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
  76         printerr(1, "doing downcall\n");
  77         if ((fname = mech2file(mech)) == NULL)
  78                 goto out_err;
  79         f = fopen(SVCGSSD_CONTEXT_CHANNEL, "w");
  80         if (f == NULL) {
  81                 printerr(0, "WARNING: unable to open downcall channel "
  82                              "%s: %s\n",
  83                              SVCGSSD_CONTEXT_CHANNEL, strerror(errno));
  84                 goto out_err;
  85         }
  86         qword_printhex(f, out_handle->value, out_handle->length);
  87         /* XXX are types OK for the rest of this? */
  88         qword_printint(f, 0x7fffffff); /*XXX need a better timeout */
  89         qword_printint(f, cred->cr_uid);
  90         qword_printint(f, cred->cr_gid);
  91         qword_printint(f, cred->cr_ngroups);
  92         for (i=0; i < cred->cr_ngroups; i++)
  93                 qword_printint(f, cred->cr_groups[i]);
  94         qword_print(f, fname);
  95         qword_printhex(f, context_token->value, context_token->length);
  96         qword_eol(f);
  97         fclose(f);
  98         return 0;
  99 out_err:
 100         printerr(0, "WARNING: downcall failed\n");
 101         return -1;
 102 }
 103
 104 struct gss_verifier {
 105         u_int32_t       flav;
 106         gss_buffer_desc body;
 107 };
 108
 109 #define RPCSEC_GSS_SEQ_WIN      5
 110
 111 static int
 112 send_response(FILE *f, gss_buffer_desc *in_handle, gss_buffer_desc *in_token,
 113               u_int32_t maj_stat, u_int32_t min_stat,
 114               gss_buffer_desc *out_handle, gss_buffer_desc *out_token)
 115 {
 116         char buf[2 * TOKEN_BUF_SIZE];
 117         char *bp = buf;
 118         int blen = sizeof(buf);
 119         /* XXXARG: */
 120         int g;
 121
 122         printerr(1, "sending null reply\n");
 123
 124         qword_addhex(&bp, &blen, in_handle->value, in_handle->length);
 125         qword_addhex(&bp, &blen, in_token->value, in_token->length);
 126         qword_addint(&bp, &blen, 0x7fffffff); /*XXX need a better timeout */
 127         qword_addint(&bp, &blen, maj_stat);
 128         qword_addint(&bp, &blen, min_stat);
 129         qword_addhex(&bp, &blen, out_handle->value, out_handle->length);
 130         qword_addhex(&bp, &blen, out_token->value, out_token->length);
 131         qword_addeol(&bp, &blen);
 132         if (blen <= 0) {
 133                 printerr(0, "WARNING: send_respsonse: message too long\n");
 134                 return -1;
 135         }
 136         g = open(SVCGSSD_INIT_CHANNEL, O_WRONLY);
 137         if (g == -1) {
 138                 printerr(0, "WARNING: open %s failed: %s\n",
 139                                 SVCGSSD_INIT_CHANNEL, strerror(errno));
 140                 return -1;
 141         }
 142         *bp = '\0';
 143         printerr(3, "writing message: %s", buf);
 144         if (write(g, buf, bp - buf) == -1) {
 145                 printerr(0, "WARNING: failed to write message\n");
 146                 close(g);
 147                 return -1;
 148         }
 149         close(g);
 150         return 0;
 151 }
 152
 153 #define rpc_auth_ok                     0
 154 #define rpc_autherr_badcred             1
 155 #define rpc_autherr_rejectedcred        2
 156 #define rpc_autherr_badverf             3
 157 #define rpc_autherr_rejectedverf        4
 158 #define rpc_autherr_tooweak             5
 159 #define rpcsec_gsserr_credproblem       13
 160 #define rpcsec_gsserr_ctxproblem        14
 161
 162 static void
 163 add_supplementary_groups(char *secname, char *name, struct svc_cred *cred)
 164 {
 165         int ret;
 166         static gid_t *groups = NULL;
 167
 168         cred->cr_ngroups = NGROUPS;
 169         ret = nfs4_gss_princ_to_grouplist(secname, name,
 170                         cred->cr_groups, &cred->cr_ngroups);
 171         if (ret < 0) {
 172                 groups = realloc(groups, cred->cr_ngroups*sizeof(gid_t));
 173                 ret = nfs4_gss_princ_to_grouplist(secname, name,
 174                                 groups, &cred->cr_ngroups);
 175                 if (ret < 0)
 176                         cred->cr_ngroups = 0;
 177                 else {
 178                         if (cred->cr_ngroups > NGROUPS)
 179                                 cred->cr_ngroups = NGROUPS;
 180                         memcpy(cred->cr_groups, groups,
 181                                         cred->cr_ngroups*sizeof(gid_t));
 182                 }
 183         }
 184 }
 185
 186 static int
 187 get_ids(gss_name_t client_name, gss_OID mech, struct svc_cred *cred)
 188 {
 189         u_int32_t       maj_stat, min_stat;
 190         gss_buffer_desc name;
 191         char            *sname;
 192         int             res = -1;
 193         uid_t           uid, gid;
 194         gss_OID         name_type = GSS_C_NO_OID;
 195         char            *secname;
 196
 197         maj_stat = gss_display_name(&min_stat, client_name, &name, &name_type);
 198         if (maj_stat != GSS_S_COMPLETE) {
 199                 pgsserr("get_ids: gss_display_name",
 200                         maj_stat, min_stat, mech);
 201                 goto out;
 202         }
 203         if (name.length >= 0xffff || /* be certain name.length+1 doesn't overflow */
 204             !(sname = calloc(name.length + 1, 1))) {
 205                 printerr(0, "WARNING: get_ids: error allocating %d bytes "
 206                         "for sname\n", name.length + 1);
 207                 gss_release_buffer(&min_stat, &name);
 208                 goto out;
 209         }
 210         memcpy(sname, name.value, name.length);
 211         printerr(1, "sname = %s\n", sname);
 212         gss_release_buffer(&min_stat, &name);
 213
 214         res = -EINVAL;
 215         if ((secname = mech2file(mech)) == NULL) {
 216                 printerr(0, "WARNING: get_ids: error mapping mech to "
 217                         "file for name '%s'\n", sname);
 218                 goto out_free;
 219         }
 220         nfs4_init_name_mapping(NULL); /* XXX: should only do this once */
 221         res = nfs4_gss_princ_to_ids(secname, sname, &uid, &gid);
 222         if (res < 0) {
 223                 /*
 224                  * -ENOENT means there was no mapping, any other error
 225                  * value means there was an error trying to do the
 226                  * mapping.
 227                  */
 228                 if (res == -ENOENT) {
 229                         cred->cr_uid = 65534;   /* XXX */
 230                         cred->cr_gid = 65534;   /* XXX */
 231                         cred->cr_ngroups = 0;
 232                         res = 0;
 233                         goto out_free;
 234                 }
 235                 printerr(0, "WARNING: get_ids: failed to map name '%s' "
 236                         "to uid/gid: %s\n", sname, strerror(-res));
 237                 goto out_free;
 238         }
 239         cred->cr_uid = uid;
 240         cred->cr_gid = gid;
 241         add_supplementary_groups(secname, sname, cred);
 242         res = 0;
 243 out_free:
 244         free(sname);
 245 out:
 246         return res;
 247 }
 248
 249 void
 250 print_hexl(int pri, unsigned char *cp, int length)
 251 {
 252         int i, j, jm;
 253         unsigned char c;
 254
 255         printerr(pri, "length %d\n",length);
 256         printerr(pri, "\n");
 257
 258         for (i = 0; i < length; i += 0x10) {
 259                 printerr(pri, "  %04x: ", (u_int)i);
 260                 jm = length - i;
 261                 jm = jm > 16 ? 16 : jm;
 262
 263                 for (j = 0; j < jm; j++) {
 264                         if ((j % 2) == 1)
 265                                 printerr(pri,"%02x ", (u_int)cp[i+j]);
 266                         else
 267                                 printerr(pri,"%02x", (u_int)cp[i+j]);
 268                 }
 269                 for (; j < 16; j++) {
 270                         if ((j % 2) == 1)
 271                                 printerr(pri,"   ");
 272                         else
 273                                 printerr(pri,"  ");
 274                 }
 275                 printerr(pri," ");
 276
 277                 for (j = 0; j < jm; j++) {
 278                         c = cp[i+j];
 279                         c = isprint(c) ? c : '.';
 280                         printerr(pri,"%c", c);
 281                 }
 282                 printerr(pri,"\n");
 283         }
 284 }
 285
 286 void
 287 handle_nullreq(FILE *f) {
 288         /* XXX initialize to a random integer to reduce chances of unnecessary
 289          * invalidation of existing ctx's on restarting svcgssd. */
 290         static u_int32_t        handle_seq = 0;
 291         char                    in_tok_buf[TOKEN_BUF_SIZE];
 292         char                    in_handle_buf[15];
 293         char                    out_handle_buf[15];
 294         gss_buffer_desc         in_tok = {.value = in_tok_buf},
 295                                 out_tok = {.value = NULL},
 296                                 in_handle = {.value = in_handle_buf},
 297                                 out_handle = {.value = out_handle_buf},
 298                                 ctx_token = {.value = NULL},
 299                                 ignore_out_tok = {.value = NULL},
 300         /* XXX isn't there a define for this?: */
 301                                 null_token = {.value = NULL};
 302         u_int32_t               ret_flags;
 303         gss_ctx_id_t            ctx = GSS_C_NO_CONTEXT;
 304         gss_name_t              client_name;
 305         gss_OID                 mech = GSS_C_NO_OID;
 306         u_int32_t               maj_stat = GSS_S_FAILURE, min_stat = 0;
 307         u_int32_t               ignore_min_stat;
 308         struct svc_cred         cred;
 309         static char             *lbuf = NULL;
 310         static int              lbuflen = 0;
 311         static char             *cp;
 312
 313         printerr(1, "handling null request\n");
 314
 315         if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
 316                 printerr(0, "WARNING: handle_nullreq: "
 317                             "failed reading request\n");
 318                 return;
 319         }
 320
 321         cp = lbuf;
 322
 323         in_handle.length = (size_t) qword_get(&cp, in_handle.value,
 324                                               sizeof(in_handle_buf));
 325         printerr(2, "in_handle: \n");
 326         print_hexl(2, in_handle.value, in_handle.length);
 327
 328         in_tok.length = (size_t) qword_get(&cp, in_tok.value,
 329                                            sizeof(in_tok_buf));
 330         printerr(2, "in_tok: \n");
 331         print_hexl(2, in_tok.value, in_tok.length);
 332
 333         if (in_tok.length < 0) {
 334                 printerr(0, "WARNING: handle_nullreq: "
 335                             "failed parsing request\n");
 336                 goto out_err;
 337         }
 338
 339         if (in_handle.length != 0) { /* CONTINUE_INIT case */
 340                 if (in_handle.length != sizeof(ctx)) {
 341                         printerr(0, "WARNING: handle_nullreq: "
 342                                     "input handle has unexpected length %d\n",
 343                                     in_handle.length);
 344                         goto out_err;
 345                 }
 346                 /* in_handle is the context id stored in the out_handle
 347                  * for the GSS_S_CONTINUE_NEEDED case below.  */
 348                 memcpy(&ctx, in_handle.value, in_handle.length);
 349         }
 350
 351         maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
 352                         &in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
 353                         &mech, &out_tok, &ret_flags, NULL, NULL);
 354
 355         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 356                 printerr(1, "gss_accept_sec_context GSS_S_CONTINUE_NEEDED\n");
 357
 358                 /* Save the context handle for future calls */
 359                 out_handle.length = sizeof(ctx);
 360                 memcpy(out_handle.value, &ctx, sizeof(ctx));
 361                 goto continue_needed;
 362         }
 363         else if (maj_stat != GSS_S_COMPLETE) {
 364                 printerr(0, "WARNING: gss_accept_sec_context failed\n");
 365                 pgsserr("handle_nullreq: gss_accept_sec_context",
 366                         maj_stat, min_stat, mech);
 367                 goto out_err;
 368         }
 369         if (get_ids(client_name, mech, &cred)) {
 370                 /* get_ids() prints error msg */
 371                 maj_stat = GSS_S_BAD_NAME; /* XXX ? */
 372                 gss_release_name(&ignore_min_stat, &client_name);
 373                 goto out_err;
 374         }
 375         gss_release_name(&ignore_min_stat, &client_name);
 376
 377
 378         /* Context complete. Pass handle_seq in out_handle to use
 379          * for context lookup in the kernel. */
 380         handle_seq++;
 381         out_handle.length = sizeof(handle_seq);
 382         memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));
 383
 384         /* kernel needs ctx to calculate verifier on null response, so
 385          * must give it context before doing null call: */
 386         if (serialize_context_for_kernel(ctx, &ctx_token, mech)) {
 387                 printerr(0, "WARNING: handle_nullreq: "
 388                             "serialize_context_for_kernel failed\n");
 389                 maj_stat = GSS_S_FAILURE;
 390                 goto out_err;
 391         }
 392         /* We no longer need the gss context */
 393         gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 394
 395         do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
 396 continue_needed:
 397         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 398                         &out_handle, &out_tok);
 399 out:
 400         if (ctx_token.value != NULL)
 401                 free(ctx_token.value);
 402         if (out_tok.value != NULL)
 403                 gss_release_buffer(&ignore_min_stat, &out_tok);
 404         printerr(1, "finished handling null request\n");
 405         return;
 406
 407 out_err:
 408         if (ctx != GSS_C_NO_CONTEXT)
 409                 gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 410         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 411                         &null_token, &null_token);
 412         goto out;
 413 }