimd()
pmull_gcm_encrypt(nbytes, dst, src, ctx->ghash_key.h,
dg, iv, ctx->aes_key.k.rndkeys,
ctx->aes_key.nrounds, tag);
if (unlikely(!nbytes))
break;
if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
memcpy(walk.dst.virt.addr,
buf + sizeof(buf) - nbytes, nbytes);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
} while (walk.nbytes);
if (err)
return err;
scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
crypto_aead_authsize(aead), 1);
return 0;
}
static int gcm_decrypt(struct aead_request *req, char *iv, int assoclen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
unsigned int authsize = crypto_aead_authsize(aead);
struct skcipher_walk walk;
u8 otag[AES_BLOCK_SIZE];
u8 buf[AES_BLOCK_SIZE];
u64 dg[2] = {};
be128 lengths;
u8 *tag;
int ret;
int err;
lengths.a = cpu_to_be64(assoclen * 8);
lengths.b = cpu_to_be64((req->cryptlen - authsize) * 8);
if (assoclen)
gcm_calculate_auth_mac(req, dg, assoclen);
put_unaligned_be32(2, iv + GCM_AES_IV_SIZE);
scatterwalk_map_and_copy(otag, req->src,
req->assoclen + req->cryptlen - authsize,
authsize, 0);
err = skcipher_walk_aead_decrypt(&walk, req, false);
do {
const u8 *src = walk.src.virt.addr;
u8 *dst = walk.dst.virt.addr;
int nbytes = walk.nbytes;
tag = (u8 *)&lengths;
if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
src = dst = memcpy(buf + sizeof(buf) - nbytes,
src, nbytes);
} else if (nbytes < walk.total) {
nbytes &= ~(AES_BLOCK_SIZE - 1);
tag = NULL;
}
scoped_ksimd()
ret = pmull_gcm_decrypt(nbytes, dst, src,
ctx->ghash_key.h,
dg, iv, ctx->aes_key.k.rndkeys,
ctx->aes_key.nrounds, tag, otag,
authsize);
if (unlikely(!nbytes))
break;
if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
memcpy(walk.dst.virt.addr,
buf + sizeof(buf) - nbytes, nbytes);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
} while (walk.nbytes);
if (err)
return err;
return ret ? -EBADMSG : 0;
}
static int gcm_aes_encrypt(struct aead_request *req)
{
u8 iv[AES_BLOCK_SIZE];
memcpy(iv, req->iv, GCM_AES_IV_SIZE);
return gcm_encrypt(req, iv, req->assoclen);
}
static int gcm_aes_decrypt(struct aead_request *req)
{
u8 iv[AES_BLOCK_SIZE];
memcpy(iv, req->iv, GCM_AES_IV_SIZE);
return gcm_decrypt(req, iv, req->assoclen);
}
static int rfc4106_setkey(struct crypto_aead *tfm, const u8 *inkey,
unsigned int keylen)
{
struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
int err;
keylen -= RFC4106_NONCE_SIZE;
err = gcm_aes_setkey(tfm, inkey, keylen);
if (err)
return err;
memcpy(ctx->nonce, inkey + keylen, RFC4106_NONCE_SIZE);
return 0;
}
static int rfc4106_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
return crypto_rfc4106_check_authsize(authsize);
}
static int rfc4106_encrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
u8 iv[AES_BLOCK_SIZE];
memcpy(iv, ctx->nonce, RFC4106_NONCE_SIZE);
memcpy(iv + RFC4106_NONCE_SIZE, req->iv, GCM_RFC4106_IV_SIZE);
return crypto_ipsec_check_assoclen(req->assoclen) ?:
gcm_encrypt(req, iv, req->assoclen - GCM_RFC4106_IV_SIZE);
}
static int rfc4106_decrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
u8 iv[AES_BLOCK_SIZE];
memcpy(iv, ctx->nonce, RFC4106_NONCE_SIZE);
memcpy(iv + RFC4106_NONCE_SIZE, req->iv, GCM_RFC4106_IV_SIZE);
return crypto_ipsec_check_assoclen(req->assoclen) ?:
gcm_decrypt(req, iv, req->assoclen - GCM_RFC4106_IV_SIZE);
}
static struct aead_alg gcm_aes_algs[] = {{
.ivsize = GCM_AES_IV_SIZE,
.chunksize = AES_BLOCK_SIZE,
.maxauthsize = AES_BLOCK_SIZE,
.setkey = gcm_aes_setkey,
.setauthsize = gcm_aes_setauthsize,
.encrypt = gcm_aes_encrypt,
.decrypt = gcm_aes_decrypt,
.base.cra_name = "gcm(aes)",
.base.cra_driver_name = "gcm-aes-ce",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct gcm_aes_ctx),
.base.cra_module = THIS_MODULE,
}, {
.ivsize = GCM_RFC4106_IV_SIZE,
.chunksize = AES_BLOCK_SIZE,
.maxauthsize = AES_BLOCK_SIZE,
.setkey = rfc4106_setkey,
.setauthsize = rfc4106_setauthsize,
.encrypt = rfc4106_encrypt,
.decrypt = rfc4106_decrypt,
.base.cra_name = "rfc4106(gcm(aes))",
.base.cra_driver_name = "rfc4106-gcm-aes-ce",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct gcm_aes_ctx),
.base.cra_module = THIS_MODULE,
}};
static int __init ghash_ce_mod_init(void)
{
if (!cpu_have_named_feature(ASIMD) || !cpu_have_named_feature(PMULL))
return -ENODEV;
return crypto_register_aeads(gcm_aes_algs, ARRAY_SIZE(gcm_aes_algs));
}
static void __exit ghash_ce_mod_exit(void)
{
crypto_unregister_aeads(gcm_aes_algs, ARRAY_SIZE(gcm_aes_algs));
}
static const struct cpu_feature __maybe_unused ghash_cpu_feature[] = {
{ cpu_feature(PMULL) }, { }
};
MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);
module_init(ghash_ce_mod_init);
module_exit(ghash_ce_mod_exit);
