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