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 1.15 2004/05/21 15:41:23 drhodus 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/namei.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 nameidata nd; 257 258 curp->p_traceflag |= KTRFAC_ACTIVE; 259 if (ops != KTROP_CLEAR) { 260 /* 261 * an operation which requires a file argument. 262 */ 263 NDINIT(&nd, NAMEI_LOOKUP, 0, UIO_USERSPACE, uap->fname, td); 264 error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0); 265 if (error) { 266 curp->p_traceflag &= ~KTRFAC_ACTIVE; 267 return (error); 268 } 269 NDFREE(&nd, NDF_ONLY_PNBUF); 270 vp = nd.ni_vp; 271 VOP_UNLOCK(vp, NULL, 0, td); 272 if (vp->v_type != VREG) { 273 (void) vn_close(vp, FREAD|FWRITE, td); 274 curp->p_traceflag &= ~KTRFAC_ACTIVE; 275 return (EACCES); 276 } 277 } 278 /* 279 * Clear all uses of the tracefile. XXX umm, what happens to the 280 * loop if vn_close() blocks? 281 */ 282 if (ops == KTROP_CLEARFILE) { 283 FOREACH_PROC_IN_SYSTEM(p) { 284 if (p->p_tracep == vp) { 285 if (ktrcanset(curp, p) && p->p_tracep == vp) { 286 p->p_tracep = NULL; 287 p->p_traceflag = 0; 288 (void) vn_close(vp, FREAD|FWRITE, td); 289 } else { 290 error = EPERM; 291 } 292 } 293 } 294 goto done; 295 } 296 /* 297 * need something to (un)trace (XXX - why is this here?) 298 */ 299 if (!facs) { 300 error = EINVAL; 301 goto done; 302 } 303 /* 304 * do it 305 */ 306 if (uap->pid < 0) { 307 /* 308 * by process group 309 */ 310 pg = pgfind(-uap->pid); 311 if (pg == NULL) { 312 error = ESRCH; 313 goto done; 314 } 315 LIST_FOREACH(p, &pg->pg_members, p_pglist) 316 if (descend) 317 ret |= ktrsetchildren(curp, p, ops, facs, vp); 318 else 319 ret |= ktrops(curp, p, ops, facs, vp); 320 321 } else { 322 /* 323 * by pid 324 */ 325 p = pfind(uap->pid); 326 if (p == NULL) { 327 error = ESRCH; 328 goto done; 329 } 330 if (descend) 331 ret |= ktrsetchildren(curp, p, ops, facs, vp); 332 else 333 ret |= ktrops(curp, p, ops, facs, vp); 334 } 335 if (!ret) 336 error = EPERM; 337 done: 338 if (vp != NULL) 339 (void) vn_close(vp, FWRITE, td); 340 curp->p_traceflag &= ~KTRFAC_ACTIVE; 341 return (error); 342 #else 343 return ENOSYS; 344 #endif 345 } 346 347 /* 348 * utrace system call 349 */ 350 /* ARGSUSED */ 351 int 352 utrace(struct utrace_args *uap) 353 { 354 #ifdef KTRACE 355 struct ktr_header *kth; 356 struct thread *td = curthread; /* XXX */ 357 struct proc *p = td->td_proc; 358 struct vnode *vp; 359 caddr_t cp; 360 361 if (!KTRPOINT(td, KTR_USER)) 362 return (0); 363 if (SCARG(uap, len) > KTR_USER_MAXLEN) 364 return (EINVAL); 365 p->p_traceflag |= KTRFAC_ACTIVE; 366 /* 367 * don't let p_tracep get ripped out from under us while we are 368 * writing. 369 */ 370 if ((vp = p->p_tracep) != NULL) 371 vref(vp); 372 kth = ktrgetheader(KTR_USER); 373 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 374 if (!copyin(uap->addr, cp, uap->len)) { 375 kth->ktr_buf = cp; 376 kth->ktr_len = uap->len; 377 ktrwrite(vp, kth, NULL); 378 } 379 if (vp) 380 vrele(vp); 381 FREE(kth, M_KTRACE); 382 FREE(cp, M_KTRACE); 383 p->p_traceflag &= ~KTRFAC_ACTIVE; 384 385 return (0); 386 #else 387 return (ENOSYS); 388 #endif 389 } 390 391 #ifdef KTRACE 392 static int 393 ktrops(struct proc *curp, struct proc *p, int ops, int facs, struct vnode *vp) 394 { 395 396 if (!ktrcanset(curp, p)) 397 return (0); 398 if (ops == KTROP_SET) { 399 if (p->p_tracep != vp) { 400 struct vnode *vtmp; 401 402 /* 403 * if trace file already in use, relinquish 404 */ 405 vref(vp); 406 while ((vtmp = p->p_tracep) != NULL) { 407 p->p_tracep = NULL; 408 vrele(vtmp); 409 } 410 p->p_tracep = vp; 411 } 412 p->p_traceflag |= facs; 413 if (curp->p_ucred->cr_uid == 0) 414 p->p_traceflag |= KTRFAC_ROOT; 415 } else { 416 /* KTROP_CLEAR */ 417 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 418 struct vnode *vtmp; 419 420 /* no more tracing */ 421 p->p_traceflag = 0; 422 if ((vtmp = p->p_tracep) != NULL) { 423 p->p_tracep = NULL; 424 vrele(vtmp); 425 } 426 } 427 } 428 429 return (1); 430 } 431 432 static int 433 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs, 434 struct vnode *vp) 435 { 436 struct proc *p; 437 int ret = 0; 438 439 p = top; 440 for (;;) { 441 ret |= ktrops(curp, p, ops, facs, vp); 442 /* 443 * If this process has children, descend to them next, 444 * otherwise do any siblings, and if done with this level, 445 * follow back up the tree (but not past top). 446 */ 447 if (!LIST_EMPTY(&p->p_children)) 448 p = LIST_FIRST(&p->p_children); 449 else for (;;) { 450 if (p == top) 451 return (ret); 452 if (LIST_NEXT(p, p_sibling)) { 453 p = LIST_NEXT(p, p_sibling); 454 break; 455 } 456 p = p->p_pptr; 457 } 458 } 459 /*NOTREACHED*/ 460 } 461 462 static void 463 ktrwrite(struct vnode *vp, struct ktr_header *kth, struct uio *uio) 464 { 465 struct uio auio; 466 struct iovec aiov[2]; 467 struct thread *td = curthread; 468 struct proc *p = td->td_proc; /* XXX */ 469 int error; 470 471 if (vp == NULL) 472 return; 473 auio.uio_iov = &aiov[0]; 474 auio.uio_offset = 0; 475 auio.uio_segflg = UIO_SYSSPACE; 476 auio.uio_rw = UIO_WRITE; 477 aiov[0].iov_base = (caddr_t)kth; 478 aiov[0].iov_len = sizeof(struct ktr_header); 479 auio.uio_resid = sizeof(struct ktr_header); 480 auio.uio_iovcnt = 1; 481 auio.uio_td = curthread; 482 if (kth->ktr_len > 0) { 483 auio.uio_iovcnt++; 484 aiov[1].iov_base = kth->ktr_buf; 485 aiov[1].iov_len = kth->ktr_len; 486 auio.uio_resid += kth->ktr_len; 487 if (uio != NULL) 488 kth->ktr_len += uio->uio_resid; 489 } 490 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE); 491 vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td); 492 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred); 493 if (error == 0 && uio != NULL) { 494 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE); 495 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred); 496 } 497 VOP_UNLOCK(vp, NULL, 0, td); 498 if (!error) 499 return; 500 /* 501 * If error encountered, give up tracing on this vnode. XXX what 502 * happens to the loop if vrele() blocks? 503 */ 504 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 505 error); 506 FOREACH_PROC_IN_SYSTEM(p) { 507 if (p->p_tracep == vp) { 508 p->p_tracep = NULL; 509 p->p_traceflag = 0; 510 vrele(vp); 511 } 512 } 513 } 514 515 /* 516 * Return true if caller has permission to set the ktracing state 517 * of target. Essentially, the target can't possess any 518 * more permissions than the caller. KTRFAC_ROOT signifies that 519 * root previously set the tracing status on the target process, and 520 * so, only root may further change it. 521 * 522 * TODO: check groups. use caller effective gid. 523 */ 524 static int 525 ktrcanset(struct proc *callp, struct proc *targetp) 526 { 527 struct ucred *caller = callp->p_ucred; 528 struct ucred *target = targetp->p_ucred; 529 530 if (!PRISON_CHECK(caller, target)) 531 return (0); 532 if ((caller->cr_uid == target->cr_ruid && 533 target->cr_ruid == target->cr_svuid && 534 caller->cr_rgid == target->cr_rgid && /* XXX */ 535 target->cr_rgid == target->cr_svgid && 536 (targetp->p_traceflag & KTRFAC_ROOT) == 0 && 537 (targetp->p_flag & P_SUGID) == 0) || 538 caller->cr_uid == 0) 539 return (1); 540 541 return (0); 542 } 543 544 #endif /* KTRACE */ 545