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/slab.h>
  41 #include <linux/scatterlist.h>
  42 #include <linux/crypto.h>
  43 #include <linux/highmem.h>
  44 #include <linux/pagemap.h>
  45 #include <linux/sunrpc/gss_krb5.h>
  46 #include <linux/sunrpc/xdr.h>
  47
  48 #ifdef RPC_DEBUG
  49 # define RPCDBG_FACILITY        RPCDBG_AUTH
  50 #endif
  51
  52 u32
  53 krb5_encrypt(
  54         struct crypto_blkcipher *tfm,
  55         void * iv,
  56         void * in,
  57         void * out,
  58         int length)
  59 {
  60         u32 ret = -EINVAL;
  61         struct scatterlist sg[1];
  62         u8 local_iv[16] = {0};
  63         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
  64
  65         if (length % crypto_blkcipher_blocksize(tfm) != 0)
  66                 goto out;
  67
  68         if (crypto_blkcipher_ivsize(tfm) > 16) {
  69                 dprintk("RPC:       gss_k5encrypt: tfm iv size to large %d\n",
  70                          crypto_blkcipher_ivsize(tfm));
  71                 goto out;
  72         }
  73
  74         if (iv)
  75                 memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
  76
  77         memcpy(out, in, length);
  78         sg_set_buf(sg, out, length);
  79
  80         ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
  81 out:
  82         dprintk("RPC:       krb5_encrypt returns %d\n", ret);
  83         return ret;
  84 }
  85
  86 EXPORT_SYMBOL(krb5_encrypt);
  87
  88 u32
  89 krb5_decrypt(
  90      struct crypto_blkcipher *tfm,
  91      void * iv,
  92      void * in,
  93      void * out,
  94      int length)
  95 {
  96         u32 ret = -EINVAL;
  97         struct scatterlist sg[1];
  98         u8 local_iv[16] = {0};
  99         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
 100
 101         if (length % crypto_blkcipher_blocksize(tfm) != 0)
 102                 goto out;
 103
 104         if (crypto_blkcipher_ivsize(tfm) > 16) {
 105                 dprintk("RPC:       gss_k5decrypt: tfm iv size to large %d\n",
 106                         crypto_blkcipher_ivsize(tfm));
 107                 goto out;
 108         }
 109         if (iv)
 110                 memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
 111
 112         memcpy(out, in, length);
 113         sg_set_buf(sg, out, length);
 114
 115         ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
 116 out:
 117         dprintk("RPC:       gss_k5decrypt returns %d\n",ret);
 118         return ret;
 119 }
 120
 121 EXPORT_SYMBOL(krb5_decrypt);
 122
 123 static int
 124 checksummer(struct scatterlist *sg, void *data)
 125 {
 126         struct hash_desc *desc = data;
 127
 128         return crypto_hash_update(desc, sg, sg->length);
 129 }
 130
 131 /* checksum the plaintext data and hdrlen bytes of the token header */
 132 s32
 133 make_checksum(char *cksumname, char *header, int hdrlen, struct xdr_buf *body,
 134                    int body_offset, struct xdr_netobj *cksum)
 135 {
 136         struct hash_desc                desc; /* XXX add to ctx? */
 137         struct scatterlist              sg[1];
 138         int err;
 139
 140         desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
 141         if (IS_ERR(desc.tfm))
 142                 return GSS_S_FAILURE;
 143         cksum->len = crypto_hash_digestsize(desc.tfm);
 144         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 145
 146         err = crypto_hash_init(&desc);
 147         if (err)
 148                 goto out;
 149         sg_set_buf(sg, header, hdrlen);
 150         err = crypto_hash_update(&desc, sg, hdrlen);
 151         if (err)
 152                 goto out;
 153         err = xdr_process_buf(body, body_offset, body->len - body_offset,
 154                               checksummer, &desc);
 155         if (err)
 156                 goto out;
 157         err = crypto_hash_final(&desc, cksum->data);
 158
 159 out:
 160         crypto_free_hash(desc.tfm);
 161         return err ? GSS_S_FAILURE : 0;
 162 }
 163
 164 EXPORT_SYMBOL(make_checksum);
 165
 166 struct encryptor_desc {
 167         u8 iv[8]; /* XXX hard-coded blocksize */
 168         struct blkcipher_desc desc;
 169         int pos;
 170         struct xdr_buf *outbuf;
 171         struct page **pages;
 172         struct scatterlist infrags[4];
 173         struct scatterlist outfrags[4];
 174         int fragno;
 175         int fraglen;
 176 };
 177
 178 static int
 179 encryptor(struct scatterlist *sg, void *data)
 180 {
 181         struct encryptor_desc *desc = data;
 182         struct xdr_buf *outbuf = desc->outbuf;
 183         struct page *in_page;
 184         int thislen = desc->fraglen + sg->length;
 185         int fraglen, ret;
 186         int page_pos;
 187
 188         /* Worst case is 4 fragments: head, end of page 1, start
 189          * of page 2, tail.  Anything more is a bug. */
 190         BUG_ON(desc->fragno > 3);
 191         desc->infrags[desc->fragno] = *sg;
 192         desc->outfrags[desc->fragno] = *sg;
 193
 194         page_pos = desc->pos - outbuf->head[0].iov_len;
 195         if (page_pos >= 0 && page_pos < outbuf->page_len) {
 196                 /* pages are not in place: */
 197                 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
 198                 in_page = desc->pages[i];
 199         } else {
 200                 in_page = sg->page;
 201         }
 202         desc->infrags[desc->fragno].page = in_page;
 203         desc->fragno++;
 204         desc->fraglen += sg->length;
 205         desc->pos += sg->length;
 206
 207         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 208         thislen -= fraglen;
 209
 210         if (thislen == 0)
 211                 return 0;
 212
 213         ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
 214                                           desc->infrags, thislen);
 215         if (ret)
 216                 return ret;
 217         if (fraglen) {
 218                 desc->outfrags[0].page = sg->page;
 219                 desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
 220                 desc->outfrags[0].length = fraglen;
 221                 desc->infrags[0] = desc->outfrags[0];
 222                 desc->infrags[0].page = 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         ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
 252         return ret;
 253 }
 254
 255 EXPORT_SYMBOL(gss_encrypt_xdr_buf);
 256
 257 struct decryptor_desc {
 258         u8 iv[8]; /* XXX hard-coded blocksize */
 259         struct blkcipher_desc desc;
 260         struct scatterlist frags[4];
 261         int fragno;
 262         int fraglen;
 263 };
 264
 265 static int
 266 decryptor(struct scatterlist *sg, void *data)
 267 {
 268         struct decryptor_desc *desc = data;
 269         int thislen = desc->fraglen + sg->length;
 270         int fraglen, ret;
 271
 272         /* Worst case is 4 fragments: head, end of page 1, start
 273          * of page 2, tail.  Anything more is a bug. */
 274         BUG_ON(desc->fragno > 3);
 275         desc->frags[desc->fragno] = *sg;
 276         desc->fragno++;
 277         desc->fraglen += sg->length;
 278
 279         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 280         thislen -= fraglen;
 281
 282         if (thislen == 0)
 283                 return 0;
 284
 285         ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
 286                                           desc->frags, thislen);
 287         if (ret)
 288                 return ret;
 289         if (fraglen) {
 290                 desc->frags[0].page = sg->page;
 291                 desc->frags[0].offset = sg->offset + sg->length - fraglen;
 292                 desc->frags[0].length = fraglen;
 293                 desc->fragno = 1;
 294                 desc->fraglen = fraglen;
 295         } else {
 296                 desc->fragno = 0;
 297                 desc->fraglen = 0;
 298         }
 299         return 0;
 300 }
 301
 302 int
 303 gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
 304                     int offset)
 305 {
 306         struct decryptor_desc desc;
 307
 308         /* XXXJBF: */
 309         BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
 310
 311         memset(desc.iv, 0, sizeof(desc.iv));
 312         desc.desc.tfm = tfm;
 313         desc.desc.info = desc.iv;
 314         desc.desc.flags = 0;
 315         desc.fragno = 0;
 316         desc.fraglen = 0;
 317         return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
 318 }
 319
 320 EXPORT_SYMBOL(gss_decrypt_xdr_buf);