1 /* 2 * Copyright (c) 1993, David Greenman 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include "opt_ktrace.h" 30 #include "opt_mac.h" 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/lock.h> 35 #include <sys/mutex.h> 36 #include <sys/sysproto.h> 37 #include <sys/signalvar.h> 38 #include <sys/kernel.h> 39 #include <sys/mac.h> 40 #include <sys/mount.h> 41 #include <sys/filedesc.h> 42 #include <sys/fcntl.h> 43 #include <sys/acct.h> 44 #include <sys/exec.h> 45 #include <sys/imgact.h> 46 #include <sys/imgact_elf.h> 47 #include <sys/wait.h> 48 #include <sys/malloc.h> 49 #include <sys/proc.h> 50 #include <sys/pioctl.h> 51 #include <sys/namei.h> 52 #include <sys/sysent.h> 53 #include <sys/shm.h> 54 #include <sys/sysctl.h> 55 #include <sys/user.h> 56 #include <sys/vnode.h> 57 #ifdef KTRACE 58 #include <sys/ktrace.h> 59 #endif 60 61 #include <vm/vm.h> 62 #include <vm/vm_param.h> 63 #include <vm/pmap.h> 64 #include <vm/vm_page.h> 65 #include <vm/vm_map.h> 66 #include <vm/vm_kern.h> 67 #include <vm/vm_extern.h> 68 #include <vm/vm_object.h> 69 #include <vm/vm_pager.h> 70 71 #include <machine/reg.h> 72 73 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 74 75 static MALLOC_DEFINE(M_ATEXEC, "atexec", "atexec callback"); 76 77 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 78 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 79 80 /* 81 * callout list for things to do at exec time 82 */ 83 struct execlist { 84 execlist_fn function; 85 TAILQ_ENTRY(execlist) next; 86 }; 87 88 TAILQ_HEAD(exec_list_head, execlist); 89 static struct exec_list_head exec_list = TAILQ_HEAD_INITIALIZER(exec_list); 90 91 /* XXX This should be vm_size_t. */ 92 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 93 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 94 95 /* XXX This should be vm_size_t. */ 96 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 97 NULL, 0, sysctl_kern_usrstack, "LU", ""); 98 99 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 100 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 101 &ps_arg_cache_limit, 0, ""); 102 103 int ps_argsopen = 1; 104 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); 105 106 #ifdef __ia64__ 107 /* XXX HACK */ 108 static int regstkpages = 256; 109 SYSCTL_INT(_machdep, OID_AUTO, regstkpages, CTLFLAG_RW, ®stkpages, 0, ""); 110 #endif 111 112 static int 113 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 114 { 115 struct proc *p; 116 117 p = curproc; 118 return (SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 119 sizeof(p->p_sysent->sv_psstrings))); 120 } 121 122 static int 123 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 124 { 125 struct proc *p; 126 127 p = curproc; 128 return (SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 129 sizeof(p->p_sysent->sv_usrstack))); 130 } 131 132 /* 133 * Each of the items is a pointer to a `const struct execsw', hence the 134 * double pointer here. 135 */ 136 static const struct execsw **execsw; 137 138 #ifndef _SYS_SYSPROTO_H_ 139 struct execve_args { 140 char *fname; 141 char **argv; 142 char **envv; 143 }; 144 #endif 145 146 /* 147 * execve() system call. 148 * 149 * MPSAFE 150 */ 151 int 152 execve(td, uap) 153 struct thread *td; 154 register struct execve_args *uap; 155 { 156 struct proc *p = td->td_proc; 157 struct nameidata nd, *ndp; 158 struct ucred *newcred = NULL, *oldcred; 159 struct uidinfo *euip; 160 register_t *stack_base; 161 int error, len, i; 162 struct image_params image_params, *imgp; 163 struct vattr attr; 164 int (*img_first)(struct image_params *); 165 struct pargs *oldargs = NULL, *newargs = NULL; 166 struct procsig *oldprocsig, *newprocsig; 167 #ifdef KTRACE 168 struct vnode *tracevp = NULL; 169 #endif 170 struct vnode *textvp = NULL; 171 int credential_changing; 172 int textset; 173 174 imgp = &image_params; 175 176 /* 177 * Lock the process and set the P_INEXEC flag to indicate that 178 * it should be left alone until we're done here. This is 179 * necessary to avoid race conditions - e.g. in ptrace() - 180 * that might allow a local user to illicitly obtain elevated 181 * privileges. 182 */ 183 PROC_LOCK(p); 184 KASSERT((p->p_flag & P_INEXEC) == 0, 185 ("%s(): process already has P_INEXEC flag", __func__)); 186 if (p->p_flag & P_KSES) { 187 if (thread_single(SINGLE_EXIT)) { 188 PROC_UNLOCK(p); 189 return (ERESTART); /* Try again later. */ 190 } 191 /* 192 * If we get here all other threads are dead, 193 * so unset the associated flags and lose KSE mode. 194 */ 195 p->p_flag &= ~P_KSES; 196 td->td_flags &= ~TDF_UNBOUND; 197 thread_single_end(); 198 } 199 p->p_flag |= P_INEXEC; 200 PROC_UNLOCK(p); 201 202 /* 203 * Initialize part of the common data 204 */ 205 imgp->proc = p; 206 imgp->uap = uap; 207 imgp->attr = &attr; 208 imgp->argc = imgp->envc = 0; 209 imgp->argv0 = NULL; 210 imgp->entry_addr = 0; 211 imgp->vmspace_destroyed = 0; 212 imgp->interpreted = 0; 213 imgp->interpreter_name[0] = '\0'; 214 imgp->auxargs = NULL; 215 imgp->vp = NULL; 216 imgp->object = NULL; 217 imgp->firstpage = NULL; 218 imgp->ps_strings = 0; 219 imgp->auxarg_size = 0; 220 221 /* 222 * Allocate temporary demand zeroed space for argument and 223 * environment strings 224 */ 225 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + 226 PAGE_SIZE); 227 if (imgp->stringbase == NULL) { 228 error = ENOMEM; 229 mtx_lock(&Giant); 230 goto exec_fail; 231 } 232 imgp->stringp = imgp->stringbase; 233 imgp->stringspace = ARG_MAX; 234 imgp->image_header = imgp->stringbase + ARG_MAX; 235 236 /* 237 * Translate the file name. namei() returns a vnode pointer 238 * in ni_vp amoung other things. 239 */ 240 ndp = &nd; 241 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 242 UIO_USERSPACE, uap->fname, td); 243 244 mtx_lock(&Giant); 245 interpret: 246 247 error = namei(ndp); 248 if (error) { 249 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 250 ARG_MAX + PAGE_SIZE); 251 goto exec_fail; 252 } 253 254 imgp->vp = ndp->ni_vp; 255 imgp->fname = uap->fname; 256 257 /* 258 * Check file permissions (also 'opens' file) 259 */ 260 error = exec_check_permissions(imgp); 261 if (error) 262 goto exec_fail_dealloc; 263 264 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 265 vm_object_reference(imgp->object); 266 267 /* 268 * Set VV_TEXT now so no one can write to the executable while we're 269 * activating it. 270 * 271 * Remember if this was set before and unset it in case this is not 272 * actually an executable image. 273 */ 274 textset = imgp->vp->v_vflag & VV_TEXT; 275 imgp->vp->v_vflag |= VV_TEXT; 276 277 error = exec_map_first_page(imgp); 278 if (error) 279 goto exec_fail_dealloc; 280 281 /* 282 * If the current process has a special image activator it 283 * wants to try first, call it. For example, emulating shell 284 * scripts differently. 285 */ 286 error = -1; 287 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 288 error = img_first(imgp); 289 290 /* 291 * Loop through the list of image activators, calling each one. 292 * An activator returns -1 if there is no match, 0 on success, 293 * and an error otherwise. 294 */ 295 for (i = 0; error == -1 && execsw[i]; ++i) { 296 if (execsw[i]->ex_imgact == NULL || 297 execsw[i]->ex_imgact == img_first) { 298 continue; 299 } 300 error = (*execsw[i]->ex_imgact)(imgp); 301 } 302 303 if (error) { 304 if (error == -1) { 305 if (textset == 0) 306 imgp->vp->v_vflag &= ~VV_TEXT; 307 error = ENOEXEC; 308 } 309 goto exec_fail_dealloc; 310 } 311 312 /* 313 * Special interpreter operation, cleanup and loop up to try to 314 * activate the interpreter. 315 */ 316 if (imgp->interpreted) { 317 exec_unmap_first_page(imgp); 318 /* 319 * VV_TEXT needs to be unset for scripts. There is a short 320 * period before we determine that something is a script where 321 * VV_TEXT will be set. The vnode lock is held over this 322 * entire period so nothing should illegitimately be blocked. 323 */ 324 imgp->vp->v_vflag &= ~VV_TEXT; 325 /* free name buffer and old vnode */ 326 NDFREE(ndp, NDF_ONLY_PNBUF); 327 vput(ndp->ni_vp); 328 vm_object_deallocate(imgp->object); 329 imgp->object = NULL; 330 /* set new name to that of the interpreter */ 331 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 332 UIO_SYSSPACE, imgp->interpreter_name, td); 333 goto interpret; 334 } 335 336 /* 337 * Copy out strings (args and env) and initialize stack base 338 */ 339 if (p->p_sysent->sv_copyout_strings) 340 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 341 else 342 stack_base = exec_copyout_strings(imgp); 343 344 /* 345 * If custom stack fixup routine present for this process 346 * let it do the stack setup. 347 * Else stuff argument count as first item on stack 348 */ 349 if (p->p_sysent->sv_fixup) 350 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 351 else 352 suword(--stack_base, imgp->argc); 353 354 /* 355 * For security and other reasons, the file descriptor table cannot 356 * be shared after an exec. 357 */ 358 FILEDESC_LOCK(p->p_fd); 359 if (p->p_fd->fd_refcnt > 1) { 360 struct filedesc *tmp; 361 362 tmp = fdcopy(td); 363 FILEDESC_UNLOCK(p->p_fd); 364 fdfree(td); 365 p->p_fd = tmp; 366 } else 367 FILEDESC_UNLOCK(p->p_fd); 368 369 /* 370 * Malloc things before we need locks. 371 */ 372 newcred = crget(); 373 euip = uifind(attr.va_uid); 374 i = imgp->endargs - imgp->stringbase; 375 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 376 newargs = pargs_alloc(i); 377 378 /* close files on exec */ 379 fdcloseexec(td); 380 381 /* Get a reference to the vnode prior to locking the proc */ 382 VREF(ndp->ni_vp); 383 384 /* 385 * For security and other reasons, signal handlers cannot 386 * be shared after an exec. The new process gets a copy of the old 387 * handlers. In execsigs(), the new process will have its signals 388 * reset. 389 */ 390 PROC_LOCK(p); 391 mp_fixme("procsig needs a lock"); 392 if (p->p_procsig->ps_refcnt > 1) { 393 oldprocsig = p->p_procsig; 394 PROC_UNLOCK(p); 395 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), 396 M_SUBPROC, M_WAITOK); 397 bcopy(oldprocsig, newprocsig, sizeof(*newprocsig)); 398 newprocsig->ps_refcnt = 1; 399 oldprocsig->ps_refcnt--; 400 PROC_LOCK(p); 401 p->p_procsig = newprocsig; 402 if (p->p_sigacts == &p->p_uarea->u_sigacts) 403 panic("shared procsig but private sigacts?"); 404 405 p->p_uarea->u_sigacts = *p->p_sigacts; 406 p->p_sigacts = &p->p_uarea->u_sigacts; 407 } 408 /* Stop profiling */ 409 stopprofclock(p); 410 411 /* reset caught signals */ 412 execsigs(p); 413 414 /* name this process - nameiexec(p, ndp) */ 415 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 416 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 417 p->p_comm[len] = 0; 418 419 /* 420 * mark as execed, wakeup the process that vforked (if any) and tell 421 * it that it now has its own resources back 422 */ 423 p->p_flag |= P_EXEC; 424 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 425 p->p_flag &= ~P_PPWAIT; 426 wakeup(p->p_pptr); 427 } 428 429 /* 430 * Implement image setuid/setgid. 431 * 432 * Don't honor setuid/setgid if the filesystem prohibits it or if 433 * the process is being traced. 434 */ 435 oldcred = p->p_ucred; 436 credential_changing = 0; 437 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 438 attr.va_uid; 439 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 440 attr.va_gid; 441 442 if (credential_changing && 443 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 444 (p->p_flag & P_TRACED) == 0) { 445 /* 446 * Turn off syscall tracing for set-id programs, except for 447 * root. Record any set-id flags first to make sure that 448 * we do not regain any tracing during a possible block. 449 */ 450 setsugid(p); 451 #ifdef KTRACE 452 if (p->p_tracep && suser_cred(oldcred, PRISON_ROOT)) { 453 mtx_lock(&ktrace_mtx); 454 p->p_traceflag = 0; 455 tracevp = p->p_tracep; 456 p->p_tracep = NULL; 457 mtx_unlock(&ktrace_mtx); 458 } 459 #endif 460 /* 461 * Close any file descriptors 0..2 that reference procfs, 462 * then make sure file descriptors 0..2 are in use. 463 * 464 * setugidsafety() may call closef() and then pfind() 465 * which may grab the process lock. 466 * fdcheckstd() may call falloc() which may block to 467 * allocate memory, so temporarily drop the process lock. 468 */ 469 PROC_UNLOCK(p); 470 setugidsafety(td); 471 error = fdcheckstd(td); 472 if (error != 0) 473 goto done1; 474 PROC_LOCK(p); 475 /* 476 * Set the new credentials. 477 */ 478 crcopy(newcred, oldcred); 479 if (attr.va_mode & VSUID) 480 change_euid(newcred, euip); 481 if (attr.va_mode & VSGID) 482 change_egid(newcred, attr.va_gid); 483 /* 484 * Implement correct POSIX saved-id behavior. 485 */ 486 change_svuid(newcred, newcred->cr_uid); 487 change_svgid(newcred, newcred->cr_gid); 488 p->p_ucred = newcred; 489 newcred = NULL; 490 } else { 491 if (oldcred->cr_uid == oldcred->cr_ruid && 492 oldcred->cr_gid == oldcred->cr_rgid) 493 p->p_flag &= ~P_SUGID; 494 /* 495 * Implement correct POSIX saved-id behavior. 496 * 497 * XXX: It's not clear that the existing behavior is 498 * POSIX-compliant. A number of sources indicate that the 499 * saved uid/gid should only be updated if the new ruid is 500 * not equal to the old ruid, or the new euid is not equal 501 * to the old euid and the new euid is not equal to the old 502 * ruid. The FreeBSD code always updates the saved uid/gid. 503 * Also, this code uses the new (replaced) euid and egid as 504 * the source, which may or may not be the right ones to use. 505 */ 506 if (oldcred->cr_svuid != oldcred->cr_uid || 507 oldcred->cr_svgid != oldcred->cr_gid) { 508 crcopy(newcred, oldcred); 509 change_svuid(newcred, newcred->cr_uid); 510 change_svgid(newcred, newcred->cr_gid); 511 p->p_ucred = newcred; 512 newcred = NULL; 513 } 514 } 515 516 /* 517 * Store the vp for use in procfs. This vnode was referenced prior 518 * to locking the proc lock. 519 */ 520 textvp = p->p_textvp; 521 p->p_textvp = ndp->ni_vp; 522 523 /* 524 * Notify others that we exec'd, and clear the P_INEXEC flag 525 * as we're now a bona fide freshly-execed process. 526 */ 527 KNOTE(&p->p_klist, NOTE_EXEC); 528 p->p_flag &= ~P_INEXEC; 529 530 /* 531 * If tracing the process, trap to debugger so breakpoints 532 * can be set before the program executes. 533 */ 534 _STOPEVENT(p, S_EXEC, 0); 535 536 if (p->p_flag & P_TRACED) 537 psignal(p, SIGTRAP); 538 539 /* clear "fork but no exec" flag, as we _are_ execing */ 540 p->p_acflag &= ~AFORK; 541 542 /* Free any previous argument cache */ 543 oldargs = p->p_args; 544 p->p_args = NULL; 545 546 /* Cache arguments if they fit inside our allowance */ 547 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 548 bcopy(imgp->stringbase, newargs->ar_args, i); 549 p->p_args = newargs; 550 newargs = NULL; 551 } 552 PROC_UNLOCK(p); 553 554 /* Set values passed into the program in registers. */ 555 if (p->p_sysent->sv_setregs) 556 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 557 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 558 else 559 exec_setregs(td, imgp->entry_addr, 560 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 561 562 done1: 563 /* 564 * Free any resources malloc'd earlier that we didn't use. 565 */ 566 uifree(euip); 567 if (newcred == NULL) 568 crfree(oldcred); 569 else 570 crfree(newcred); 571 /* 572 * Handle deferred decrement of ref counts. 573 */ 574 if (textvp != NULL) 575 vrele(textvp); 576 if (ndp->ni_vp && error != 0) 577 vrele(ndp->ni_vp); 578 #ifdef KTRACE 579 if (tracevp != NULL) 580 vrele(tracevp); 581 #endif 582 if (oldargs != NULL) 583 pargs_drop(oldargs); 584 if (newargs != NULL) 585 pargs_drop(newargs); 586 587 exec_fail_dealloc: 588 589 /* 590 * free various allocated resources 591 */ 592 if (imgp->firstpage) 593 exec_unmap_first_page(imgp); 594 595 if (imgp->stringbase != NULL) 596 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 597 ARG_MAX + PAGE_SIZE); 598 599 if (imgp->vp) { 600 NDFREE(ndp, NDF_ONLY_PNBUF); 601 vput(imgp->vp); 602 } 603 604 if (imgp->object) 605 vm_object_deallocate(imgp->object); 606 607 if (error == 0) 608 goto done2; 609 610 exec_fail: 611 /* we're done here, clear P_INEXEC */ 612 PROC_LOCK(p); 613 p->p_flag &= ~P_INEXEC; 614 PROC_UNLOCK(p); 615 616 if (imgp->vmspace_destroyed) { 617 /* sorry, no more process anymore. exit gracefully */ 618 exit1(td, W_EXITCODE(0, SIGABRT)); 619 /* NOT REACHED */ 620 error = 0; 621 } 622 done2: 623 mtx_unlock(&Giant); 624 return (error); 625 } 626 627 int 628 exec_map_first_page(imgp) 629 struct image_params *imgp; 630 { 631 int rv, i; 632 int initial_pagein; 633 vm_page_t ma[VM_INITIAL_PAGEIN]; 634 vm_object_t object; 635 636 GIANT_REQUIRED; 637 638 if (imgp->firstpage) { 639 exec_unmap_first_page(imgp); 640 } 641 642 VOP_GETVOBJECT(imgp->vp, &object); 643 644 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 645 646 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 647 initial_pagein = VM_INITIAL_PAGEIN; 648 if (initial_pagein > object->size) 649 initial_pagein = object->size; 650 for (i = 1; i < initial_pagein; i++) { 651 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 652 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 653 break; 654 if (ma[i]->valid) 655 break; 656 vm_page_busy(ma[i]); 657 } else { 658 ma[i] = vm_page_alloc(object, i, 659 VM_ALLOC_NORMAL); 660 if (ma[i] == NULL) 661 break; 662 } 663 } 664 initial_pagein = i; 665 666 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 667 ma[0] = vm_page_lookup(object, 0); 668 669 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 670 (ma[0]->valid == 0)) { 671 if (ma[0]) { 672 vm_page_lock_queues(); 673 vm_page_protect(ma[0], VM_PROT_NONE); 674 vm_page_free(ma[0]); 675 vm_page_unlock_queues(); 676 } 677 return (EIO); 678 } 679 } 680 vm_page_lock_queues(); 681 vm_page_wire(ma[0]); 682 vm_page_wakeup(ma[0]); 683 vm_page_unlock_queues(); 684 685 pmap_qenter((vm_offset_t)imgp->image_header, ma, 1); 686 imgp->firstpage = ma[0]; 687 688 return (0); 689 } 690 691 void 692 exec_unmap_first_page(imgp) 693 struct image_params *imgp; 694 { 695 GIANT_REQUIRED; 696 697 if (imgp->firstpage) { 698 pmap_qremove((vm_offset_t)imgp->image_header, 1); 699 vm_page_lock_queues(); 700 vm_page_unwire(imgp->firstpage, 1); 701 vm_page_unlock_queues(); 702 imgp->firstpage = NULL; 703 } 704 } 705 706 /* 707 * Destroy old address space, and allocate a new stack 708 * The new stack is only SGROWSIZ large because it is grown 709 * automatically in trap.c. 710 */ 711 int 712 exec_new_vmspace(imgp, sv) 713 struct image_params *imgp; 714 struct sysentvec *sv; 715 { 716 int error; 717 struct execlist *ep; 718 struct proc *p = imgp->proc; 719 struct vmspace *vmspace = p->p_vmspace; 720 vm_offset_t stack_addr; 721 vm_map_t map; 722 723 GIANT_REQUIRED; 724 725 stack_addr = sv->sv_usrstack - maxssiz; 726 727 imgp->vmspace_destroyed = 1; 728 729 /* 730 * Perform functions registered with at_exec(). 731 */ 732 TAILQ_FOREACH(ep, &exec_list, next) 733 (*ep->function)(p); 734 735 /* 736 * Blow away entire process VM, if address space not shared, 737 * otherwise, create a new VM space so that other threads are 738 * not disrupted 739 */ 740 map = &vmspace->vm_map; 741 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 742 vm_map_max(map) == sv->sv_maxuser) { 743 if (vmspace->vm_shm) 744 shmexit(p); 745 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 746 vm_map_max(map)); 747 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 748 } else { 749 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 750 vmspace = p->p_vmspace; 751 map = &vmspace->vm_map; 752 } 753 754 /* Allocate a new stack */ 755 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 756 sv->sv_stackprot, VM_PROT_ALL, 0); 757 if (error) 758 return (error); 759 760 #ifdef __ia64__ 761 { 762 /* 763 * Allocate backing store. We really need something 764 * similar to vm_map_stack which can allow the backing 765 * store to grow upwards. This will do for now. 766 */ 767 vm_offset_t bsaddr; 768 bsaddr = p->p_sysent->sv_usrstack - 2 * maxssiz; 769 error = vm_map_find(map, 0, 0, &bsaddr, 770 regstkpages * PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0); 771 FIRST_THREAD_IN_PROC(p)->td_md.md_bspstore = bsaddr; 772 } 773 #endif 774 775 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 776 * VM_STACK case, but they are still used to monitor the size of the 777 * process stack so we can check the stack rlimit. 778 */ 779 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 780 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 781 782 return (0); 783 } 784 785 /* 786 * Copy out argument and environment strings from the old process 787 * address space into the temporary string buffer. 788 */ 789 int 790 exec_extract_strings(imgp) 791 struct image_params *imgp; 792 { 793 char **argv, **envv; 794 char *argp, *envp; 795 int error; 796 size_t length; 797 798 /* 799 * extract arguments first 800 */ 801 802 argv = imgp->uap->argv; 803 804 if (argv) { 805 argp = (caddr_t)(intptr_t)fuword(argv); 806 if (argp == (caddr_t)-1) 807 return (EFAULT); 808 if (argp) 809 argv++; 810 if (imgp->argv0) 811 argp = imgp->argv0; 812 if (argp) { 813 do { 814 if (argp == (caddr_t)-1) 815 return (EFAULT); 816 if ((error = copyinstr(argp, imgp->stringp, 817 imgp->stringspace, &length))) { 818 if (error == ENAMETOOLONG) 819 return (E2BIG); 820 return (error); 821 } 822 imgp->stringspace -= length; 823 imgp->stringp += length; 824 imgp->argc++; 825 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 826 } 827 } 828 829 imgp->endargs = imgp->stringp; 830 831 /* 832 * extract environment strings 833 */ 834 835 envv = imgp->uap->envv; 836 837 if (envv) { 838 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 839 if (envp == (caddr_t)-1) 840 return (EFAULT); 841 if ((error = copyinstr(envp, imgp->stringp, 842 imgp->stringspace, &length))) { 843 if (error == ENAMETOOLONG) 844 return (E2BIG); 845 return (error); 846 } 847 imgp->stringspace -= length; 848 imgp->stringp += length; 849 imgp->envc++; 850 } 851 } 852 853 return (0); 854 } 855 856 /* 857 * Copy strings out to the new process address space, constructing 858 * new arg and env vector tables. Return a pointer to the base 859 * so that it can be used as the initial stack pointer. 860 */ 861 register_t * 862 exec_copyout_strings(imgp) 863 struct image_params *imgp; 864 { 865 int argc, envc; 866 char **vectp; 867 char *stringp, *destp; 868 register_t *stack_base; 869 struct ps_strings *arginfo; 870 struct proc *p; 871 int szsigcode; 872 873 /* 874 * Calculate string base and vector table pointers. 875 * Also deal with signal trampoline code for this exec type. 876 */ 877 p = imgp->proc; 878 szsigcode = 0; 879 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 880 if (p->p_sysent->sv_szsigcode != NULL) 881 szsigcode = *(p->p_sysent->sv_szsigcode); 882 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 883 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 884 885 /* 886 * install sigcode 887 */ 888 if (szsigcode) 889 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 890 szsigcode), szsigcode); 891 892 /* 893 * If we have a valid auxargs ptr, prepare some room 894 * on the stack. 895 */ 896 if (imgp->auxargs) { 897 /* 898 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 899 * lower compatibility. 900 */ 901 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 902 (AT_COUNT * 2); 903 /* 904 * The '+ 2' is for the null pointers at the end of each of 905 * the arg and env vector sets,and imgp->auxarg_size is room 906 * for argument of Runtime loader. 907 */ 908 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 909 imgp->auxarg_size) * sizeof(char *)); 910 911 } else 912 /* 913 * The '+ 2' is for the null pointers at the end of each of 914 * the arg and env vector sets 915 */ 916 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 917 sizeof(char *)); 918 919 /* 920 * vectp also becomes our initial stack base 921 */ 922 stack_base = (register_t *)vectp; 923 924 stringp = imgp->stringbase; 925 argc = imgp->argc; 926 envc = imgp->envc; 927 928 /* 929 * Copy out strings - arguments and environment. 930 */ 931 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 932 933 /* 934 * Fill in "ps_strings" struct for ps, w, etc. 935 */ 936 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 937 suword(&arginfo->ps_nargvstr, argc); 938 939 /* 940 * Fill in argument portion of vector table. 941 */ 942 for (; argc > 0; --argc) { 943 suword(vectp++, (long)(intptr_t)destp); 944 while (*stringp++ != 0) 945 destp++; 946 destp++; 947 } 948 949 /* a null vector table pointer separates the argp's from the envp's */ 950 suword(vectp++, 0); 951 952 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 953 suword(&arginfo->ps_nenvstr, envc); 954 955 /* 956 * Fill in environment portion of vector table. 957 */ 958 for (; envc > 0; --envc) { 959 suword(vectp++, (long)(intptr_t)destp); 960 while (*stringp++ != 0) 961 destp++; 962 destp++; 963 } 964 965 /* end of vector table is a null pointer */ 966 suword(vectp, 0); 967 968 return (stack_base); 969 } 970 971 /* 972 * Check permissions of file to execute. 973 * Called with imgp->vp locked. 974 * Return 0 for success or error code on failure. 975 */ 976 int 977 exec_check_permissions(imgp) 978 struct image_params *imgp; 979 { 980 struct vnode *vp = imgp->vp; 981 struct vattr *attr = imgp->attr; 982 struct thread *td; 983 int error; 984 985 td = curthread; /* XXXKSE */ 986 987 #ifdef MAC 988 error = mac_check_vnode_exec(td->td_ucred, imgp->vp); 989 if (error) 990 return (error); 991 #endif 992 993 /* Get file attributes */ 994 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 995 if (error) 996 return (error); 997 998 /* 999 * 1) Check if file execution is disabled for the filesystem that this 1000 * file resides on. 1001 * 2) Insure that at least one execute bit is on - otherwise root 1002 * will always succeed, and we don't want to happen unless the 1003 * file really is executable. 1004 * 3) Insure that the file is a regular file. 1005 */ 1006 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1007 ((attr->va_mode & 0111) == 0) || 1008 (attr->va_type != VREG)) 1009 return (EACCES); 1010 1011 /* 1012 * Zero length files can't be exec'd 1013 */ 1014 if (attr->va_size == 0) 1015 return (ENOEXEC); 1016 1017 /* 1018 * Check for execute permission to file based on current credentials. 1019 */ 1020 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1021 if (error) 1022 return (error); 1023 1024 /* 1025 * Check number of open-for-writes on the file and deny execution 1026 * if there are any. 1027 */ 1028 if (vp->v_writecount) 1029 return (ETXTBSY); 1030 1031 /* 1032 * Call filesystem specific open routine (which does nothing in the 1033 * general case). 1034 */ 1035 error = VOP_OPEN(vp, FREAD, td->td_ucred, td); 1036 return (error); 1037 } 1038 1039 /* 1040 * Exec handler registration 1041 */ 1042 int 1043 exec_register(execsw_arg) 1044 const struct execsw *execsw_arg; 1045 { 1046 const struct execsw **es, **xs, **newexecsw; 1047 int count = 2; /* New slot and trailing NULL */ 1048 1049 if (execsw) 1050 for (es = execsw; *es; es++) 1051 count++; 1052 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1053 if (newexecsw == NULL) 1054 return (ENOMEM); 1055 xs = newexecsw; 1056 if (execsw) 1057 for (es = execsw; *es; es++) 1058 *xs++ = *es; 1059 *xs++ = execsw_arg; 1060 *xs = NULL; 1061 if (execsw) 1062 free(execsw, M_TEMP); 1063 execsw = newexecsw; 1064 return (0); 1065 } 1066 1067 int 1068 exec_unregister(execsw_arg) 1069 const struct execsw *execsw_arg; 1070 { 1071 const struct execsw **es, **xs, **newexecsw; 1072 int count = 1; 1073 1074 if (execsw == NULL) 1075 panic("unregister with no handlers left?\n"); 1076 1077 for (es = execsw; *es; es++) { 1078 if (*es == execsw_arg) 1079 break; 1080 } 1081 if (*es == NULL) 1082 return (ENOENT); 1083 for (es = execsw; *es; es++) 1084 if (*es != execsw_arg) 1085 count++; 1086 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1087 if (newexecsw == NULL) 1088 return (ENOMEM); 1089 xs = newexecsw; 1090 for (es = execsw; *es; es++) 1091 if (*es != execsw_arg) 1092 *xs++ = *es; 1093 *xs = NULL; 1094 if (execsw) 1095 free(execsw, M_TEMP); 1096 execsw = newexecsw; 1097 return (0); 1098 } 1099 1100 int 1101 at_exec(function) 1102 execlist_fn function; 1103 { 1104 struct execlist *ep; 1105 1106 #ifdef INVARIANTS 1107 /* Be noisy if the programmer has lost track of things */ 1108 if (rm_at_exec(function)) 1109 printf("WARNING: exec callout entry (%p) already present\n", 1110 function); 1111 #endif 1112 ep = malloc(sizeof(*ep), M_ATEXEC, M_NOWAIT); 1113 if (ep == NULL) 1114 return (ENOMEM); 1115 ep->function = function; 1116 TAILQ_INSERT_TAIL(&exec_list, ep, next); 1117 return (0); 1118 } 1119 1120 /* 1121 * Scan the exec callout list for the given item and remove it. 1122 * Returns the number of items removed (0 or 1) 1123 */ 1124 int 1125 rm_at_exec(function) 1126 execlist_fn function; 1127 { 1128 struct execlist *ep; 1129 1130 TAILQ_FOREACH(ep, &exec_list, next) { 1131 if (ep->function == function) { 1132 TAILQ_REMOVE(&exec_list, ep, next); 1133 free(ep, M_ATEXEC); 1134 return (1); 1135 } 1136 } 1137 return (0); 1138 } 1139