1 /* 2 * Copyright (c) 1994, Sean Eric Fagan 3 * 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 Sean Eric Fagan. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $FreeBSD: src/sys/kern/sys_process.c,v 1.51.2.6 2003/01/08 03:06:45 kan Exp $ 32 * $DragonFly: src/sys/kern/sys_process.c,v 1.30 2007/02/19 01:14:23 corecode Exp $ 33 */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/sysproto.h> 38 #include <sys/proc.h> 39 #include <sys/priv.h> 40 #include <sys/vnode.h> 41 #include <sys/ptrace.h> 42 #include <sys/reg.h> 43 #include <sys/lock.h> 44 45 #include <vm/vm.h> 46 #include <vm/pmap.h> 47 #include <vm/vm_map.h> 48 #include <vm/vm_page.h> 49 50 #include <sys/user.h> 51 #include <vfs/procfs/procfs.h> 52 #include <sys/thread2.h> 53 54 /* use the equivalent procfs code */ 55 #if 0 56 static int 57 pread (struct proc *procp, unsigned int addr, unsigned int *retval) { 58 int rv; 59 vm_map_t map, tmap; 60 vm_object_t object; 61 vm_offset_t kva = 0; 62 int page_offset; /* offset into page */ 63 vm_offset_t pageno; /* page number */ 64 vm_map_entry_t out_entry; 65 vm_prot_t out_prot; 66 boolean_t wired; 67 vm_pindex_t pindex; 68 69 /* Map page into kernel space */ 70 71 map = &procp->p_vmspace->vm_map; 72 73 page_offset = addr - trunc_page(addr); 74 pageno = trunc_page(addr); 75 76 tmap = map; 77 rv = vm_map_lookup (&tmap, pageno, VM_PROT_READ, &out_entry, 78 &object, &pindex, &out_prot, &wired); 79 80 if (rv != KERN_SUCCESS) 81 return EINVAL; 82 83 vm_map_lookup_done (tmap, out_entry, 0); 84 85 /* Find space in kernel_map for the page we're interested in */ 86 rv = vm_map_find (&kernel_map, object, IDX_TO_OFF(pindex), 87 &kva, PAGE_SIZE, 88 0, 89 VM_MAPTYPE_NORMAL, 90 VM_PROT_ALL, VM_PROT_ALL, 91 0); 92 93 if (!rv) { 94 vm_object_reference (object); 95 96 rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0); 97 if (!rv) { 98 *retval = 0; 99 bcopy ((caddr_t)kva + page_offset, 100 retval, sizeof *retval); 101 } 102 vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE); 103 } 104 105 return rv; 106 } 107 108 static int 109 pwrite (struct proc *procp, unsigned int addr, unsigned int datum) { 110 int rv; 111 vm_map_t map, tmap; 112 vm_object_t object; 113 vm_offset_t kva = 0; 114 int page_offset; /* offset into page */ 115 vm_offset_t pageno; /* page number */ 116 vm_map_entry_t out_entry; 117 vm_prot_t out_prot; 118 boolean_t wired; 119 vm_pindex_t pindex; 120 boolean_t fix_prot = 0; 121 122 /* Map page into kernel space */ 123 124 map = &procp->p_vmspace->vm_map; 125 126 page_offset = addr - trunc_page(addr); 127 pageno = trunc_page(addr); 128 129 /* 130 * Check the permissions for the area we're interested in. 131 */ 132 133 if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE, 134 VM_PROT_WRITE) == FALSE) { 135 /* 136 * If the page was not writable, we make it so. 137 * XXX It is possible a page may *not* be read/executable, 138 * if a process changes that! 139 */ 140 fix_prot = 1; 141 /* The page isn't writable, so let's try making it so... */ 142 if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE, 143 VM_PROT_ALL, 0)) != KERN_SUCCESS) 144 return EFAULT; /* I guess... */ 145 } 146 147 /* 148 * Now we need to get the page. out_entry, out_prot, wired, and 149 * single_use aren't used. One would think the vm code would be 150 * a *bit* nicer... We use tmap because vm_map_lookup() can 151 * change the map argument. 152 */ 153 154 tmap = map; 155 rv = vm_map_lookup (&tmap, pageno, VM_PROT_WRITE, &out_entry, 156 &object, &pindex, &out_prot, &wired); 157 if (rv != KERN_SUCCESS) { 158 return EINVAL; 159 } 160 161 /* 162 * Okay, we've got the page. Let's release tmap. 163 */ 164 165 vm_map_lookup_done (tmap, out_entry, 0); 166 167 /* 168 * Fault the page in... 169 */ 170 171 rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE); 172 if (rv != KERN_SUCCESS) 173 return EFAULT; 174 175 /* Find space in kernel_map for the page we're interested in */ 176 rv = vm_map_find (&kernel_map, object, IDX_TO_OFF(pindex), 177 &kva, PAGE_SIZE, 178 0, 179 VM_MAPTYPE_NORMAL, 180 VM_PROT_ALL, VM_PROT_ALL, 181 0); 182 if (!rv) { 183 vm_object_reference (object); 184 185 rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0); 186 if (!rv) { 187 bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum); 188 } 189 vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE); 190 } 191 192 if (fix_prot) 193 vm_map_protect (map, pageno, pageno + PAGE_SIZE, 194 VM_PROT_READ|VM_PROT_EXECUTE, 0); 195 return rv; 196 } 197 #endif 198 199 /* 200 * Process debugging system call. 201 */ 202 int 203 sys_ptrace(struct ptrace_args *uap) 204 { 205 struct proc *p = curproc; 206 207 /* 208 * XXX this obfuscation is to reduce stack usage, but the register 209 * structs may be too large to put on the stack anyway. 210 */ 211 union { 212 struct ptrace_io_desc piod; 213 struct dbreg dbreg; 214 struct fpreg fpreg; 215 struct reg reg; 216 } r; 217 void *addr; 218 int error = 0; 219 220 addr = &r; 221 switch (uap->req) { 222 case PT_GETREGS: 223 case PT_GETFPREGS: 224 #ifdef PT_GETDBREGS 225 case PT_GETDBREGS: 226 #endif 227 break; 228 case PT_SETREGS: 229 error = copyin(uap->addr, &r.reg, sizeof r.reg); 230 break; 231 case PT_SETFPREGS: 232 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg); 233 break; 234 #ifdef PT_SETDBREGS 235 case PT_SETDBREGS: 236 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg); 237 break; 238 #endif 239 case PT_IO: 240 error = copyin(uap->addr, &r.piod, sizeof r.piod); 241 break; 242 default: 243 addr = uap->addr; 244 } 245 if (error) 246 return (error); 247 248 error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data, 249 &uap->sysmsg_result); 250 if (error) 251 return (error); 252 253 switch (uap->req) { 254 case PT_IO: 255 (void)copyout(&r.piod, uap->addr, sizeof r.piod); 256 break; 257 case PT_GETREGS: 258 error = copyout(&r.reg, uap->addr, sizeof r.reg); 259 break; 260 case PT_GETFPREGS: 261 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg); 262 break; 263 #ifdef PT_GETDBREGS 264 case PT_GETDBREGS: 265 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg); 266 break; 267 #endif 268 } 269 270 return (error); 271 } 272 273 int 274 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr, int data, int *res) 275 { 276 struct proc *p, *pp; 277 struct lwp *lp; 278 struct iovec iov; 279 struct uio uio; 280 struct ptrace_io_desc *piod; 281 int error = 0; 282 int write, tmp; 283 284 write = 0; 285 if (req == PT_TRACE_ME) { 286 p = curp; 287 } else { 288 if ((p = pfind(pid)) == NULL) 289 return ESRCH; 290 } 291 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) 292 return (ESRCH); 293 294 /* Can't trace a process that's currently exec'ing. */ 295 if ((p->p_flag & P_INEXEC) != 0) 296 return EAGAIN; 297 298 /* 299 * Permissions check 300 */ 301 switch (req) { 302 case PT_TRACE_ME: 303 /* Always legal. */ 304 break; 305 306 case PT_ATTACH: 307 /* Self */ 308 if (p->p_pid == curp->p_pid) 309 return EINVAL; 310 311 /* Already traced */ 312 if (p->p_flag & P_TRACED) 313 return EBUSY; 314 315 if (curp->p_flag & P_TRACED) 316 for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) 317 if (pp == p) 318 return (EINVAL); 319 320 /* not owned by you, has done setuid (unless you're root) */ 321 if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) || 322 (p->p_flag & P_SUGID)) { 323 if ((error = priv_check_cred(curp->p_ucred, PRIV_ROOT, 0)) != 0) 324 return error; 325 } 326 327 /* can't trace init when securelevel > 0 */ 328 if (securelevel > 0 && p->p_pid == 1) 329 return EPERM; 330 331 /* OK */ 332 break; 333 334 case PT_READ_I: 335 case PT_READ_D: 336 case PT_WRITE_I: 337 case PT_WRITE_D: 338 case PT_IO: 339 case PT_CONTINUE: 340 case PT_KILL: 341 case PT_STEP: 342 case PT_DETACH: 343 #ifdef PT_GETREGS 344 case PT_GETREGS: 345 #endif 346 #ifdef PT_SETREGS 347 case PT_SETREGS: 348 #endif 349 #ifdef PT_GETFPREGS 350 case PT_GETFPREGS: 351 #endif 352 #ifdef PT_SETFPREGS 353 case PT_SETFPREGS: 354 #endif 355 #ifdef PT_GETDBREGS 356 case PT_GETDBREGS: 357 #endif 358 #ifdef PT_SETDBREGS 359 case PT_SETDBREGS: 360 #endif 361 /* not being traced... */ 362 if ((p->p_flag & P_TRACED) == 0) 363 return EPERM; 364 365 /* not being traced by YOU */ 366 if (p->p_pptr != curp) 367 return EBUSY; 368 369 /* not currently stopped */ 370 if (p->p_stat != SSTOP || 371 (p->p_flag & P_WAITED) == 0) { 372 return EBUSY; 373 } 374 375 /* OK */ 376 break; 377 378 default: 379 return EINVAL; 380 } 381 382 /* XXX lwp */ 383 lp = FIRST_LWP_IN_PROC(p); 384 #ifdef FIX_SSTEP 385 /* 386 * Single step fixup ala procfs 387 */ 388 FIX_SSTEP(lp); 389 #endif 390 391 /* 392 * Actually do the requests 393 */ 394 395 *res = 0; 396 397 switch (req) { 398 case PT_TRACE_ME: 399 /* set my trace flag and "owner" so it can read/write me */ 400 p->p_flag |= P_TRACED; 401 p->p_oppid = p->p_pptr->p_pid; 402 return 0; 403 404 case PT_ATTACH: 405 /* security check done above */ 406 p->p_flag |= P_TRACED; 407 p->p_oppid = p->p_pptr->p_pid; 408 if (p->p_pptr != curp) 409 proc_reparent(p, curp); 410 data = SIGSTOP; 411 goto sendsig; /* in PT_CONTINUE below */ 412 413 case PT_STEP: 414 case PT_CONTINUE: 415 case PT_DETACH: 416 /* Zero means do not send any signal */ 417 if (data < 0 || data > _SIG_MAXSIG) 418 return EINVAL; 419 420 LWPHOLD(lp); 421 422 if (req == PT_STEP) { 423 if ((error = ptrace_single_step (lp))) { 424 LWPRELE(lp); 425 return error; 426 } 427 } 428 429 if (addr != (void *)1) { 430 if ((error = ptrace_set_pc (lp, 431 (u_long)(uintfptr_t)addr))) { 432 LWPRELE(lp); 433 return error; 434 } 435 } 436 LWPRELE(lp); 437 438 if (req == PT_DETACH) { 439 /* reset process parent */ 440 if (p->p_oppid != p->p_pptr->p_pid) { 441 struct proc *pp; 442 443 pp = pfind(p->p_oppid); 444 proc_reparent(p, pp ? pp : initproc); 445 } 446 447 p->p_flag &= ~(P_TRACED | P_WAITED); 448 p->p_oppid = 0; 449 450 /* should we send SIGCHLD? */ 451 } 452 453 sendsig: 454 /* 455 * Deliver or queue signal. If the process is stopped 456 * force it to be SACTIVE again. 457 */ 458 crit_enter(); 459 if (p->p_stat == SSTOP) { 460 p->p_xstat = data; 461 lp->lwp_flag |= LWP_BREAKTSLEEP; 462 proc_unstop(p); 463 } else if (data) { 464 ksignal(p, data); 465 } 466 crit_exit(); 467 return 0; 468 469 case PT_WRITE_I: 470 case PT_WRITE_D: 471 write = 1; 472 /* fallthrough */ 473 case PT_READ_I: 474 case PT_READ_D: 475 /* 476 * NOTE! uio_offset represents the offset in the target 477 * process. The iov is in the current process (the guy 478 * making the ptrace call) so uio_td must be the current 479 * process (though for a SYSSPACE transfer it doesn't 480 * really matter). 481 */ 482 tmp = 0; 483 /* write = 0 set above */ 484 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp; 485 iov.iov_len = sizeof(int); 486 uio.uio_iov = &iov; 487 uio.uio_iovcnt = 1; 488 uio.uio_offset = (off_t)(uintptr_t)addr; 489 uio.uio_resid = sizeof(int); 490 uio.uio_segflg = UIO_SYSSPACE; 491 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 492 uio.uio_td = curthread; 493 error = procfs_domem(curp, lp, NULL, &uio); 494 if (uio.uio_resid != 0) { 495 /* 496 * XXX procfs_domem() doesn't currently return ENOSPC, 497 * so I think write() can bogusly return 0. 498 * XXX what happens for short writes? We don't want 499 * to write partial data. 500 * XXX procfs_domem() returns EPERM for other invalid 501 * addresses. Convert this to EINVAL. Does this 502 * clobber returns of EPERM for other reasons? 503 */ 504 if (error == 0 || error == ENOSPC || error == EPERM) 505 error = EINVAL; /* EOF */ 506 } 507 if (!write) 508 *res = tmp; 509 return (error); 510 511 case PT_IO: 512 /* 513 * NOTE! uio_offset represents the offset in the target 514 * process. The iov is in the current process (the guy 515 * making the ptrace call) so uio_td must be the current 516 * process. 517 */ 518 piod = addr; 519 iov.iov_base = piod->piod_addr; 520 iov.iov_len = piod->piod_len; 521 uio.uio_iov = &iov; 522 uio.uio_iovcnt = 1; 523 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs; 524 uio.uio_resid = piod->piod_len; 525 uio.uio_segflg = UIO_USERSPACE; 526 uio.uio_td = curthread; 527 switch (piod->piod_op) { 528 case PIOD_READ_D: 529 case PIOD_READ_I: 530 uio.uio_rw = UIO_READ; 531 break; 532 case PIOD_WRITE_D: 533 case PIOD_WRITE_I: 534 uio.uio_rw = UIO_WRITE; 535 break; 536 default: 537 return (EINVAL); 538 } 539 error = procfs_domem(curp, lp, NULL, &uio); 540 piod->piod_len -= uio.uio_resid; 541 return (error); 542 543 case PT_KILL: 544 data = SIGKILL; 545 goto sendsig; /* in PT_CONTINUE above */ 546 547 #ifdef PT_SETREGS 548 case PT_SETREGS: 549 write = 1; 550 /* fallthrough */ 551 #endif /* PT_SETREGS */ 552 #ifdef PT_GETREGS 553 case PT_GETREGS: 554 /* write = 0 above */ 555 #endif /* PT_SETREGS */ 556 #if defined(PT_SETREGS) || defined(PT_GETREGS) 557 if (!procfs_validregs(lp)) /* no P_SYSTEM procs please */ 558 return EINVAL; 559 else { 560 iov.iov_base = addr; 561 iov.iov_len = sizeof(struct reg); 562 uio.uio_iov = &iov; 563 uio.uio_iovcnt = 1; 564 uio.uio_offset = 0; 565 uio.uio_resid = sizeof(struct reg); 566 uio.uio_segflg = UIO_SYSSPACE; 567 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 568 uio.uio_td = curthread; 569 return (procfs_doregs(curp, lp, NULL, &uio)); 570 } 571 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */ 572 573 #ifdef PT_SETFPREGS 574 case PT_SETFPREGS: 575 write = 1; 576 /* fallthrough */ 577 #endif /* PT_SETFPREGS */ 578 #ifdef PT_GETFPREGS 579 case PT_GETFPREGS: 580 /* write = 0 above */ 581 #endif /* PT_SETFPREGS */ 582 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 583 if (!procfs_validfpregs(lp)) /* no P_SYSTEM procs please */ 584 return EINVAL; 585 else { 586 iov.iov_base = addr; 587 iov.iov_len = sizeof(struct fpreg); 588 uio.uio_iov = &iov; 589 uio.uio_iovcnt = 1; 590 uio.uio_offset = 0; 591 uio.uio_resid = sizeof(struct fpreg); 592 uio.uio_segflg = UIO_SYSSPACE; 593 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 594 uio.uio_td = curthread; 595 return (procfs_dofpregs(curp, lp, NULL, &uio)); 596 } 597 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */ 598 599 #ifdef PT_SETDBREGS 600 case PT_SETDBREGS: 601 write = 1; 602 /* fallthrough */ 603 #endif /* PT_SETDBREGS */ 604 #ifdef PT_GETDBREGS 605 case PT_GETDBREGS: 606 /* write = 0 above */ 607 #endif /* PT_SETDBREGS */ 608 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS) 609 if (!procfs_validdbregs(lp)) /* no P_SYSTEM procs please */ 610 return EINVAL; 611 else { 612 iov.iov_base = addr; 613 iov.iov_len = sizeof(struct dbreg); 614 uio.uio_iov = &iov; 615 uio.uio_iovcnt = 1; 616 uio.uio_offset = 0; 617 uio.uio_resid = sizeof(struct dbreg); 618 uio.uio_segflg = UIO_SYSSPACE; 619 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 620 uio.uio_td = curthread; 621 return (procfs_dodbregs(curp, lp, NULL, &uio)); 622 } 623 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */ 624 625 default: 626 break; 627 } 628 629 return 0; 630 } 631 632 int 633 trace_req(struct proc *p) 634 { 635 return 1; 636 } 637 638 /* 639 * stopevent() 640 * 641 * Stop a process because of a procfs event. Stay stopped until p->p_step 642 * is cleared (cleared by PIOCCONT in procfs). 643 * 644 * MPSAFE 645 */ 646 void 647 stopevent(struct proc *p, unsigned int event, unsigned int val) 648 { 649 p->p_step = 1; 650 651 do { 652 crit_enter(); 653 wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */ 654 p->p_xstat = val; 655 p->p_stype = event; /* Which event caused the stop? */ 656 tsleep(&p->p_step, 0, "stopevent", 0); 657 crit_exit(); 658 } while (p->p_step); 659 } 660 661