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 */ 48 struct cred { 49 uid_t cr_euid, cr_ruid, cr_svuid; 50 int cr_issetugid; 51 }; 52 53 /* 54 * Description of a scenario. 55 */ 56 struct 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 */ 70 static 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 */ 91 static 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 }; 139 int 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 */ 145 static char * 146 errno_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 */ 173 static int 174 cred_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 */ 191 int 192 setugid(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 */ 209 static int 210 cred_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 */ 245 static void 246 cred_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 */ 266 static int 267 enact_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 } 294 295 /* 296 * XXX 297 * This really isn't ideal -- give proc 1 a chance to set 298 * its credentials, or we may get spurious errors. Really, 299 * some for of IPC should be used to allow the parent to 300 * wait for the first child to be ready before spawning 301 * the second child. 302 */ 303 sleep(1); 304 305 /* 306 * Spawn the second child, source of the operation. 307 */ 308 pid2 = fork(); 309 switch (pid2) { 310 case -1: 311 return (-1); 312 313 case 0: 314 /* child */ 315 error = cred_set(scenarios[scenario].sc_cred1); 316 if (error) { 317 perror("cred_set"); 318 return (error); 319 } 320 321 /* 322 * Initialize errno to zero so as to catch any 323 * generated errors. In each case, perform the 324 * operation. Preserve the error number for later 325 * use so it doesn't get stomped on by any I/O. 326 * Determine the desired error for the given case 327 * by extracting it from the scenario table. 328 * Initialize a function name string for output 329 * prettiness. 330 */ 331 errno = 0; 332 switch (loop) { 333 case LOOP_PTRACE: 334 error = ptrace(PT_ATTACH, pid1, NULL, 0); 335 error = errno; 336 name = "ptrace"; 337 desirederror = 338 scenarios[scenario].sc_canptrace_errno; 339 break; 340 case LOOP_KTRACE: 341 tracefile = mktemp("/tmp/testuid_ktrace.XXXXXX"); 342 if (tracefile == NULL) { 343 error = errno; 344 perror("mktemp"); 345 break; 346 } 347 error = ktrace(tracefile, KTROP_SET, 348 KTRFAC_SYSCALL, pid1); 349 error = errno; 350 name = "ktrace"; 351 desirederror = 352 scenarios[scenario].sc_canktrace_errno; 353 unlink(tracefile); 354 break; 355 case LOOP_SIGHUP: 356 error = kill(pid1, SIGHUP); 357 error = errno; 358 name = "sighup"; 359 desirederror = 360 scenarios[scenario].sc_cansighup_errno; 361 break; 362 case LOOP_SIGSEGV: 363 error = kill(pid1, SIGSEGV); 364 error = errno; 365 name = "sigsegv"; 366 desirederror = 367 scenarios[scenario].sc_cansigsegv_errno; 368 break; 369 case LOOP_SEE: 370 getpriority(PRIO_PROCESS, pid1); 371 error = errno; 372 name = "see"; 373 desirederror = 374 scenarios[scenario].sc_cansee_errno; 375 break; 376 case LOOP_SCHED: 377 error = setpriority(PRIO_PROCESS, pid1, 378 0); 379 error = errno; 380 name = "sched"; 381 desirederror = 382 scenarios[scenario].sc_cansched_errno; 383 break; 384 default: 385 name = "broken"; 386 } 387 388 if (error != desirederror) { 389 fprintf(stdout, 390 "[%s].%s: expected %s, got %s\n ", 391 scenarios[scenario].sc_name, name, 392 errno_to_string(desirederror), 393 errno_to_string(error)); 394 cred_print(stdout, 395 scenarios[scenario].sc_cred1); 396 cred_print(stdout, 397 scenarios[scenario].sc_cred2); 398 fprintf(stdout, "\n"); 399 } 400 401 exit(0); 402 403 default: 404 /* parent */ 405 } 406 407 error = waitpid(pid2, NULL, 0); 408 /* 409 * Once pid2 has died, it's safe to kill pid1, if it's still 410 * alive. Mask signal failure in case the test actually 411 * killed pid1 (not unlikely: can occur in both signal and 412 * ptrace cases). 413 */ 414 kill(pid1, SIGKILL); 415 error = waitpid(pid2, NULL, 0); 416 } 417 418 return (0); 419 } 420 421 void 422 enact_scenarios(void) 423 { 424 int i, error; 425 426 for (i = 0; i < scenarios_count; i++) { 427 error = enact_scenario(i); 428 if (error) 429 perror("enact_scenario"); 430 } 431 } 432