drivers/crypto/nx/nx-aes-gcm.c

   1 /**
   2  * AES GCM routines supporting the Power 7+ Nest Accelerators driver
   3  *
   4  * Copyright (C) 2012 International Business Machines Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 only.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  * Author: Kent Yoder <[email protected]>
  20  */
  21
  22 #include <crypto/internal/aead.h>
  23 #include <crypto/aes.h>
  24 #include <crypto/algapi.h>
  25 #include <crypto/scatterwalk.h>
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/crypto.h>
  29 #include <asm/vio.h>
  30
  31 #include "nx_csbcpb.h"
  32 #include "nx.h"
  33
  34
  35 static int gcm_aes_nx_set_key(struct crypto_aead *tfm,
  36                               const u8           *in_key,
  37                               unsigned int        key_len)
  38 {
  39         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
  40         struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
  41         struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
  42
  43         nx_ctx_init(nx_ctx, HCOP_FC_AES);
  44
  45         switch (key_len) {
  46         case AES_KEYSIZE_128:
  47                 NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
  48                 NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_128);
  49                 nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
  50                 break;
  51         case AES_KEYSIZE_192:
  52                 NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
  53                 NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_192);
  54                 nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
  55                 break;
  56         case AES_KEYSIZE_256:
  57                 NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
  58                 NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_256);
  59                 nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
  60                 break;
  61         default:
  62                 return -EINVAL;
  63         }
  64
  65         csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
  66         memcpy(csbcpb->cpb.aes_gcm.key, in_key, key_len);
  67
  68         csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_GCA;
  69         memcpy(csbcpb_aead->cpb.aes_gca.key, in_key, key_len);
  70
  71         return 0;
  72 }
  73
  74 static int gcm4106_aes_nx_set_key(struct crypto_aead *tfm,
  75                                   const u8           *in_key,
  76                                   unsigned int        key_len)
  77 {
  78         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
  79         char *nonce = nx_ctx->priv.gcm.nonce;
  80         int rc;
  81
  82         if (key_len < 4)
  83                 return -EINVAL;
  84
  85         key_len -= 4;
  86
  87         rc = gcm_aes_nx_set_key(tfm, in_key, key_len);
  88         if (rc)
  89                 goto out;
  90
  91         memcpy(nonce, in_key + key_len, 4);
  92 out:
  93         return rc;
  94 }
  95
  96 static int gcm_aes_nx_setauthsize(struct crypto_aead *tfm,
  97                                   unsigned int authsize)
  98 {
  99         if (authsize > crypto_aead_alg(tfm)->maxauthsize)
 100                 return -EINVAL;
 101
 102         crypto_aead_crt(tfm)->authsize = authsize;
 103
 104         return 0;
 105 }
 106
 107 static int gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
 108                                       unsigned int authsize)
 109 {
 110         switch (authsize) {
 111         case 8:
 112         case 12:
 113         case 16:
 114                 break;
 115         default:
 116                 return -EINVAL;
 117         }
 118
 119         crypto_aead_crt(tfm)->authsize = authsize;
 120
 121         return 0;
 122 }
 123
 124 static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
 125                   struct aead_request   *req,
 126                   u8                    *out)
 127 {
 128         struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
 129         int rc = -EINVAL;
 130         struct scatter_walk walk;
 131         struct nx_sg *nx_sg = nx_ctx->in_sg;
 132
 133         if (req->assoclen > nx_ctx->ap->databytelen)
 134                 goto out;
 135
 136         if (req->assoclen <= AES_BLOCK_SIZE) {
 137                 scatterwalk_start(&walk, req->assoc);
 138                 scatterwalk_copychunks(out, &walk, req->assoclen,
 139                                        SCATTERWALK_FROM_SG);
 140                 scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);
 141
 142                 rc = 0;
 143                 goto out;
 144         }
 145
 146         nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
 147                                   req->assoclen);
 148         nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);
 149
 150         rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
 151                            req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
 152         if (rc)
 153                 goto out;
 154
 155         atomic_inc(&(nx_ctx->stats->aes_ops));
 156         atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
 157
 158         memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
 159 out:
 160         return rc;
 161 }
 162
 163 static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
 164 {
 165         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 166         struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 167         struct blkcipher_desc desc;
 168         unsigned int nbytes = req->cryptlen;
 169         int rc = -EINVAL;
 170
 171         if (nbytes > nx_ctx->ap->databytelen)
 172                 goto out;
 173
 174         desc.info = nx_ctx->priv.gcm.iv;
 175         /* initialize the counter */
 176         *(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;
 177
 178         /* For scenarios where the input message is zero length, AES CTR mode
 179          * may be used. Set the source data to be a single block (16B) of all
 180          * zeros, and set the input IV value to be the same as the GMAC IV
 181          * value. - nx_wb 4.8.1.3 */
 182         if (nbytes == 0) {
 183                 char src[AES_BLOCK_SIZE] = {};
 184                 struct scatterlist sg;
 185
 186                 desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
 187                 if (IS_ERR(desc.tfm)) {
 188                         rc = -ENOMEM;
 189                         goto out;
 190                 }
 191
 192                 crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
 193                         NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
 194                         NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);
 195
 196                 sg_init_one(&sg, src, AES_BLOCK_SIZE);
 197                 if (enc)
 198                         crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
 199                                                     AES_BLOCK_SIZE);
 200                 else
 201                         crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
 202                                                     AES_BLOCK_SIZE);
 203                 crypto_free_blkcipher(desc.tfm);
 204
 205                 rc = 0;
 206                 goto out;
 207         }
 208
 209         desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
 210
 211         csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;
 212
 213         if (req->assoclen) {
 214                 rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
 215                 if (rc)
 216                         goto out;
 217         }
 218
 219         if (enc)
 220                 NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
 221         else
 222                 nbytes -= crypto_aead_authsize(crypto_aead_reqtfm(req));
 223
 224         csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;
 225
 226         rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes,
 227                                csbcpb->cpb.aes_gcm.iv_or_cnt);
 228         if (rc)
 229                 goto out;
 230
 231         rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
 232                            req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
 233         if (rc)
 234                 goto out;
 235
 236         atomic_inc(&(nx_ctx->stats->aes_ops));
 237         atomic64_add(csbcpb->csb.processed_byte_count,
 238                      &(nx_ctx->stats->aes_bytes));
 239
 240         if (enc) {
 241                 /* copy out the auth tag */
 242                 scatterwalk_map_and_copy(csbcpb->cpb.aes_gcm.out_pat_or_mac,
 243                                  req->dst, nbytes,
 244                                  crypto_aead_authsize(crypto_aead_reqtfm(req)),
 245                                  SCATTERWALK_TO_SG);
 246         } else if (req->assoclen) {
 247                 u8 *itag = nx_ctx->priv.gcm.iauth_tag;
 248                 u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;
 249
 250                 scatterwalk_map_and_copy(itag, req->dst, nbytes,
 251                                  crypto_aead_authsize(crypto_aead_reqtfm(req)),
 252                                  SCATTERWALK_FROM_SG);
 253                 rc = memcmp(itag, otag,
 254                             crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
 255                      -EBADMSG : 0;
 256         }
 257 out:
 258         return rc;
 259 }
 260
 261 static int gcm_aes_nx_encrypt(struct aead_request *req)
 262 {
 263         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 264         char *iv = nx_ctx->priv.gcm.iv;
 265
 266         memcpy(iv, req->iv, 12);
 267
 268         return gcm_aes_nx_crypt(req, 1);
 269 }
 270
 271 static int gcm_aes_nx_decrypt(struct aead_request *req)
 272 {
 273         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 274         char *iv = nx_ctx->priv.gcm.iv;
 275
 276         memcpy(iv, req->iv, 12);
 277
 278         return gcm_aes_nx_crypt(req, 0);
 279 }
 280
 281 static int gcm4106_aes_nx_encrypt(struct aead_request *req)
 282 {
 283         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 284         char *iv = nx_ctx->priv.gcm.iv;
 285         char *nonce = nx_ctx->priv.gcm.nonce;
 286
 287         memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
 288         memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
 289
 290         return gcm_aes_nx_crypt(req, 1);
 291 }
 292
 293 static int gcm4106_aes_nx_decrypt(struct aead_request *req)
 294 {
 295         struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 296         char *iv = nx_ctx->priv.gcm.iv;
 297         char *nonce = nx_ctx->priv.gcm.nonce;
 298
 299         memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
 300         memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
 301
 302         return gcm_aes_nx_crypt(req, 0);
 303 }
 304
 305 /* tell the block cipher walk routines that this is a stream cipher by
 306  * setting cra_blocksize to 1. Even using blkcipher_walk_virt_block
 307  * during encrypt/decrypt doesn't solve this problem, because it calls
 308  * blkcipher_walk_done under the covers, which doesn't use walk->blocksize,
 309  * but instead uses this tfm->blocksize. */
 310 struct crypto_alg nx_gcm_aes_alg = {
 311         .cra_name        = "gcm(aes)",
 312         .cra_driver_name = "gcm-aes-nx",
 313         .cra_priority    = 300,
 314         .cra_flags       = CRYPTO_ALG_TYPE_AEAD,
 315         .cra_blocksize   = 1,
 316         .cra_ctxsize     = sizeof(struct nx_crypto_ctx),
 317         .cra_type        = &crypto_aead_type,
 318         .cra_module      = THIS_MODULE,
 319         .cra_init        = nx_crypto_ctx_aes_gcm_init,
 320         .cra_exit        = nx_crypto_ctx_exit,
 321         .cra_aead = {
 322                 .ivsize      = AES_BLOCK_SIZE,
 323                 .maxauthsize = AES_BLOCK_SIZE,
 324                 .setkey      = gcm_aes_nx_set_key,
 325                 .setauthsize = gcm_aes_nx_setauthsize,
 326                 .encrypt     = gcm_aes_nx_encrypt,
 327                 .decrypt     = gcm_aes_nx_decrypt,
 328         }
 329 };
 330
 331 struct crypto_alg nx_gcm4106_aes_alg = {
 332         .cra_name        = "rfc4106(gcm(aes))",
 333         .cra_driver_name = "rfc4106-gcm-aes-nx",
 334         .cra_priority    = 300,
 335         .cra_flags       = CRYPTO_ALG_TYPE_AEAD,
 336         .cra_blocksize   = 1,
 337         .cra_ctxsize     = sizeof(struct nx_crypto_ctx),
 338         .cra_type        = &crypto_nivaead_type,
 339         .cra_module      = THIS_MODULE,
 340         .cra_init        = nx_crypto_ctx_aes_gcm_init,
 341         .cra_exit        = nx_crypto_ctx_exit,
 342         .cra_aead = {
 343                 .ivsize      = 8,
 344                 .maxauthsize = AES_BLOCK_SIZE,
 345                 .geniv       = "seqiv",
 346                 .setkey      = gcm4106_aes_nx_set_key,
 347                 .setauthsize = gcm4106_aes_nx_setauthsize,
 348                 .encrypt     = gcm4106_aes_nx_encrypt,
 349                 .decrypt     = gcm4106_aes_nx_decrypt,
 350         }
 351 };