1/*- 2 * Copyright (c) 2001 Robert N. M. Watson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29#include <sys/param.h> 30#include <sys/uio.h> 31#include <sys/ptrace.h> 32#include <sys/time.h> 33#include <sys/resource.h> 34#include <sys/syscall.h> 35#include <sys/wait.h> 36#include <sys/ktrace.h> 37 38#include <assert.h> 39#include <errno.h> 40#include <signal.h> 41#include <stdio.h> 42#include <string.h> 43#include <unistd.h> 44 45/* 46 * Relevant parts of a process credential. 47 */ 48struct cred { 49 uid_t cr_euid, cr_ruid, cr_svuid; 50 int cr_issetugid; 51}; 52 53/* 54 * Description of a scenario. 55 */ 56struct scenario { 57 struct cred *sc_cred1, *sc_cred2; /* credentials of p1 and p2 */ 58 int sc_canptrace_errno; /* desired ptrace failure */ 59 int sc_canktrace_errno; /* desired ktrace failure */ 60 int sc_cansighup_errno; /* desired SIGHUP failure */ 61 int sc_cansigsegv_errno; /* desired SIGSEGV failure */ 62 int sc_cansee_errno; /* desired getprio failure */ 63 int sc_cansched_errno; /* desired setprio failure */ 64 char *sc_name; /* test name */ 65}; 66 67/* 68 * Table of relevant credential combinations. 69 */ 70static struct cred creds[] = { 71/* euid ruid svuid issetugid */ 72/* 0 */ { 0, 0, 0, 0 }, /* privileged */ 73/* 1 */ { 0, 0, 0, 1 }, /* privileged + issetugid */ 74/* 2 */ { 1000, 1000, 1000, 0 }, /* unprivileged1 */ 75/* 3 */ { 1000, 1000, 1000, 1 }, /* unprivileged1 + issetugid */ 76/* 4 */ { 1001, 1001, 1001, 0 }, /* unprivileged2 */ 77/* 5 */ { 1001, 1001, 1001, 1 }, /* unprivileged2 + issetugid */ 78/* 6 */ { 1000, 0, 0, 0 }, /* daemon1 */ 79/* 7 */ { 1000, 0, 0, 1 }, /* daemon1 + issetugid */ 80/* 8 */ { 1001, 0, 0, 0 }, /* daemon2 */ 81/* 9 */ { 1001, 0, 0, 1 }, /* daemon2 + issetugid */ 82/* 10 */{ 0, 1000, 1000, 0 }, /* setuid1 */ 83/* 11 */{ 0, 1000, 1000, 1 }, /* setuid1 + issetugid */ 84/* 12 */{ 0, 1001, 1001, 0 }, /* setuid2 */ 85/* 13 */{ 0, 1001, 1001, 1 }, /* setuid2 + issetugid */ 86}; 87 88/* 89 * Table of scenarios. 90 */ 91static const struct scenario scenarios[] = { 92/* cred1 cred2 ptrace ktrace, sighup sigsegv see sched name */ 93/* privileged on privileged */ 94{ &creds[0], &creds[0], 0, 0, 0, 0, 0, 0, "0. priv on priv"}, 95{ &creds[0], &creds[1], 0, 0, 0, 0, 0, 0, "1. priv on priv"}, 96{ &creds[1], &creds[0], 0, 0, 0, 0, 0, 0, "2. priv on priv"}, 97{ &creds[1], &creds[1], 0, 0, 0, 0, 0, 0, "3. priv on priv"}, 98/* privileged on unprivileged */ 99{ &creds[0], &creds[2], 0, 0, 0, 0, 0, 0, "4. priv on unpriv1"}, 100{ &creds[0], &creds[3], 0, 0, 0, 0, 0, 0, "5. priv on unpriv1"}, 101{ &creds[1], &creds[2], 0, 0, 0, 0, 0, 0, "6. priv on unpriv1"}, 102{ &creds[1], &creds[3], 0, 0, 0, 0, 0, 0, "7. priv on unpriv1"}, 103/* unprivileged on privileged */ 104{ &creds[2], &creds[0], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "8. unpriv1 on priv"}, 105{ &creds[2], &creds[1], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "9. unpriv1 on priv"}, 106{ &creds[3], &creds[0], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "10. unpriv1 on priv"}, 107{ &creds[3], &creds[1], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "11. unpriv1 on priv"}, 108/* unprivileged on same unprivileged */ 109{ &creds[2], &creds[2], 0, 0, 0, 0, 0, 0, "12. unpriv1 on unpriv1"}, 110{ &creds[2], &creds[3], EPERM, EPERM, 0, EPERM, 0, 0, "13. unpriv1 on unpriv1"}, 111{ &creds[3], &creds[2], 0, 0, 0, 0, 0, 0, "14. unpriv1 on unpriv1"}, 112{ &creds[3], &creds[3], EPERM, EPERM, 0, EPERM, 0, 0, "15. unpriv1 on unpriv1"}, 113/* unprivileged on different unprivileged */ 114{ &creds[2], &creds[4], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "16. unpriv1 on unpriv2"}, 115{ &creds[2], &creds[5], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "17. unpriv1 on unpriv2"}, 116{ &creds[3], &creds[4], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "18. unpriv1 on unpriv2"}, 117{ &creds[3], &creds[5], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "19. unpriv1 on unpriv2"}, 118/* unprivileged on daemon, same */ 119{ &creds[2], &creds[6], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "20. unpriv1 on daemon1"}, 120{ &creds[2], &creds[7], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "21. unpriv1 on daemon1"}, 121{ &creds[3], &creds[6], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "22. unpriv1 on daemon1"}, 122{ &creds[3], &creds[7], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "23. unpriv1 on daemon1"}, 123/* unprivileged on daemon, different */ 124{ &creds[2], &creds[8], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "24. unpriv1 on daemon2"}, 125{ &creds[2], &creds[9], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "25. unpriv1 on daemon2"}, 126{ &creds[3], &creds[8], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "26. unpriv1 on daemon2"}, 127{ &creds[3], &creds[9], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "27. unpriv1 on daemon2"}, 128/* unprivileged on setuid, same */ 129{ &creds[2], &creds[10], EPERM, EPERM, 0, 0, 0, 0, "28. unpriv1 on setuid1"}, 130{ &creds[2], &creds[11], EPERM, EPERM, 0, EPERM, 0, 0, "29. unpriv1 on setuid1"}, 131{ &creds[3], &creds[10], EPERM, EPERM, 0, 0, 0, 0, "30. unpriv1 on setuid1"}, 132{ &creds[3], &creds[11], EPERM, EPERM, 0, EPERM, 0, 0, "31. unpriv1 on setuid1"}, 133/* unprivileged on setuid, different */ 134{ &creds[2], &creds[12], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "32. unpriv1 on setuid2"}, 135{ &creds[2], &creds[13], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "33. unpriv1 on setuid2"}, 136{ &creds[3], &creds[12], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "34. unpriv1 on setuid2"}, 137{ &creds[3], &creds[13], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "35. unpriv1 on setuid2"}, 138}; 139int scenarios_count = sizeof(scenarios) / sizeof(struct scenario); 140 141/* 142 * Convert an error number to a compact string representation. For now, 143 * implement only the error numbers we are likely to see. 144 */ 145static char * 146errno_to_string(int error) 147{ 148 149 switch (error) { 150 case EPERM: 151 return ("EPERM"); 152 case EACCES: 153 return ("EACCES"); 154 case EINVAL: 155 return ("EINVAL"); 156 case ENOSYS: 157 return ("ENOSYS"); 158 case ESRCH: 159 return ("ESRCH"); 160 case EOPNOTSUPP: 161 return ("EOPNOTSUPP"); 162 case 0: 163 return ("0"); 164 default: 165 printf("%d\n", error); 166 return ("unknown"); 167 } 168} 169 170/* 171 * Return a process credential describing the current process. 172 */ 173static int 174cred_get(struct cred *cred) 175{ 176 int error; 177 178 error = getresuid(&cred->cr_ruid, &cred->cr_euid, &cred->cr_svuid); 179 if (error) 180 return (error); 181 182 cred->cr_issetugid = issetugid(); 183 184 return (0); 185} 186 187/* 188 * Userland stub for __setsugid() to take into account possible presence 189 * in C library, kernel, et al. 190 */ 191int 192setugid(int flag) 193{ 194 195#ifdef SETSUGID_SUPPORTED 196 return (__setugid(flag)); 197#else 198#ifdef SETSUGID_SUPPORTED_BUT_NO_LIBC_STUB 199 return (syscall(374, flag)); 200#else 201 return (ENOSYS); 202#endif 203#endif 204} 205 206/* 207 * Set the current process's credentials to match the passed credential. 208 */ 209static int 210cred_set(struct cred *cred) 211{ 212 int error; 213 214 error = setresuid(cred->cr_ruid, cred->cr_euid, cred->cr_svuid); 215 if (error) 216 return (error); 217 218 error = setugid(cred->cr_issetugid); 219 if (error) { 220 perror("__setugid"); 221 return (error); 222 } 223 224#ifdef CHECK_CRED_SET 225 { 226 uid_t ruid, euid, svuid; 227 error = getresuid(&ruid, &euid, &svuid); 228 if (error) { 229 perror("getresuid"); 230 return (-1); 231 } 232 assert(ruid == cred->cr_ruid); 233 assert(euid == cred->cr_euid); 234 assert(svuid == cred->cr_svuid); 235 assert(cred->cr_issetugid == issetugid()); 236 } 237#endif /* !CHECK_CRED_SET */ 238 239 return (0); 240} 241 242/* 243 * Print the passed process credential to the passed I/O stream. 244 */ 245static void 246cred_print(FILE *output, struct cred *cred) 247{ 248 249 fprintf(output, "(e:%d r:%d s:%d P_SUGID:%d)", cred->cr_euid, 250 cred->cr_ruid, cred->cr_svuid, cred->cr_issetugid); 251} 252 253#define LOOP_PTRACE 0 254#define LOOP_KTRACE 1 255#define LOOP_SIGHUP 2 256#define LOOP_SIGSEGV 3 257#define LOOP_SEE 4 258#define LOOP_SCHED 5 259#define LOOP_MAX LOOP_SCHED 260 261/* 262 * Enact a scenario by looping through the four test cases for the scenario, 263 * spawning off pairs of processes with the desired credentials, and 264 * reporting results to stdout. 265 */ 266static int 267enact_scenario(int scenario) 268{ 269 pid_t pid1, pid2; 270 char *name, *tracefile; 271 int error, desirederror, loop; 272 273 for (loop = 0; loop < LOOP_MAX+1; loop++) { 274 /* 275 * Spawn the first child, target of the operation. 276 */ 277 pid1 = fork(); 278 switch (pid1) { 279 case -1: 280 return (-1); 281 case 0: 282 /* child */ 283 error = cred_set(scenarios[scenario].sc_cred2); 284 if (error) { 285 perror("cred_set"); 286 return (error); 287 } 288 /* 200 seconds should be plenty of time. */ 289 sleep(200); 290 exit(0); 291 default: 292 /* parent */ 293 break; 294 } 295 296 /* 297 * XXX 298 * This really isn't ideal -- give proc 1 a chance to set 299 * its credentials, or we may get spurious errors. Really, 300 * some for of IPC should be used to allow the parent to 301 * wait for the first child to be ready before spawning 302 * the second child. 303 */ 304 sleep(1); 305 306 /* 307 * Spawn the second child, source of the operation. 308 */ 309 pid2 = fork(); 310 switch (pid2) { 311 case -1: 312 return (-1); 313 314 case 0: 315 /* child */ 316 error = cred_set(scenarios[scenario].sc_cred1); 317 if (error) { 318 perror("cred_set"); 319 return (error); 320 } 321 322 /* 323 * Initialize errno to zero so as to catch any 324 * generated errors. In each case, perform the 325 * operation. Preserve the error number for later 326 * use so it doesn't get stomped on by any I/O. 327 * Determine the desired error for the given case 328 * by extracting it from the scenario table. 329 * Initialize a function name string for output 330 * prettiness. 331 */ 332 errno = 0; 333 switch (loop) { 334 case LOOP_PTRACE: 335 error = ptrace(PT_ATTACH, pid1, NULL, 0); 336 error = errno; 337 name = "ptrace"; 338 desirederror = 339 scenarios[scenario].sc_canptrace_errno; 340 break; 341 case LOOP_KTRACE: 342 tracefile = mktemp("/tmp/testuid_ktrace.XXXXXX"); 343 if (tracefile == NULL) { 344 error = errno; 345 perror("mktemp"); 346 break; 347 } 348 error = ktrace(tracefile, KTROP_SET, 349 KTRFAC_SYSCALL, pid1); 350 error = errno; 351 name = "ktrace"; 352 desirederror = 353 scenarios[scenario].sc_canktrace_errno; 354 unlink(tracefile); 355 break; 356 case LOOP_SIGHUP: 357 error = kill(pid1, SIGHUP); 358 error = errno; 359 name = "sighup"; 360 desirederror = 361 scenarios[scenario].sc_cansighup_errno; 362 break; 363 case LOOP_SIGSEGV: 364 error = kill(pid1, SIGSEGV); 365 error = errno; 366 name = "sigsegv"; 367 desirederror = 368 scenarios[scenario].sc_cansigsegv_errno; 369 break; 370 case LOOP_SEE: 371 getpriority(PRIO_PROCESS, pid1); 372 error = errno; 373 name = "see"; 374 desirederror = 375 scenarios[scenario].sc_cansee_errno; 376 break; 377 case LOOP_SCHED: 378 error = setpriority(PRIO_PROCESS, pid1, 379 0); 380 error = errno; 381 name = "sched"; 382 desirederror = 383 scenarios[scenario].sc_cansched_errno; 384 break; 385 default: 386 name = "broken"; 387 } 388 389 if (error != desirederror) { 390 fprintf(stdout, 391 "[%s].%s: expected %s, got %s\n ", 392 scenarios[scenario].sc_name, name, 393 errno_to_string(desirederror), 394 errno_to_string(error)); 395 cred_print(stdout, 396 scenarios[scenario].sc_cred1); 397 cred_print(stdout, 398 scenarios[scenario].sc_cred2); 399 fprintf(stdout, "\n"); 400 } 401 402 exit(0); 403 404 default: 405 /* parent */ 406 break; 407 } 408 409 error = waitpid(pid2, NULL, 0); 410 /* 411 * Once pid2 has died, it's safe to kill pid1, if it's still 412 * alive. Mask signal failure in case the test actually 413 * killed pid1 (not unlikely: can occur in both signal and 414 * ptrace cases). 415 */ 416 kill(pid1, SIGKILL); 417 error = waitpid(pid2, NULL, 0); 418 } 419 420 return (0); 421} 422 423void 424enact_scenarios(void) 425{ 426 int i, error; 427 428 for (i = 0; i < scenarios_count; i++) { 429 error = enact_scenario(i); 430 if (error) 431 perror("enact_scenario"); 432 } 433} 434