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 static int kern_execve(struct thread *td, char *fname, char **argv, 80 char **envv, struct mac *mac_p); 81 82 /* 83 * callout list for things to do at exec time 84 */ 85 struct execlist { 86 execlist_fn function; 87 TAILQ_ENTRY(execlist) next; 88 }; 89 90 TAILQ_HEAD(exec_list_head, execlist); 91 static struct exec_list_head exec_list = TAILQ_HEAD_INITIALIZER(exec_list); 92 93 /* XXX This should be vm_size_t. */ 94 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD, 95 NULL, 0, sysctl_kern_ps_strings, "LU", ""); 96 97 /* XXX This should be vm_size_t. */ 98 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD, 99 NULL, 0, sysctl_kern_usrstack, "LU", ""); 100 101 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 102 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 103 &ps_arg_cache_limit, 0, ""); 104 105 int ps_argsopen = 1; 106 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); 107 108 #ifdef __ia64__ 109 /* XXX HACK */ 110 static int regstkpages = 256; 111 SYSCTL_INT(_machdep, OID_AUTO, regstkpages, CTLFLAG_RW, ®stkpages, 0, ""); 112 #endif 113 114 static int 115 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 116 { 117 struct proc *p; 118 119 p = curproc; 120 return (SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 121 sizeof(p->p_sysent->sv_psstrings))); 122 } 123 124 static int 125 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 126 { 127 struct proc *p; 128 129 p = curproc; 130 return (SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 131 sizeof(p->p_sysent->sv_usrstack))); 132 } 133 134 /* 135 * Each of the items is a pointer to a `const struct execsw', hence the 136 * double pointer here. 137 */ 138 static const struct execsw **execsw; 139 140 /* 141 * In-kernel implementation of execve(). All arguments are assumed to be 142 * userspace pointers from the passed thread. 143 * 144 * MPSAFE 145 */ 146 static int 147 kern_execve(td, fname, argv, envv, mac_p) 148 struct thread *td; 149 char *fname; 150 char **argv; 151 char **envv; 152 struct mac *mac_p; 153 { 154 struct proc *p = td->td_proc; 155 struct nameidata nd, *ndp; 156 struct ucred *newcred = NULL, *oldcred; 157 struct uidinfo *euip; 158 register_t *stack_base; 159 int error, len, i; 160 struct image_params image_params, *imgp; 161 struct vattr attr; 162 int (*img_first)(struct image_params *); 163 struct pargs *oldargs = NULL, *newargs = NULL; 164 struct procsig *oldprocsig, *newprocsig; 165 #ifdef KTRACE 166 struct vnode *tracevp = NULL; 167 #endif 168 struct vnode *textvp = NULL; 169 int credential_changing; 170 int textset; 171 #ifdef MAC 172 struct label interplabel; /* label of the interpreted vnode */ 173 struct label execlabel; /* optional label argument */ 174 int will_transition, interplabelvalid = 0; 175 #endif 176 177 imgp = &image_params; 178 179 /* 180 * Lock the process and set the P_INEXEC flag to indicate that 181 * it should be left alone until we're done here. This is 182 * necessary to avoid race conditions - e.g. in ptrace() - 183 * that might allow a local user to illicitly obtain elevated 184 * privileges. 185 */ 186 PROC_LOCK(p); 187 KASSERT((p->p_flag & P_INEXEC) == 0, 188 ("%s(): process already has P_INEXEC flag", __func__)); 189 if (p->p_flag & P_KSES) { 190 if (thread_single(SINGLE_EXIT)) { 191 PROC_UNLOCK(p); 192 return (ERESTART); /* Try again later. */ 193 } 194 /* 195 * If we get here all other threads are dead, 196 * so unset the associated flags and lose KSE mode. 197 */ 198 p->p_flag &= ~P_KSES; 199 td->td_flags &= ~TDF_UNBOUND; 200 thread_single_end(); 201 } 202 p->p_flag |= P_INEXEC; 203 PROC_UNLOCK(p); 204 205 /* 206 * Initialize part of the common data 207 */ 208 imgp->proc = p; 209 imgp->userspace_argv = argv; 210 imgp->userspace_envv = envv; 211 imgp->execlabel = NULL; 212 imgp->attr = &attr; 213 imgp->argc = imgp->envc = 0; 214 imgp->argv0 = NULL; 215 imgp->entry_addr = 0; 216 imgp->vmspace_destroyed = 0; 217 imgp->interpreted = 0; 218 imgp->interpreter_name[0] = '\0'; 219 imgp->auxargs = NULL; 220 imgp->vp = NULL; 221 imgp->object = NULL; 222 imgp->firstpage = NULL; 223 imgp->ps_strings = 0; 224 imgp->auxarg_size = 0; 225 226 #ifdef MAC 227 error = mac_execve_enter(imgp, mac_p, &execlabel); 228 if (error) { 229 mtx_lock(&Giant); 230 goto exec_fail; 231 } 232 #endif 233 234 /* 235 * Allocate temporary demand zeroed space for argument and 236 * environment strings 237 */ 238 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + 239 PAGE_SIZE); 240 if (imgp->stringbase == NULL) { 241 error = ENOMEM; 242 mtx_lock(&Giant); 243 goto exec_fail; 244 } 245 imgp->stringp = imgp->stringbase; 246 imgp->stringspace = ARG_MAX; 247 imgp->image_header = imgp->stringbase + ARG_MAX; 248 249 /* 250 * Translate the file name. namei() returns a vnode pointer 251 * in ni_vp amoung other things. 252 */ 253 ndp = &nd; 254 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 255 UIO_USERSPACE, fname, td); 256 257 mtx_lock(&Giant); 258 interpret: 259 260 error = namei(ndp); 261 if (error) { 262 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 263 ARG_MAX + PAGE_SIZE); 264 goto exec_fail; 265 } 266 267 imgp->vp = ndp->ni_vp; 268 imgp->fname = fname; 269 270 /* 271 * Check file permissions (also 'opens' file) 272 */ 273 error = exec_check_permissions(imgp); 274 if (error) 275 goto exec_fail_dealloc; 276 277 if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0) 278 vm_object_reference(imgp->object); 279 280 /* 281 * Set VV_TEXT now so no one can write to the executable while we're 282 * activating it. 283 * 284 * Remember if this was set before and unset it in case this is not 285 * actually an executable image. 286 */ 287 textset = imgp->vp->v_vflag & VV_TEXT; 288 imgp->vp->v_vflag |= VV_TEXT; 289 290 error = exec_map_first_page(imgp); 291 if (error) 292 goto exec_fail_dealloc; 293 294 /* 295 * If the current process has a special image activator it 296 * wants to try first, call it. For example, emulating shell 297 * scripts differently. 298 */ 299 error = -1; 300 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 301 error = img_first(imgp); 302 303 /* 304 * Loop through the list of image activators, calling each one. 305 * An activator returns -1 if there is no match, 0 on success, 306 * and an error otherwise. 307 */ 308 for (i = 0; error == -1 && execsw[i]; ++i) { 309 if (execsw[i]->ex_imgact == NULL || 310 execsw[i]->ex_imgact == img_first) { 311 continue; 312 } 313 error = (*execsw[i]->ex_imgact)(imgp); 314 } 315 316 if (error) { 317 if (error == -1) { 318 if (textset == 0) 319 imgp->vp->v_vflag &= ~VV_TEXT; 320 error = ENOEXEC; 321 } 322 goto exec_fail_dealloc; 323 } 324 325 /* 326 * Special interpreter operation, cleanup and loop up to try to 327 * activate the interpreter. 328 */ 329 if (imgp->interpreted) { 330 exec_unmap_first_page(imgp); 331 /* 332 * VV_TEXT needs to be unset for scripts. There is a short 333 * period before we determine that something is a script where 334 * VV_TEXT will be set. The vnode lock is held over this 335 * entire period so nothing should illegitimately be blocked. 336 */ 337 imgp->vp->v_vflag &= ~VV_TEXT; 338 /* free name buffer and old vnode */ 339 NDFREE(ndp, NDF_ONLY_PNBUF); 340 #ifdef MAC 341 mac_init_vnode_label(&interplabel); 342 mac_copy_vnode_label(&ndp->ni_vp->v_label, &interplabel); 343 interplabelvalid = 1; 344 #endif 345 vput(ndp->ni_vp); 346 vm_object_deallocate(imgp->object); 347 imgp->object = NULL; 348 /* set new name to that of the interpreter */ 349 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 350 UIO_SYSSPACE, imgp->interpreter_name, td); 351 goto interpret; 352 } 353 354 /* 355 * Copy out strings (args and env) and initialize stack base 356 */ 357 if (p->p_sysent->sv_copyout_strings) 358 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp); 359 else 360 stack_base = exec_copyout_strings(imgp); 361 362 /* 363 * If custom stack fixup routine present for this process 364 * let it do the stack setup. 365 * Else stuff argument count as first item on stack 366 */ 367 if (p->p_sysent->sv_fixup) 368 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 369 else 370 suword(--stack_base, imgp->argc); 371 372 /* 373 * For security and other reasons, the file descriptor table cannot 374 * be shared after an exec. 375 */ 376 FILEDESC_LOCK(p->p_fd); 377 if (p->p_fd->fd_refcnt > 1) { 378 struct filedesc *tmp; 379 380 tmp = fdcopy(td); 381 FILEDESC_UNLOCK(p->p_fd); 382 fdfree(td); 383 p->p_fd = tmp; 384 } else 385 FILEDESC_UNLOCK(p->p_fd); 386 387 /* 388 * Malloc things before we need locks. 389 */ 390 newcred = crget(); 391 euip = uifind(attr.va_uid); 392 i = imgp->endargs - imgp->stringbase; 393 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) 394 newargs = pargs_alloc(i); 395 396 /* close files on exec */ 397 fdcloseexec(td); 398 399 /* Get a reference to the vnode prior to locking the proc */ 400 VREF(ndp->ni_vp); 401 402 /* 403 * For security and other reasons, signal handlers cannot 404 * be shared after an exec. The new process gets a copy of the old 405 * handlers. In execsigs(), the new process will have its signals 406 * reset. 407 */ 408 PROC_LOCK(p); 409 mp_fixme("procsig needs a lock"); 410 if (p->p_procsig->ps_refcnt > 1) { 411 oldprocsig = p->p_procsig; 412 PROC_UNLOCK(p); 413 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), 414 M_SUBPROC, M_WAITOK); 415 bcopy(oldprocsig, newprocsig, sizeof(*newprocsig)); 416 newprocsig->ps_refcnt = 1; 417 oldprocsig->ps_refcnt--; 418 PROC_LOCK(p); 419 p->p_procsig = newprocsig; 420 if (p->p_sigacts == &p->p_uarea->u_sigacts) 421 panic("shared procsig but private sigacts?"); 422 423 p->p_uarea->u_sigacts = *p->p_sigacts; 424 p->p_sigacts = &p->p_uarea->u_sigacts; 425 } 426 /* Stop profiling */ 427 stopprofclock(p); 428 429 /* reset caught signals */ 430 execsigs(p); 431 432 /* name this process - nameiexec(p, ndp) */ 433 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 434 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 435 p->p_comm[len] = 0; 436 437 /* 438 * mark as execed, wakeup the process that vforked (if any) and tell 439 * it that it now has its own resources back 440 */ 441 p->p_flag |= P_EXEC; 442 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 443 p->p_flag &= ~P_PPWAIT; 444 wakeup(p->p_pptr); 445 } 446 447 /* 448 * Implement image setuid/setgid. 449 * 450 * Don't honor setuid/setgid if the filesystem prohibits it or if 451 * the process is being traced. 452 * 453 * XXXMAC: For the time being, use NOSUID to also prohibit 454 * transitions on the file system. 455 */ 456 oldcred = p->p_ucred; 457 credential_changing = 0; 458 credential_changing |= (attr.va_mode & VSUID) && oldcred->cr_uid != 459 attr.va_uid; 460 credential_changing |= (attr.va_mode & VSGID) && oldcred->cr_gid != 461 attr.va_gid; 462 #ifdef MAC 463 will_transition = mac_execve_will_transition(oldcred, imgp->vp, 464 interplabelvalid ? &interplabel : NULL, imgp); 465 credential_changing |= will_transition; 466 #endif 467 468 if (credential_changing && 469 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 470 (p->p_flag & P_TRACED) == 0) { 471 /* 472 * Turn off syscall tracing for set-id programs, except for 473 * root. Record any set-id flags first to make sure that 474 * we do not regain any tracing during a possible block. 475 */ 476 setsugid(p); 477 #ifdef KTRACE 478 if (p->p_tracep && suser_cred(oldcred, PRISON_ROOT)) { 479 mtx_lock(&ktrace_mtx); 480 p->p_traceflag = 0; 481 tracevp = p->p_tracep; 482 p->p_tracep = NULL; 483 mtx_unlock(&ktrace_mtx); 484 } 485 #endif 486 /* 487 * Close any file descriptors 0..2 that reference procfs, 488 * then make sure file descriptors 0..2 are in use. 489 * 490 * setugidsafety() may call closef() and then pfind() 491 * which may grab the process lock. 492 * fdcheckstd() may call falloc() which may block to 493 * allocate memory, so temporarily drop the process lock. 494 */ 495 PROC_UNLOCK(p); 496 setugidsafety(td); 497 error = fdcheckstd(td); 498 if (error != 0) 499 goto done1; 500 PROC_LOCK(p); 501 /* 502 * Set the new credentials. 503 */ 504 crcopy(newcred, oldcred); 505 if (attr.va_mode & VSUID) 506 change_euid(newcred, euip); 507 if (attr.va_mode & VSGID) 508 change_egid(newcred, attr.va_gid); 509 #ifdef MAC 510 if (will_transition) { 511 mac_execve_transition(oldcred, newcred, imgp->vp, 512 interplabelvalid ? &interplabel : NULL, imgp); 513 } 514 #endif 515 /* 516 * Implement correct POSIX saved-id behavior. 517 * 518 * XXXMAC: Note that the current logic will save the 519 * uid and gid if a MAC domain transition occurs, even 520 * though maybe it shouldn't. 521 */ 522 change_svuid(newcred, newcred->cr_uid); 523 change_svgid(newcred, newcred->cr_gid); 524 p->p_ucred = newcred; 525 newcred = NULL; 526 } else { 527 if (oldcred->cr_uid == oldcred->cr_ruid && 528 oldcred->cr_gid == oldcred->cr_rgid) 529 p->p_flag &= ~P_SUGID; 530 /* 531 * Implement correct POSIX saved-id behavior. 532 * 533 * XXX: It's not clear that the existing behavior is 534 * POSIX-compliant. A number of sources indicate that the 535 * saved uid/gid should only be updated if the new ruid is 536 * not equal to the old ruid, or the new euid is not equal 537 * to the old euid and the new euid is not equal to the old 538 * ruid. The FreeBSD code always updates the saved uid/gid. 539 * Also, this code uses the new (replaced) euid and egid as 540 * the source, which may or may not be the right ones to use. 541 */ 542 if (oldcred->cr_svuid != oldcred->cr_uid || 543 oldcred->cr_svgid != oldcred->cr_gid) { 544 crcopy(newcred, oldcred); 545 change_svuid(newcred, newcred->cr_uid); 546 change_svgid(newcred, newcred->cr_gid); 547 p->p_ucred = newcred; 548 newcred = NULL; 549 } 550 } 551 552 /* 553 * Store the vp for use in procfs. This vnode was referenced prior 554 * to locking the proc lock. 555 */ 556 textvp = p->p_textvp; 557 p->p_textvp = ndp->ni_vp; 558 559 /* 560 * Notify others that we exec'd, and clear the P_INEXEC flag 561 * as we're now a bona fide freshly-execed process. 562 */ 563 KNOTE(&p->p_klist, NOTE_EXEC); 564 p->p_flag &= ~P_INEXEC; 565 566 /* 567 * If tracing the process, trap to debugger so breakpoints 568 * can be set before the program executes. 569 */ 570 _STOPEVENT(p, S_EXEC, 0); 571 572 if (p->p_flag & P_TRACED) 573 psignal(p, SIGTRAP); 574 575 /* clear "fork but no exec" flag, as we _are_ execing */ 576 p->p_acflag &= ~AFORK; 577 578 /* Free any previous argument cache */ 579 oldargs = p->p_args; 580 p->p_args = NULL; 581 582 /* Cache arguments if they fit inside our allowance */ 583 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 584 bcopy(imgp->stringbase, newargs->ar_args, i); 585 p->p_args = newargs; 586 newargs = NULL; 587 } 588 PROC_UNLOCK(p); 589 590 /* Set values passed into the program in registers. */ 591 if (p->p_sysent->sv_setregs) 592 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr, 593 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 594 else 595 exec_setregs(td, imgp->entry_addr, 596 (u_long)(uintptr_t)stack_base, imgp->ps_strings); 597 598 done1: 599 /* 600 * Free any resources malloc'd earlier that we didn't use. 601 */ 602 uifree(euip); 603 if (newcred == NULL) 604 crfree(oldcred); 605 else 606 crfree(newcred); 607 /* 608 * Handle deferred decrement of ref counts. 609 */ 610 if (textvp != NULL) 611 vrele(textvp); 612 if (ndp->ni_vp && error != 0) 613 vrele(ndp->ni_vp); 614 #ifdef KTRACE 615 if (tracevp != NULL) 616 vrele(tracevp); 617 #endif 618 if (oldargs != NULL) 619 pargs_drop(oldargs); 620 if (newargs != NULL) 621 pargs_drop(newargs); 622 623 exec_fail_dealloc: 624 625 /* 626 * free various allocated resources 627 */ 628 if (imgp->firstpage) 629 exec_unmap_first_page(imgp); 630 631 if (imgp->stringbase != NULL) 632 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 633 ARG_MAX + PAGE_SIZE); 634 635 if (imgp->vp) { 636 NDFREE(ndp, NDF_ONLY_PNBUF); 637 vput(imgp->vp); 638 } 639 640 if (imgp->object) 641 vm_object_deallocate(imgp->object); 642 643 if (error == 0) 644 goto done2; 645 646 exec_fail: 647 /* we're done here, clear P_INEXEC */ 648 PROC_LOCK(p); 649 p->p_flag &= ~P_INEXEC; 650 PROC_UNLOCK(p); 651 652 if (imgp->vmspace_destroyed) { 653 /* sorry, no more process anymore. exit gracefully */ 654 #ifdef MAC 655 mac_execve_exit(imgp); 656 if (interplabelvalid) 657 mac_destroy_vnode_label(&interplabel); 658 #endif 659 exit1(td, W_EXITCODE(0, SIGABRT)); 660 /* NOT REACHED */ 661 error = 0; 662 } 663 done2: 664 #ifdef MAC 665 mac_execve_exit(imgp); 666 if (interplabelvalid) 667 mac_destroy_vnode_label(&interplabel); 668 #endif 669 mtx_unlock(&Giant); 670 return (error); 671 } 672 673 #ifndef _SYS_SYSPROTO_H_ 674 struct execve_args { 675 char *fname; 676 char **argv; 677 char **envv; 678 }; 679 #endif 680 681 /* 682 * MPSAFE 683 */ 684 int 685 execve(td, uap) 686 struct thread *td; 687 struct execve_args /* { 688 syscallarg(char *) fname; 689 syscallarg(char **) argv; 690 syscallarg(char **) envv; 691 } */ *uap; 692 { 693 694 return (kern_execve(td, uap->fname, uap->argv, uap->envv, NULL)); 695 } 696 697 #ifndef _SYS_SYSPROTO_H_ 698 struct __mac_execve_args { 699 char *fname; 700 char **argv; 701 char **envv; 702 struct mac *mac_p; 703 }; 704 #endif 705 706 /* 707 * MPSAFE 708 */ 709 int 710 __mac_execve(td, uap) 711 struct thread *td; 712 struct __mac_execve_args /* { 713 syscallarg(char *) fname; 714 syscallarg(char **) argv; 715 syscallarg(char **) envv; 716 syscallarg(struct mac *) mac_p; 717 } */ *uap; 718 { 719 720 #ifdef MAC 721 return (kern_execve(td, uap->fname, uap->argv, uap->envv, 722 uap->mac_p)); 723 #else 724 return (ENOSYS); 725 #endif 726 } 727 728 int 729 exec_map_first_page(imgp) 730 struct image_params *imgp; 731 { 732 int rv, i; 733 int initial_pagein; 734 vm_page_t ma[VM_INITIAL_PAGEIN]; 735 vm_object_t object; 736 737 GIANT_REQUIRED; 738 739 if (imgp->firstpage) { 740 exec_unmap_first_page(imgp); 741 } 742 743 VOP_GETVOBJECT(imgp->vp, &object); 744 745 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 746 747 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 748 initial_pagein = VM_INITIAL_PAGEIN; 749 if (initial_pagein > object->size) 750 initial_pagein = object->size; 751 for (i = 1; i < initial_pagein; i++) { 752 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 753 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 754 break; 755 if (ma[i]->valid) 756 break; 757 vm_page_busy(ma[i]); 758 } else { 759 ma[i] = vm_page_alloc(object, i, 760 VM_ALLOC_NORMAL); 761 if (ma[i] == NULL) 762 break; 763 } 764 } 765 initial_pagein = i; 766 767 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 768 ma[0] = vm_page_lookup(object, 0); 769 770 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || 771 (ma[0]->valid == 0)) { 772 if (ma[0]) { 773 vm_page_lock_queues(); 774 vm_page_protect(ma[0], VM_PROT_NONE); 775 vm_page_free(ma[0]); 776 vm_page_unlock_queues(); 777 } 778 return (EIO); 779 } 780 } 781 vm_page_lock_queues(); 782 vm_page_wire(ma[0]); 783 vm_page_wakeup(ma[0]); 784 vm_page_unlock_queues(); 785 786 pmap_qenter((vm_offset_t)imgp->image_header, ma, 1); 787 imgp->firstpage = ma[0]; 788 789 return (0); 790 } 791 792 void 793 exec_unmap_first_page(imgp) 794 struct image_params *imgp; 795 { 796 GIANT_REQUIRED; 797 798 if (imgp->firstpage) { 799 pmap_qremove((vm_offset_t)imgp->image_header, 1); 800 vm_page_lock_queues(); 801 vm_page_unwire(imgp->firstpage, 1); 802 vm_page_unlock_queues(); 803 imgp->firstpage = NULL; 804 } 805 } 806 807 /* 808 * Destroy old address space, and allocate a new stack 809 * The new stack is only SGROWSIZ large because it is grown 810 * automatically in trap.c. 811 */ 812 int 813 exec_new_vmspace(imgp, sv) 814 struct image_params *imgp; 815 struct sysentvec *sv; 816 { 817 int error; 818 struct execlist *ep; 819 struct proc *p = imgp->proc; 820 struct vmspace *vmspace = p->p_vmspace; 821 vm_offset_t stack_addr; 822 vm_map_t map; 823 824 GIANT_REQUIRED; 825 826 stack_addr = sv->sv_usrstack - maxssiz; 827 828 imgp->vmspace_destroyed = 1; 829 830 /* 831 * Perform functions registered with at_exec(). 832 */ 833 TAILQ_FOREACH(ep, &exec_list, next) 834 (*ep->function)(p); 835 836 /* 837 * Blow away entire process VM, if address space not shared, 838 * otherwise, create a new VM space so that other threads are 839 * not disrupted 840 */ 841 map = &vmspace->vm_map; 842 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser && 843 vm_map_max(map) == sv->sv_maxuser) { 844 if (vmspace->vm_shm) 845 shmexit(p); 846 pmap_remove_pages(vmspace_pmap(vmspace), vm_map_min(map), 847 vm_map_max(map)); 848 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 849 } else { 850 vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser); 851 vmspace = p->p_vmspace; 852 map = &vmspace->vm_map; 853 } 854 855 /* Allocate a new stack */ 856 error = vm_map_stack(map, stack_addr, (vm_size_t)maxssiz, 857 sv->sv_stackprot, VM_PROT_ALL, 0); 858 if (error) 859 return (error); 860 861 #ifdef __ia64__ 862 { 863 /* 864 * Allocate backing store. We really need something 865 * similar to vm_map_stack which can allow the backing 866 * store to grow upwards. This will do for now. 867 */ 868 vm_offset_t bsaddr; 869 bsaddr = p->p_sysent->sv_usrstack - 2 * maxssiz; 870 error = vm_map_find(map, 0, 0, &bsaddr, 871 regstkpages * PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0); 872 FIRST_THREAD_IN_PROC(p)->td_md.md_bspstore = bsaddr; 873 } 874 #endif 875 876 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 877 * VM_STACK case, but they are still used to monitor the size of the 878 * process stack so we can check the stack rlimit. 879 */ 880 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 881 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - maxssiz; 882 883 return (0); 884 } 885 886 /* 887 * Copy out argument and environment strings from the old process 888 * address space into the temporary string buffer. 889 */ 890 int 891 exec_extract_strings(imgp) 892 struct image_params *imgp; 893 { 894 char **argv, **envv; 895 char *argp, *envp; 896 int error; 897 size_t length; 898 899 /* 900 * extract arguments first 901 */ 902 903 argv = imgp->userspace_argv; 904 905 if (argv) { 906 argp = (caddr_t)(intptr_t)fuword(argv); 907 if (argp == (caddr_t)-1) 908 return (EFAULT); 909 if (argp) 910 argv++; 911 if (imgp->argv0) 912 argp = imgp->argv0; 913 if (argp) { 914 do { 915 if (argp == (caddr_t)-1) 916 return (EFAULT); 917 if ((error = copyinstr(argp, imgp->stringp, 918 imgp->stringspace, &length))) { 919 if (error == ENAMETOOLONG) 920 return (E2BIG); 921 return (error); 922 } 923 imgp->stringspace -= length; 924 imgp->stringp += length; 925 imgp->argc++; 926 } while ((argp = (caddr_t)(intptr_t)fuword(argv++))); 927 } 928 } 929 930 imgp->endargs = imgp->stringp; 931 932 /* 933 * extract environment strings 934 */ 935 936 envv = imgp->userspace_envv; 937 938 if (envv) { 939 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) { 940 if (envp == (caddr_t)-1) 941 return (EFAULT); 942 if ((error = copyinstr(envp, imgp->stringp, 943 imgp->stringspace, &length))) { 944 if (error == ENAMETOOLONG) 945 return (E2BIG); 946 return (error); 947 } 948 imgp->stringspace -= length; 949 imgp->stringp += length; 950 imgp->envc++; 951 } 952 } 953 954 return (0); 955 } 956 957 /* 958 * Copy strings out to the new process address space, constructing 959 * new arg and env vector tables. Return a pointer to the base 960 * so that it can be used as the initial stack pointer. 961 */ 962 register_t * 963 exec_copyout_strings(imgp) 964 struct image_params *imgp; 965 { 966 int argc, envc; 967 char **vectp; 968 char *stringp, *destp; 969 register_t *stack_base; 970 struct ps_strings *arginfo; 971 struct proc *p; 972 int szsigcode; 973 974 /* 975 * Calculate string base and vector table pointers. 976 * Also deal with signal trampoline code for this exec type. 977 */ 978 p = imgp->proc; 979 szsigcode = 0; 980 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 981 if (p->p_sysent->sv_szsigcode != NULL) 982 szsigcode = *(p->p_sysent->sv_szsigcode); 983 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 984 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 985 986 /* 987 * install sigcode 988 */ 989 if (szsigcode) 990 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo - 991 szsigcode), szsigcode); 992 993 /* 994 * If we have a valid auxargs ptr, prepare some room 995 * on the stack. 996 */ 997 if (imgp->auxargs) { 998 /* 999 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 1000 * lower compatibility. 1001 */ 1002 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size : 1003 (AT_COUNT * 2); 1004 /* 1005 * The '+ 2' is for the null pointers at the end of each of 1006 * the arg and env vector sets,and imgp->auxarg_size is room 1007 * for argument of Runtime loader. 1008 */ 1009 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 1010 imgp->auxarg_size) * sizeof(char *)); 1011 1012 } else 1013 /* 1014 * The '+ 2' is for the null pointers at the end of each of 1015 * the arg and env vector sets 1016 */ 1017 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2) * 1018 sizeof(char *)); 1019 1020 /* 1021 * vectp also becomes our initial stack base 1022 */ 1023 stack_base = (register_t *)vectp; 1024 1025 stringp = imgp->stringbase; 1026 argc = imgp->argc; 1027 envc = imgp->envc; 1028 1029 /* 1030 * Copy out strings - arguments and environment. 1031 */ 1032 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 1033 1034 /* 1035 * Fill in "ps_strings" struct for ps, w, etc. 1036 */ 1037 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 1038 suword(&arginfo->ps_nargvstr, argc); 1039 1040 /* 1041 * Fill in argument portion of vector table. 1042 */ 1043 for (; argc > 0; --argc) { 1044 suword(vectp++, (long)(intptr_t)destp); 1045 while (*stringp++ != 0) 1046 destp++; 1047 destp++; 1048 } 1049 1050 /* a null vector table pointer separates the argp's from the envp's */ 1051 suword(vectp++, 0); 1052 1053 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 1054 suword(&arginfo->ps_nenvstr, envc); 1055 1056 /* 1057 * Fill in environment portion of vector table. 1058 */ 1059 for (; envc > 0; --envc) { 1060 suword(vectp++, (long)(intptr_t)destp); 1061 while (*stringp++ != 0) 1062 destp++; 1063 destp++; 1064 } 1065 1066 /* end of vector table is a null pointer */ 1067 suword(vectp, 0); 1068 1069 return (stack_base); 1070 } 1071 1072 /* 1073 * Check permissions of file to execute. 1074 * Called with imgp->vp locked. 1075 * Return 0 for success or error code on failure. 1076 */ 1077 int 1078 exec_check_permissions(imgp) 1079 struct image_params *imgp; 1080 { 1081 struct vnode *vp = imgp->vp; 1082 struct vattr *attr = imgp->attr; 1083 struct thread *td; 1084 int error; 1085 1086 td = curthread; /* XXXKSE */ 1087 1088 #ifdef MAC 1089 error = mac_check_vnode_exec(td->td_ucred, imgp->vp, imgp); 1090 if (error) 1091 return (error); 1092 #endif 1093 1094 /* Get file attributes */ 1095 error = VOP_GETATTR(vp, attr, td->td_ucred, td); 1096 if (error) 1097 return (error); 1098 1099 /* 1100 * 1) Check if file execution is disabled for the filesystem that this 1101 * file resides on. 1102 * 2) Insure that at least one execute bit is on - otherwise root 1103 * will always succeed, and we don't want to happen unless the 1104 * file really is executable. 1105 * 3) Insure that the file is a regular file. 1106 */ 1107 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1108 ((attr->va_mode & 0111) == 0) || 1109 (attr->va_type != VREG)) 1110 return (EACCES); 1111 1112 /* 1113 * Zero length files can't be exec'd 1114 */ 1115 if (attr->va_size == 0) 1116 return (ENOEXEC); 1117 1118 /* 1119 * Check for execute permission to file based on current credentials. 1120 */ 1121 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1122 if (error) 1123 return (error); 1124 1125 /* 1126 * Check number of open-for-writes on the file and deny execution 1127 * if there are any. 1128 */ 1129 if (vp->v_writecount) 1130 return (ETXTBSY); 1131 1132 /* 1133 * Call filesystem specific open routine (which does nothing in the 1134 * general case). 1135 */ 1136 error = VOP_OPEN(vp, FREAD, td->td_ucred, td); 1137 return (error); 1138 } 1139 1140 /* 1141 * Exec handler registration 1142 */ 1143 int 1144 exec_register(execsw_arg) 1145 const struct execsw *execsw_arg; 1146 { 1147 const struct execsw **es, **xs, **newexecsw; 1148 int count = 2; /* New slot and trailing NULL */ 1149 1150 if (execsw) 1151 for (es = execsw; *es; es++) 1152 count++; 1153 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1154 if (newexecsw == NULL) 1155 return (ENOMEM); 1156 xs = newexecsw; 1157 if (execsw) 1158 for (es = execsw; *es; es++) 1159 *xs++ = *es; 1160 *xs++ = execsw_arg; 1161 *xs = NULL; 1162 if (execsw) 1163 free(execsw, M_TEMP); 1164 execsw = newexecsw; 1165 return (0); 1166 } 1167 1168 int 1169 exec_unregister(execsw_arg) 1170 const struct execsw *execsw_arg; 1171 { 1172 const struct execsw **es, **xs, **newexecsw; 1173 int count = 1; 1174 1175 if (execsw == NULL) 1176 panic("unregister with no handlers left?\n"); 1177 1178 for (es = execsw; *es; es++) { 1179 if (*es == execsw_arg) 1180 break; 1181 } 1182 if (*es == NULL) 1183 return (ENOENT); 1184 for (es = execsw; *es; es++) 1185 if (*es != execsw_arg) 1186 count++; 1187 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1188 if (newexecsw == NULL) 1189 return (ENOMEM); 1190 xs = newexecsw; 1191 for (es = execsw; *es; es++) 1192 if (*es != execsw_arg) 1193 *xs++ = *es; 1194 *xs = NULL; 1195 if (execsw) 1196 free(execsw, M_TEMP); 1197 execsw = newexecsw; 1198 return (0); 1199 } 1200 1201 int 1202 at_exec(function) 1203 execlist_fn function; 1204 { 1205 struct execlist *ep; 1206 1207 #ifdef INVARIANTS 1208 /* Be noisy if the programmer has lost track of things */ 1209 if (rm_at_exec(function)) 1210 printf("WARNING: exec callout entry (%p) already present\n", 1211 function); 1212 #endif 1213 ep = malloc(sizeof(*ep), M_ATEXEC, M_NOWAIT); 1214 if (ep == NULL) 1215 return (ENOMEM); 1216 ep->function = function; 1217 TAILQ_INSERT_TAIL(&exec_list, ep, next); 1218 return (0); 1219 } 1220 1221 /* 1222 * Scan the exec callout list for the given item and remove it. 1223 * Returns the number of items removed (0 or 1) 1224 */ 1225 int 1226 rm_at_exec(function) 1227 execlist_fn function; 1228 { 1229 struct execlist *ep; 1230 1231 TAILQ_FOREACH(ep, &exec_list, next) { 1232 if (ep->function == function) { 1233 TAILQ_REMOVE(&exec_list, ep, next); 1234 free(ep, M_ATEXEC); 1235 return (1); 1236 } 1237 } 1238 return (0); 1239 } 1240