// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Glue code for accelerated AES-GCM stitched implementation for ppc64le.
*
* Copyright 2022- IBM Inc. All rights reserved
*/
#include <asm/unaligned.h>
#include <asm/simd.h>
#include <asm/switch_to.h>
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/cpufeature.h>
#include <linux/crypto.h>
#include <linux/module.h>
#include <linux/types.h>
#define PPC_ALIGN 16
#define GCM_IV_SIZE 12
MODULE_DESCRIPTION("PPC64le AES-GCM with Stitched implementation");
MODULE_AUTHOR("Danny Tsen <[email protected]");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("aes");
asmlinkage int aes_p10_set_encrypt_key(const u8 *userKey, const int bits,
void *key);
asmlinkage void aes_p10_encrypt(const u8 *in, u8 *out, const void *key);
asmlinkage void aes_p10_gcm_encrypt(u8 *in, u8 *out, size_t len,
void *rkey, u8 *iv, void *Xi);
asmlinkage void aes_p10_gcm_decrypt(u8 *in, u8 *out, size_t len,
void *rkey, u8 *iv, void *Xi);
asmlinkage void gcm_init_htable(unsigned char htable[], unsigned char Xi[]);
asmlinkage void gcm_ghash_p10(unsigned char *Xi, unsigned char *Htable,
unsigned char *aad, unsigned int alen);
struct aes_key {
u8 key[AES_MAX_KEYLENGTH];
u64 rounds;
};
struct gcm_ctx {
u8 iv[16];
u8 ivtag[16];
u8 aad_hash[16];
u64 aadLen;
u64 Plen; /* offset 56 - used in aes_p10_gcm_{en/de}crypt */
};
struct Hash_ctx {
u8 H[16]; /* subkey */
u8 Htable[256]; /* Xi, Hash table(offset 32) */
};
struct p10_aes_gcm_ctx {
struct aes_key enc_key;
};
static void vsx_begin(void)
{
preempt_disable();
enable_kernel_vsx();
}
static void vsx_end(void)
{
disable_kernel_vsx();
preempt_enable();
}
static void set_subkey(unsigned char *hash)
{
*(u64 *)&hash[0] = be64_to_cpup((__be64 *)&hash[0]);
*(u64 *)&hash[8] = be64_to_cpup((__be64 *)&hash[8]);
}
/*
* Compute aad if any.
* - Hash aad and copy to Xi.
*/
static void set_aad(struct gcm_ctx *gctx, struct Hash_ctx *hash,
unsigned char *aad, int alen)
{
int i;
u8 nXi[16] = {0, };
gctx->aadLen = alen;
i = alen & ~0xf;
if (i) {
gcm_ghash_p10(nXi, hash->Htable+32, aad, i);
aad += i;
alen -= i;
}
if (alen) {
for (i = 0; i < alen; i++)
nXi[i] ^= aad[i];
memset(gctx->aad_hash, 0, 16);
gcm_ghash_p10(gctx->aad_hash, hash->Htable+32, nXi, 16);
} else {
memcpy(gctx->aad_hash, nXi, 16);
}
memcpy(hash->Htable, gctx->aad_hash, 16);
}
static void gcmp10_init(struct gcm_ctx *gctx, u8 *iv, unsigned char *rdkey,
struct Hash_ctx *hash, u8 *assoc, unsigned int assoclen)
{
__be32 counter = cpu_to_be32(1);
aes_p10_encrypt(hash->H, hash->H, rdkey);
set_subkey(hash->H);
gcm_init_htable(hash->Htable+32, hash->H);
*((__be32 *)(iv+12)) = counter;
gctx->Plen = 0;
/*
* Encrypt counter vector as iv tag and increment counter.
*/
aes_p10_encrypt(iv, gctx->ivtag, rdkey);
counter = cpu_to_be32(2);
*((__be32 *)(iv+12)) = counter;
memcpy(gctx->iv, iv, 16);
gctx->aadLen = assoclen;
memset(gctx->aad_hash, 0, 16);
if (assoclen)
set_aad(gctx, hash, assoc, assoclen);
}
static void finish_tag(struct gcm_ctx *gctx, struct Hash_ctx *hash, int len)
{
int i;
unsigned char len_ac[16 + PPC_ALIGN];
unsigned char *aclen = PTR_ALIGN((void *)len_ac, PPC_ALIGN);
__be64 clen = cpu_to_be64(len << 3);
__be64 alen = cpu_to_be64(gctx->aadLen << 3);
if (len == 0 && gctx->aadLen == 0) {
memcpy(hash->Htable, gctx->ivtag, 16);
return;
}
/*
* Len is in bits.
*/
*((__be64 *)(aclen)) = alen;
*((__be64 *)(aclen+8)) = clen;
/*
* hash (AAD len and len)
*/
gcm_ghash_p10(hash->Htable, hash->Htable+32, aclen, 16);
for (i = 0; i < 16; i++)
hash->Htable[i] ^= gctx->ivtag[i];
}
static int set_authsize(struct crypto_aead *tfm, unsigned int authsize)
{
switch (authsize) {
case 4:
case 8:
case 12:
case 13:
case 14:
case 15:
case 16:
break;
default:
return -EINVAL;
}
return 0;
}
static int p10_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct crypto_tfm *tfm = crypto_aead_tfm(aead);
struct p10_aes_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
vsx_begin();
ret = aes_p10_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
vsx_end();
return ret ? -EINVAL : 0;
}
static int p10_aes_gcm_crypt(struct aead_request *req, int enc)
{
struct crypto_tfm *tfm = req->base.tfm;
struct p10_aes_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
u8 databuf[sizeof(struct gcm_ctx) + PPC_ALIGN];
struct gcm_ctx *gctx = PTR_ALIGN((void *)databuf, PPC_ALIGN);
u8 hashbuf[sizeof(struct Hash_ctx) + PPC_ALIGN];
struct Hash_ctx *hash = PTR_ALIGN((void *)hashbuf, PPC_ALIGN);
struct scatter_walk assoc_sg_walk;
struct skcipher_walk walk;
u8 *assocmem = NULL;
u8 *assoc;
unsigned int assoclen = req->assoclen;
unsigned int cryptlen = req->cryptlen;
unsigned char ivbuf[AES_BLOCK_SIZE+PPC_ALIGN];
unsigned char *iv = PTR_ALIGN((void *)ivbuf, PPC_ALIGN);
int ret;
unsigned long auth_tag_len = crypto_aead_authsize(__crypto_aead_cast(tfm));
u8 otag[16];
int total_processed = 0;
memset(databuf, 0, sizeof(databuf));
memset(hashbuf, 0, sizeof(hashbuf));
memset(ivbuf, 0, sizeof(ivbuf));
memcpy(iv, req->iv, GCM_IV_SIZE);
/* Linearize assoc, if not already linear */
if (req->src->length >= assoclen && req->src->length) {
scatterwalk_start(&assoc_sg_walk, req->src);
assoc = scatterwalk_map(&assoc_sg_walk);
} else {
gfp_t flags = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC;
/* assoc can be any length, so must be on heap */
assocmem = kmalloc(assoclen, flags);
if (unlikely(!assocmem))
return -ENOMEM;
assoc = assocmem;
scatterwalk_map_and_copy(assoc, req->src, 0, assoclen, 0);
}
vsx_begin();
gcmp10_init(gctx, iv, (unsigned char *) &ctx->enc_key, hash, assoc, assoclen);
vsx_end();
if (!assocmem)
scatterwalk_unmap(assoc);
else
kfree(assocmem);
if (enc)
ret = skcipher_walk_aead_encrypt(&walk, req, false);
else
ret = skcipher_walk_aead_decrypt(&walk, req, false);
if (ret)
return ret;
while (walk.nbytes > 0 && ret == 0) {
vsx_begin();
if (enc)
aes_p10_gcm_encrypt(walk.src.virt.addr,
walk.dst.virt.addr,
walk.nbytes,
&ctx->enc_key, gctx->iv, hash->Htable);
else
aes_p10_gcm_decrypt(walk.src.virt.addr,
walk.dst.virt.addr,
walk.nbytes,
&ctx->enc_key, gctx->iv, hash->Htable);
vsx_end();
total_processed += walk.nbytes;
ret = skcipher_walk_done(&walk, 0);
}
if (ret)
return ret;
/* Finalize hash */
vsx_begin();
finish_tag(gctx, hash, total_processed);
vsx_end();
/* copy Xi to end of dst */
if (enc)
scatterwalk_map_and_copy(hash->Htable, req->dst, req->assoclen + cryptlen,
auth_tag_len, 1);
else {
scatterwalk_map_and_copy(otag, req->src,
req->assoclen + cryptlen - auth_tag_len,
auth_tag_len, 0);
if (crypto_memneq(otag, hash->Htable, auth_tag_len)) {
memzero_explicit(hash->Htable, 16);
return -EBADMSG;
}
}
return 0;
}
static int p10_aes_gcm_encrypt(struct aead_request *req)
{
return p10_aes_gcm_crypt(req, 1);
}
static int p10_aes_gcm_decrypt(struct aead_request *req)
{
return p10_aes_gcm_crypt(req, 0);
}
static struct aead_alg gcm_aes_alg = {
.ivsize = GCM_IV_SIZE,
.maxauthsize = 16,
.setauthsize = set_authsize,
.setkey = p10_aes_gcm_setkey,
.encrypt = p10_aes_gcm_encrypt,
.decrypt = p10_aes_gcm_decrypt,
.base.cra_name = "gcm(aes)",
.base.cra_driver_name = "aes_gcm_p10",
.base.cra_priority = 2100,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct p10_aes_gcm_ctx),
.base.cra_module = THIS_MODULE,
};
static int __init p10_init(void)
{
return crypto_register_aead(&gcm_aes_alg);
}
static void __exit p10_exit(void)
{
crypto_unregister_aead(&gcm_aes_alg);
}
module_cpu_feature_match(PPC_MODULE_FEATURE_P10, p10_init);
module_exit(p10_exit);
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