utils/gssd/svcgssd_proc.c

   1 /*
   2   svc_in_gssd_proc.c
   3
   4   Copyright (c) 2000 The Regents of the University of Michigan.
   5   All rights reserved.
   6
   7   Copyright (c) 2002 Bruce Fields <bfields@UMICH.EDU>
   8
   9   Redistribution and use in source and binary forms, with or without
  10   modification, are permitted provided that the following conditions
  11   are met:
  12
  13   1. Redistributions of source code must retain the above copyright
  14      notice, this list of conditions and the following disclaimer.
  15   2. Redistributions in binary form must reproduce the above copyright
  16      notice, this list of conditions and the following disclaimer in the
  17      documentation and/or other materials provided with the distribution.
  18   3. Neither the name of the University nor the names of its
  19      contributors may be used to endorse or promote products derived
  20      from this software without specific prior written permission.
  21
  22   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  25   DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  29   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  30   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  31   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  32   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33
  34 */
  35
  36 #include <sys/param.h>
  37 #include <sys/stat.h>
  38 #include <rpc/rpc.h>
  39
  40 #include <pwd.h>
  41 #include <stdio.h>
  42 #include <unistd.h>
  43 #include <ctype.h>
  44 #include <string.h>
  45 #include <fcntl.h>
  46 #include <errno.h>
  47 #include <nfsidmap.h>
  48
  49 #include "svcgssd.h"
  50 #include "gss_util.h"
  51 #include "err_util.h"
  52 #include "context.h"
  53 #include "cacheio.h"
  54
  55 extern char * mech2file(gss_OID mech);
  56 #define SVCGSSD_CONTEXT_CHANNEL "/proc/net/rpc/auth.rpcsec.context/channel"
  57 #define SVCGSSD_INIT_CHANNEL    "/proc/net/rpc/auth.rpcsec.init/channel"
  58
  59 #define TOKEN_BUF_SIZE          8192
  60
  61 struct svc_cred {
  62         uid_t   cr_uid;
  63         gid_t   cr_gid;
  64         int     cr_ngroups;
  65         gid_t   cr_groups[NGROUPS];
  66 };
  67
  68 static int
  69 do_svc_downcall(gss_buffer_desc *out_handle, struct svc_cred *cred,
  70                 gss_OID mech, gss_buffer_desc *context_token)
  71 {
  72         FILE *f;
  73         int i;
  74         char *fname = NULL;
  75         int err;
  76
  77         printerr(1, "doing downcall\n");
  78         if ((fname = mech2file(mech)) == NULL)
  79                 goto out_err;
  80         f = fopen(SVCGSSD_CONTEXT_CHANNEL, "w");
  81         if (f == NULL) {
  82                 printerr(0, "WARNING: unable to open downcall channel "
  83                              "%s: %s\n",
  84                              SVCGSSD_CONTEXT_CHANNEL, strerror(errno));
  85                 goto out_err;
  86         }
  87         qword_printhex(f, out_handle->value, out_handle->length);
  88         /* XXX are types OK for the rest of this? */
  89         qword_printint(f, 0x7fffffff); /*XXX need a better timeout */
  90         qword_printint(f, cred->cr_uid);
  91         qword_printint(f, cred->cr_gid);
  92         qword_printint(f, cred->cr_ngroups);
  93         for (i=0; i < cred->cr_ngroups; i++)
  94                 qword_printint(f, cred->cr_groups[i]);
  95         qword_print(f, fname);
  96         qword_printhex(f, context_token->value, context_token->length);
  97         err = qword_eol(f);
  98         fclose(f);
  99         return err;
 100 out_err:
 101         printerr(0, "WARNING: downcall failed\n");
 102         return -1;
 103 }
 104
 105 struct gss_verifier {
 106         u_int32_t       flav;
 107         gss_buffer_desc body;
 108 };
 109
 110 #define RPCSEC_GSS_SEQ_WIN      5
 111
 112 static int
 113 send_response(FILE *f, gss_buffer_desc *in_handle, gss_buffer_desc *in_token,
 114               u_int32_t maj_stat, u_int32_t min_stat,
 115               gss_buffer_desc *out_handle, gss_buffer_desc *out_token)
 116 {
 117         char buf[2 * TOKEN_BUF_SIZE];
 118         char *bp = buf;
 119         int blen = sizeof(buf);
 120         /* XXXARG: */
 121         int g;
 122
 123         printerr(1, "sending null reply\n");
 124
 125         qword_addhex(&bp, &blen, in_handle->value, in_handle->length);
 126         qword_addhex(&bp, &blen, in_token->value, in_token->length);
 127         qword_addint(&bp, &blen, 0x7fffffff); /*XXX need a better timeout */
 128         qword_adduint(&bp, &blen, maj_stat);
 129         qword_adduint(&bp, &blen, min_stat);
 130         qword_addhex(&bp, &blen, out_handle->value, out_handle->length);
 131         qword_addhex(&bp, &blen, out_token->value, out_token->length);
 132         qword_addeol(&bp, &blen);
 133         if (blen <= 0) {
 134                 printerr(0, "WARNING: send_respsonse: message too long\n");
 135                 return -1;
 136         }
 137         g = open(SVCGSSD_INIT_CHANNEL, O_WRONLY);
 138         if (g == -1) {
 139                 printerr(0, "WARNING: open %s failed: %s\n",
 140                                 SVCGSSD_INIT_CHANNEL, strerror(errno));
 141                 return -1;
 142         }
 143         *bp = '\0';
 144         printerr(3, "writing message: %s", buf);
 145         if (write(g, buf, bp - buf) == -1) {
 146                 printerr(0, "WARNING: failed to write message\n");
 147                 close(g);
 148                 return -1;
 149         }
 150         close(g);
 151         return 0;
 152 }
 153
 154 #define rpc_auth_ok                     0
 155 #define rpc_autherr_badcred             1
 156 #define rpc_autherr_rejectedcred        2
 157 #define rpc_autherr_badverf             3
 158 #define rpc_autherr_rejectedverf        4
 159 #define rpc_autherr_tooweak             5
 160 #define rpcsec_gsserr_credproblem       13
 161 #define rpcsec_gsserr_ctxproblem        14
 162
 163 static void
 164 add_supplementary_groups(char *secname, char *name, struct svc_cred *cred)
 165 {
 166         int ret;
 167         static gid_t *groups = NULL;
 168
 169         cred->cr_ngroups = NGROUPS;
 170         ret = nfs4_gss_princ_to_grouplist(secname, name,
 171                         cred->cr_groups, &cred->cr_ngroups);
 172         if (ret < 0) {
 173                 groups = realloc(groups, cred->cr_ngroups*sizeof(gid_t));
 174                 ret = nfs4_gss_princ_to_grouplist(secname, name,
 175                                 groups, &cred->cr_ngroups);
 176                 if (ret < 0)
 177                         cred->cr_ngroups = 0;
 178                 else {
 179                         if (cred->cr_ngroups > NGROUPS)
 180                                 cred->cr_ngroups = NGROUPS;
 181                         memcpy(cred->cr_groups, groups,
 182                                         cred->cr_ngroups*sizeof(gid_t));
 183                 }
 184         }
 185 }
 186
 187 static int
 188 get_ids(gss_name_t client_name, gss_OID mech, struct svc_cred *cred)
 189 {
 190         u_int32_t       maj_stat, min_stat;
 191         gss_buffer_desc name;
 192         char            *sname;
 193         int             res = -1;
 194         uid_t           uid, gid;
 195         gss_OID         name_type = GSS_C_NO_OID;
 196         char            *secname;
 197
 198         maj_stat = gss_display_name(&min_stat, client_name, &name, &name_type);
 199         if (maj_stat != GSS_S_COMPLETE) {
 200                 pgsserr("get_ids: gss_display_name",
 201                         maj_stat, min_stat, mech);
 202                 goto out;
 203         }
 204         if (name.length >= 0xffff || /* be certain name.length+1 doesn't overflow */
 205             !(sname = calloc(name.length + 1, 1))) {
 206                 printerr(0, "WARNING: get_ids: error allocating %d bytes "
 207                         "for sname\n", name.length + 1);
 208                 gss_release_buffer(&min_stat, &name);
 209                 goto out;
 210         }
 211         memcpy(sname, name.value, name.length);
 212         printerr(1, "sname = %s\n", sname);
 213         gss_release_buffer(&min_stat, &name);
 214
 215         res = -EINVAL;
 216         if ((secname = mech2file(mech)) == NULL) {
 217                 printerr(0, "WARNING: get_ids: error mapping mech to "
 218                         "file for name '%s'\n", sname);
 219                 goto out_free;
 220         }
 221         nfs4_init_name_mapping(NULL); /* XXX: should only do this once */
 222         res = nfs4_gss_princ_to_ids(secname, sname, &uid, &gid);
 223         if (res < 0) {
 224                 /*
 225                  * -ENOENT means there was no mapping, any other error
 226                  * value means there was an error trying to do the
 227                  * mapping.
 228                  * If there was no mapping, we send down the value -1
 229                  * to indicate that the anonuid/anongid for the export
 230                  * should be used.
 231                  */
 232                 if (res == -ENOENT) {
 233                         cred->cr_uid = -1;
 234                         cred->cr_gid = -1;
 235                         cred->cr_ngroups = 0;
 236                         res = 0;
 237                         goto out_free;
 238                 }
 239                 printerr(0, "WARNING: get_ids: failed to map name '%s' "
 240                         "to uid/gid: %s\n", sname, strerror(-res));
 241                 goto out_free;
 242         }
 243         cred->cr_uid = uid;
 244         cred->cr_gid = gid;
 245         add_supplementary_groups(secname, sname, cred);
 246         res = 0;
 247 out_free:
 248         free(sname);
 249 out:
 250         return res;
 251 }
 252
 253 #ifdef DEBUG
 254 void
 255 print_hexl(const char *description, unsigned char *cp, int length)
 256 {
 257         int i, j, jm;
 258         unsigned char c;
 259
 260         printf("%s (length %d)\n", description, length);
 261
 262         for (i = 0; i < length; i += 0x10) {
 263                 printf("  %04x: ", (u_int)i);
 264                 jm = length - i;
 265                 jm = jm > 16 ? 16 : jm;
 266
 267                 for (j = 0; j < jm; j++) {
 268                         if ((j % 2) == 1)
 269                                 printf("%02x ", (u_int)cp[i+j]);
 270                         else
 271                                 printf("%02x", (u_int)cp[i+j]);
 272                 }
 273                 for (; j < 16; j++) {
 274                         if ((j % 2) == 1)
 275                                 printf("   ");
 276                         else
 277                                 printf("  ");
 278                 }
 279                 printf(" ");
 280
 281                 for (j = 0; j < jm; j++) {
 282                         c = cp[i+j];
 283                         c = isprint(c) ? c : '.';
 284                         printf("%c", c);
 285                 }
 286                 printf("\n");
 287         }
 288 }
 289 #endif
 290
 291 void
 292 handle_nullreq(FILE *f) {
 293         /* XXX initialize to a random integer to reduce chances of unnecessary
 294          * invalidation of existing ctx's on restarting svcgssd. */
 295         static u_int32_t        handle_seq = 0;
 296         char                    in_tok_buf[TOKEN_BUF_SIZE];
 297         char                    in_handle_buf[15];
 298         char                    out_handle_buf[15];
 299         gss_buffer_desc         in_tok = {.value = in_tok_buf},
 300                                 out_tok = {.value = NULL},
 301                                 in_handle = {.value = in_handle_buf},
 302                                 out_handle = {.value = out_handle_buf},
 303                                 ctx_token = {.value = NULL},
 304                                 ignore_out_tok = {.value = NULL},
 305         /* XXX isn't there a define for this?: */
 306                                 null_token = {.value = NULL};
 307         u_int32_t               ret_flags;
 308         gss_ctx_id_t            ctx = GSS_C_NO_CONTEXT;
 309         gss_name_t              client_name;
 310         gss_OID                 mech = GSS_C_NO_OID;
 311         u_int32_t               maj_stat = GSS_S_FAILURE, min_stat = 0;
 312         u_int32_t               ignore_min_stat;
 313         struct svc_cred         cred;
 314         static char             *lbuf = NULL;
 315         static int              lbuflen = 0;
 316         static char             *cp;
 317
 318         printerr(1, "handling null request\n");
 319
 320         if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
 321                 printerr(0, "WARNING: handle_nullreq: "
 322                             "failed reading request\n");
 323                 return;
 324         }
 325
 326         cp = lbuf;
 327
 328         in_handle.length = (size_t) qword_get(&cp, in_handle.value,
 329                                               sizeof(in_handle_buf));
 330 #ifdef DEBUG
 331         print_hexl("in_handle", in_handle.value, in_handle.length);
 332 #endif
 333
 334         in_tok.length = (size_t) qword_get(&cp, in_tok.value,
 335                                            sizeof(in_tok_buf));
 336 #ifdef DEBUG
 337         print_hexl("in_tok", in_tok.value, in_tok.length);
 338 #endif
 339
 340         if (in_tok.length < 0) {
 341                 printerr(0, "WARNING: handle_nullreq: "
 342                             "failed parsing request\n");
 343                 goto out_err;
 344         }
 345
 346         if (in_handle.length != 0) { /* CONTINUE_INIT case */
 347                 if (in_handle.length != sizeof(ctx)) {
 348                         printerr(0, "WARNING: handle_nullreq: "
 349                                     "input handle has unexpected length %d\n",
 350                                     in_handle.length);
 351                         goto out_err;
 352                 }
 353                 /* in_handle is the context id stored in the out_handle
 354                  * for the GSS_S_CONTINUE_NEEDED case below.  */
 355                 memcpy(&ctx, in_handle.value, in_handle.length);
 356         }
 357
 358         maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
 359                         &in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
 360                         &mech, &out_tok, &ret_flags, NULL, NULL);
 361
 362         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 363                 printerr(1, "gss_accept_sec_context GSS_S_CONTINUE_NEEDED\n");
 364
 365                 /* Save the context handle for future calls */
 366                 out_handle.length = sizeof(ctx);
 367                 memcpy(out_handle.value, &ctx, sizeof(ctx));
 368                 goto continue_needed;
 369         }
 370         else if (maj_stat != GSS_S_COMPLETE) {
 371                 printerr(0, "WARNING: gss_accept_sec_context failed\n");
 372                 pgsserr("handle_nullreq: gss_accept_sec_context",
 373                         maj_stat, min_stat, mech);
 374                 goto out_err;
 375         }
 376         if (get_ids(client_name, mech, &cred)) {
 377                 /* get_ids() prints error msg */
 378                 maj_stat = GSS_S_BAD_NAME; /* XXX ? */
 379                 gss_release_name(&ignore_min_stat, &client_name);
 380                 goto out_err;
 381         }
 382         gss_release_name(&ignore_min_stat, &client_name);
 383
 384
 385         /* Context complete. Pass handle_seq in out_handle to use
 386          * for context lookup in the kernel. */
 387         handle_seq++;
 388         out_handle.length = sizeof(handle_seq);
 389         memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));
 390
 391         /* kernel needs ctx to calculate verifier on null response, so
 392          * must give it context before doing null call: */
 393         if (serialize_context_for_kernel(ctx, &ctx_token, mech)) {
 394                 printerr(0, "WARNING: handle_nullreq: "
 395                             "serialize_context_for_kernel failed\n");
 396                 maj_stat = GSS_S_FAILURE;
 397                 goto out_err;
 398         }
 399         /* We no longer need the gss context */
 400         gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 401
 402         do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
 403 continue_needed:
 404         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 405                         &out_handle, &out_tok);
 406 out:
 407         if (ctx_token.value != NULL)
 408                 free(ctx_token.value);
 409         if (out_tok.value != NULL)
 410                 gss_release_buffer(&ignore_min_stat, &out_tok);
 411         printerr(1, "finished handling null request\n");
 412         return;
 413
 414 out_err:
 415         if (ctx != GSS_C_NO_CONTEXT)
 416                 gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 417         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 418                         &null_token, &null_token);
 419         goto out;
 420 }