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   1 /*
   2  *  linux/net/sunrpc/gss_krb5_crypto.c
   3  *
   4  *  Copyright (c) 2000 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Andy Adamson   <andros@umich.edu>
   8  *  Bruce Fields   <bfields@umich.edu>
   9  */
  10
  11 /*
  12  * Copyright (C) 1998 by the FundsXpress, INC.
  13  *
  14  * All rights reserved.
  15  *
  16  * Export of this software from the United States of America may require
  17  * a specific license from the United States Government.  It is the
  18  * responsibility of any person or organization contemplating export to
  19  * obtain such a license before exporting.
  20  *
  21  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  22  * distribute this software and its documentation for any purpose and
  23  * without fee is hereby granted, provided that the above copyright
  24  * notice appear in all copies and that both that copyright notice and
  25  * this permission notice appear in supporting documentation, and that
  26  * the name of FundsXpress. not be used in advertising or publicity pertaining
  27  * to distribution of the software without specific, written prior
  28  * permission.  FundsXpress makes no representations about the suitability of
  29  * this software for any purpose.  It is provided "as is" without express
  30  * or implied warranty.
  31  *
  32  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  33  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  34  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  35  */
  36
  37 #include <linux/types.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include <linux/scatterlist.h>
  41 #include <linux/crypto.h>
  42 #include <linux/highmem.h>
  43 #include <linux/pagemap.h>
  44 #include <linux/sunrpc/gss_krb5.h>
  45
  46 #ifdef RPC_DEBUG
  47 # define RPCDBG_FACILITY        RPCDBG_AUTH
  48 #endif
  49
  50 u32
  51 krb5_encrypt(
  52         struct crypto_tfm *tfm,
  53         void * iv,
  54         void * in,
  55         void * out,
  56         int length)
  57 {
  58         u32 ret = -EINVAL;
  59         struct scatterlist sg[1];
  60         u8 local_iv[16] = {0};
  61
  62         dprintk("RPC:      krb5_encrypt: input data:\n");
  63         print_hexl((u32 *)in, length, 0);
  64
  65         if (length % crypto_tfm_alg_blocksize(tfm) != 0)
  66                 goto out;
  67
  68         if (crypto_tfm_alg_ivsize(tfm) > 16) {
  69                 dprintk("RPC:      gss_k5encrypt: tfm iv size to large %d\n",
  70                          crypto_tfm_alg_ivsize(tfm));
  71                 goto out;
  72         }
  73
  74         if (iv)
  75                 memcpy(local_iv, iv, crypto_tfm_alg_ivsize(tfm));
  76
  77         memcpy(out, in, length);
  78         sg_set_buf(sg, out, length);
  79
  80         ret = crypto_cipher_encrypt_iv(tfm, sg, sg, length, local_iv);
  81
  82         dprintk("RPC:      krb5_encrypt: output data:\n");
  83         print_hexl((u32 *)out, length, 0);
  84 out:
  85         dprintk("RPC:      krb5_encrypt returns %d\n",ret);
  86         return(ret);
  87 }
  88
  89 EXPORT_SYMBOL(krb5_encrypt);
  90
  91 u32
  92 krb5_decrypt(
  93      struct crypto_tfm *tfm,
  94      void * iv,
  95      void * in,
  96      void * out,
  97      int length)
  98 {
  99         u32 ret = -EINVAL;
 100         struct scatterlist sg[1];
 101         u8 local_iv[16] = {0};
 102
 103         dprintk("RPC:      krb5_decrypt: input data:\n");
 104         print_hexl((u32 *)in, length, 0);
 105
 106         if (length % crypto_tfm_alg_blocksize(tfm) != 0)
 107                 goto out;
 108
 109         if (crypto_tfm_alg_ivsize(tfm) > 16) {
 110                 dprintk("RPC:      gss_k5decrypt: tfm iv size to large %d\n",
 111                         crypto_tfm_alg_ivsize(tfm));
 112                 goto out;
 113         }
 114         if (iv)
 115                 memcpy(local_iv,iv, crypto_tfm_alg_ivsize(tfm));
 116
 117         memcpy(out, in, length);
 118         sg_set_buf(sg, out, length);
 119
 120         ret = crypto_cipher_decrypt_iv(tfm, sg, sg, length, local_iv);
 121
 122         dprintk("RPC:      krb5_decrypt: output_data:\n");
 123         print_hexl((u32 *)out, length, 0);
 124 out:
 125         dprintk("RPC:      gss_k5decrypt returns %d\n",ret);
 126         return(ret);
 127 }
 128
 129 EXPORT_SYMBOL(krb5_decrypt);
 130
 131 static int
 132 process_xdr_buf(struct xdr_buf *buf, int offset, int len,
 133                 int (*actor)(struct scatterlist *, void *), void *data)
 134 {
 135         int i, page_len, thislen, page_offset, ret = 0;
 136         struct scatterlist      sg[1];
 137
 138         if (offset >= buf->head[0].iov_len) {
 139                 offset -= buf->head[0].iov_len;
 140         } else {
 141                 thislen = buf->head[0].iov_len - offset;
 142                 if (thislen > len)
 143                         thislen = len;
 144                 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
 145                 ret = actor(sg, data);
 146                 if (ret)
 147                         goto out;
 148                 offset = 0;
 149                 len -= thislen;
 150         }
 151         if (len == 0)
 152                 goto out;
 153
 154         if (offset >= buf->page_len) {
 155                 offset -= buf->page_len;
 156         } else {
 157                 page_len = buf->page_len - offset;
 158                 if (page_len > len)
 159                         page_len = len;
 160                 len -= page_len;
 161                 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
 162                 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
 163                 thislen = PAGE_CACHE_SIZE - page_offset;
 164                 do {
 165                         if (thislen > page_len)
 166                                 thislen = page_len;
 167                         sg->page = buf->pages[i];
 168                         sg->offset = page_offset;
 169                         sg->length = thislen;
 170                         ret = actor(sg, data);
 171                         if (ret)
 172                                 goto out;
 173                         page_len -= thislen;
 174                         i++;
 175                         page_offset = 0;
 176                         thislen = PAGE_CACHE_SIZE;
 177                 } while (page_len != 0);
 178                 offset = 0;
 179         }
 180         if (len == 0)
 181                 goto out;
 182
 183         if (offset < buf->tail[0].iov_len) {
 184                 thislen = buf->tail[0].iov_len - offset;
 185                 if (thislen > len)
 186                         thislen = len;
 187                 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
 188                 ret = actor(sg, data);
 189                 len -= thislen;
 190         }
 191         if (len != 0)
 192                 ret = -EINVAL;
 193 out:
 194         return ret;
 195 }
 196
 197 static int
 198 checksummer(struct scatterlist *sg, void *data)
 199 {
 200         struct crypto_tfm *tfm = (struct crypto_tfm *)data;
 201
 202         crypto_digest_update(tfm, sg, 1);
 203
 204         return 0;
 205 }
 206
 207 /* checksum the plaintext data and hdrlen bytes of the token header */
 208 s32
 209 make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
 210                    int body_offset, struct xdr_netobj *cksum)
 211 {
 212         char                            *cksumname;
 213         struct crypto_tfm               *tfm = NULL; /* XXX add to ctx? */
 214         struct scatterlist              sg[1];
 215
 216         switch (cksumtype) {
 217                 case CKSUMTYPE_RSA_MD5:
 218                         cksumname = "md5";
 219                         break;
 220                 default:
 221                         dprintk("RPC:      krb5_make_checksum:"
 222                                 " unsupported checksum %d", cksumtype);
 223                         return GSS_S_FAILURE;
 224         }
 225         if (!(tfm = crypto_alloc_tfm(cksumname, CRYPTO_TFM_REQ_MAY_SLEEP)))
 226                 return GSS_S_FAILURE;
 227         cksum->len = crypto_tfm_alg_digestsize(tfm);
 228
 229         crypto_digest_init(tfm);
 230         sg_set_buf(sg, header, hdrlen);
 231         crypto_digest_update(tfm, sg, 1);
 232         process_xdr_buf(body, body_offset, body->len - body_offset,
 233                         checksummer, tfm);
 234         crypto_digest_final(tfm, cksum->data);
 235         crypto_free_tfm(tfm);
 236         return 0;
 237 }
 238
 239 EXPORT_SYMBOL(make_checksum);
 240
 241 struct encryptor_desc {
 242         u8 iv[8]; /* XXX hard-coded blocksize */
 243         struct crypto_tfm *tfm;
 244         int pos;
 245         struct xdr_buf *outbuf;
 246         struct page **pages;
 247         struct scatterlist infrags[4];
 248         struct scatterlist outfrags[4];
 249         int fragno;
 250         int fraglen;
 251 };
 252
 253 static int
 254 encryptor(struct scatterlist *sg, void *data)
 255 {
 256         struct encryptor_desc *desc = data;
 257         struct xdr_buf *outbuf = desc->outbuf;
 258         struct page *in_page;
 259         int thislen = desc->fraglen + sg->length;
 260         int fraglen, ret;
 261         int page_pos;
 262
 263         /* Worst case is 4 fragments: head, end of page 1, start
 264          * of page 2, tail.  Anything more is a bug. */
 265         BUG_ON(desc->fragno > 3);
 266         desc->infrags[desc->fragno] = *sg;
 267         desc->outfrags[desc->fragno] = *sg;
 268
 269         page_pos = desc->pos - outbuf->head[0].iov_len;
 270         if (page_pos >= 0 && page_pos < outbuf->page_len) {
 271                 /* pages are not in place: */
 272                 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
 273                 in_page = desc->pages[i];
 274         } else {
 275                 in_page = sg->page;
 276         }
 277         desc->infrags[desc->fragno].page = in_page;
 278         desc->fragno++;
 279         desc->fraglen += sg->length;
 280         desc->pos += sg->length;
 281
 282         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 283         thislen -= fraglen;
 284
 285         if (thislen == 0)
 286                 return 0;
 287
 288         ret = crypto_cipher_encrypt_iv(desc->tfm, desc->outfrags, desc->infrags,
 289                                         thislen, desc->iv);
 290         if (ret)
 291                 return ret;
 292         if (fraglen) {
 293                 desc->outfrags[0].page = sg->page;
 294                 desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
 295                 desc->outfrags[0].length = fraglen;
 296                 desc->infrags[0] = desc->outfrags[0];
 297                 desc->infrags[0].page = in_page;
 298                 desc->fragno = 1;
 299                 desc->fraglen = fraglen;
 300         } else {
 301                 desc->fragno = 0;
 302                 desc->fraglen = 0;
 303         }
 304         return 0;
 305 }
 306
 307 int
 308 gss_encrypt_xdr_buf(struct crypto_tfm *tfm, struct xdr_buf *buf, int offset,
 309                 struct page **pages)
 310 {
 311         int ret;
 312         struct encryptor_desc desc;
 313
 314         BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
 315
 316         memset(desc.iv, 0, sizeof(desc.iv));
 317         desc.tfm = tfm;
 318         desc.pos = offset;
 319         desc.outbuf = buf;
 320         desc.pages = pages;
 321         desc.fragno = 0;
 322         desc.fraglen = 0;
 323
 324         ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
 325         return ret;
 326 }
 327
 328 EXPORT_SYMBOL(gss_encrypt_xdr_buf);
 329
 330 struct decryptor_desc {
 331         u8 iv[8]; /* XXX hard-coded blocksize */
 332         struct crypto_tfm *tfm;
 333         struct scatterlist frags[4];
 334         int fragno;
 335         int fraglen;
 336 };
 337
 338 static int
 339 decryptor(struct scatterlist *sg, void *data)
 340 {
 341         struct decryptor_desc *desc = data;
 342         int thislen = desc->fraglen + sg->length;
 343         int fraglen, ret;
 344
 345         /* Worst case is 4 fragments: head, end of page 1, start
 346          * of page 2, tail.  Anything more is a bug. */
 347         BUG_ON(desc->fragno > 3);
 348         desc->frags[desc->fragno] = *sg;
 349         desc->fragno++;
 350         desc->fraglen += sg->length;
 351
 352         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 353         thislen -= fraglen;
 354
 355         if (thislen == 0)
 356                 return 0;
 357
 358         ret = crypto_cipher_decrypt_iv(desc->tfm, desc->frags, desc->frags,
 359                                         thislen, desc->iv);
 360         if (ret)
 361                 return ret;
 362         if (fraglen) {
 363                 desc->frags[0].page = sg->page;
 364                 desc->frags[0].offset = sg->offset + sg->length - fraglen;
 365                 desc->frags[0].length = fraglen;
 366                 desc->fragno = 1;
 367                 desc->fraglen = fraglen;
 368         } else {
 369                 desc->fragno = 0;
 370                 desc->fraglen = 0;
 371         }
 372         return 0;
 373 }
 374
 375 int
 376 gss_decrypt_xdr_buf(struct crypto_tfm *tfm, struct xdr_buf *buf, int offset)
 377 {
 378         struct decryptor_desc desc;
 379
 380         /* XXXJBF: */
 381         BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
 382
 383         memset(desc.iv, 0, sizeof(desc.iv));
 384         desc.tfm = tfm;
 385         desc.fragno = 0;
 386         desc.fraglen = 0;
 387         return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
 388 }
 389
 390 EXPORT_SYMBOL(gss_decrypt_xdr_buf);