1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93 34 * $FreeBSD: src/sys/kern/kern_ktrace.c,v 1.35.2.6 2002/07/05 22:36:38 darrenr Exp $ 35 * $DragonFly: src/sys/kern/kern_ktrace.c,v 1.27 2006/06/05 07:26:10 dillon Exp $ 36 */ 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/sysproto.h> 43 #include <sys/kernel.h> 44 #include <sys/proc.h> 45 #include <sys/fcntl.h> 46 #include <sys/lock.h> 47 #include <sys/nlookup.h> 48 #include <sys/vnode.h> 49 #include <sys/ktrace.h> 50 #include <sys/malloc.h> 51 #include <sys/syslog.h> 52 #include <sys/sysent.h> 53 54 #include <vm/vm_zone.h> 55 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 56 57 #ifdef KTRACE 58 static struct ktr_header *ktrgetheader (int type); 59 static void ktrwrite (struct proc *, struct ktr_header *, struct uio *); 60 static int ktrcanset (struct proc *,struct proc *); 61 static int ktrsetchildren (struct proc *,struct proc *,int,int, ktrace_node_t); 62 static int ktrops (struct proc *,struct proc *,int,int, ktrace_node_t); 63 64 static struct ktr_header * 65 ktrgetheader(int type) 66 { 67 struct ktr_header *kth; 68 struct proc *p = curproc; /* XXX */ 69 70 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 71 M_KTRACE, M_WAITOK); 72 kth->ktr_type = type; 73 microtime(&kth->ktr_time); 74 kth->ktr_pid = p->p_pid; 75 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1); 76 return (kth); 77 } 78 79 void 80 ktrsyscall(struct proc *p, int code, int narg, register_t args[]) 81 { 82 struct ktr_header *kth; 83 struct ktr_syscall *ktp; 84 int len; 85 register_t *argp; 86 int i; 87 88 len = offsetof(struct ktr_syscall, ktr_args) + 89 (narg * sizeof(register_t)); 90 91 /* 92 * Setting the active bit prevents a ktrace recursion from the 93 * ktracing op itself. 94 */ 95 p->p_traceflag |= KTRFAC_ACTIVE; 96 kth = ktrgetheader(KTR_SYSCALL); 97 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK); 98 ktp->ktr_code = code; 99 ktp->ktr_narg = narg; 100 argp = &ktp->ktr_args[0]; 101 for (i = 0; i < narg; i++) 102 *argp++ = args[i]; 103 kth->ktr_buf = (caddr_t)ktp; 104 kth->ktr_len = len; 105 ktrwrite(p, kth, NULL); 106 FREE(ktp, M_KTRACE); 107 FREE(kth, M_KTRACE); 108 p->p_traceflag &= ~KTRFAC_ACTIVE; 109 } 110 111 void 112 ktrsysret(struct proc *p, int code, int error, register_t retval) 113 { 114 struct ktr_header *kth; 115 struct ktr_sysret ktp; 116 117 p->p_traceflag |= KTRFAC_ACTIVE; 118 kth = ktrgetheader(KTR_SYSRET); 119 ktp.ktr_code = code; 120 ktp.ktr_error = error; 121 ktp.ktr_retval = retval; /* what about val2 ? */ 122 123 kth->ktr_buf = (caddr_t)&ktp; 124 kth->ktr_len = sizeof(struct ktr_sysret); 125 126 ktrwrite(p, kth, NULL); 127 FREE(kth, M_KTRACE); 128 p->p_traceflag &= ~KTRFAC_ACTIVE; 129 } 130 131 void 132 ktrnamei(struct proc *p, char *path) 133 { 134 struct ktr_header *kth; 135 136 p->p_traceflag |= KTRFAC_ACTIVE; 137 kth = ktrgetheader(KTR_NAMEI); 138 kth->ktr_len = strlen(path); 139 kth->ktr_buf = path; 140 141 ktrwrite(p, kth, NULL); 142 FREE(kth, M_KTRACE); 143 p->p_traceflag &= ~KTRFAC_ACTIVE; 144 } 145 146 void 147 ktrgenio(struct proc *p, int fd, enum uio_rw rw, struct uio *uio, int error) 148 { 149 struct ktr_header *kth; 150 struct ktr_genio ktg; 151 152 if (error) 153 return; 154 p->p_traceflag |= KTRFAC_ACTIVE; 155 kth = ktrgetheader(KTR_GENIO); 156 ktg.ktr_fd = fd; 157 ktg.ktr_rw = rw; 158 kth->ktr_buf = (caddr_t)&ktg; 159 kth->ktr_len = sizeof(struct ktr_genio); 160 uio->uio_offset = 0; 161 uio->uio_rw = UIO_WRITE; 162 163 ktrwrite(p, kth, uio); 164 FREE(kth, M_KTRACE); 165 p->p_traceflag &= ~KTRFAC_ACTIVE; 166 } 167 168 void 169 ktrpsig(struct proc *p, int sig, sig_t action, sigset_t *mask, int code) 170 { 171 struct ktr_header *kth; 172 struct ktr_psig kp; 173 174 p->p_traceflag |= KTRFAC_ACTIVE; 175 kth = ktrgetheader(KTR_PSIG); 176 kp.signo = (char)sig; 177 kp.action = action; 178 kp.mask = *mask; 179 kp.code = code; 180 kth->ktr_buf = (caddr_t)&kp; 181 kth->ktr_len = sizeof (struct ktr_psig); 182 183 ktrwrite(p, kth, NULL); 184 FREE(kth, M_KTRACE); 185 p->p_traceflag &= ~KTRFAC_ACTIVE; 186 } 187 188 void 189 ktrcsw(struct proc *p, int out, int user) 190 { 191 struct ktr_header *kth; 192 struct ktr_csw kc; 193 194 p->p_traceflag |= KTRFAC_ACTIVE; 195 kth = ktrgetheader(KTR_CSW); 196 kc.out = out; 197 kc.user = user; 198 kth->ktr_buf = (caddr_t)&kc; 199 kth->ktr_len = sizeof (struct ktr_csw); 200 201 ktrwrite(p, kth, NULL); 202 FREE(kth, M_KTRACE); 203 p->p_traceflag &= ~KTRFAC_ACTIVE; 204 } 205 #endif 206 207 /* Interface and common routines */ 208 209 #ifdef KTRACE 210 /* 211 * ktrace system call 212 */ 213 struct ktrace_clear_info { 214 ktrace_node_t tracenode; 215 int rootclear; 216 int error; 217 }; 218 219 static int ktrace_clear_callback(struct proc *p, void *data); 220 221 #endif 222 223 int 224 sys_ktrace(struct ktrace_args *uap) 225 { 226 #ifdef KTRACE 227 struct ktrace_clear_info info; 228 struct thread *td = curthread; 229 struct proc *curp = td->td_proc; 230 struct proc *p; 231 struct pgrp *pg; 232 int facs = uap->facs & ~KTRFAC_ROOT; 233 int ops = KTROP(uap->ops); 234 int descend = uap->ops & KTRFLAG_DESCEND; 235 int ret = 0; 236 int error = 0; 237 struct nlookupdata nd; 238 ktrace_node_t tracenode = NULL; 239 240 curp->p_traceflag |= KTRFAC_ACTIVE; 241 if (ops != KTROP_CLEAR) { 242 /* 243 * an operation which requires a file argument. 244 */ 245 error = nlookup_init(&nd, uap->fname, 246 UIO_USERSPACE, NLC_LOCKVP); 247 if (error == 0) 248 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0); 249 if (error == 0 && nd.nl_open_vp->v_type != VREG) 250 error = EACCES; 251 if (error) { 252 curp->p_traceflag &= ~KTRFAC_ACTIVE; 253 nlookup_done(&nd); 254 return (error); 255 } 256 MALLOC(tracenode, ktrace_node_t, sizeof (struct ktrace_node), 257 M_KTRACE, M_WAITOK | M_ZERO); 258 tracenode->kn_vp = nd.nl_open_vp; 259 tracenode->kn_refs = 1; 260 nd.nl_open_vp = NULL; 261 nlookup_done(&nd); 262 VOP_UNLOCK(tracenode->kn_vp, 0); 263 } 264 /* 265 * Clear all uses of the tracefile. Not the most efficient operation 266 * in the world. 267 */ 268 if (ops == KTROP_CLEARFILE) { 269 info.tracenode = tracenode; 270 info.error = 0; 271 info.rootclear = 0; 272 allproc_scan(ktrace_clear_callback, &info); 273 error = info.error; 274 goto done; 275 } 276 /* 277 * need something to (un)trace (XXX - why is this here?) 278 */ 279 if (!facs) { 280 error = EINVAL; 281 goto done; 282 } 283 /* 284 * do it 285 */ 286 if (uap->pid < 0) { 287 /* 288 * by process group 289 */ 290 pg = pgfind(-uap->pid); 291 if (pg == NULL) { 292 error = ESRCH; 293 goto done; 294 } 295 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 296 if (descend) 297 ret |= ktrsetchildren(curp, p, ops, facs, tracenode); 298 else 299 ret |= ktrops(curp, p, ops, facs, tracenode); 300 } 301 } else { 302 /* 303 * by pid 304 */ 305 p = pfind(uap->pid); 306 if (p == NULL) { 307 error = ESRCH; 308 goto done; 309 } 310 if (descend) 311 ret |= ktrsetchildren(curp, p, ops, facs, tracenode); 312 else 313 ret |= ktrops(curp, p, ops, facs, tracenode); 314 } 315 if (!ret) 316 error = EPERM; 317 done: 318 if (tracenode) 319 ktrdestroy(&tracenode); 320 curp->p_traceflag &= ~KTRFAC_ACTIVE; 321 return (error); 322 #else 323 return ENOSYS; 324 #endif 325 } 326 327 #ifdef KTRACE 328 329 /* 330 * NOTE: NOT MPSAFE (yet) 331 */ 332 static int 333 ktrace_clear_callback(struct proc *p, void *data) 334 { 335 struct ktrace_clear_info *info = data; 336 337 if (info->rootclear) { 338 if (p->p_tracenode == info->tracenode) { 339 ktrdestroy(&p->p_tracenode); 340 p->p_traceflag = 0; 341 } 342 } else { 343 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) { 344 if (ktrcanset(curproc, p)) { 345 ktrdestroy(&p->p_tracenode); 346 p->p_traceflag = 0; 347 } else { 348 info->error = EPERM; 349 } 350 } 351 } 352 return(0); 353 } 354 355 #endif 356 357 /* 358 * utrace system call 359 */ 360 /* ARGSUSED */ 361 int 362 sys_utrace(struct utrace_args *uap) 363 { 364 #ifdef KTRACE 365 struct ktr_header *kth; 366 struct thread *td = curthread; /* XXX */ 367 struct proc *p = td->td_proc; 368 caddr_t cp; 369 370 if (!KTRPOINT(td, KTR_USER)) 371 return (0); 372 if (uap->len > KTR_USER_MAXLEN) 373 return (EINVAL); 374 p->p_traceflag |= KTRFAC_ACTIVE; 375 kth = ktrgetheader(KTR_USER); 376 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 377 if (!copyin(uap->addr, cp, uap->len)) { 378 kth->ktr_buf = cp; 379 kth->ktr_len = uap->len; 380 ktrwrite(p, kth, NULL); 381 } 382 FREE(kth, M_KTRACE); 383 FREE(cp, M_KTRACE); 384 p->p_traceflag &= ~KTRFAC_ACTIVE; 385 386 return (0); 387 #else 388 return (ENOSYS); 389 #endif 390 } 391 392 void 393 ktrdestroy(struct ktrace_node **tracenodep) 394 { 395 ktrace_node_t tracenode; 396 397 if ((tracenode = *tracenodep) != NULL) { 398 *tracenodep = NULL; 399 KKASSERT(tracenode->kn_refs > 0); 400 /* XXX not MP safe yet */ 401 --tracenode->kn_refs; 402 if (tracenode->kn_refs == 0) { 403 vn_close(tracenode->kn_vp, FREAD|FWRITE); 404 tracenode->kn_vp = NULL; 405 FREE(tracenode, M_KTRACE); 406 } 407 } 408 } 409 410 /* 411 * This allows a process to inherit a ref on a tracenode and is also used 412 * as a temporary ref to prevent a tracenode from being destroyed out from 413 * under an active operation. 414 */ 415 ktrace_node_t 416 ktrinherit(ktrace_node_t tracenode) 417 { 418 if (tracenode) { 419 KKASSERT(tracenode->kn_refs > 0); 420 ++tracenode->kn_refs; 421 } 422 return(tracenode); 423 } 424 425 #ifdef KTRACE 426 static int 427 ktrops(struct proc *curp, struct proc *p, int ops, int facs, 428 ktrace_node_t tracenode) 429 { 430 ktrace_node_t oldnode; 431 432 if (!ktrcanset(curp, p)) 433 return (0); 434 if (ops == KTROP_SET) { 435 if ((oldnode = p->p_tracenode) != tracenode) { 436 p->p_tracenode = ktrinherit(tracenode); 437 ktrdestroy(&oldnode); 438 } 439 p->p_traceflag |= facs; 440 if (curp->p_ucred->cr_uid == 0) 441 p->p_traceflag |= KTRFAC_ROOT; 442 } else { 443 /* KTROP_CLEAR */ 444 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 445 /* no more tracing */ 446 p->p_traceflag = 0; 447 ktrdestroy(&p->p_tracenode); 448 } 449 } 450 451 return (1); 452 } 453 454 static int 455 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs, 456 ktrace_node_t tracenode) 457 { 458 struct proc *p; 459 int ret = 0; 460 461 p = top; 462 for (;;) { 463 ret |= ktrops(curp, p, ops, facs, tracenode); 464 /* 465 * If this process has children, descend to them next, 466 * otherwise do any siblings, and if done with this level, 467 * follow back up the tree (but not past top). 468 */ 469 if (!LIST_EMPTY(&p->p_children)) 470 p = LIST_FIRST(&p->p_children); 471 else for (;;) { 472 if (p == top) 473 return (ret); 474 if (LIST_NEXT(p, p_sibling)) { 475 p = LIST_NEXT(p, p_sibling); 476 break; 477 } 478 p = p->p_pptr; 479 } 480 } 481 /*NOTREACHED*/ 482 } 483 484 static void 485 ktrwrite(struct proc *p, struct ktr_header *kth, struct uio *uio) 486 { 487 struct ktrace_clear_info info; 488 struct uio auio; 489 struct iovec aiov[2]; 490 int error; 491 ktrace_node_t tracenode; 492 493 /* 494 * We have to ref our tracenode to prevent it from being ripped out 495 * from under us while we are trying to use it. p_tracenode can 496 * go away at any time if another process gets a write error. 497 * 498 * XXX not MP safe 499 */ 500 if (p->p_tracenode == NULL) 501 return; 502 tracenode = ktrinherit(p->p_tracenode); 503 auio.uio_iov = &aiov[0]; 504 auio.uio_offset = 0; 505 auio.uio_segflg = UIO_SYSSPACE; 506 auio.uio_rw = UIO_WRITE; 507 aiov[0].iov_base = (caddr_t)kth; 508 aiov[0].iov_len = sizeof(struct ktr_header); 509 auio.uio_resid = sizeof(struct ktr_header); 510 auio.uio_iovcnt = 1; 511 auio.uio_td = curthread; 512 if (kth->ktr_len > 0) { 513 auio.uio_iovcnt++; 514 aiov[1].iov_base = kth->ktr_buf; 515 aiov[1].iov_len = kth->ktr_len; 516 auio.uio_resid += kth->ktr_len; 517 if (uio != NULL) 518 kth->ktr_len += uio->uio_resid; 519 } 520 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY); 521 error = VOP_WRITE(tracenode->kn_vp, &auio, 522 IO_UNIT | IO_APPEND, p->p_ucred); 523 if (error == 0 && uio != NULL) { 524 error = VOP_WRITE(tracenode->kn_vp, uio, 525 IO_UNIT | IO_APPEND, p->p_ucred); 526 } 527 VOP_UNLOCK(tracenode->kn_vp, 0); 528 if (error) { 529 /* 530 * If an error occured, give up tracing on all processes 531 * using this tracenode. This is not MP safe but is 532 * blocking-safe. 533 */ 534 log(LOG_NOTICE, 535 "ktrace write failed, errno %d, tracing stopped\n", error); 536 info.tracenode = tracenode; 537 info.error = 0; 538 info.rootclear = 1; 539 allproc_scan(ktrace_clear_callback, &info); 540 } 541 ktrdestroy(&tracenode); 542 } 543 544 /* 545 * Return true if caller has permission to set the ktracing state 546 * of target. Essentially, the target can't possess any 547 * more permissions than the caller. KTRFAC_ROOT signifies that 548 * root previously set the tracing status on the target process, and 549 * so, only root may further change it. 550 * 551 * TODO: check groups. use caller effective gid. 552 */ 553 static int 554 ktrcanset(struct proc *callp, struct proc *targetp) 555 { 556 struct ucred *caller = callp->p_ucred; 557 struct ucred *target = targetp->p_ucred; 558 559 if (!PRISON_CHECK(caller, target)) 560 return (0); 561 if ((caller->cr_uid == target->cr_ruid && 562 target->cr_ruid == target->cr_svuid && 563 caller->cr_rgid == target->cr_rgid && /* XXX */ 564 target->cr_rgid == target->cr_svgid && 565 (targetp->p_traceflag & KTRFAC_ROOT) == 0 && 566 (targetp->p_flag & P_SUGID) == 0) || 567 caller->cr_uid == 0) 568 return (1); 569 570 return (0); 571 } 572 573 #endif /* KTRACE */ 574