net/sunrpc/auth_gss/gss_krb5_mech.c

   1 /*
   2  *  linux/net/sunrpc/gss_krb5_mech.c
   3  *
   4  *  Copyright (c) 2001 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Andy Adamson <andros@umich.edu>
   8  *  J. Bruce Fields <bfields@umich.edu>
   9  *
  10  *  Redistribution and use in source and binary forms, with or without
  11  *  modification, are permitted provided that the following conditions
  12  *  are met:
  13  *
  14  *  1. Redistributions of source code must retain the above copyright
  15  *     notice, this list of conditions and the following disclaimer.
  16  *  2. Redistributions in binary form must reproduce the above copyright
  17  *     notice, this list of conditions and the following disclaimer in the
  18  *     documentation and/or other materials provided with the distribution.
  19  *  3. Neither the name of the University nor the names of its
  20  *     contributors may be used to endorse or promote products derived
  21  *     from this software without specific prior written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  24  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  26  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  28  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  29  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  30  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  */
  36
  37 #include <linux/err.h>
  38 #include <linux/module.h>
  39 #include <linux/init.h>
  40 #include <linux/types.h>
  41 #include <linux/slab.h>
  42 #include <linux/sunrpc/auth.h>
  43 #include <linux/sunrpc/gss_krb5.h>
  44 #include <linux/sunrpc/xdr.h>
  45 #include <linux/crypto.h>
  46
  47 #ifdef RPC_DEBUG
  48 # define RPCDBG_FACILITY        RPCDBG_AUTH
  49 #endif
  50
  51 static const void *
  52 simple_get_bytes(const void *p, const void *end, void *res, int len)
  53 {
  54         const void *q = (const void *)((const char *)p + len);
  55         if (unlikely(q > end || q < p))
  56                 return ERR_PTR(-EFAULT);
  57         memcpy(res, p, len);
  58         return q;
  59 }
  60
  61 static const void *
  62 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
  63 {
  64         const void *q;
  65         unsigned int len;
  66
  67         p = simple_get_bytes(p, end, &len, sizeof(len));
  68         if (IS_ERR(p))
  69                 return p;
  70         q = (const void *)((const char *)p + len);
  71         if (unlikely(q > end || q < p))
  72                 return ERR_PTR(-EFAULT);
  73         res->data = kmemdup(p, len, GFP_NOFS);
  74         if (unlikely(res->data == NULL))
  75                 return ERR_PTR(-ENOMEM);
  76         res->len = len;
  77         return q;
  78 }
  79
  80 static inline const void *
  81 get_key(const void *p, const void *end, struct crypto_blkcipher **res)
  82 {
  83         struct xdr_netobj       key;
  84         int                     alg;
  85         char                    *alg_name;
  86
  87         p = simple_get_bytes(p, end, &alg, sizeof(alg));
  88         if (IS_ERR(p))
  89                 goto out_err;
  90         p = simple_get_netobj(p, end, &key);
  91         if (IS_ERR(p))
  92                 goto out_err;
  93
  94         switch (alg) {
  95                 case ENCTYPE_DES_CBC_RAW:
  96                         alg_name = "cbc(des)";
  97                         break;
  98                 default:
  99                         printk("gss_kerberos_mech: unsupported algorithm %d\n", alg);
 100                         goto out_err_free_key;
 101         }
 102         *res = crypto_alloc_blkcipher(alg_name, 0, CRYPTO_ALG_ASYNC);
 103         if (IS_ERR(*res)) {
 104                 printk("gss_kerberos_mech: unable to initialize crypto algorithm %s\n", alg_name);
 105                 *res = NULL;
 106                 goto out_err_free_key;
 107         }
 108         if (crypto_blkcipher_setkey(*res, key.data, key.len)) {
 109                 printk("gss_kerberos_mech: error setting key for crypto algorithm %s\n", alg_name);
 110                 goto out_err_free_tfm;
 111         }
 112
 113         kfree(key.data);
 114         return p;
 115
 116 out_err_free_tfm:
 117         crypto_free_blkcipher(*res);
 118 out_err_free_key:
 119         kfree(key.data);
 120         p = ERR_PTR(-EINVAL);
 121 out_err:
 122         return p;
 123 }
 124
 125 static int
 126 gss_import_sec_context_kerberos(const void *p,
 127                                 size_t len,
 128                                 struct gss_ctx *ctx_id)
 129 {
 130         const void *end = (const void *)((const char *)p + len);
 131         struct  krb5_ctx *ctx;
 132         int tmp;
 133
 134         if (!(ctx = kzalloc(sizeof(*ctx), GFP_NOFS)))
 135                 goto out_err;
 136
 137         p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
 138         if (IS_ERR(p))
 139                 goto out_err_free_ctx;
 140         /* The downcall format was designed before we completely understood
 141          * the uses of the context fields; so it includes some stuff we
 142          * just give some minimal sanity-checking, and some we ignore
 143          * completely (like the next twenty bytes): */
 144         if (unlikely(p + 20 > end || p + 20 < p))
 145                 goto out_err_free_ctx;
 146         p += 20;
 147         p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
 148         if (IS_ERR(p))
 149                 goto out_err_free_ctx;
 150         if (tmp != SGN_ALG_DES_MAC_MD5) {
 151                 p = ERR_PTR(-ENOSYS);
 152                 goto out_err_free_ctx;
 153         }
 154         p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
 155         if (IS_ERR(p))
 156                 goto out_err_free_ctx;
 157         if (tmp != SEAL_ALG_DES) {
 158                 p = ERR_PTR(-ENOSYS);
 159                 goto out_err_free_ctx;
 160         }
 161         p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
 162         if (IS_ERR(p))
 163                 goto out_err_free_ctx;
 164         p = simple_get_bytes(p, end, &ctx->seq_send, sizeof(ctx->seq_send));
 165         if (IS_ERR(p))
 166                 goto out_err_free_ctx;
 167         p = simple_get_netobj(p, end, &ctx->mech_used);
 168         if (IS_ERR(p))
 169                 goto out_err_free_ctx;
 170         p = get_key(p, end, &ctx->enc);
 171         if (IS_ERR(p))
 172                 goto out_err_free_mech;
 173         p = get_key(p, end, &ctx->seq);
 174         if (IS_ERR(p))
 175                 goto out_err_free_key1;
 176         if (p != end) {
 177                 p = ERR_PTR(-EFAULT);
 178                 goto out_err_free_key2;
 179         }
 180
 181         ctx_id->internal_ctx_id = ctx;
 182
 183         dprintk("RPC:       Successfully imported new context.\n");
 184         return 0;
 185
 186 out_err_free_key2:
 187         crypto_free_blkcipher(ctx->seq);
 188 out_err_free_key1:
 189         crypto_free_blkcipher(ctx->enc);
 190 out_err_free_mech:
 191         kfree(ctx->mech_used.data);
 192 out_err_free_ctx:
 193         kfree(ctx);
 194 out_err:
 195         return PTR_ERR(p);
 196 }
 197
 198 static void
 199 gss_delete_sec_context_kerberos(void *internal_ctx) {
 200         struct krb5_ctx *kctx = internal_ctx;
 201
 202         crypto_free_blkcipher(kctx->seq);
 203         crypto_free_blkcipher(kctx->enc);
 204         kfree(kctx->mech_used.data);
 205         kfree(kctx);
 206 }
 207
 208 static const struct gss_api_ops gss_kerberos_ops = {
 209         .gss_import_sec_context = gss_import_sec_context_kerberos,
 210         .gss_get_mic            = gss_get_mic_kerberos,
 211         .gss_verify_mic         = gss_verify_mic_kerberos,
 212         .gss_wrap               = gss_wrap_kerberos,
 213         .gss_unwrap             = gss_unwrap_kerberos,
 214         .gss_delete_sec_context = gss_delete_sec_context_kerberos,
 215 };
 216
 217 static struct pf_desc gss_kerberos_pfs[] = {
 218         [0] = {
 219                 .pseudoflavor = RPC_AUTH_GSS_KRB5,
 220                 .service = RPC_GSS_SVC_NONE,
 221                 .name = "krb5",
 222         },
 223         [1] = {
 224                 .pseudoflavor = RPC_AUTH_GSS_KRB5I,
 225                 .service = RPC_GSS_SVC_INTEGRITY,
 226                 .name = "krb5i",
 227         },
 228         [2] = {
 229                 .pseudoflavor = RPC_AUTH_GSS_KRB5P,
 230                 .service = RPC_GSS_SVC_PRIVACY,
 231                 .name = "krb5p",
 232         },
 233 };
 234
 235 static struct gss_api_mech gss_kerberos_mech = {
 236         .gm_name        = "krb5",
 237         .gm_owner       = THIS_MODULE,
 238         .gm_oid         = {9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"},
 239         .gm_ops         = &gss_kerberos_ops,
 240         .gm_pf_num      = ARRAY_SIZE(gss_kerberos_pfs),
 241         .gm_pfs         = gss_kerberos_pfs,
 242 };
 243
 244 static int __init init_kerberos_module(void)
 245 {
 246         int status;
 247
 248         status = gss_mech_register(&gss_kerberos_mech);
 249         if (status)
 250                 printk("Failed to register kerberos gss mechanism!\n");
 251         return status;
 252 }
 253
 254 static void __exit cleanup_kerberos_module(void)
 255 {
 256         gss_mech_unregister(&gss_kerberos_mech);
 257 }
 258
 259 MODULE_LICENSE("GPL");
 260 module_init(init_kerberos_module);
 261 module_exit(cleanup_kerberos_module);