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