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 1.19 2005/07/28 18:10:23 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 vnode *, struct ktr_header *, struct uio *); 60 static int ktrcanset (struct proc *,struct proc *); 61 static int ktrsetchildren (struct proc *,struct proc *,int,int,struct vnode *); 62 static int ktrops (struct proc *,struct proc *,int,int,struct vnode *); 63 64 65 static struct ktr_header * 66 ktrgetheader(int type) 67 { 68 struct ktr_header *kth; 69 struct proc *p = curproc; /* XXX */ 70 71 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 72 M_KTRACE, M_WAITOK); 73 kth->ktr_type = type; 74 microtime(&kth->ktr_time); 75 kth->ktr_pid = p->p_pid; 76 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1); 77 return (kth); 78 } 79 80 void 81 ktrsyscall(struct vnode *vp, int code, int narg, register_t args[]) 82 { 83 struct ktr_header *kth; 84 struct ktr_syscall *ktp; 85 int len = offsetof(struct ktr_syscall, ktr_args) + 86 (narg * sizeof(register_t)); 87 struct proc *p = curproc; /* XXX */ 88 register_t *argp; 89 int i; 90 91 p->p_traceflag |= KTRFAC_ACTIVE; 92 kth = ktrgetheader(KTR_SYSCALL); 93 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK); 94 ktp->ktr_code = code; 95 ktp->ktr_narg = narg; 96 argp = &ktp->ktr_args[0]; 97 for (i = 0; i < narg; i++) 98 *argp++ = args[i]; 99 kth->ktr_buf = (caddr_t)ktp; 100 kth->ktr_len = len; 101 ktrwrite(vp, kth, NULL); 102 FREE(ktp, M_KTRACE); 103 FREE(kth, M_KTRACE); 104 p->p_traceflag &= ~KTRFAC_ACTIVE; 105 } 106 107 void 108 ktrsysret(struct vnode *vp, int code, int error, register_t retval) 109 { 110 struct ktr_header *kth; 111 struct ktr_sysret ktp; 112 struct proc *p = curproc; /* XXX */ 113 114 p->p_traceflag |= KTRFAC_ACTIVE; 115 kth = ktrgetheader(KTR_SYSRET); 116 ktp.ktr_code = code; 117 ktp.ktr_error = error; 118 ktp.ktr_retval = retval; /* what about val2 ? */ 119 120 kth->ktr_buf = (caddr_t)&ktp; 121 kth->ktr_len = sizeof(struct ktr_sysret); 122 123 ktrwrite(vp, kth, NULL); 124 FREE(kth, M_KTRACE); 125 p->p_traceflag &= ~KTRFAC_ACTIVE; 126 } 127 128 void 129 ktrnamei(struct vnode *vp, char *path) 130 { 131 struct ktr_header *kth; 132 struct proc *p = curproc; /* XXX */ 133 134 /* 135 * don't let vp get ripped out from under us 136 */ 137 if (vp) 138 vref(vp); 139 p->p_traceflag |= KTRFAC_ACTIVE; 140 kth = ktrgetheader(KTR_NAMEI); 141 kth->ktr_len = strlen(path); 142 kth->ktr_buf = path; 143 144 ktrwrite(vp, kth, NULL); 145 if (vp) 146 vrele(vp); 147 FREE(kth, M_KTRACE); 148 p->p_traceflag &= ~KTRFAC_ACTIVE; 149 } 150 151 void 152 ktrgenio(struct vnode *vp, int fd, enum uio_rw rw, struct uio *uio, int error) 153 { 154 struct ktr_header *kth; 155 struct ktr_genio ktg; 156 struct proc *p = curproc; /* XXX */ 157 158 if (error) 159 return; 160 /* 161 * don't let p_tracep get ripped out from under us 162 */ 163 if (vp) 164 vref(vp); 165 p->p_traceflag |= KTRFAC_ACTIVE; 166 kth = ktrgetheader(KTR_GENIO); 167 ktg.ktr_fd = fd; 168 ktg.ktr_rw = rw; 169 kth->ktr_buf = (caddr_t)&ktg; 170 kth->ktr_len = sizeof(struct ktr_genio); 171 uio->uio_offset = 0; 172 uio->uio_rw = UIO_WRITE; 173 174 ktrwrite(vp, kth, uio); 175 if (vp) 176 vrele(vp); 177 FREE(kth, M_KTRACE); 178 p->p_traceflag &= ~KTRFAC_ACTIVE; 179 } 180 181 void 182 ktrpsig(struct vnode *vp, int sig, sig_t action, sigset_t *mask, int code) 183 { 184 struct ktr_header *kth; 185 struct ktr_psig kp; 186 struct proc *p = curproc; /* XXX */ 187 188 /* 189 * don't let vp get ripped out from under us 190 */ 191 if (vp) 192 vref(vp); 193 p->p_traceflag |= KTRFAC_ACTIVE; 194 kth = ktrgetheader(KTR_PSIG); 195 kp.signo = (char)sig; 196 kp.action = action; 197 kp.mask = *mask; 198 kp.code = code; 199 kth->ktr_buf = (caddr_t)&kp; 200 kth->ktr_len = sizeof (struct ktr_psig); 201 202 ktrwrite(vp, kth, NULL); 203 if (vp) 204 vrele(vp); 205 FREE(kth, M_KTRACE); 206 p->p_traceflag &= ~KTRFAC_ACTIVE; 207 } 208 209 void 210 ktrcsw(struct vnode *vp, int out, int user) 211 { 212 struct ktr_header *kth; 213 struct ktr_csw kc; 214 struct proc *p = curproc; /* XXX */ 215 216 /* 217 * don't let vp get ripped out from under us 218 */ 219 if (vp) 220 vref(vp); 221 p->p_traceflag |= KTRFAC_ACTIVE; 222 kth = ktrgetheader(KTR_CSW); 223 kc.out = out; 224 kc.user = user; 225 kth->ktr_buf = (caddr_t)&kc; 226 kth->ktr_len = sizeof (struct ktr_csw); 227 228 ktrwrite(vp, kth, NULL); 229 if (vp) 230 vrele(vp); 231 FREE(kth, M_KTRACE); 232 p->p_traceflag &= ~KTRFAC_ACTIVE; 233 } 234 #endif 235 236 /* Interface and common routines */ 237 238 /* 239 * ktrace system call 240 */ 241 /* ARGSUSED */ 242 int 243 ktrace(struct ktrace_args *uap) 244 { 245 #ifdef KTRACE 246 struct thread *td = curthread; 247 struct proc *curp = td->td_proc; 248 struct vnode *vp = NULL; 249 struct proc *p; 250 struct pgrp *pg; 251 int facs = uap->facs & ~KTRFAC_ROOT; 252 int ops = KTROP(uap->ops); 253 int descend = uap->ops & KTRFLAG_DESCEND; 254 int ret = 0; 255 int error = 0; 256 struct nlookupdata nd; 257 258 curp->p_traceflag |= KTRFAC_ACTIVE; 259 if (ops != KTROP_CLEAR) { 260 /* 261 * an operation which requires a file argument. 262 */ 263 error = nlookup_init(&nd, uap->fname, 264 UIO_USERSPACE, NLC_LOCKVP); 265 if (error == 0) 266 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0); 267 if (error == 0 && nd.nl_open_vp->v_type != VREG) 268 error = EACCES; 269 if (error) { 270 curp->p_traceflag &= ~KTRFAC_ACTIVE; 271 nlookup_done(&nd); 272 return (error); 273 } 274 vp = nd.nl_open_vp; 275 nd.nl_open_vp = NULL; 276 nlookup_done(&nd); 277 VOP_UNLOCK(vp, 0, td); 278 } 279 /* 280 * Clear all uses of the tracefile. XXX umm, what happens to the 281 * loop if vn_close() blocks? 282 */ 283 if (ops == KTROP_CLEARFILE) { 284 FOREACH_PROC_IN_SYSTEM(p) { 285 if (p->p_tracep == vp) { 286 if (ktrcanset(curp, p) && p->p_tracep == vp) { 287 p->p_tracep = NULL; 288 p->p_traceflag = 0; 289 vn_close(vp, FREAD|FWRITE, td); 290 } else { 291 error = EPERM; 292 } 293 } 294 } 295 goto done; 296 } 297 /* 298 * need something to (un)trace (XXX - why is this here?) 299 */ 300 if (!facs) { 301 error = EINVAL; 302 goto done; 303 } 304 /* 305 * do it 306 */ 307 if (uap->pid < 0) { 308 /* 309 * by process group 310 */ 311 pg = pgfind(-uap->pid); 312 if (pg == NULL) { 313 error = ESRCH; 314 goto done; 315 } 316 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 317 if (descend) 318 ret |= ktrsetchildren(curp, p, ops, facs, vp); 319 else 320 ret |= ktrops(curp, p, ops, facs, vp); 321 } 322 } else { 323 /* 324 * by pid 325 */ 326 p = pfind(uap->pid); 327 if (p == NULL) { 328 error = ESRCH; 329 goto done; 330 } 331 if (descend) 332 ret |= ktrsetchildren(curp, p, ops, facs, vp); 333 else 334 ret |= ktrops(curp, p, ops, facs, vp); 335 } 336 if (!ret) 337 error = EPERM; 338 done: 339 if (vp != NULL) 340 vn_close(vp, FWRITE, td); 341 curp->p_traceflag &= ~KTRFAC_ACTIVE; 342 return (error); 343 #else 344 return ENOSYS; 345 #endif 346 } 347 348 /* 349 * utrace system call 350 */ 351 /* ARGSUSED */ 352 int 353 utrace(struct utrace_args *uap) 354 { 355 #ifdef KTRACE 356 struct ktr_header *kth; 357 struct thread *td = curthread; /* XXX */ 358 struct proc *p = td->td_proc; 359 struct vnode *vp; 360 caddr_t cp; 361 362 if (!KTRPOINT(td, KTR_USER)) 363 return (0); 364 if (uap->len > KTR_USER_MAXLEN) 365 return (EINVAL); 366 p->p_traceflag |= KTRFAC_ACTIVE; 367 /* 368 * don't let p_tracep get ripped out from under us while we are 369 * writing. 370 */ 371 if ((vp = p->p_tracep) != NULL) 372 vref(vp); 373 kth = ktrgetheader(KTR_USER); 374 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 375 if (!copyin(uap->addr, cp, uap->len)) { 376 kth->ktr_buf = cp; 377 kth->ktr_len = uap->len; 378 ktrwrite(vp, kth, NULL); 379 } 380 if (vp) 381 vrele(vp); 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 #ifdef KTRACE 393 static int 394 ktrops(struct proc *curp, struct proc *p, int ops, int facs, struct vnode *vp) 395 { 396 397 if (!ktrcanset(curp, p)) 398 return (0); 399 if (ops == KTROP_SET) { 400 if (p->p_tracep != vp) { 401 struct vnode *vtmp; 402 403 /* 404 * if trace file already in use, relinquish 405 */ 406 vref(vp); 407 while ((vtmp = p->p_tracep) != NULL) { 408 p->p_tracep = NULL; 409 vrele(vtmp); 410 } 411 p->p_tracep = vp; 412 } 413 p->p_traceflag |= facs; 414 if (curp->p_ucred->cr_uid == 0) 415 p->p_traceflag |= KTRFAC_ROOT; 416 } else { 417 /* KTROP_CLEAR */ 418 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 419 struct vnode *vtmp; 420 421 /* no more tracing */ 422 p->p_traceflag = 0; 423 if ((vtmp = p->p_tracep) != NULL) { 424 p->p_tracep = NULL; 425 vrele(vtmp); 426 } 427 } 428 } 429 430 return (1); 431 } 432 433 static int 434 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs, 435 struct vnode *vp) 436 { 437 struct proc *p; 438 int ret = 0; 439 440 p = top; 441 for (;;) { 442 ret |= ktrops(curp, p, ops, facs, vp); 443 /* 444 * If this process has children, descend to them next, 445 * otherwise do any siblings, and if done with this level, 446 * follow back up the tree (but not past top). 447 */ 448 if (!LIST_EMPTY(&p->p_children)) 449 p = LIST_FIRST(&p->p_children); 450 else for (;;) { 451 if (p == top) 452 return (ret); 453 if (LIST_NEXT(p, p_sibling)) { 454 p = LIST_NEXT(p, p_sibling); 455 break; 456 } 457 p = p->p_pptr; 458 } 459 } 460 /*NOTREACHED*/ 461 } 462 463 static void 464 ktrwrite(struct vnode *vp, struct ktr_header *kth, struct uio *uio) 465 { 466 struct uio auio; 467 struct iovec aiov[2]; 468 struct thread *td = curthread; 469 struct proc *p = td->td_proc; /* XXX */ 470 int error; 471 472 /* 473 * Since multiple processes may be trying to ktrace, we must vref 474 * the vnode to prevent it from being ripped out from under us in 475 * case another process gets a write error while ktracing and removes 476 * the reference from the proc. 477 */ 478 if (vp == NULL) 479 return; 480 vref(vp); 481 auio.uio_iov = &aiov[0]; 482 auio.uio_offset = 0; 483 auio.uio_segflg = UIO_SYSSPACE; 484 auio.uio_rw = UIO_WRITE; 485 aiov[0].iov_base = (caddr_t)kth; 486 aiov[0].iov_len = sizeof(struct ktr_header); 487 auio.uio_resid = sizeof(struct ktr_header); 488 auio.uio_iovcnt = 1; 489 auio.uio_td = curthread; 490 if (kth->ktr_len > 0) { 491 auio.uio_iovcnt++; 492 aiov[1].iov_base = kth->ktr_buf; 493 aiov[1].iov_len = kth->ktr_len; 494 auio.uio_resid += kth->ktr_len; 495 if (uio != NULL) 496 kth->ktr_len += uio->uio_resid; 497 } 498 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE); 499 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 500 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred); 501 if (error == 0 && uio != NULL) { 502 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE); 503 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred); 504 } 505 VOP_UNLOCK(vp, 0, td); 506 vrele(vp); 507 if (!error) 508 return; 509 /* 510 * If error encountered, give up tracing on this vnode. XXX what 511 * happens to the loop if vrele() blocks? 512 */ 513 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 514 error); 515 FOREACH_PROC_IN_SYSTEM(p) { 516 if (p->p_tracep == vp) { 517 p->p_tracep = NULL; 518 p->p_traceflag = 0; 519 vrele(vp); 520 } 521 } 522 } 523 524 /* 525 * Return true if caller has permission to set the ktracing state 526 * of target. Essentially, the target can't possess any 527 * more permissions than the caller. KTRFAC_ROOT signifies that 528 * root previously set the tracing status on the target process, and 529 * so, only root may further change it. 530 * 531 * TODO: check groups. use caller effective gid. 532 */ 533 static int 534 ktrcanset(struct proc *callp, struct proc *targetp) 535 { 536 struct ucred *caller = callp->p_ucred; 537 struct ucred *target = targetp->p_ucred; 538 539 if (!PRISON_CHECK(caller, target)) 540 return (0); 541 if ((caller->cr_uid == target->cr_ruid && 542 target->cr_ruid == target->cr_svuid && 543 caller->cr_rgid == target->cr_rgid && /* XXX */ 544 target->cr_rgid == target->cr_svgid && 545 (targetp->p_traceflag & KTRFAC_ROOT) == 0 && 546 (targetp->p_flag & P_SUGID) == 0) || 547 caller->cr_uid == 0) 548 return (1); 549 550 return (0); 551 } 552 553 #endif /* KTRACE */ 554