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 * $FreeBSD$ 35 */ 36 37 #include "opt_ktrace.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/sysproto.h> 42 #include <sys/kernel.h> 43 #include <sys/proc.h> 44 #include <sys/fcntl.h> 45 #include <sys/lock.h> 46 #include <sys/namei.h> 47 #include <sys/vnode.h> 48 #include <sys/ktrace.h> 49 #include <sys/malloc.h> 50 #include <sys/syslog.h> 51 52 #include <stddef.h> 53 54 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 55 56 #ifdef KTRACE 57 static struct ktr_header *ktrgetheader __P((int type)); 58 static void ktrwrite __P((struct vnode *, struct ktr_header *)); 59 static int ktrcanset __P((struct proc *,struct proc *)); 60 static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *)); 61 static int ktrops __P((struct proc *,struct proc *,int,int,struct vnode *)); 62 63 64 static struct ktr_header * 65 ktrgetheader(type) 66 int type; 67 { 68 register 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(vp, code, narg, args) 82 struct vnode *vp; 83 int code, narg; 84 register_t args[]; 85 { 86 struct ktr_header *kth; 87 struct ktr_syscall *ktp; 88 register int len = offsetof(struct ktr_syscall, ktr_args) + 89 (narg * sizeof(register_t)); 90 struct proc *p = curproc; /* XXX */ 91 register_t *argp; 92 int i; 93 94 p->p_traceflag |= KTRFAC_ACTIVE; 95 kth = ktrgetheader(KTR_SYSCALL); 96 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK); 97 ktp->ktr_code = code; 98 ktp->ktr_narg = narg; 99 argp = &ktp->ktr_args[0]; 100 for (i = 0; i < narg; i++) 101 *argp++ = args[i]; 102 kth->ktr_buf = (caddr_t)ktp; 103 kth->ktr_len = len; 104 ktrwrite(vp, kth); 105 FREE(ktp, M_KTRACE); 106 FREE(kth, M_KTRACE); 107 p->p_traceflag &= ~KTRFAC_ACTIVE; 108 } 109 110 void 111 ktrsysret(vp, code, error, retval) 112 struct vnode *vp; 113 int code, error; 114 register_t retval; 115 { 116 struct ktr_header *kth; 117 struct ktr_sysret ktp; 118 struct proc *p = curproc; /* XXX */ 119 120 p->p_traceflag |= KTRFAC_ACTIVE; 121 kth = ktrgetheader(KTR_SYSRET); 122 ktp.ktr_code = code; 123 ktp.ktr_error = error; 124 ktp.ktr_retval = retval; /* what about val2 ? */ 125 126 kth->ktr_buf = (caddr_t)&ktp; 127 kth->ktr_len = sizeof(struct ktr_sysret); 128 129 ktrwrite(vp, kth); 130 FREE(kth, M_KTRACE); 131 p->p_traceflag &= ~KTRFAC_ACTIVE; 132 } 133 134 void 135 ktrnamei(vp, path) 136 struct vnode *vp; 137 char *path; 138 { 139 struct ktr_header *kth; 140 struct proc *p = curproc; /* XXX */ 141 142 p->p_traceflag |= KTRFAC_ACTIVE; 143 kth = ktrgetheader(KTR_NAMEI); 144 kth->ktr_len = strlen(path); 145 kth->ktr_buf = path; 146 147 ktrwrite(vp, kth); 148 FREE(kth, M_KTRACE); 149 p->p_traceflag &= ~KTRFAC_ACTIVE; 150 } 151 152 void 153 ktrgenio(vp, fd, rw, iov, len, error) 154 struct vnode *vp; 155 int fd; 156 enum uio_rw rw; 157 register struct iovec *iov; 158 int len, error; 159 { 160 struct ktr_header *kth; 161 register struct ktr_genio *ktp; 162 register caddr_t cp; 163 register int resid = len, cnt; 164 struct proc *p = curproc; /* XXX */ 165 166 if (error) 167 return; 168 p->p_traceflag |= KTRFAC_ACTIVE; 169 kth = ktrgetheader(KTR_GENIO); 170 MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len, 171 M_KTRACE, M_WAITOK); 172 ktp->ktr_fd = fd; 173 ktp->ktr_rw = rw; 174 cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio)); 175 while (resid > 0) { 176 if ((cnt = iov->iov_len) > resid) 177 cnt = resid; 178 if (copyin(iov->iov_base, cp, (unsigned)cnt)) 179 goto done; 180 cp += cnt; 181 resid -= cnt; 182 iov++; 183 } 184 kth->ktr_buf = (caddr_t)ktp; 185 kth->ktr_len = sizeof (struct ktr_genio) + len; 186 187 ktrwrite(vp, kth); 188 done: 189 FREE(kth, M_KTRACE); 190 FREE(ktp, M_KTRACE); 191 p->p_traceflag &= ~KTRFAC_ACTIVE; 192 } 193 194 void 195 ktrpsig(vp, sig, action, mask, code) 196 struct vnode *vp; 197 int sig; 198 sig_t action; 199 sigset_t *mask; 200 int code; 201 { 202 struct ktr_header *kth; 203 struct ktr_psig kp; 204 struct proc *p = curproc; /* XXX */ 205 206 p->p_traceflag |= KTRFAC_ACTIVE; 207 kth = ktrgetheader(KTR_PSIG); 208 kp.signo = (char)sig; 209 kp.action = action; 210 kp.mask = *mask; 211 kp.code = code; 212 kth->ktr_buf = (caddr_t)&kp; 213 kth->ktr_len = sizeof (struct ktr_psig); 214 215 ktrwrite(vp, kth); 216 FREE(kth, M_KTRACE); 217 p->p_traceflag &= ~KTRFAC_ACTIVE; 218 } 219 220 void 221 ktrcsw(vp, out, user) 222 struct vnode *vp; 223 int out, user; 224 { 225 struct ktr_header *kth; 226 struct ktr_csw kc; 227 struct proc *p = curproc; /* XXX */ 228 229 p->p_traceflag |= KTRFAC_ACTIVE; 230 kth = ktrgetheader(KTR_CSW); 231 kc.out = out; 232 kc.user = user; 233 kth->ktr_buf = (caddr_t)&kc; 234 kth->ktr_len = sizeof (struct ktr_csw); 235 236 ktrwrite(vp, kth); 237 FREE(kth, M_KTRACE); 238 p->p_traceflag &= ~KTRFAC_ACTIVE; 239 } 240 #endif 241 242 /* Interface and common routines */ 243 244 /* 245 * ktrace system call 246 */ 247 #ifndef _SYS_SYSPROTO_H_ 248 struct ktrace_args { 249 char *fname; 250 int ops; 251 int facs; 252 int pid; 253 }; 254 #endif 255 /* ARGSUSED */ 256 int 257 ktrace(curp, uap) 258 struct proc *curp; 259 register struct ktrace_args *uap; 260 { 261 #ifdef KTRACE 262 register struct vnode *vp = NULL; 263 register struct proc *p; 264 struct pgrp *pg; 265 int facs = uap->facs & ~KTRFAC_ROOT; 266 int ops = KTROP(uap->ops); 267 int descend = uap->ops & KTRFLAG_DESCEND; 268 int ret = 0; 269 int error = 0; 270 struct nameidata nd; 271 272 curp->p_traceflag |= KTRFAC_ACTIVE; 273 if (ops != KTROP_CLEAR) { 274 /* 275 * an operation which requires a file argument. 276 */ 277 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, curp); 278 error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0); 279 if (error) { 280 curp->p_traceflag &= ~KTRFAC_ACTIVE; 281 return (error); 282 } 283 vp = nd.ni_vp; 284 VOP_UNLOCK(vp, 0, curp); 285 if (vp->v_type != VREG) { 286 (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp); 287 curp->p_traceflag &= ~KTRFAC_ACTIVE; 288 return (EACCES); 289 } 290 } 291 /* 292 * Clear all uses of the tracefile 293 */ 294 if (ops == KTROP_CLEARFILE) { 295 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 296 if (p->p_tracep == vp) { 297 if (ktrcanset(curp, p)) { 298 p->p_tracep = NULL; 299 p->p_traceflag = 0; 300 (void) vn_close(vp, FREAD|FWRITE, 301 p->p_ucred, p); 302 } else 303 error = EPERM; 304 } 305 } 306 goto done; 307 } 308 /* 309 * need something to (un)trace (XXX - why is this here?) 310 */ 311 if (!facs) { 312 error = EINVAL; 313 goto done; 314 } 315 /* 316 * do it 317 */ 318 if (uap->pid < 0) { 319 /* 320 * by process group 321 */ 322 pg = pgfind(-uap->pid); 323 if (pg == NULL) { 324 error = ESRCH; 325 goto done; 326 } 327 for (p = pg->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) 328 if (descend) 329 ret |= ktrsetchildren(curp, p, ops, facs, vp); 330 else 331 ret |= ktrops(curp, p, ops, facs, vp); 332 333 } else { 334 /* 335 * by pid 336 */ 337 p = pfind(uap->pid); 338 if (p == NULL) { 339 error = ESRCH; 340 goto done; 341 } 342 if (descend) 343 ret |= ktrsetchildren(curp, p, ops, facs, vp); 344 else 345 ret |= ktrops(curp, p, ops, facs, vp); 346 } 347 if (!ret) 348 error = EPERM; 349 done: 350 if (vp != NULL) 351 (void) vn_close(vp, FWRITE, curp->p_ucred, curp); 352 curp->p_traceflag &= ~KTRFAC_ACTIVE; 353 return (error); 354 #else 355 return ENOSYS; 356 #endif 357 } 358 359 /* 360 * utrace system call 361 */ 362 /* ARGSUSED */ 363 int 364 utrace(curp, uap) 365 struct proc *curp; 366 register struct utrace_args *uap; 367 { 368 #ifdef KTRACE 369 struct ktr_header *kth; 370 struct proc *p = curproc; /* XXX */ 371 register caddr_t cp; 372 373 if (!KTRPOINT(p, KTR_USER)) 374 return (0); 375 p->p_traceflag |= KTRFAC_ACTIVE; 376 kth = ktrgetheader(KTR_USER); 377 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 378 if (!copyin(uap->addr, cp, uap->len)) { 379 kth->ktr_buf = cp; 380 kth->ktr_len = uap->len; 381 ktrwrite(p->p_tracep, kth); 382 } 383 FREE(kth, M_KTRACE); 384 FREE(cp, M_KTRACE); 385 p->p_traceflag &= ~KTRFAC_ACTIVE; 386 387 return (0); 388 #else 389 return (ENOSYS); 390 #endif 391 } 392 393 #ifdef KTRACE 394 static int 395 ktrops(curp, p, ops, facs, vp) 396 struct proc *p, *curp; 397 int ops, facs; 398 struct vnode *vp; 399 { 400 401 if (!ktrcanset(curp, p)) 402 return (0); 403 if (ops == KTROP_SET) { 404 if (p->p_tracep != vp) { 405 /* 406 * if trace file already in use, relinquish 407 */ 408 if (p->p_tracep != NULL) 409 vrele(p->p_tracep); 410 VREF(vp); 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 /* no more tracing */ 420 p->p_traceflag = 0; 421 if (p->p_tracep != NULL) { 422 vrele(p->p_tracep); 423 p->p_tracep = NULL; 424 } 425 } 426 } 427 428 return (1); 429 } 430 431 static int 432 ktrsetchildren(curp, top, ops, facs, vp) 433 struct proc *curp, *top; 434 int ops, facs; 435 struct vnode *vp; 436 { 437 register struct proc *p; 438 register 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 (p->p_children.lh_first) 449 p = p->p_children.lh_first; 450 else for (;;) { 451 if (p == top) 452 return (ret); 453 if (p->p_sibling.le_next) { 454 p = p->p_sibling.le_next; 455 break; 456 } 457 p = p->p_pptr; 458 } 459 } 460 /*NOTREACHED*/ 461 } 462 463 static void 464 ktrwrite(vp, kth) 465 struct vnode *vp; 466 register struct ktr_header *kth; 467 { 468 struct uio auio; 469 struct iovec aiov[2]; 470 register struct proc *p = curproc; /* XXX */ 471 int error; 472 473 if (vp == NULL) 474 return; 475 auio.uio_iov = &aiov[0]; 476 auio.uio_offset = 0; 477 auio.uio_segflg = UIO_SYSSPACE; 478 auio.uio_rw = UIO_WRITE; 479 aiov[0].iov_base = (caddr_t)kth; 480 aiov[0].iov_len = sizeof(struct ktr_header); 481 auio.uio_resid = sizeof(struct ktr_header); 482 auio.uio_iovcnt = 1; 483 auio.uio_procp = curproc; 484 if (kth->ktr_len > 0) { 485 auio.uio_iovcnt++; 486 aiov[1].iov_base = kth->ktr_buf; 487 aiov[1].iov_len = kth->ktr_len; 488 auio.uio_resid += kth->ktr_len; 489 } 490 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 491 error = VOP_WRITE(vp, &auio, IO_UNIT|IO_APPEND, p->p_ucred); 492 VOP_UNLOCK(vp, 0, p); 493 if (!error) 494 return; 495 /* 496 * If error encountered, give up tracing on this vnode. 497 */ 498 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 499 error); 500 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 501 if (p->p_tracep == vp) { 502 p->p_tracep = NULL; 503 p->p_traceflag = 0; 504 vrele(vp); 505 } 506 } 507 } 508 509 /* 510 * Return true if caller has permission to set the ktracing state 511 * of target. Essentially, the target can't possess any 512 * more permissions than the caller. KTRFAC_ROOT signifies that 513 * root previously set the tracing status on the target process, and 514 * so, only root may further change it. 515 * 516 * TODO: check groups. use caller effective gid. 517 */ 518 static int 519 ktrcanset(callp, targetp) 520 struct proc *callp, *targetp; 521 { 522 register struct pcred *caller = callp->p_cred; 523 register struct pcred *target = targetp->p_cred; 524 525 if (!PRISON_CHECK(callp, targetp)) 526 return (0); 527 if ((caller->pc_ucred->cr_uid == target->p_ruid && 528 target->p_ruid == target->p_svuid && 529 caller->p_rgid == target->p_rgid && /* XXX */ 530 target->p_rgid == target->p_svgid && 531 (targetp->p_traceflag & KTRFAC_ROOT) == 0) || 532 caller->pc_ucred->cr_uid == 0) 533 return (1); 534 535 return (0); 536 } 537 538 #endif /* KTRACE */ 539