net/sunrpc/auth_gss/gss_krb5_crypto.c

   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/err.h>
  38 #include <linux/types.h>
  39 #include <linux/mm.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 #include <linux/sunrpc/xdr.h>
  46
  47 #ifdef RPC_DEBUG
  48 # define RPCDBG_FACILITY        RPCDBG_AUTH
  49 #endif
  50
  51 u32
  52 krb5_encrypt(
  53         struct crypto_blkcipher *tfm,
  54         void * iv,
  55         void * in,
  56         void * out,
  57         int length)
  58 {
  59         u32 ret = -EINVAL;
  60         struct scatterlist sg[1];
  61         u8 local_iv[16] = {0};
  62         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
  63
  64         if (length % crypto_blkcipher_blocksize(tfm) != 0)
  65                 goto out;
  66
  67         if (crypto_blkcipher_ivsize(tfm) > 16) {
  68                 dprintk("RPC:       gss_k5encrypt: tfm iv size too large %d\n",
  69                         crypto_blkcipher_ivsize(tfm));
  70                 goto out;
  71         }
  72
  73         if (iv)
  74                 memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
  75
  76         memcpy(out, in, length);
  77         sg_init_one(sg, out, length);
  78
  79         ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
  80 out:
  81         dprintk("RPC:       krb5_encrypt returns %d\n", ret);
  82         return ret;
  83 }
  84
  85 u32
  86 krb5_decrypt(
  87      struct crypto_blkcipher *tfm,
  88      void * iv,
  89      void * in,
  90      void * out,
  91      int length)
  92 {
  93         u32 ret = -EINVAL;
  94         struct scatterlist sg[1];
  95         u8 local_iv[16] = {0};
  96         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
  97
  98         if (length % crypto_blkcipher_blocksize(tfm) != 0)
  99                 goto out;
 100
 101         if (crypto_blkcipher_ivsize(tfm) > 16) {
 102                 dprintk("RPC:       gss_k5decrypt: tfm iv size too large %d\n",
 103                         crypto_blkcipher_ivsize(tfm));
 104                 goto out;
 105         }
 106         if (iv)
 107                 memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
 108
 109         memcpy(out, in, length);
 110         sg_init_one(sg, out, length);
 111
 112         ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
 113 out:
 114         dprintk("RPC:       gss_k5decrypt returns %d\n",ret);
 115         return ret;
 116 }
 117
 118 static int
 119 checksummer(struct scatterlist *sg, void *data)
 120 {
 121         struct hash_desc *desc = data;
 122
 123         return crypto_hash_update(desc, sg, sg->length);
 124 }
 125
 126 /* checksum the plaintext data and hdrlen bytes of the token header */
 127 s32
 128 make_checksum(char *cksumname, char *header, int hdrlen, struct xdr_buf *body,
 129                    int body_offset, struct xdr_netobj *cksum)
 130 {
 131         struct hash_desc                desc; /* XXX add to ctx? */
 132         struct scatterlist              sg[1];
 133         int err;
 134
 135         desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
 136         if (IS_ERR(desc.tfm))
 137                 return GSS_S_FAILURE;
 138         cksum->len = crypto_hash_digestsize(desc.tfm);
 139         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 140
 141         err = crypto_hash_init(&desc);
 142         if (err)
 143                 goto out;
 144         sg_init_one(sg, header, hdrlen);
 145         err = crypto_hash_update(&desc, sg, hdrlen);
 146         if (err)
 147                 goto out;
 148         err = xdr_process_buf(body, body_offset, body->len - body_offset,
 149                               checksummer, &desc);
 150         if (err)
 151                 goto out;
 152         err = crypto_hash_final(&desc, cksum->data);
 153
 154 out:
 155         crypto_free_hash(desc.tfm);
 156         return err ? GSS_S_FAILURE : 0;
 157 }
 158
 159 struct encryptor_desc {
 160         u8 iv[8]; /* XXX hard-coded blocksize */
 161         struct blkcipher_desc desc;
 162         int pos;
 163         struct xdr_buf *outbuf;
 164         struct page **pages;
 165         struct scatterlist infrags[4];
 166         struct scatterlist outfrags[4];
 167         int fragno;
 168         int fraglen;
 169 };
 170
 171 static int
 172 encryptor(struct scatterlist *sg, void *data)
 173 {
 174         struct encryptor_desc *desc = data;
 175         struct xdr_buf *outbuf = desc->outbuf;
 176         struct page *in_page;
 177         int thislen = desc->fraglen + sg->length;
 178         int fraglen, ret;
 179         int page_pos;
 180
 181         /* Worst case is 4 fragments: head, end of page 1, start
 182          * of page 2, tail.  Anything more is a bug. */
 183         BUG_ON(desc->fragno > 3);
 184
 185         page_pos = desc->pos - outbuf->head[0].iov_len;
 186         if (page_pos >= 0 && page_pos < outbuf->page_len) {
 187                 /* pages are not in place: */
 188                 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
 189                 in_page = desc->pages[i];
 190         } else {
 191                 in_page = sg_page(sg);
 192         }
 193         sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
 194                     sg->offset);
 195         sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
 196                     sg->offset);
 197         desc->fragno++;
 198         desc->fraglen += sg->length;
 199         desc->pos += sg->length;
 200
 201         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 202         thislen -= fraglen;
 203
 204         if (thislen == 0)
 205                 return 0;
 206
 207         sg_mark_end(&desc->infrags[desc->fragno - 1]);
 208         sg_mark_end(&desc->outfrags[desc->fragno - 1]);
 209
 210         ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
 211                                           desc->infrags, thislen);
 212         if (ret)
 213                 return ret;
 214
 215         sg_init_table(desc->infrags, 4);
 216         sg_init_table(desc->outfrags, 4);
 217
 218         if (fraglen) {
 219                 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
 220                                 sg->offset + sg->length - fraglen);
 221                 desc->infrags[0] = desc->outfrags[0];
 222                 sg_assign_page(&desc->infrags[0], in_page);
 223                 desc->fragno = 1;
 224                 desc->fraglen = fraglen;
 225         } else {
 226                 desc->fragno = 0;
 227                 desc->fraglen = 0;
 228         }
 229         return 0;
 230 }
 231
 232 int
 233 gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
 234                     int offset, struct page **pages)
 235 {
 236         int ret;
 237         struct encryptor_desc desc;
 238
 239         BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
 240
 241         memset(desc.iv, 0, sizeof(desc.iv));
 242         desc.desc.tfm = tfm;
 243         desc.desc.info = desc.iv;
 244         desc.desc.flags = 0;
 245         desc.pos = offset;
 246         desc.outbuf = buf;
 247         desc.pages = pages;
 248         desc.fragno = 0;
 249         desc.fraglen = 0;
 250
 251         sg_init_table(desc.infrags, 4);
 252         sg_init_table(desc.outfrags, 4);
 253
 254         ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
 255         return ret;
 256 }
 257
 258 struct decryptor_desc {
 259         u8 iv[8]; /* XXX hard-coded blocksize */
 260         struct blkcipher_desc desc;
 261         struct scatterlist frags[4];
 262         int fragno;
 263         int fraglen;
 264 };
 265
 266 static int
 267 decryptor(struct scatterlist *sg, void *data)
 268 {
 269         struct decryptor_desc *desc = data;
 270         int thislen = desc->fraglen + sg->length;
 271         int fraglen, ret;
 272
 273         /* Worst case is 4 fragments: head, end of page 1, start
 274          * of page 2, tail.  Anything more is a bug. */
 275         BUG_ON(desc->fragno > 3);
 276         sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
 277                     sg->offset);
 278         desc->fragno++;
 279         desc->fraglen += sg->length;
 280
 281         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 282         thislen -= fraglen;
 283
 284         if (thislen == 0)
 285                 return 0;
 286
 287         sg_mark_end(&desc->frags[desc->fragno - 1]);
 288
 289         ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
 290                                           desc->frags, thislen);
 291         if (ret)
 292                 return ret;
 293
 294         sg_init_table(desc->frags, 4);
 295
 296         if (fraglen) {
 297                 sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
 298                                 sg->offset + sg->length - fraglen);
 299                 desc->fragno = 1;
 300                 desc->fraglen = fraglen;
 301         } else {
 302                 desc->fragno = 0;
 303                 desc->fraglen = 0;
 304         }
 305         return 0;
 306 }
 307
 308 int
 309 gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
 310                     int offset)
 311 {
 312         struct decryptor_desc desc;
 313
 314         /* XXXJBF: */
 315         BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
 316
 317         memset(desc.iv, 0, sizeof(desc.iv));
 318         desc.desc.tfm = tfm;
 319         desc.desc.info = desc.iv;
 320         desc.desc.flags = 0;
 321         desc.fragno = 0;
 322         desc.fraglen = 0;
 323
 324         sg_init_table(desc.frags, 4);
 325
 326         return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
 327 }