bin/systrace/openbsd-syscalls.c

   1 /*      $OpenBSD: openbsd-syscalls.c,v 1.43 2013/04/29 00:28:23 okan Exp $      */
   2 /*
   3  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by Niels Provos.
  17  * 4. The name of the author may not be used to endorse or promote products
  18  *    derived from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 #include <sys/types.h>
  32 #include <sys/param.h>
  33
  34 #include <sys/syscall.h>
  35
  36 #include <compat/linux/linux_syscall.h>
  37
  38 #define KTRACE
  39 #define PTRACE
  40 #define NFSCLIENT
  41 #define NFSSERVER
  42 #define SYSVSEM
  43 #define SYSVMSG
  44 #define SYSVSHM
  45 #include <kern/syscalls.c>
  46
  47 #include <compat/linux/linux_syscalls.c>
  48 #undef KTRACE
  49 #undef PTRACE
  50 #undef NFSCLIENT
  51 #undef NFSSERVER
  52 #undef SYSVSEM
  53 #undef SYSVMSG
  54 #undef SYSVSHM
  55
  56 #include <sys/ioctl.h>
  57 #include <sys/tree.h>
  58 #include <dev/systrace.h>
  59
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include <fcntl.h>
  63 #include <unistd.h>
  64 #include <string.h>
  65 #include <errno.h>
  66 #include <err.h>
  67
  68 #include "intercept.h"
  69
  70 struct emulation {
  71         const char *name;       /* Emulation name */
  72         char **sysnames;        /* Array of system call names */
  73         int  nsysnames;         /* Number of */
  74 };
  75
  76 static struct emulation emulations[] = {
  77         { "native",     syscallnames,           SYS_MAXSYSCALL },
  78         { "aout",       syscallnames,           SYS_MAXSYSCALL },
  79         { "linux",      linux_syscallnames,     LINUX_SYS_MAXSYSCALL },
  80         { NULL,         NULL,                   0 }
  81 };
  82
  83 struct obsd_data {
  84         struct emulation *current;
  85         struct emulation *commit;
  86 };
  87
  88 static int obsd_init(void);
  89 static int obsd_attach(int, pid_t);
  90 static int obsd_report(int, pid_t);
  91 static int obsd_detach(int, pid_t);
  92 static int obsd_open(void);
  93 static struct intercept_pid *obsd_getpid(pid_t);
  94 static void obsd_freepid(struct intercept_pid *);
  95 static void obsd_clonepid(struct intercept_pid *, struct intercept_pid *);
  96 static struct emulation *obsd_find_emulation(const char *);
  97 static int obsd_set_emulation(pid_t, const char *);
  98 static struct emulation *obsd_switch_emulation(struct obsd_data *);
  99 static const char *obsd_syscall_name(pid_t, int);
 100 static int obsd_syscall_number(const char *, const char *);
 101 static short obsd_translate_policy(short);
 102 static short obsd_translate_flags(short);
 103 static int obsd_translate_errno(int);
 104 static int obsd_answer(int, pid_t, u_int16_t, short, int, short,
 105     struct elevate *);
 106 static int obsd_newpolicy(int);
 107 static int obsd_assignpolicy(int, pid_t, int);
 108 static int obsd_modifypolicy(int, int, int, short);
 109 static int obsd_replace(int, pid_t, u_int16_t, struct intercept_replace *);
 110 static int obsd_io(int, pid_t, int, void *, u_char *, size_t);
 111 static int obsd_setcwd(int, pid_t, int);
 112 static int obsd_restcwd(int);
 113 static int obsd_argument(int, void *, int, void **);
 114 static int obsd_read(int);
 115 static int obsd_scriptname(int, pid_t, char *);
 116
 117 static int
 118 obsd_init(void)
 119 {
 120         return (0);
 121 }
 122
 123 static int
 124 obsd_attach(int fd, pid_t pid)
 125 {
 126         if (ioctl(fd, STRIOCATTACH, &pid) == -1)
 127                 return (-1);
 128
 129         return (0);
 130 }
 131
 132 static int
 133 obsd_report(int fd, pid_t pid)
 134 {
 135         if (ioctl(fd, STRIOCREPORT, &pid) == -1)
 136                 return (-1);
 137
 138         return (0);
 139 }
 140
 141 static int
 142 obsd_detach(int fd, pid_t pid)
 143 {
 144         if (ioctl(fd, STRIOCDETACH, &pid) == -1)
 145                 return (-1);
 146
 147         return (0);
 148 }
 149
 150 static int
 151 obsd_open(void)
 152 {
 153         char *path = "/dev/systrace";
 154         int fd, cfd = -1;
 155
 156         fd = open(path, O_RDONLY, 0);
 157         if (fd == -1) {
 158                 warn("open: %s", path);
 159                 return (-1);
 160         }
 161
 162         if (ioctl(fd, STRIOCCLONE, &cfd) == -1) {
 163                 warn("ioctl(STRIOCCLONE)");
 164                 goto out;
 165         }
 166
 167         if (fcntl(cfd, F_SETFD, FD_CLOEXEC) == -1)
 168                 warn("fcntl(F_SETFD)");
 169
 170  out:
 171         close (fd);
 172         return (cfd);
 173 }
 174
 175 static struct intercept_pid *
 176 obsd_getpid(pid_t pid)
 177 {
 178         struct intercept_pid *icpid;
 179         struct obsd_data *data;
 180
 181         icpid = intercept_getpid(pid);
 182         if (icpid == NULL)
 183                 return (NULL);
 184         if (icpid->data != NULL)
 185                 return (icpid);
 186
 187         if ((icpid->data = malloc(sizeof(struct obsd_data))) == NULL)
 188                 err(1, "%s:%d: malloc", __func__, __LINE__);
 189
 190         data = icpid->data;
 191         data->current = &emulations[0];
 192         data->commit = NULL;
 193
 194         return (icpid);
 195 }
 196
 197 static void
 198 obsd_freepid(struct intercept_pid *ipid)
 199 {
 200         if (ipid->data != NULL)
 201                 free(ipid->data);
 202 }
 203
 204 static void
 205 obsd_clonepid(struct intercept_pid *opid, struct intercept_pid *npid)
 206 {
 207         if (opid->data == NULL) {
 208                 npid->data = NULL;
 209                 return;
 210         }
 211
 212         if ((npid->data = malloc(sizeof(struct obsd_data))) == NULL)
 213                 err(1, "%s:%d: malloc", __func__, __LINE__);
 214         memcpy(npid->data, opid->data, sizeof(struct obsd_data));
 215 }
 216
 217 static struct emulation *
 218 obsd_find_emulation(const char *name)
 219 {
 220         struct emulation *tmp;
 221
 222         tmp = emulations;
 223         while (tmp->name) {
 224                 if (!strcmp(tmp->name, name))
 225                         break;
 226                 tmp++;
 227         }
 228
 229         if (!tmp->name)
 230                 return (NULL);
 231
 232         return (tmp);
 233 }
 234
 235 static int
 236 obsd_set_emulation(pid_t pidnr, const char *name)
 237 {
 238         struct emulation *tmp;
 239         struct intercept_pid *pid;
 240         struct obsd_data *data;
 241
 242         if ((tmp = obsd_find_emulation(name)) == NULL)
 243                 return (-1);
 244
 245         pid = intercept_getpid(pidnr);
 246         if (pid == NULL)
 247                 return (-1);
 248         data = pid->data;
 249
 250         data->commit = tmp;
 251
 252         return (0);
 253 }
 254
 255 static struct emulation *
 256 obsd_switch_emulation(struct obsd_data *data)
 257 {
 258         data->current = data->commit;
 259         data->commit = NULL;
 260
 261         return (data->current);
 262 }
 263
 264 static const char *
 265 obsd_syscall_name(pid_t pidnr, int number)
 266 {
 267         struct intercept_pid *pid;
 268         struct emulation *current;
 269
 270         pid = obsd_getpid(pidnr);
 271         if (pid == NULL)
 272                 return (NULL);
 273         current = ((struct obsd_data *)pid->data)->current;
 274
 275         if (number < 0 || number >= current->nsysnames)
 276                 return (NULL);
 277
 278         return (current->sysnames[number]);
 279 }
 280
 281 static int
 282 obsd_syscall_number(const char *emulation, const char *name)
 283 {
 284         struct emulation *current;
 285         int i;
 286
 287         current = obsd_find_emulation(emulation);
 288         if (current == NULL)
 289                 return (-1);
 290
 291         for (i = 0; i < current->nsysnames; i++)
 292                 if (!strcmp(name, current->sysnames[i]))
 293                         return (i);
 294
 295         return (-1);
 296 }
 297
 298 static short
 299 obsd_translate_policy(short policy)
 300 {
 301         switch (policy) {
 302         case ICPOLICY_ASK:
 303                 return (SYSTR_POLICY_ASK);
 304         case ICPOLICY_PERMIT:
 305                 return (SYSTR_POLICY_PERMIT);
 306         case ICPOLICY_NEVER:
 307         default:
 308                 return (SYSTR_POLICY_NEVER);
 309         }
 310 }
 311
 312 static short
 313 obsd_translate_flags(short flags)
 314 {
 315         switch (flags) {
 316         case ICFLAGS_RESULT:
 317                 return (SYSTR_FLAGS_RESULT);
 318         default:
 319                 return (0);
 320         }
 321 }
 322
 323 static int
 324 obsd_translate_errno(int nerrno)
 325 {
 326         return (nerrno);
 327 }
 328
 329 static int
 330 obsd_answer(int fd, pid_t pid, u_int16_t seqnr, short policy, int nerrno,
 331     short flags, struct elevate *elevate)
 332 {
 333         struct systrace_answer ans;
 334
 335         memset(&ans, 0, sizeof(ans));
 336         ans.stra_pid = pid;
 337         ans.stra_seqnr = seqnr;
 338         ans.stra_policy = obsd_translate_policy(policy);
 339         ans.stra_flags = obsd_translate_flags(flags);
 340         ans.stra_error = obsd_translate_errno(nerrno);
 341
 342         if (elevate != NULL) {
 343                 if (elevate->e_flags & ELEVATE_UID) {
 344                         ans.stra_flags |= SYSTR_FLAGS_SETEUID;
 345                         ans.stra_seteuid = elevate->e_uid;
 346                 }
 347                 if (elevate->e_flags & ELEVATE_GID) {
 348                         ans.stra_flags |= SYSTR_FLAGS_SETEGID;
 349                         ans.stra_setegid = elevate->e_gid;
 350                 }
 351         }
 352
 353         if (ioctl(fd, STRIOCANSWER, &ans) == -1)
 354                 return (-1);
 355
 356         return (0);
 357 }
 358
 359 static int
 360 obsd_scriptname(int fd, pid_t pid, char *scriptname)
 361 {
 362         struct systrace_scriptname sn;
 363
 364         sn.sn_pid = pid;
 365         strlcpy(sn.sn_scriptname, scriptname, sizeof(sn.sn_scriptname));
 366
 367         return (ioctl(fd, STRIOCSCRIPTNAME, &sn));
 368 }
 369
 370 static int
 371 obsd_newpolicy(int fd)
 372 {
 373         struct systrace_policy pol;
 374
 375         pol.strp_op = SYSTR_POLICY_NEW;
 376         pol.strp_num = -1;
 377         pol.strp_maxents = 512;
 378
 379         if (ioctl(fd, STRIOCPOLICY, &pol) == -1)
 380                 return (-1);
 381
 382         return (pol.strp_num);
 383 }
 384
 385 static int
 386 obsd_assignpolicy(int fd, pid_t pid, int num)
 387 {
 388         struct systrace_policy pol;
 389
 390         pol.strp_op = SYSTR_POLICY_ASSIGN;
 391         pol.strp_num = num;
 392         pol.strp_pid = pid;
 393
 394         if (ioctl(fd, STRIOCPOLICY, &pol) == -1)
 395                 return (-1);
 396
 397         return (0);
 398 }
 399
 400 static int
 401 obsd_modifypolicy(int fd, int num, int code, short policy)
 402 {
 403         struct systrace_policy pol;
 404
 405         pol.strp_op = SYSTR_POLICY_MODIFY;
 406         pol.strp_num = num;
 407         pol.strp_code = code;
 408         pol.strp_policy = obsd_translate_policy(policy);
 409
 410         if (ioctl(fd, STRIOCPOLICY, &pol) == -1)
 411                 return (-1);
 412
 413         return (0);
 414 }
 415
 416 static int
 417 obsd_replace(int fd, pid_t pid, u_int16_t seqnr,
 418     struct intercept_replace *repl)
 419 {
 420         struct systrace_replace replace;
 421         size_t len, off;
 422         int i, ret;
 423
 424         memset(&replace, 0, sizeof(replace));
 425
 426         for (i = 0, len = 0; i < repl->num; i++) {
 427                 len += repl->len[i];
 428         }
 429
 430         replace.strr_pid = pid;
 431         replace.strr_seqnr = seqnr;
 432         replace.strr_nrepl = repl->num;
 433         replace.strr_base = malloc(len);
 434         replace.strr_len = len;
 435         if (replace.strr_base == NULL)
 436                 err(1, "%s: malloc", __func__);
 437
 438         for (i = 0, off = 0; i < repl->num; i++) {
 439                 replace.strr_argind[i] = repl->ind[i];
 440                 replace.strr_offlen[i] = repl->len[i];
 441                 if (repl->len[i] == 0) {
 442                         replace.strr_off[i] = (size_t)repl->address[i];
 443                         continue;
 444                 }
 445
 446                 replace.strr_off[i] = off;
 447                 memcpy(replace.strr_base + off,
 448                     repl->address[i], repl->len[i]);
 449                 if (repl->flags[i] & ICTRANS_NOLINKS) {
 450                         replace.strr_flags[i] = SYSTR_NOLINKS;
 451                 } else
 452                         replace.strr_flags[i] = 0;
 453
 454                 off += repl->len[i];
 455         }
 456
 457         ret = ioctl(fd, STRIOCREPLACE, &replace);
 458         if (ret == -1 && errno != EBUSY) {
 459                 warn("%s: ioctl", __func__);
 460         }
 461
 462         free(replace.strr_base);
 463
 464         return (ret);
 465 }
 466
 467 static int
 468 obsd_io(int fd, pid_t pid, int op, void *addr, u_char *buf, size_t size)
 469 {
 470         struct systrace_io io;
 471         extern int ic_abort;
 472
 473         memset(&io, 0, sizeof(io));
 474         io.strio_pid = pid;
 475         io.strio_addr = buf;
 476         io.strio_len = size;
 477         io.strio_offs = addr;
 478         io.strio_op = (op == INTERCEPT_READ ? SYSTR_READ : SYSTR_WRITE);
 479         if (ioctl(fd, STRIOCIO, &io) == -1) {
 480                 if (errno == EBUSY)
 481                         ic_abort = 1;
 482                 return (-1);
 483         }
 484
 485         return (0);
 486 }
 487
 488 static int
 489 obsd_setcwd(int fd, pid_t pid, int atfd)
 490 {
 491         struct systrace_getcwd gd;
 492         gd.strgd_pid = pid;
 493         gd.strgd_atfd = atfd;
 494         return (ioctl(fd, STRIOCGETCWD, &gd));
 495 }
 496
 497 static int
 498 obsd_restcwd(int fd)
 499 {
 500         int res;
 501         if ((res = ioctl(fd, STRIOCRESCWD, 0)) == -1)
 502                 warn("%s: ioctl", __func__); /* XXX */
 503
 504         return (res);
 505 }
 506
 507 static int
 508 obsd_argument(int off, void *pargs, int argsize, void **pres)
 509 {
 510         register_t *args = (register_t *)pargs;
 511
 512         if (off >= argsize / sizeof(register_t))
 513                 return (-1);
 514
 515         *pres = (void *)args[off];
 516
 517         return (0);
 518 }
 519
 520 static int
 521 obsd_read(int fd)
 522 {
 523         struct str_message msg;
 524         struct intercept_pid *icpid;
 525         struct obsd_data *data;
 526         struct emulation *current;
 527
 528         char name[SYSTR_EMULEN+1];
 529         const char *sysname;
 530         u_int16_t seqnr;
 531         pid_t pid;
 532         int code;
 533
 534         if (read(fd, &msg, sizeof(msg)) != sizeof(msg))
 535                 return (-1);
 536
 537         icpid = obsd_getpid(msg.msg_pid);
 538         if (icpid == NULL)
 539                 return (-1);
 540         data = icpid->data;
 541
 542         current = data->current;
 543
 544         seqnr = msg.msg_seqnr;
 545         pid = msg.msg_pid;
 546         switch (msg.msg_type) {
 547         case SYSTR_MSG_ASK:
 548                 code = msg.msg_data.msg_ask.code;
 549                 sysname = obsd_syscall_name(pid, code);
 550
 551                 intercept_syscall(fd, pid, seqnr, msg.msg_policy,
 552                     sysname, code, current->name,
 553                     (void *)msg.msg_data.msg_ask.args,
 554                     msg.msg_data.msg_ask.argsize);
 555                 break;
 556
 557         case SYSTR_MSG_RES:
 558                 code = msg.msg_data.msg_ask.code;
 559                 sysname = obsd_syscall_name(pid, code);
 560
 561                 /* Switch emulation around at the right time */
 562                 if (data->commit != NULL) {
 563                         current = obsd_switch_emulation(data);
 564                 }
 565
 566                 intercept_syscall_result(fd, pid, seqnr, msg.msg_policy,
 567                     sysname, code, current->name,
 568                     (void *)msg.msg_data.msg_ask.args,
 569                     msg.msg_data.msg_ask.argsize,
 570                     msg.msg_data.msg_ask.result,
 571                     msg.msg_data.msg_ask.rval);
 572                 break;
 573
 574         case SYSTR_MSG_EMUL:
 575                 memcpy(name, msg.msg_data.msg_emul.emul, SYSTR_EMULEN);
 576                 name[SYSTR_EMULEN] = '\0';
 577
 578                 if (obsd_set_emulation(pid, name) == -1)
 579                         errx(1, "%s:%d: set_emulation(%s)",
 580                             __func__, __LINE__, name);
 581
 582                 if (icpid->execve_code == -1) {
 583                         icpid->execve_code = 0;
 584
 585                         /* A running attach fake a exec cb */
 586                         current = obsd_switch_emulation(data);
 587
 588                         intercept_syscall_result(fd,
 589                             pid, seqnr, msg.msg_policy,
 590                             "execve", 0, current->name,
 591                             NULL, 0, 0, NULL);
 592                         break;
 593                 }
 594
 595                 if (obsd_answer(fd, pid, seqnr, 0, 0, 0, NULL) == -1)
 596                         err(1, "%s:%d: answer", __func__, __LINE__);
 597                 break;
 598
 599         case SYSTR_MSG_UGID: {
 600                 struct str_msg_ugid *msg_ugid;
 601
 602                 msg_ugid = &msg.msg_data.msg_ugid;
 603
 604                 intercept_ugid(icpid, msg_ugid->uid, msg_ugid->uid);
 605
 606                 if (obsd_answer(fd, pid, seqnr, 0, 0, 0, NULL) == -1)
 607                         err(1, "%s:%d: answer", __func__, __LINE__);
 608                 break;
 609         }
 610         case SYSTR_MSG_CHILD:
 611                 intercept_child_info(msg.msg_pid,
 612                     msg.msg_data.msg_child.new_pid);
 613                 break;
 614 #ifdef SYSTR_MSG_EXECVE
 615         case SYSTR_MSG_EXECVE: {
 616                 struct str_msg_execve *msg_execve = &msg.msg_data.msg_execve;
 617
 618                 intercept_newimage(fd, pid, msg.msg_policy, current->name,
 619                     msg_execve->path, NULL);
 620
 621                 if (obsd_answer(fd, pid, seqnr, 0, 0, 0, NULL) == -1)
 622                         err(1, "%s:%d: answer", __func__, __LINE__);
 623                 break;
 624         }
 625 #endif
 626
 627 #ifdef SYSTR_MSG_POLICYFREE
 628         case SYSTR_MSG_POLICYFREE:
 629                 intercept_policy_free(msg.msg_policy);
 630                 break;
 631 #endif
 632         }
 633         return (0);
 634 }
 635
 636 struct intercept_system intercept = {
 637         "openbsd",
 638         obsd_init,
 639         obsd_open,
 640         obsd_attach,
 641         obsd_detach,
 642         obsd_report,
 643         obsd_read,
 644         obsd_syscall_number,
 645         obsd_setcwd,
 646         obsd_restcwd,
 647         obsd_io,
 648         obsd_argument,
 649         obsd_answer,
 650         obsd_newpolicy,
 651         obsd_assignpolicy,
 652         obsd_modifypolicy,
 653         obsd_replace,
 654         obsd_clonepid,
 655         obsd_freepid,
 656         obsd_scriptname,
 657 };