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(1, "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 (!(sname = calloc(name.length + 1, 1))) {
 204                 printerr(0, "WARNING: get_ids: error allocating %d bytes "
 205                         "for sname\n", name.length + 1);
 206                 goto out;
 207         }
 208         memcpy(sname, name.value, name.length);
 209         printerr(1, "sname = %s\n", sname);
 210
 211         res = -EINVAL;
 212         if ((secname = mech2file(mech)) == NULL) {
 213                 printerr(0, "WARNING: get_ids: error mapping mech to "
 214                         "file for name '%s'\n", sname);
 215                 goto out_free;
 216         }
 217         nfs4_init_name_mapping(NULL); /* XXX: should only do this once */
 218         res = nfs4_gss_princ_to_ids(secname, sname, &uid, &gid);
 219         if (res < 0) {
 220                 printerr(0, "WARNING: get_ids: unable to map "
 221                         "name '%s' to a uid\n", sname);
 222                 goto out_free;
 223         }
 224         cred->cr_uid = uid;
 225         cred->cr_gid = gid;
 226         add_supplementary_groups(secname, sname, cred);
 227         res = 0;
 228 out_free:
 229         free(sname);
 230 out:
 231         return res;
 232 }
 233
 234 void
 235 print_hexl(int pri, unsigned char *cp, int length)
 236 {
 237         int i, j, jm;
 238         unsigned char c;
 239
 240         printerr(pri, "length %d\n",length);
 241         printerr(pri, "\n");
 242
 243         for (i = 0; i < length; i += 0x10) {
 244                 printerr(pri, "  %04x: ", (u_int)i);
 245                 jm = length - i;
 246                 jm = jm > 16 ? 16 : jm;
 247
 248                 for (j = 0; j < jm; j++) {
 249                         if ((j % 2) == 1)
 250                                 printerr(pri,"%02x ", (u_int)cp[i+j]);
 251                         else
 252                                 printerr(pri,"%02x", (u_int)cp[i+j]);
 253                 }
 254                 for (; j < 16; j++) {
 255                         if ((j % 2) == 1)
 256                                 printerr(pri,"   ");
 257                         else
 258                                 printerr(pri,"  ");
 259                 }
 260                 printerr(pri," ");
 261
 262                 for (j = 0; j < jm; j++) {
 263                         c = cp[i+j];
 264                         c = isprint(c) ? c : '.';
 265                         printerr(pri,"%c", c);
 266                 }
 267                 printerr(pri,"\n");
 268         }
 269 }
 270
 271 void
 272 handle_nullreq(FILE *f) {
 273         /* XXX initialize to a random integer to reduce chances of unnecessary
 274          * invalidation of existing ctx's on restarting svcgssd. */
 275         static u_int32_t        handle_seq = 0;
 276         char                    in_tok_buf[TOKEN_BUF_SIZE];
 277         char                    in_handle_buf[15];
 278         char                    out_handle_buf[15];
 279         gss_buffer_desc         in_tok = {.value = in_tok_buf},
 280                                 out_tok = {.value = NULL},
 281                                 in_handle = {.value = in_handle_buf},
 282                                 out_handle = {.value = out_handle_buf},
 283                                 ctx_token = {.value = NULL},
 284         /* XXX isn't there a define for this?: */
 285                                 null_token = {.value = NULL};
 286         u_int32_t               ret_flags;
 287         gss_ctx_id_t            ctx = GSS_C_NO_CONTEXT;
 288         gss_name_t              client_name;
 289         gss_OID                 mech = GSS_C_NO_OID;
 290         u_int32_t               maj_stat = GSS_S_FAILURE, min_stat = 0;
 291         struct svc_cred         cred;
 292         static char             *lbuf = NULL;
 293         static int              lbuflen = 0;
 294         static char             *cp;
 295
 296         printerr(1, "handling null request\n");
 297
 298         if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
 299                 printerr(0, "WARNING: handle_nullreq: "
 300                             "failed reading request\n");
 301                 return;
 302         }
 303
 304         cp = lbuf;
 305
 306         in_handle.length = (size_t) qword_get(&cp, in_handle.value,
 307                                               sizeof(in_handle_buf));
 308         printerr(2, "in_handle: \n");
 309         print_hexl(2, in_handle.value, in_handle.length);
 310
 311         in_tok.length = (size_t) qword_get(&cp, in_tok.value,
 312                                            sizeof(in_tok_buf));
 313         printerr(2, "in_tok: \n");
 314         print_hexl(2, in_tok.value, in_tok.length);
 315
 316         if (in_tok.length < 0) {
 317                 printerr(0, "WARNING: handle_nullreq: "
 318                             "failed parsing request\n");
 319                 goto out_err;
 320         }
 321
 322         if (in_handle.length != 0) { /* CONTINUE_INIT case */
 323                 if (in_handle.length != sizeof(ctx)) {
 324                         printerr(0, "WARNING: handle_nullreq: "
 325                                     "input handle has unexpected length %d\n",
 326                                     in_handle.length);
 327                         goto out_err;
 328                 }
 329                 /* in_handle is the context id stored in the out_handle
 330                  * for the GSS_S_CONTINUE_NEEDED case below.  */
 331                 memcpy(&ctx, in_handle.value, in_handle.length);
 332         }
 333
 334         maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
 335                         &in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
 336                         &mech, &out_tok, &ret_flags, NULL, NULL);
 337
 338         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 339                 printerr(1, "gss_accept_sec_context GSS_S_CONTINUE_NEEDED\n");
 340
 341                 /* Save the context handle for future calls */
 342                 out_handle.length = sizeof(ctx);
 343                 memcpy(out_handle.value, &ctx, sizeof(ctx));
 344                 goto continue_needed;
 345         }
 346         else if (maj_stat != GSS_S_COMPLETE) {
 347                 printerr(0, "WARNING: gss_accept_sec_context failed\n");
 348                 pgsserr("handle_nullreq: gss_accept_sec_context",
 349                         maj_stat, min_stat, mech);
 350                 goto out_err;
 351         }
 352         if (get_ids(client_name, mech, &cred)) {
 353                 /* get_ids() prints error msg */
 354                 maj_stat = GSS_S_BAD_NAME; /* XXX ? */
 355                 goto out_err;
 356         }
 357
 358
 359         /* Context complete. Pass handle_seq in out_handle to use
 360          * for context lookup in the kernel. */
 361         handle_seq++;
 362         out_handle.length = sizeof(handle_seq);
 363         memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));
 364
 365         /* kernel needs ctx to calculate verifier on null response, so
 366          * must give it context before doing null call: */
 367         if (serialize_context_for_kernel(ctx, &ctx_token, mech)) {
 368                 printerr(0, "WARNING: handle_nullreq: "
 369                             "serialize_context_for_kernel failed\n");
 370                 maj_stat = GSS_S_FAILURE;
 371                 goto out_err;
 372         }
 373         do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
 374 continue_needed:
 375         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 376                         &out_handle, &out_tok);
 377 out:
 378         if (ctx_token.value != NULL)
 379                 free(ctx_token.value);
 380         printerr(1, "finished handling null request\n");
 381         return;
 382
 383 out_err:
 384         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 385                         &null_token, &null_token);
 386         goto out;
 387 }