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                 gss_release_buffer(&min_stat, &name);
 207                 goto out;
 208         }
 209         memcpy(sname, name.value, name.length);
 210         printerr(1, "sname = %s\n", sname);
 211         gss_release_buffer(&min_stat, &name);
 212
 213         res = -EINVAL;
 214         if ((secname = mech2file(mech)) == NULL) {
 215                 printerr(0, "WARNING: get_ids: error mapping mech to "
 216                         "file for name '%s'\n", sname);
 217                 goto out_free;
 218         }
 219         nfs4_init_name_mapping(NULL); /* XXX: should only do this once */
 220         res = nfs4_gss_princ_to_ids(secname, sname, &uid, &gid);
 221         if (res < 0) {
 222                 printerr(0, "WARNING: get_ids: unable to map "
 223                         "name '%s' to a uid\n", sname);
 224                 goto out_free;
 225         }
 226         cred->cr_uid = uid;
 227         cred->cr_gid = gid;
 228         add_supplementary_groups(secname, sname, cred);
 229         res = 0;
 230 out_free:
 231         free(sname);
 232 out:
 233         return res;
 234 }
 235
 236 void
 237 print_hexl(int pri, unsigned char *cp, int length)
 238 {
 239         int i, j, jm;
 240         unsigned char c;
 241
 242         printerr(pri, "length %d\n",length);
 243         printerr(pri, "\n");
 244
 245         for (i = 0; i < length; i += 0x10) {
 246                 printerr(pri, "  %04x: ", (u_int)i);
 247                 jm = length - i;
 248                 jm = jm > 16 ? 16 : jm;
 249
 250                 for (j = 0; j < jm; j++) {
 251                         if ((j % 2) == 1)
 252                                 printerr(pri,"%02x ", (u_int)cp[i+j]);
 253                         else
 254                                 printerr(pri,"%02x", (u_int)cp[i+j]);
 255                 }
 256                 for (; j < 16; j++) {
 257                         if ((j % 2) == 1)
 258                                 printerr(pri,"   ");
 259                         else
 260                                 printerr(pri,"  ");
 261                 }
 262                 printerr(pri," ");
 263
 264                 for (j = 0; j < jm; j++) {
 265                         c = cp[i+j];
 266                         c = isprint(c) ? c : '.';
 267                         printerr(pri,"%c", c);
 268                 }
 269                 printerr(pri,"\n");
 270         }
 271 }
 272
 273 void
 274 handle_nullreq(FILE *f) {
 275         /* XXX initialize to a random integer to reduce chances of unnecessary
 276          * invalidation of existing ctx's on restarting svcgssd. */
 277         static u_int32_t        handle_seq = 0;
 278         char                    in_tok_buf[TOKEN_BUF_SIZE];
 279         char                    in_handle_buf[15];
 280         char                    out_handle_buf[15];
 281         gss_buffer_desc         in_tok = {.value = in_tok_buf},
 282                                 out_tok = {.value = NULL},
 283                                 in_handle = {.value = in_handle_buf},
 284                                 out_handle = {.value = out_handle_buf},
 285                                 ctx_token = {.value = NULL},
 286                                 ignore_out_tok = {.value = NULL},
 287         /* XXX isn't there a define for this?: */
 288                                 null_token = {.value = NULL};
 289         u_int32_t               ret_flags;
 290         gss_ctx_id_t            ctx = GSS_C_NO_CONTEXT;
 291         gss_name_t              client_name;
 292         gss_OID                 mech = GSS_C_NO_OID;
 293         u_int32_t               maj_stat = GSS_S_FAILURE, min_stat = 0;
 294         u_int32_t               ignore_min_stat;
 295         struct svc_cred         cred;
 296         static char             *lbuf = NULL;
 297         static int              lbuflen = 0;
 298         static char             *cp;
 299
 300         printerr(1, "handling null request\n");
 301
 302         if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
 303                 printerr(0, "WARNING: handle_nullreq: "
 304                             "failed reading request\n");
 305                 return;
 306         }
 307
 308         cp = lbuf;
 309
 310         in_handle.length = (size_t) qword_get(&cp, in_handle.value,
 311                                               sizeof(in_handle_buf));
 312         printerr(2, "in_handle: \n");
 313         print_hexl(2, in_handle.value, in_handle.length);
 314
 315         in_tok.length = (size_t) qword_get(&cp, in_tok.value,
 316                                            sizeof(in_tok_buf));
 317         printerr(2, "in_tok: \n");
 318         print_hexl(2, in_tok.value, in_tok.length);
 319
 320         if (in_tok.length < 0) {
 321                 printerr(0, "WARNING: handle_nullreq: "
 322                             "failed parsing request\n");
 323                 goto out_err;
 324         }
 325
 326         if (in_handle.length != 0) { /* CONTINUE_INIT case */
 327                 if (in_handle.length != sizeof(ctx)) {
 328                         printerr(0, "WARNING: handle_nullreq: "
 329                                     "input handle has unexpected length %d\n",
 330                                     in_handle.length);
 331                         goto out_err;
 332                 }
 333                 /* in_handle is the context id stored in the out_handle
 334                  * for the GSS_S_CONTINUE_NEEDED case below.  */
 335                 memcpy(&ctx, in_handle.value, in_handle.length);
 336         }
 337
 338         maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
 339                         &in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
 340                         &mech, &out_tok, &ret_flags, NULL, NULL);
 341
 342         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 343                 printerr(1, "gss_accept_sec_context GSS_S_CONTINUE_NEEDED\n");
 344
 345                 /* Save the context handle for future calls */
 346                 out_handle.length = sizeof(ctx);
 347                 memcpy(out_handle.value, &ctx, sizeof(ctx));
 348                 goto continue_needed;
 349         }
 350         else if (maj_stat != GSS_S_COMPLETE) {
 351                 printerr(0, "WARNING: gss_accept_sec_context failed\n");
 352                 pgsserr("handle_nullreq: gss_accept_sec_context",
 353                         maj_stat, min_stat, mech);
 354                 goto out_err;
 355         }
 356         if (get_ids(client_name, mech, &cred)) {
 357                 /* get_ids() prints error msg */
 358                 maj_stat = GSS_S_BAD_NAME; /* XXX ? */
 359                 gss_release_name(&ignore_min_stat, &client_name);
 360                 goto out_err;
 361         }
 362         gss_release_name(&ignore_min_stat, &client_name);
 363
 364
 365         /* Context complete. Pass handle_seq in out_handle to use
 366          * for context lookup in the kernel. */
 367         handle_seq++;
 368         out_handle.length = sizeof(handle_seq);
 369         memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));
 370
 371         /* kernel needs ctx to calculate verifier on null response, so
 372          * must give it context before doing null call: */
 373         if (serialize_context_for_kernel(ctx, &ctx_token, mech)) {
 374                 printerr(0, "WARNING: handle_nullreq: "
 375                             "serialize_context_for_kernel failed\n");
 376                 maj_stat = GSS_S_FAILURE;
 377                 goto out_err;
 378         }
 379         /* We no longer need the gss context */
 380         gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 381
 382         do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
 383 continue_needed:
 384         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 385                         &out_handle, &out_tok);
 386 out:
 387         if (ctx_token.value != NULL)
 388                 free(ctx_token.value);
 389         if (out_tok.value != NULL)
 390                 gss_release_buffer(&ignore_min_stat, &out_tok);
 391         printerr(1, "finished handling null request\n");
 392         return;
 393
 394 out_err:
 395         if (ctx != GSS_C_NO_CONTEXT)
 396                 gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 397         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 398                         &null_token, &null_token);
 399         goto out;
 400 }