drivers/staging/rtl8192u/ieee80211/cipher.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * Cipher operations.
   5  *
   6  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2 of the License, or (at your option)
  11  * any later version.
  12  *
  13  */
  14 #include <linux/kernel.h>
  15 //#include <linux/crypto.h>
  16 #include "rtl_crypto.h"
  17 #include <linux/errno.h>
  18 #include <linux/mm.h>
  19 #include <linux/slab.h>
  20 #include <asm/scatterlist.h>
  21 #include "internal.h"
  22 #include "scatterwalk.h"
  23
  24 typedef void (cryptfn_t)(void *, u8 *, const u8 *);
  25 typedef void (procfn_t)(struct crypto_tfm *, u8 *,
  26                         u8*, cryptfn_t, int enc, void *, int);
  27
  28 static inline void xor_64(u8 *a, const u8 *b)
  29 {
  30         ((u32 *)a)[0] ^= ((u32 *)b)[0];
  31         ((u32 *)a)[1] ^= ((u32 *)b)[1];
  32 }
  33
  34 static inline void xor_128(u8 *a, const u8 *b)
  35 {
  36         ((u32 *)a)[0] ^= ((u32 *)b)[0];
  37         ((u32 *)a)[1] ^= ((u32 *)b)[1];
  38         ((u32 *)a)[2] ^= ((u32 *)b)[2];
  39         ((u32 *)a)[3] ^= ((u32 *)b)[3];
  40 }
  41
  42
  43 /*
  44  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
  45  * multiple page boundaries by using temporary blocks.  In user context,
  46  * the kernel is given a chance to schedule us once per block.
  47  */
  48 static int crypt(struct crypto_tfm *tfm,
  49                  struct scatterlist *dst,
  50                  struct scatterlist *src,
  51                  unsigned int nbytes, cryptfn_t crfn,
  52                  procfn_t prfn, int enc, void *info)
  53 {
  54         struct scatter_walk walk_in, walk_out;
  55         const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
  56         u8 tmp_src[bsize];
  57         u8 tmp_dst[bsize];
  58
  59         if (!nbytes)
  60                 return 0;
  61
  62         if (nbytes % bsize) {
  63                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
  64                 return -EINVAL;
  65         }
  66
  67         scatterwalk_start(&walk_in, src);
  68         scatterwalk_start(&walk_out, dst);
  69
  70         for(;;) {
  71                 u8 *src_p, *dst_p;
  72                 int in_place;
  73
  74                 scatterwalk_map(&walk_in, 0);
  75                 scatterwalk_map(&walk_out, 1);
  76                 src_p = scatterwalk_whichbuf(&walk_in, bsize, tmp_src);
  77                 dst_p = scatterwalk_whichbuf(&walk_out, bsize, tmp_dst);
  78                 in_place = scatterwalk_samebuf(&walk_in, &walk_out,
  79                                                src_p, dst_p);
  80
  81                 nbytes -= bsize;
  82
  83                 scatterwalk_copychunks(src_p, &walk_in, bsize, 0);
  84
  85                 prfn(tfm, dst_p, src_p, crfn, enc, info, in_place);
  86
  87                 scatterwalk_done(&walk_in, 0, nbytes);
  88
  89                 scatterwalk_copychunks(dst_p, &walk_out, bsize, 1);
  90                 scatterwalk_done(&walk_out, 1, nbytes);
  91
  92                 if (!nbytes)
  93                         return 0;
  94
  95                 crypto_yield(tfm);
  96         }
  97 }
  98
  99 static void cbc_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
 100                         cryptfn_t fn, int enc, void *info, int in_place)
 101 {
 102         u8 *iv = info;
 103
 104         /* Null encryption */
 105         if (!iv)
 106                 return;
 107
 108         if (enc) {
 109                 tfm->crt_u.cipher.cit_xor_block(iv, src);
 110                 fn(crypto_tfm_ctx(tfm), dst, iv);
 111                 memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
 112         } else {
 113                 u8 stack[in_place ? crypto_tfm_alg_blocksize(tfm) : 0];
 114                 u8 *buf = in_place ? stack : dst;
 115
 116                 fn(crypto_tfm_ctx(tfm), buf, src);
 117                 tfm->crt_u.cipher.cit_xor_block(buf, iv);
 118                 memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
 119                 if (buf != dst)
 120                         memcpy(dst, buf, crypto_tfm_alg_blocksize(tfm));
 121         }
 122 }
 123
 124 static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
 125                         cryptfn_t fn, int enc, void *info, int in_place)
 126 {
 127         fn(crypto_tfm_ctx(tfm), dst, src);
 128 }
 129
 130 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 131 {
 132         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
 133
 134         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
 135                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 136                 return -EINVAL;
 137         } else
 138                 return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
 139                                        &tfm->crt_flags);
 140 }
 141
 142 static int ecb_encrypt(struct crypto_tfm *tfm,
 143                        struct scatterlist *dst,
 144                        struct scatterlist *src, unsigned int nbytes)
 145 {
 146         return crypt(tfm, dst, src, nbytes,
 147                      tfm->__crt_alg->cra_cipher.cia_encrypt,
 148                      ecb_process, 1, NULL);
 149 }
 150
 151 static int ecb_decrypt(struct crypto_tfm *tfm,
 152                        struct scatterlist *dst,
 153                        struct scatterlist *src,
 154                        unsigned int nbytes)
 155 {
 156         return crypt(tfm, dst, src, nbytes,
 157                      tfm->__crt_alg->cra_cipher.cia_decrypt,
 158                      ecb_process, 1, NULL);
 159 }
 160
 161 static int cbc_encrypt(struct crypto_tfm *tfm,
 162                        struct scatterlist *dst,
 163                        struct scatterlist *src,
 164                        unsigned int nbytes)
 165 {
 166         return crypt(tfm, dst, src, nbytes,
 167                      tfm->__crt_alg->cra_cipher.cia_encrypt,
 168                      cbc_process, 1, tfm->crt_cipher.cit_iv);
 169 }
 170
 171 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
 172                           struct scatterlist *dst,
 173                           struct scatterlist *src,
 174                           unsigned int nbytes, u8 *iv)
 175 {
 176         return crypt(tfm, dst, src, nbytes,
 177                      tfm->__crt_alg->cra_cipher.cia_encrypt,
 178                      cbc_process, 1, iv);
 179 }
 180
 181 static int cbc_decrypt(struct crypto_tfm *tfm,
 182                        struct scatterlist *dst,
 183                        struct scatterlist *src,
 184                        unsigned int nbytes)
 185 {
 186         return crypt(tfm, dst, src, nbytes,
 187                      tfm->__crt_alg->cra_cipher.cia_decrypt,
 188                      cbc_process, 0, tfm->crt_cipher.cit_iv);
 189 }
 190
 191 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
 192                           struct scatterlist *dst,
 193                           struct scatterlist *src,
 194                           unsigned int nbytes, u8 *iv)
 195 {
 196         return crypt(tfm, dst, src, nbytes,
 197                      tfm->__crt_alg->cra_cipher.cia_decrypt,
 198                      cbc_process, 0, iv);
 199 }
 200
 201 static int nocrypt(struct crypto_tfm *tfm,
 202                    struct scatterlist *dst,
 203                    struct scatterlist *src,
 204                    unsigned int nbytes)
 205 {
 206         return -ENOSYS;
 207 }
 208
 209 static int nocrypt_iv(struct crypto_tfm *tfm,
 210                       struct scatterlist *dst,
 211                       struct scatterlist *src,
 212                       unsigned int nbytes, u8 *iv)
 213 {
 214         return -ENOSYS;
 215 }
 216
 217 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
 218 {
 219         u32 mode = flags & CRYPTO_TFM_MODE_MASK;
 220
 221         tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
 222         if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
 223                 tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;
 224
 225         return 0;
 226 }
 227
 228 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 229 {
 230         int ret = 0;
 231         struct cipher_tfm *ops = &tfm->crt_cipher;
 232
 233         ops->cit_setkey = setkey;
 234
 235         switch (tfm->crt_cipher.cit_mode) {
 236         case CRYPTO_TFM_MODE_ECB:
 237                 ops->cit_encrypt = ecb_encrypt;
 238                 ops->cit_decrypt = ecb_decrypt;
 239                 break;
 240
 241         case CRYPTO_TFM_MODE_CBC:
 242                 ops->cit_encrypt = cbc_encrypt;
 243                 ops->cit_decrypt = cbc_decrypt;
 244                 ops->cit_encrypt_iv = cbc_encrypt_iv;
 245                 ops->cit_decrypt_iv = cbc_decrypt_iv;
 246                 break;
 247
 248         case CRYPTO_TFM_MODE_CFB:
 249                 ops->cit_encrypt = nocrypt;
 250                 ops->cit_decrypt = nocrypt;
 251                 ops->cit_encrypt_iv = nocrypt_iv;
 252                 ops->cit_decrypt_iv = nocrypt_iv;
 253                 break;
 254
 255         case CRYPTO_TFM_MODE_CTR:
 256                 ops->cit_encrypt = nocrypt;
 257                 ops->cit_decrypt = nocrypt;
 258                 ops->cit_encrypt_iv = nocrypt_iv;
 259                 ops->cit_decrypt_iv = nocrypt_iv;
 260                 break;
 261
 262         default:
 263                 BUG();
 264         }
 265
 266         if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
 267
 268                 switch (crypto_tfm_alg_blocksize(tfm)) {
 269                 case 8:
 270                         ops->cit_xor_block = xor_64;
 271                         break;
 272
 273                 case 16:
 274                         ops->cit_xor_block = xor_128;
 275                         break;
 276
 277                 default:
 278                         printk(KERN_WARNING "%s: block size %u not supported\n",
 279                                crypto_tfm_alg_name(tfm),
 280                                crypto_tfm_alg_blocksize(tfm));
 281                         ret = -EINVAL;
 282                         goto out;
 283                 }
 284
 285                 ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
 286                 ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
 287                 if (ops->cit_iv == NULL)
 288                         ret = -ENOMEM;
 289         }
 290
 291 out:
 292         return ret;
 293 }
 294
 295 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 296 {
 297         kfree(tfm->crt_cipher.cit_iv);
 298 }