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 * MPALMOSTSAFE 203 */ 204 int 205 sys_ptrace(struct ptrace_args *uap) 206 { 207 struct proc *p = curproc; 208 209 /* 210 * XXX this obfuscation is to reduce stack usage, but the register 211 * structs may be too large to put on the stack anyway. 212 */ 213 union { 214 struct ptrace_io_desc piod; 215 struct dbreg dbreg; 216 struct fpreg fpreg; 217 struct reg reg; 218 } r; 219 void *addr; 220 int error = 0; 221 222 addr = &r; 223 switch (uap->req) { 224 case PT_GETREGS: 225 case PT_GETFPREGS: 226 #ifdef PT_GETDBREGS 227 case PT_GETDBREGS: 228 #endif 229 break; 230 case PT_SETREGS: 231 error = copyin(uap->addr, &r.reg, sizeof r.reg); 232 break; 233 case PT_SETFPREGS: 234 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg); 235 break; 236 #ifdef PT_SETDBREGS 237 case PT_SETDBREGS: 238 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg); 239 break; 240 #endif 241 case PT_IO: 242 error = copyin(uap->addr, &r.piod, sizeof r.piod); 243 break; 244 default: 245 addr = uap->addr; 246 } 247 if (error) 248 return (error); 249 250 get_mplock(); 251 error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data, 252 &uap->sysmsg_result); 253 rel_mplock(); 254 if (error) 255 return (error); 256 257 switch (uap->req) { 258 case PT_IO: 259 (void)copyout(&r.piod, uap->addr, sizeof r.piod); 260 break; 261 case PT_GETREGS: 262 error = copyout(&r.reg, uap->addr, sizeof r.reg); 263 break; 264 case PT_GETFPREGS: 265 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg); 266 break; 267 #ifdef PT_GETDBREGS 268 case PT_GETDBREGS: 269 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg); 270 break; 271 #endif 272 } 273 274 return (error); 275 } 276 277 int 278 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr, int data, int *res) 279 { 280 struct proc *p, *pp; 281 struct lwp *lp; 282 struct iovec iov; 283 struct uio uio; 284 struct ptrace_io_desc *piod; 285 int error = 0; 286 int write, tmp; 287 288 write = 0; 289 if (req == PT_TRACE_ME) { 290 p = curp; 291 } else { 292 if ((p = pfind(pid)) == NULL) 293 return ESRCH; 294 } 295 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) 296 return (ESRCH); 297 298 /* Can't trace a process that's currently exec'ing. */ 299 if ((p->p_flag & P_INEXEC) != 0) 300 return EAGAIN; 301 302 /* 303 * Permissions check 304 */ 305 switch (req) { 306 case PT_TRACE_ME: 307 /* Always legal. */ 308 break; 309 310 case PT_ATTACH: 311 /* Self */ 312 if (p->p_pid == curp->p_pid) 313 return EINVAL; 314 315 /* Already traced */ 316 if (p->p_flag & P_TRACED) 317 return EBUSY; 318 319 if (curp->p_flag & P_TRACED) 320 for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) 321 if (pp == p) 322 return (EINVAL); 323 324 /* not owned by you, has done setuid (unless you're root) */ 325 if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) || 326 (p->p_flag & P_SUGID)) { 327 if ((error = priv_check_cred(curp->p_ucred, PRIV_ROOT, 0)) != 0) 328 return error; 329 } 330 331 /* can't trace init when securelevel > 0 */ 332 if (securelevel > 0 && p->p_pid == 1) 333 return EPERM; 334 335 /* OK */ 336 break; 337 338 case PT_READ_I: 339 case PT_READ_D: 340 case PT_WRITE_I: 341 case PT_WRITE_D: 342 case PT_IO: 343 case PT_CONTINUE: 344 case PT_KILL: 345 case PT_STEP: 346 case PT_DETACH: 347 #ifdef PT_GETREGS 348 case PT_GETREGS: 349 #endif 350 #ifdef PT_SETREGS 351 case PT_SETREGS: 352 #endif 353 #ifdef PT_GETFPREGS 354 case PT_GETFPREGS: 355 #endif 356 #ifdef PT_SETFPREGS 357 case PT_SETFPREGS: 358 #endif 359 #ifdef PT_GETDBREGS 360 case PT_GETDBREGS: 361 #endif 362 #ifdef PT_SETDBREGS 363 case PT_SETDBREGS: 364 #endif 365 /* not being traced... */ 366 if ((p->p_flag & P_TRACED) == 0) 367 return EPERM; 368 369 /* not being traced by YOU */ 370 if (p->p_pptr != curp) 371 return EBUSY; 372 373 /* not currently stopped */ 374 if (p->p_stat != SSTOP || 375 (p->p_flag & P_WAITED) == 0) { 376 return EBUSY; 377 } 378 379 /* OK */ 380 break; 381 382 default: 383 return EINVAL; 384 } 385 386 /* XXX lwp */ 387 lp = FIRST_LWP_IN_PROC(p); 388 #ifdef FIX_SSTEP 389 /* 390 * Single step fixup ala procfs 391 */ 392 FIX_SSTEP(lp); 393 #endif 394 395 /* 396 * Actually do the requests 397 */ 398 399 *res = 0; 400 401 switch (req) { 402 case PT_TRACE_ME: 403 /* set my trace flag and "owner" so it can read/write me */ 404 p->p_flag |= P_TRACED; 405 p->p_oppid = p->p_pptr->p_pid; 406 return 0; 407 408 case PT_ATTACH: 409 /* security check done above */ 410 p->p_flag |= P_TRACED; 411 p->p_oppid = p->p_pptr->p_pid; 412 if (p->p_pptr != curp) 413 proc_reparent(p, curp); 414 data = SIGSTOP; 415 goto sendsig; /* in PT_CONTINUE below */ 416 417 case PT_STEP: 418 case PT_CONTINUE: 419 case PT_DETACH: 420 /* Zero means do not send any signal */ 421 if (data < 0 || data > _SIG_MAXSIG) 422 return EINVAL; 423 424 LWPHOLD(lp); 425 426 if (req == PT_STEP) { 427 if ((error = ptrace_single_step (lp))) { 428 LWPRELE(lp); 429 return error; 430 } 431 } 432 433 if (addr != (void *)1) { 434 if ((error = ptrace_set_pc (lp, 435 (u_long)(uintfptr_t)addr))) { 436 LWPRELE(lp); 437 return error; 438 } 439 } 440 LWPRELE(lp); 441 442 if (req == PT_DETACH) { 443 /* reset process parent */ 444 if (p->p_oppid != p->p_pptr->p_pid) { 445 struct proc *pp; 446 447 pp = pfind(p->p_oppid); 448 proc_reparent(p, pp ? pp : initproc); 449 } 450 451 p->p_flag &= ~(P_TRACED | P_WAITED); 452 p->p_oppid = 0; 453 454 /* should we send SIGCHLD? */ 455 } 456 457 sendsig: 458 /* 459 * Deliver or queue signal. If the process is stopped 460 * force it to be SACTIVE again. 461 */ 462 crit_enter(); 463 if (p->p_stat == SSTOP) { 464 p->p_xstat = data; 465 lp->lwp_flag |= LWP_BREAKTSLEEP; 466 proc_unstop(p); 467 } else if (data) { 468 ksignal(p, data); 469 } 470 crit_exit(); 471 return 0; 472 473 case PT_WRITE_I: 474 case PT_WRITE_D: 475 write = 1; 476 /* fallthrough */ 477 case PT_READ_I: 478 case PT_READ_D: 479 /* 480 * NOTE! uio_offset represents the offset in the target 481 * process. The iov is in the current process (the guy 482 * making the ptrace call) so uio_td must be the current 483 * process (though for a SYSSPACE transfer it doesn't 484 * really matter). 485 */ 486 tmp = 0; 487 /* write = 0 set above */ 488 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp; 489 iov.iov_len = sizeof(int); 490 uio.uio_iov = &iov; 491 uio.uio_iovcnt = 1; 492 uio.uio_offset = (off_t)(uintptr_t)addr; 493 uio.uio_resid = sizeof(int); 494 uio.uio_segflg = UIO_SYSSPACE; 495 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 496 uio.uio_td = curthread; 497 error = procfs_domem(curp, lp, NULL, &uio); 498 if (uio.uio_resid != 0) { 499 /* 500 * XXX procfs_domem() doesn't currently return ENOSPC, 501 * so I think write() can bogusly return 0. 502 * XXX what happens for short writes? We don't want 503 * to write partial data. 504 * XXX procfs_domem() returns EPERM for other invalid 505 * addresses. Convert this to EINVAL. Does this 506 * clobber returns of EPERM for other reasons? 507 */ 508 if (error == 0 || error == ENOSPC || error == EPERM) 509 error = EINVAL; /* EOF */ 510 } 511 if (!write) 512 *res = tmp; 513 return (error); 514 515 case PT_IO: 516 /* 517 * NOTE! uio_offset represents the offset in the target 518 * process. The iov is in the current process (the guy 519 * making the ptrace call) so uio_td must be the current 520 * process. 521 */ 522 piod = addr; 523 iov.iov_base = piod->piod_addr; 524 iov.iov_len = piod->piod_len; 525 uio.uio_iov = &iov; 526 uio.uio_iovcnt = 1; 527 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs; 528 uio.uio_resid = piod->piod_len; 529 uio.uio_segflg = UIO_USERSPACE; 530 uio.uio_td = curthread; 531 switch (piod->piod_op) { 532 case PIOD_READ_D: 533 case PIOD_READ_I: 534 uio.uio_rw = UIO_READ; 535 break; 536 case PIOD_WRITE_D: 537 case PIOD_WRITE_I: 538 uio.uio_rw = UIO_WRITE; 539 break; 540 default: 541 return (EINVAL); 542 } 543 error = procfs_domem(curp, lp, NULL, &uio); 544 piod->piod_len -= uio.uio_resid; 545 return (error); 546 547 case PT_KILL: 548 data = SIGKILL; 549 goto sendsig; /* in PT_CONTINUE above */ 550 551 #ifdef PT_SETREGS 552 case PT_SETREGS: 553 write = 1; 554 /* fallthrough */ 555 #endif /* PT_SETREGS */ 556 #ifdef PT_GETREGS 557 case PT_GETREGS: 558 /* write = 0 above */ 559 #endif /* PT_SETREGS */ 560 #if defined(PT_SETREGS) || defined(PT_GETREGS) 561 if (!procfs_validregs(lp)) /* no P_SYSTEM procs please */ 562 return EINVAL; 563 else { 564 iov.iov_base = addr; 565 iov.iov_len = sizeof(struct reg); 566 uio.uio_iov = &iov; 567 uio.uio_iovcnt = 1; 568 uio.uio_offset = 0; 569 uio.uio_resid = sizeof(struct reg); 570 uio.uio_segflg = UIO_SYSSPACE; 571 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 572 uio.uio_td = curthread; 573 return (procfs_doregs(curp, lp, NULL, &uio)); 574 } 575 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */ 576 577 #ifdef PT_SETFPREGS 578 case PT_SETFPREGS: 579 write = 1; 580 /* fallthrough */ 581 #endif /* PT_SETFPREGS */ 582 #ifdef PT_GETFPREGS 583 case PT_GETFPREGS: 584 /* write = 0 above */ 585 #endif /* PT_SETFPREGS */ 586 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 587 if (!procfs_validfpregs(lp)) /* no P_SYSTEM procs please */ 588 return EINVAL; 589 else { 590 iov.iov_base = addr; 591 iov.iov_len = sizeof(struct fpreg); 592 uio.uio_iov = &iov; 593 uio.uio_iovcnt = 1; 594 uio.uio_offset = 0; 595 uio.uio_resid = sizeof(struct fpreg); 596 uio.uio_segflg = UIO_SYSSPACE; 597 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 598 uio.uio_td = curthread; 599 return (procfs_dofpregs(curp, lp, NULL, &uio)); 600 } 601 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */ 602 603 #ifdef PT_SETDBREGS 604 case PT_SETDBREGS: 605 write = 1; 606 /* fallthrough */ 607 #endif /* PT_SETDBREGS */ 608 #ifdef PT_GETDBREGS 609 case PT_GETDBREGS: 610 /* write = 0 above */ 611 #endif /* PT_SETDBREGS */ 612 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS) 613 if (!procfs_validdbregs(lp)) /* no P_SYSTEM procs please */ 614 return EINVAL; 615 else { 616 iov.iov_base = addr; 617 iov.iov_len = sizeof(struct dbreg); 618 uio.uio_iov = &iov; 619 uio.uio_iovcnt = 1; 620 uio.uio_offset = 0; 621 uio.uio_resid = sizeof(struct dbreg); 622 uio.uio_segflg = UIO_SYSSPACE; 623 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 624 uio.uio_td = curthread; 625 return (procfs_dodbregs(curp, lp, NULL, &uio)); 626 } 627 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */ 628 629 default: 630 break; 631 } 632 633 return 0; 634 } 635 636 int 637 trace_req(struct proc *p) 638 { 639 return 1; 640 } 641 642 /* 643 * stopevent() 644 * 645 * Stop a process because of a procfs event. Stay stopped until p->p_step 646 * is cleared (cleared by PIOCCONT in procfs). 647 * 648 * MPSAFE 649 */ 650 void 651 stopevent(struct proc *p, unsigned int event, unsigned int val) 652 { 653 p->p_step = 1; 654 655 do { 656 crit_enter(); 657 wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */ 658 p->p_xstat = val; 659 p->p_stype = event; /* Which event caused the stop? */ 660 tsleep(&p->p_step, 0, "stopevent", 0); 661 crit_exit(); 662 } while (p->p_step); 663 } 664 665