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 = -2;      /* XXX */
 230                         cred->cr_gid = -2;      /* XXX */
 231                         cred->cr_groups[0] = -2;/* XXX */
 232                         cred->cr_ngroups = 1;
 233                         res = 0;
 234                         goto out_free;
 235                 }
 236                 printerr(0, "WARNING: get_ids: failed to map name '%s' "
 237                         "to uid/gid: %s\n", sname, strerror(-res));
 238                 goto out_free;
 239         }
 240         cred->cr_uid = uid;
 241         cred->cr_gid = gid;
 242         add_supplementary_groups(secname, sname, cred);
 243         res = 0;
 244 out_free:
 245         free(sname);
 246 out:
 247         return res;
 248 }
 249
 250 void
 251 print_hexl(int pri, unsigned char *cp, int length)
 252 {
 253         int i, j, jm;
 254         unsigned char c;
 255
 256         printerr(pri, "length %d\n",length);
 257         printerr(pri, "\n");
 258
 259         for (i = 0; i < length; i += 0x10) {
 260                 printerr(pri, "  %04x: ", (u_int)i);
 261                 jm = length - i;
 262                 jm = jm > 16 ? 16 : jm;
 263
 264                 for (j = 0; j < jm; j++) {
 265                         if ((j % 2) == 1)
 266                                 printerr(pri,"%02x ", (u_int)cp[i+j]);
 267                         else
 268                                 printerr(pri,"%02x", (u_int)cp[i+j]);
 269                 }
 270                 for (; j < 16; j++) {
 271                         if ((j % 2) == 1)
 272                                 printerr(pri,"   ");
 273                         else
 274                                 printerr(pri,"  ");
 275                 }
 276                 printerr(pri," ");
 277
 278                 for (j = 0; j < jm; j++) {
 279                         c = cp[i+j];
 280                         c = isprint(c) ? c : '.';
 281                         printerr(pri,"%c", c);
 282                 }
 283                 printerr(pri,"\n");
 284         }
 285 }
 286
 287 void
 288 handle_nullreq(FILE *f) {
 289         /* XXX initialize to a random integer to reduce chances of unnecessary
 290          * invalidation of existing ctx's on restarting svcgssd. */
 291         static u_int32_t        handle_seq = 0;
 292         char                    in_tok_buf[TOKEN_BUF_SIZE];
 293         char                    in_handle_buf[15];
 294         char                    out_handle_buf[15];
 295         gss_buffer_desc         in_tok = {.value = in_tok_buf},
 296                                 out_tok = {.value = NULL},
 297                                 in_handle = {.value = in_handle_buf},
 298                                 out_handle = {.value = out_handle_buf},
 299                                 ctx_token = {.value = NULL},
 300                                 ignore_out_tok = {.value = NULL},
 301         /* XXX isn't there a define for this?: */
 302                                 null_token = {.value = NULL};
 303         u_int32_t               ret_flags;
 304         gss_ctx_id_t            ctx = GSS_C_NO_CONTEXT;
 305         gss_name_t              client_name;
 306         gss_OID                 mech = GSS_C_NO_OID;
 307         u_int32_t               maj_stat = GSS_S_FAILURE, min_stat = 0;
 308         u_int32_t               ignore_min_stat;
 309         struct svc_cred         cred;
 310         static char             *lbuf = NULL;
 311         static int              lbuflen = 0;
 312         static char             *cp;
 313
 314         printerr(1, "handling null request\n");
 315
 316         if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
 317                 printerr(0, "WARNING: handle_nullreq: "
 318                             "failed reading request\n");
 319                 return;
 320         }
 321
 322         cp = lbuf;
 323
 324         in_handle.length = (size_t) qword_get(&cp, in_handle.value,
 325                                               sizeof(in_handle_buf));
 326         printerr(2, "in_handle: \n");
 327         print_hexl(2, in_handle.value, in_handle.length);
 328
 329         in_tok.length = (size_t) qword_get(&cp, in_tok.value,
 330                                            sizeof(in_tok_buf));
 331         printerr(2, "in_tok: \n");
 332         print_hexl(2, in_tok.value, in_tok.length);
 333
 334         if (in_tok.length < 0) {
 335                 printerr(0, "WARNING: handle_nullreq: "
 336                             "failed parsing request\n");
 337                 goto out_err;
 338         }
 339
 340         if (in_handle.length != 0) { /* CONTINUE_INIT case */
 341                 if (in_handle.length != sizeof(ctx)) {
 342                         printerr(0, "WARNING: handle_nullreq: "
 343                                     "input handle has unexpected length %d\n",
 344                                     in_handle.length);
 345                         goto out_err;
 346                 }
 347                 /* in_handle is the context id stored in the out_handle
 348                  * for the GSS_S_CONTINUE_NEEDED case below.  */
 349                 memcpy(&ctx, in_handle.value, in_handle.length);
 350         }
 351
 352         maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
 353                         &in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
 354                         &mech, &out_tok, &ret_flags, NULL, NULL);
 355
 356         if (maj_stat == GSS_S_CONTINUE_NEEDED) {
 357                 printerr(1, "gss_accept_sec_context GSS_S_CONTINUE_NEEDED\n");
 358
 359                 /* Save the context handle for future calls */
 360                 out_handle.length = sizeof(ctx);
 361                 memcpy(out_handle.value, &ctx, sizeof(ctx));
 362                 goto continue_needed;
 363         }
 364         else if (maj_stat != GSS_S_COMPLETE) {
 365                 printerr(0, "WARNING: gss_accept_sec_context failed\n");
 366                 pgsserr("handle_nullreq: gss_accept_sec_context",
 367                         maj_stat, min_stat, mech);
 368                 goto out_err;
 369         }
 370         if (get_ids(client_name, mech, &cred)) {
 371                 /* get_ids() prints error msg */
 372                 maj_stat = GSS_S_BAD_NAME; /* XXX ? */
 373                 gss_release_name(&ignore_min_stat, &client_name);
 374                 goto out_err;
 375         }
 376         gss_release_name(&ignore_min_stat, &client_name);
 377
 378
 379         /* Context complete. Pass handle_seq in out_handle to use
 380          * for context lookup in the kernel. */
 381         handle_seq++;
 382         out_handle.length = sizeof(handle_seq);
 383         memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));
 384
 385         /* kernel needs ctx to calculate verifier on null response, so
 386          * must give it context before doing null call: */
 387         if (serialize_context_for_kernel(ctx, &ctx_token, mech)) {
 388                 printerr(0, "WARNING: handle_nullreq: "
 389                             "serialize_context_for_kernel failed\n");
 390                 maj_stat = GSS_S_FAILURE;
 391                 goto out_err;
 392         }
 393         /* We no longer need the gss context */
 394         gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 395
 396         do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
 397 continue_needed:
 398         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 399                         &out_handle, &out_tok);
 400 out:
 401         if (ctx_token.value != NULL)
 402                 free(ctx_token.value);
 403         if (out_tok.value != NULL)
 404                 gss_release_buffer(&ignore_min_stat, &out_tok);
 405         printerr(1, "finished handling null request\n");
 406         return;
 407
 408 out_err:
 409         if (ctx != GSS_C_NO_CONTEXT)
 410                 gss_delete_sec_context(&ignore_min_stat, &ctx, &ignore_out_tok);
 411         send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
 412                         &null_token, &null_token);
 413         goto out;
 414 }