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 1.30 2008/04/14 12:01:50 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 56 #include <sys/mplock2.h> 57 58 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 59 60 #ifdef KTRACE 61 static struct ktr_header *ktrgetheader (int type); 62 static void ktrwrite (struct lwp *, struct ktr_header *, struct uio *); 63 static int ktrcanset (struct thread *,struct proc *); 64 static int ktrsetchildren (struct thread *,struct proc *,int,int, ktrace_node_t); 65 static int ktrops (struct thread *,struct proc *,int,int, ktrace_node_t); 66 67 /* 68 * MPSAFE 69 */ 70 static struct ktr_header * 71 ktrgetheader(int type) 72 { 73 struct ktr_header *kth; 74 struct proc *p = curproc; /* XXX */ 75 struct lwp *lp = curthread->td_lwp; 76 77 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 78 M_KTRACE, M_WAITOK); 79 kth->ktr_type = type; 80 /* XXX threaded flag is a hack at the moment */ 81 kth->ktr_flags = (p->p_nthreads > 1) ? KTRH_THREADED : 0; 82 microtime(&kth->ktr_time); 83 kth->ktr_pid = p->p_pid; 84 kth->ktr_tid = lp->lwp_tid; 85 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1); 86 return (kth); 87 } 88 89 void 90 ktrsyscall(struct lwp *lp, int code, int narg, register_t args[]) 91 { 92 struct ktr_header *kth; 93 struct ktr_syscall *ktp; 94 int len; 95 register_t *argp; 96 int i; 97 98 len = offsetof(struct ktr_syscall, ktr_args) + 99 (narg * sizeof(register_t)); 100 101 /* 102 * Setting the active bit prevents a ktrace recursion from the 103 * ktracing op itself. 104 */ 105 lp->lwp_traceflag |= KTRFAC_ACTIVE; 106 kth = ktrgetheader(KTR_SYSCALL); 107 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK); 108 ktp->ktr_code = code; 109 ktp->ktr_narg = narg; 110 argp = &ktp->ktr_args[0]; 111 for (i = 0; i < narg; i++) 112 *argp++ = args[i]; 113 kth->ktr_buf = (caddr_t)ktp; 114 kth->ktr_len = len; 115 ktrwrite(lp, kth, NULL); 116 FREE(ktp, M_KTRACE); 117 FREE(kth, M_KTRACE); 118 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 119 } 120 121 void 122 ktrsysret(struct lwp *lp, int code, int error, register_t retval) 123 { 124 struct ktr_header *kth; 125 struct ktr_sysret ktp; 126 127 lp->lwp_traceflag |= KTRFAC_ACTIVE; 128 kth = ktrgetheader(KTR_SYSRET); 129 ktp.ktr_code = code; 130 ktp.ktr_error = error; 131 ktp.ktr_retval = retval; /* what about val2 ? */ 132 133 kth->ktr_buf = (caddr_t)&ktp; 134 kth->ktr_len = sizeof(struct ktr_sysret); 135 136 ktrwrite(lp, kth, NULL); 137 FREE(kth, M_KTRACE); 138 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 139 } 140 141 void 142 ktrnamei(struct lwp *lp, char *path) 143 { 144 struct ktr_header *kth; 145 146 lp->lwp_traceflag |= KTRFAC_ACTIVE; 147 kth = ktrgetheader(KTR_NAMEI); 148 kth->ktr_len = strlen(path); 149 kth->ktr_buf = path; 150 151 ktrwrite(lp, kth, NULL); 152 FREE(kth, M_KTRACE); 153 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 154 } 155 156 void 157 ktrgenio(struct lwp *lp, int fd, enum uio_rw rw, struct uio *uio, int error) 158 { 159 struct ktr_header *kth; 160 struct ktr_genio ktg; 161 162 if (error) 163 return; 164 lp->lwp_traceflag |= KTRFAC_ACTIVE; 165 kth = ktrgetheader(KTR_GENIO); 166 ktg.ktr_fd = fd; 167 ktg.ktr_rw = rw; 168 kth->ktr_buf = (caddr_t)&ktg; 169 kth->ktr_len = sizeof(struct ktr_genio); 170 uio->uio_offset = 0; 171 uio->uio_rw = UIO_WRITE; 172 173 ktrwrite(lp, kth, uio); 174 FREE(kth, M_KTRACE); 175 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 176 } 177 178 void 179 ktrpsig(struct lwp *lp, int sig, sig_t action, sigset_t *mask, int code) 180 { 181 struct ktr_header *kth; 182 struct ktr_psig kp; 183 184 lp->lwp_traceflag |= KTRFAC_ACTIVE; 185 kth = ktrgetheader(KTR_PSIG); 186 kp.signo = (char)sig; 187 kp.action = action; 188 kp.mask = *mask; 189 kp.code = code; 190 kth->ktr_buf = (caddr_t)&kp; 191 kth->ktr_len = sizeof (struct ktr_psig); 192 193 ktrwrite(lp, kth, NULL); 194 FREE(kth, M_KTRACE); 195 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 196 } 197 198 void 199 ktrcsw(struct lwp *lp, int out, int user) 200 { 201 struct ktr_header *kth; 202 struct ktr_csw kc; 203 204 lp->lwp_traceflag |= KTRFAC_ACTIVE; 205 kth = ktrgetheader(KTR_CSW); 206 kc.out = out; 207 kc.user = user; 208 kth->ktr_buf = (caddr_t)&kc; 209 kth->ktr_len = sizeof (struct ktr_csw); 210 211 ktrwrite(lp, kth, NULL); 212 FREE(kth, M_KTRACE); 213 lp->lwp_traceflag &= ~KTRFAC_ACTIVE; 214 } 215 #endif 216 217 /* Interface and common routines */ 218 219 #ifdef KTRACE 220 /* 221 * ktrace system call 222 */ 223 struct ktrace_clear_info { 224 ktrace_node_t tracenode; 225 int rootclear; 226 int error; 227 }; 228 229 static int ktrace_clear_callback(struct proc *p, void *data); 230 231 #endif 232 233 /* 234 * MPALMOSTSAFE 235 */ 236 int 237 sys_ktrace(struct ktrace_args *uap) 238 { 239 #ifdef KTRACE 240 struct ktrace_clear_info info; 241 struct thread *td = curthread; 242 struct proc *curp = td->td_proc; 243 struct proc *p; 244 struct pgrp *pg; 245 int facs = uap->facs & ~KTRFAC_ROOT; 246 int ops = KTROP(uap->ops); 247 int descend = uap->ops & KTRFLAG_DESCEND; 248 int ret = 0; 249 int error = 0; 250 struct nlookupdata nd; 251 ktrace_node_t tracenode = NULL; 252 253 get_mplock(); 254 curp->p_traceflag |= KTRFAC_ACTIVE; 255 if (ops != KTROP_CLEAR) { 256 /* 257 * an operation which requires a file argument. 258 */ 259 error = nlookup_init(&nd, uap->fname, 260 UIO_USERSPACE, NLC_LOCKVP); 261 if (error == 0) 262 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0); 263 if (error == 0 && nd.nl_open_vp->v_type != VREG) 264 error = EACCES; 265 if (error) { 266 curp->p_traceflag &= ~KTRFAC_ACTIVE; 267 nlookup_done(&nd); 268 goto done; 269 } 270 MALLOC(tracenode, ktrace_node_t, sizeof (struct ktrace_node), 271 M_KTRACE, M_WAITOK | M_ZERO); 272 tracenode->kn_vp = nd.nl_open_vp; 273 tracenode->kn_refs = 1; 274 nd.nl_open_vp = NULL; 275 nlookup_done(&nd); 276 vn_unlock(tracenode->kn_vp); 277 } 278 /* 279 * Clear all uses of the tracefile. Not the most efficient operation 280 * in the world. 281 */ 282 if (ops == KTROP_CLEARFILE) { 283 info.tracenode = tracenode; 284 info.error = 0; 285 info.rootclear = 0; 286 allproc_scan(ktrace_clear_callback, &info); 287 error = info.error; 288 goto done; 289 } 290 /* 291 * need something to (un)trace (XXX - why is this here?) 292 */ 293 if (!facs) { 294 error = EINVAL; 295 goto done; 296 } 297 /* 298 * do it 299 */ 300 if (uap->pid < 0) { 301 /* 302 * by process group 303 */ 304 pg = pgfind(-uap->pid); 305 if (pg == NULL) { 306 error = ESRCH; 307 goto done; 308 } 309 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 310 if (descend) 311 ret |= ktrsetchildren(td, p, ops, facs, tracenode); 312 else 313 ret |= ktrops(td, p, ops, facs, tracenode); 314 } 315 } else { 316 /* 317 * by pid 318 */ 319 p = pfind(uap->pid); 320 if (p == NULL) { 321 error = ESRCH; 322 goto done; 323 } 324 if (descend) 325 ret |= ktrsetchildren(td, p, ops, facs, tracenode); 326 else 327 ret |= ktrops(td, p, ops, facs, tracenode); 328 } 329 if (!ret) 330 error = EPERM; 331 done: 332 if (tracenode) 333 ktrdestroy(&tracenode); 334 curp->p_traceflag &= ~KTRFAC_ACTIVE; 335 rel_mplock(); 336 return (error); 337 #else 338 return ENOSYS; 339 #endif 340 } 341 342 #ifdef KTRACE 343 344 /* 345 * NOTE: NOT MPSAFE (yet) 346 */ 347 static int 348 ktrace_clear_callback(struct proc *p, void *data) 349 { 350 struct ktrace_clear_info *info = data; 351 352 if (p->p_tracenode) { 353 if (info->rootclear) { 354 if (p->p_tracenode == info->tracenode) { 355 ktrdestroy(&p->p_tracenode); 356 p->p_traceflag = 0; 357 } 358 } else { 359 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) { 360 if (ktrcanset(curthread, p)) { 361 ktrdestroy(&p->p_tracenode); 362 p->p_traceflag = 0; 363 } else { 364 info->error = EPERM; 365 } 366 } 367 } 368 } 369 return(0); 370 } 371 372 #endif 373 374 /* 375 * utrace system call 376 * 377 * MPALMOSTSAFE 378 */ 379 int 380 sys_utrace(struct utrace_args *uap) 381 { 382 #ifdef KTRACE 383 struct ktr_header *kth; 384 struct thread *td = curthread; /* XXX */ 385 caddr_t cp; 386 387 if (!KTRPOINT(td, KTR_USER)) 388 return (0); 389 if (uap->len > KTR_USER_MAXLEN) 390 return (EINVAL); 391 td->td_lwp->lwp_traceflag |= KTRFAC_ACTIVE; 392 kth = ktrgetheader(KTR_USER); 393 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 394 if (!copyin(uap->addr, cp, uap->len)) { 395 kth->ktr_buf = cp; 396 kth->ktr_len = uap->len; 397 get_mplock(); 398 ktrwrite(td->td_lwp, kth, NULL); 399 rel_mplock(); 400 } 401 FREE(kth, M_KTRACE); 402 FREE(cp, M_KTRACE); 403 td->td_lwp->lwp_traceflag &= ~KTRFAC_ACTIVE; 404 405 return (0); 406 #else 407 return (ENOSYS); 408 #endif 409 } 410 411 void 412 ktrdestroy(struct ktrace_node **tracenodep) 413 { 414 ktrace_node_t tracenode; 415 416 if ((tracenode = *tracenodep) != NULL) { 417 *tracenodep = NULL; 418 KKASSERT(tracenode->kn_refs > 0); 419 /* XXX not MP safe yet */ 420 --tracenode->kn_refs; 421 if (tracenode->kn_refs == 0) { 422 vn_close(tracenode->kn_vp, FREAD|FWRITE); 423 tracenode->kn_vp = NULL; 424 FREE(tracenode, M_KTRACE); 425 } 426 } 427 } 428 429 /* 430 * This allows a process to inherit a ref on a tracenode and is also used 431 * as a temporary ref to prevent a tracenode from being destroyed out from 432 * under an active operation. 433 */ 434 ktrace_node_t 435 ktrinherit(ktrace_node_t tracenode) 436 { 437 if (tracenode) { 438 KKASSERT(tracenode->kn_refs > 0); 439 ++tracenode->kn_refs; 440 } 441 return(tracenode); 442 } 443 444 #ifdef KTRACE 445 static int 446 ktrops(struct thread *td, struct proc *p, int ops, int facs, 447 ktrace_node_t tracenode) 448 { 449 ktrace_node_t oldnode; 450 451 if (!ktrcanset(td, p)) 452 return (0); 453 if (ops == KTROP_SET) { 454 if ((oldnode = p->p_tracenode) != tracenode) { 455 p->p_tracenode = ktrinherit(tracenode); 456 ktrdestroy(&oldnode); 457 } 458 p->p_traceflag |= facs; 459 if (td->td_ucred->cr_uid == 0) 460 p->p_traceflag |= KTRFAC_ROOT; 461 } else { 462 /* KTROP_CLEAR */ 463 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 464 /* no more tracing */ 465 p->p_traceflag = 0; 466 ktrdestroy(&p->p_tracenode); 467 } 468 } 469 470 return (1); 471 } 472 473 static int 474 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs, 475 ktrace_node_t tracenode) 476 { 477 struct proc *p; 478 int ret = 0; 479 480 p = top; 481 for (;;) { 482 ret |= ktrops(td, p, ops, facs, tracenode); 483 /* 484 * If this process has children, descend to them next, 485 * otherwise do any siblings, and if done with this level, 486 * follow back up the tree (but not past top). 487 */ 488 if (!LIST_EMPTY(&p->p_children)) 489 p = LIST_FIRST(&p->p_children); 490 else for (;;) { 491 if (p == top) 492 return (ret); 493 if (LIST_NEXT(p, p_sibling)) { 494 p = LIST_NEXT(p, p_sibling); 495 break; 496 } 497 p = p->p_pptr; 498 } 499 } 500 /*NOTREACHED*/ 501 } 502 503 static void 504 ktrwrite(struct lwp *lp, struct ktr_header *kth, struct uio *uio) 505 { 506 struct ktrace_clear_info info; 507 struct uio auio; 508 struct iovec aiov[2]; 509 int error; 510 ktrace_node_t tracenode; 511 512 /* 513 * We have to ref our tracenode to prevent it from being ripped out 514 * from under us while we are trying to use it. p_tracenode can 515 * go away at any time if another process gets a write error. 516 * 517 * XXX not MP safe 518 */ 519 if (lp->lwp_proc->p_tracenode == NULL) 520 return; 521 tracenode = ktrinherit(lp->lwp_proc->p_tracenode); 522 auio.uio_iov = &aiov[0]; 523 auio.uio_offset = 0; 524 auio.uio_segflg = UIO_SYSSPACE; 525 auio.uio_rw = UIO_WRITE; 526 aiov[0].iov_base = (caddr_t)kth; 527 aiov[0].iov_len = sizeof(struct ktr_header); 528 auio.uio_resid = sizeof(struct ktr_header); 529 auio.uio_iovcnt = 1; 530 auio.uio_td = curthread; 531 if (kth->ktr_len > 0) { 532 auio.uio_iovcnt++; 533 aiov[1].iov_base = kth->ktr_buf; 534 aiov[1].iov_len = kth->ktr_len; 535 auio.uio_resid += kth->ktr_len; 536 if (uio != NULL) 537 kth->ktr_len += uio->uio_resid; 538 } 539 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY); 540 error = VOP_WRITE(tracenode->kn_vp, &auio, 541 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred); 542 if (error == 0 && uio != NULL) { 543 error = VOP_WRITE(tracenode->kn_vp, uio, 544 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred); 545 } 546 vn_unlock(tracenode->kn_vp); 547 if (error) { 548 /* 549 * If an error occured, give up tracing on all processes 550 * using this tracenode. This is not MP safe but is 551 * blocking-safe. 552 */ 553 log(LOG_NOTICE, 554 "ktrace write failed, errno %d, tracing stopped\n", error); 555 info.tracenode = tracenode; 556 info.error = 0; 557 info.rootclear = 1; 558 allproc_scan(ktrace_clear_callback, &info); 559 } 560 ktrdestroy(&tracenode); 561 } 562 563 /* 564 * Return true if caller has permission to set the ktracing state 565 * of target. Essentially, the target can't possess any 566 * more permissions than the caller. KTRFAC_ROOT signifies that 567 * root previously set the tracing status on the target process, and 568 * so, only root may further change it. 569 * 570 * TODO: check groups. use caller effective gid. 571 */ 572 static int 573 ktrcanset(struct thread *calltd, struct proc *targetp) 574 { 575 struct ucred *caller = calltd->td_ucred; 576 struct ucred *target = targetp->p_ucred; 577 578 if (!PRISON_CHECK(caller, target)) 579 return (0); 580 if ((caller->cr_uid == target->cr_ruid && 581 target->cr_ruid == target->cr_svuid && 582 caller->cr_rgid == target->cr_rgid && /* XXX */ 583 target->cr_rgid == target->cr_svgid && 584 (targetp->p_traceflag & KTRFAC_ROOT) == 0 && 585 (targetp->p_flag & P_SUGID) == 0) || 586 caller->cr_uid == 0) 587 return (1); 588 589 return (0); 590 } 591 592 #endif /* KTRACE */ 593