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    Annotation of /alx-src/tags/kernel26-2.6.12-alx-r9/crypto/cipher.c

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    Revision 630 - (hide annotations) (download)
    Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
    File MIME type: text/plain
    File size: 8747 byte(s) 
    Tag kernel26-2.6.12-alx-r9
    1 niro 628 /*
    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/compiler.h>
    15     #include <linux/kernel.h>
    16     #include <linux/crypto.h>
    17     #include <linux/errno.h>
    18     #include <linux/mm.h>
    19     #include <linux/slab.h>
    20     #include <linux/string.h>
    21     #include <asm/scatterlist.h>
    22     #include "internal.h"
    23     #include "scatterwalk.h"
    24    
    25     typedef void (cryptfn_t)(void *, u8 *, const u8 *);
    26     typedef void (procfn_t)(struct crypto_tfm *, u8 *,
    27     u8*, cryptfn_t, void *);
    28    
    29     static inline void xor_64(u8 *a, const u8 *b)
    30     {
    31     ((u32 *)a)[0] ^= ((u32 *)b)[0];
    32     ((u32 *)a)[1] ^= ((u32 *)b)[1];
    33     }
    34    
    35     static inline void xor_128(u8 *a, const u8 *b)
    36     {
    37     ((u32 *)a)[0] ^= ((u32 *)b)[0];
    38     ((u32 *)a)[1] ^= ((u32 *)b)[1];
    39     ((u32 *)a)[2] ^= ((u32 *)b)[2];
    40     ((u32 *)a)[3] ^= ((u32 *)b)[3];
    41     }
    42    
    43     static inline void *prepare_src(struct scatter_walk *walk, int bsize,
    44     void *tmp, int in_place)
    45     {
    46     void *src = walk->data;
    47     int n = bsize;
    48    
    49     if (unlikely(scatterwalk_across_pages(walk, bsize))) {
    50     src = tmp;
    51     n = scatterwalk_copychunks(src, walk, bsize, 0);
    52     }
    53     scatterwalk_advance(walk, n);
    54     return src;
    55     }
    56    
    57     static inline void *prepare_dst(struct scatter_walk *walk, int bsize,
    58     void *tmp, int in_place)
    59     {
    60     void *dst = walk->data;
    61    
    62     if (unlikely(scatterwalk_across_pages(walk, bsize)) || in_place)
    63     dst = tmp;
    64     return dst;
    65     }
    66    
    67     static inline void complete_src(struct scatter_walk *walk, int bsize,
    68     void *src, int in_place)
    69     {
    70     }
    71    
    72     static inline void complete_dst(struct scatter_walk *walk, int bsize,
    73     void *dst, int in_place)
    74     {
    75     int n = bsize;
    76    
    77     if (unlikely(scatterwalk_across_pages(walk, bsize)))
    78     n = scatterwalk_copychunks(dst, walk, bsize, 1);
    79     else if (in_place)
    80     memcpy(walk->data, dst, bsize);
    81     scatterwalk_advance(walk, n);
    82     }
    83    
    84     /*
    85     * Generic encrypt/decrypt wrapper for ciphers, handles operations across
    86     * multiple page boundaries by using temporary blocks. In user context,
    87     * the kernel is given a chance to schedule us once per block.
    88     */
    89     static int crypt(struct crypto_tfm *tfm,
    90     struct scatterlist *dst,
    91     struct scatterlist *src,
    92     unsigned int nbytes, cryptfn_t crfn,
    93     procfn_t prfn, void *info)
    94     {
    95     struct scatter_walk walk_in, walk_out;
    96     const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
    97     u8 tmp_src[bsize];
    98     u8 tmp_dst[bsize];
    99    
    100     if (!nbytes)
    101     return 0;
    102    
    103     if (nbytes % bsize) {
    104     tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
    105     return -EINVAL;
    106     }
    107    
    108     scatterwalk_start(&walk_in, src);
    109     scatterwalk_start(&walk_out, dst);
    110    
    111     for(;;) {
    112     u8 *src_p, *dst_p;
    113     int in_place;
    114    
    115     scatterwalk_map(&walk_in, 0);
    116     scatterwalk_map(&walk_out, 1);
    117    
    118     in_place = scatterwalk_samebuf(&walk_in, &walk_out);
    119    
    120     do {
    121     src_p = prepare_src(&walk_in, bsize, tmp_src,
    122     in_place);
    123     dst_p = prepare_dst(&walk_out, bsize, tmp_dst,
    124     in_place);
    125    
    126     prfn(tfm, dst_p, src_p, crfn, info);
    127    
    128     complete_src(&walk_in, bsize, src_p, in_place);
    129     complete_dst(&walk_out, bsize, dst_p, in_place);
    130    
    131     nbytes -= bsize;
    132     } while (nbytes &&
    133     !scatterwalk_across_pages(&walk_in, bsize) &&
    134     !scatterwalk_across_pages(&walk_out, bsize));
    135    
    136     scatterwalk_done(&walk_in, 0, nbytes);
    137     scatterwalk_done(&walk_out, 1, nbytes);
    138    
    139     if (!nbytes)
    140     return 0;
    141    
    142     crypto_yield(tfm);
    143     }
    144     }
    145    
    146     static void cbc_process_encrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
    147     cryptfn_t fn, void *info)
    148     {
    149     u8 *iv = info;
    150    
    151     tfm->crt_u.cipher.cit_xor_block(iv, src);
    152     fn(crypto_tfm_ctx(tfm), dst, iv);
    153     memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
    154     }
    155    
    156     static void cbc_process_decrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
    157     cryptfn_t fn, void *info)
    158     {
    159     u8 *iv = info;
    160    
    161     fn(crypto_tfm_ctx(tfm), dst, src);
    162     tfm->crt_u.cipher.cit_xor_block(dst, iv);
    163     memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
    164     }
    165    
    166     static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
    167     cryptfn_t fn, void *info)
    168     {
    169     fn(crypto_tfm_ctx(tfm), dst, src);
    170     }
    171    
    172     static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
    173     {
    174     struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
    175    
    176     if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
    177     tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
    178     return -EINVAL;
    179     } else
    180     return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
    181     &tfm->crt_flags);
    182     }
    183    
    184     static int ecb_encrypt(struct crypto_tfm *tfm,
    185     struct scatterlist *dst,
    186     struct scatterlist *src, unsigned int nbytes)
    187     {
    188     return crypt(tfm, dst, src, nbytes,
    189     tfm->__crt_alg->cra_cipher.cia_encrypt,
    190     ecb_process, NULL);
    191     }
    192    
    193     static int ecb_decrypt(struct crypto_tfm *tfm,
    194     struct scatterlist *dst,
    195     struct scatterlist *src,
    196     unsigned int nbytes)
    197     {
    198     return crypt(tfm, dst, src, nbytes,
    199     tfm->__crt_alg->cra_cipher.cia_decrypt,
    200     ecb_process, NULL);
    201     }
    202    
    203     static int cbc_encrypt(struct crypto_tfm *tfm,
    204     struct scatterlist *dst,
    205     struct scatterlist *src,
    206     unsigned int nbytes)
    207     {
    208     return crypt(tfm, dst, src, nbytes,
    209     tfm->__crt_alg->cra_cipher.cia_encrypt,
    210     cbc_process_encrypt, tfm->crt_cipher.cit_iv);
    211     }
    212    
    213     static int cbc_encrypt_iv(struct crypto_tfm *tfm,
    214     struct scatterlist *dst,
    215     struct scatterlist *src,
    216     unsigned int nbytes, u8 *iv)
    217     {
    218     return crypt(tfm, dst, src, nbytes,
    219     tfm->__crt_alg->cra_cipher.cia_encrypt,
    220     cbc_process_encrypt, iv);
    221     }
    222    
    223     static int cbc_decrypt(struct crypto_tfm *tfm,
    224     struct scatterlist *dst,
    225     struct scatterlist *src,
    226     unsigned int nbytes)
    227     {
    228     return crypt(tfm, dst, src, nbytes,
    229     tfm->__crt_alg->cra_cipher.cia_decrypt,
    230     cbc_process_decrypt, tfm->crt_cipher.cit_iv);
    231     }
    232    
    233     static int cbc_decrypt_iv(struct crypto_tfm *tfm,
    234     struct scatterlist *dst,
    235     struct scatterlist *src,
    236     unsigned int nbytes, u8 *iv)
    237     {
    238     return crypt(tfm, dst, src, nbytes,
    239     tfm->__crt_alg->cra_cipher.cia_decrypt,
    240     cbc_process_decrypt, iv);
    241     }
    242    
    243     static int nocrypt(struct crypto_tfm *tfm,
    244     struct scatterlist *dst,
    245     struct scatterlist *src,
    246     unsigned int nbytes)
    247     {
    248     return -ENOSYS;
    249     }
    250    
    251     static int nocrypt_iv(struct crypto_tfm *tfm,
    252     struct scatterlist *dst,
    253     struct scatterlist *src,
    254     unsigned int nbytes, u8 *iv)
    255     {
    256     return -ENOSYS;
    257     }
    258    
    259     int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
    260     {
    261     u32 mode = flags & CRYPTO_TFM_MODE_MASK;
    262    
    263     tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
    264     if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
    265     tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;
    266    
    267     return 0;
    268     }
    269    
    270     int crypto_init_cipher_ops(struct crypto_tfm *tfm)
    271     {
    272     int ret = 0;
    273     struct cipher_tfm *ops = &tfm->crt_cipher;
    274    
    275     ops->cit_setkey = setkey;
    276    
    277     switch (tfm->crt_cipher.cit_mode) {
    278     case CRYPTO_TFM_MODE_ECB:
    279     ops->cit_encrypt = ecb_encrypt;
    280     ops->cit_decrypt = ecb_decrypt;
    281     break;
    282    
    283     case CRYPTO_TFM_MODE_CBC:
    284     ops->cit_encrypt = cbc_encrypt;
    285     ops->cit_decrypt = cbc_decrypt;
    286     ops->cit_encrypt_iv = cbc_encrypt_iv;
    287     ops->cit_decrypt_iv = cbc_decrypt_iv;
    288     break;
    289    
    290     case CRYPTO_TFM_MODE_CFB:
    291     ops->cit_encrypt = nocrypt;
    292     ops->cit_decrypt = nocrypt;
    293     ops->cit_encrypt_iv = nocrypt_iv;
    294     ops->cit_decrypt_iv = nocrypt_iv;
    295     break;
    296    
    297     case CRYPTO_TFM_MODE_CTR:
    298     ops->cit_encrypt = nocrypt;
    299     ops->cit_decrypt = nocrypt;
    300     ops->cit_encrypt_iv = nocrypt_iv;
    301     ops->cit_decrypt_iv = nocrypt_iv;
    302     break;
    303    
    304     default:
    305     BUG();
    306     }
    307    
    308     if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
    309    
    310     switch (crypto_tfm_alg_blocksize(tfm)) {
    311     case 8:
    312     ops->cit_xor_block = xor_64;
    313     break;
    314    
    315     case 16:
    316     ops->cit_xor_block = xor_128;
    317     break;
    318    
    319     default:
    320     printk(KERN_WARNING "%s: block size %u not supported\n",
    321     crypto_tfm_alg_name(tfm),
    322     crypto_tfm_alg_blocksize(tfm));
    323     ret = -EINVAL;
    324     goto out;
    325     }
    326    
    327     ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
    328     ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
    329     if (ops->cit_iv == NULL)
    330     ret = -ENOMEM;
    331     }
    332    
    333     out:
    334     return ret;
    335     }
    336    
    337     void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
    338     {
    339     if (tfm->crt_cipher.cit_iv)
    340     kfree(tfm->crt_cipher.cit_iv);
    341     }