1 /* $NetBSD: kern_exec.c,v 1.279 2008/10/15 06:51:20 wrstuden Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /*- 30 * Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou 31 * Copyright (C) 1992 Wolfgang Solfrank. 32 * Copyright (C) 1992 TooLs GmbH. 33 * All rights reserved. 34 * 35 * Redistribution and use in source and binary forms, with or without 36 * modification, are permitted provided that the following conditions 37 * are met: 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 3. All advertising materials mentioning features or use of this software 44 * must display the following acknowledgement: 45 * This product includes software developed by TooLs GmbH. 46 * 4. The name of TooLs GmbH may not be used to endorse or promote products 47 * derived from this software without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 50 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 51 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 52 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 53 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 54 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 55 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 56 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 57 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 58 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 59 */ 60 61 #include <sys/cdefs.h> 62 __KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.279 2008/10/15 06:51:20 wrstuden Exp $"); 63 64 #include "opt_ktrace.h" 65 #include "opt_syscall_debug.h" 66 #include "opt_compat_netbsd.h" 67 #include "veriexec.h" 68 #include "opt_pax.h" 69 #include "opt_sa.h" 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/filedesc.h> 74 #include <sys/kernel.h> 75 #include <sys/proc.h> 76 #include <sys/mount.h> 77 #include <sys/malloc.h> 78 #include <sys/kmem.h> 79 #include <sys/namei.h> 80 #include <sys/vnode.h> 81 #include <sys/file.h> 82 #include <sys/acct.h> 83 #include <sys/exec.h> 84 #include <sys/ktrace.h> 85 #include <sys/uidinfo.h> 86 #include <sys/wait.h> 87 #include <sys/mman.h> 88 #include <sys/ras.h> 89 #include <sys/signalvar.h> 90 #include <sys/stat.h> 91 #include <sys/syscall.h> 92 #include <sys/kauth.h> 93 #include <sys/lwpctl.h> 94 #include <sys/pax.h> 95 #include <sys/cpu.h> 96 97 #include <sys/sa.h> 98 #include <sys/savar.h> 99 #include <sys/syscallargs.h> 100 #if NVERIEXEC > 0 101 #include <sys/verified_exec.h> 102 #endif /* NVERIEXEC > 0 */ 103 104 #include <uvm/uvm_extern.h> 105 106 #include <machine/reg.h> 107 108 #include <compat/common/compat_util.h> 109 110 static int exec_sigcode_map(struct proc *, const struct emul *); 111 112 #ifdef DEBUG_EXEC 113 #define DPRINTF(a) uprintf a 114 #else 115 #define DPRINTF(a) 116 #endif /* DEBUG_EXEC */ 117 118 /* 119 * Exec function switch: 120 * 121 * Note that each makecmds function is responsible for loading the 122 * exec package with the necessary functions for any exec-type-specific 123 * handling. 124 * 125 * Functions for specific exec types should be defined in their own 126 * header file. 127 */ 128 extern const struct execsw execsw_builtin[]; 129 extern int nexecs_builtin; 130 static const struct execsw **execsw = NULL; 131 static int nexecs; 132 133 u_int exec_maxhdrsz; /* must not be static - netbsd32 needs it */ 134 135 #ifdef LKM 136 /* list of supported emulations */ 137 static 138 LIST_HEAD(emlist_head, emul_entry) el_head = LIST_HEAD_INITIALIZER(el_head); 139 struct emul_entry { 140 LIST_ENTRY(emul_entry) el_list; 141 const struct emul *el_emul; 142 int ro_entry; 143 }; 144 145 /* list of dynamically loaded execsw entries */ 146 static 147 LIST_HEAD(execlist_head, exec_entry) ex_head = LIST_HEAD_INITIALIZER(ex_head); 148 struct exec_entry { 149 LIST_ENTRY(exec_entry) ex_list; 150 const struct execsw *es; 151 }; 152 153 /* structure used for building execw[] */ 154 struct execsw_entry { 155 struct execsw_entry *next; 156 const struct execsw *es; 157 }; 158 #endif /* LKM */ 159 160 #ifdef SYSCALL_DEBUG 161 extern const char * const syscallnames[]; 162 #endif 163 164 #ifdef COMPAT_16 165 extern char sigcode[], esigcode[]; 166 struct uvm_object *emul_netbsd_object; 167 #endif 168 169 #ifndef __HAVE_SYSCALL_INTERN 170 void syscall(void); 171 #endif 172 173 static const struct sa_emul saemul_netbsd = { 174 sizeof(ucontext_t), 175 sizeof(struct sa_t), 176 sizeof(struct sa_t *), 177 NULL, 178 NULL, 179 cpu_upcall, 180 (void (*)(struct lwp *, void *))getucontext_sa, 181 #ifdef KERN_SA 182 sa_ucsp 183 #else 184 NULL 185 #endif 186 }; 187 188 /* NetBSD emul struct */ 189 const struct emul emul_netbsd = { 190 "netbsd", 191 NULL, /* emulation path */ 192 #ifndef __HAVE_MINIMAL_EMUL 193 EMUL_HAS_SYS___syscall, 194 NULL, 195 SYS_syscall, 196 SYS_NSYSENT, 197 #endif 198 sysent, 199 #ifdef SYSCALL_DEBUG 200 syscallnames, 201 #else 202 NULL, 203 #endif 204 sendsig, 205 trapsignal, 206 NULL, 207 #ifdef COMPAT_16 208 sigcode, 209 esigcode, 210 &emul_netbsd_object, 211 #else 212 NULL, 213 NULL, 214 NULL, 215 #endif 216 setregs, 217 NULL, 218 NULL, 219 NULL, 220 NULL, 221 NULL, 222 #ifdef __HAVE_SYSCALL_INTERN 223 syscall_intern, 224 #else 225 syscall, 226 #endif 227 NULL, 228 NULL, 229 230 uvm_default_mapaddr, 231 NULL, 232 &saemul_netbsd, 233 sizeof(ucontext_t), 234 startlwp, 235 }; 236 237 #ifdef LKM 238 /* 239 * Exec lock. Used to control access to execsw[] structures. 240 * This must not be static so that netbsd32 can access it, too. 241 */ 242 krwlock_t exec_lock; 243 244 static void link_es(struct execsw_entry **, const struct execsw *); 245 #endif /* LKM */ 246 247 static kmutex_t sigobject_lock; 248 249 static void * 250 exec_pool_alloc(struct pool *pp, int flags) 251 { 252 253 return (void *)uvm_km_alloc(kernel_map, NCARGS, 0, 254 UVM_KMF_PAGEABLE | UVM_KMF_WAITVA); 255 } 256 257 static void 258 exec_pool_free(struct pool *pp, void *addr) 259 { 260 261 uvm_km_free(kernel_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE); 262 } 263 264 static struct pool exec_pool; 265 266 static struct pool_allocator exec_palloc = { 267 .pa_alloc = exec_pool_alloc, 268 .pa_free = exec_pool_free, 269 .pa_pagesz = NCARGS 270 }; 271 272 /* 273 * check exec: 274 * given an "executable" described in the exec package's namei info, 275 * see what we can do with it. 276 * 277 * ON ENTRY: 278 * exec package with appropriate namei info 279 * lwp pointer of exec'ing lwp 280 * NO SELF-LOCKED VNODES 281 * 282 * ON EXIT: 283 * error: nothing held, etc. exec header still allocated. 284 * ok: filled exec package, executable's vnode (unlocked). 285 * 286 * EXEC SWITCH ENTRY: 287 * Locked vnode to check, exec package, proc. 288 * 289 * EXEC SWITCH EXIT: 290 * ok: return 0, filled exec package, executable's vnode (unlocked). 291 * error: destructive: 292 * everything deallocated execept exec header. 293 * non-destructive: 294 * error code, executable's vnode (unlocked), 295 * exec header unmodified. 296 */ 297 int 298 /*ARGSUSED*/ 299 check_exec(struct lwp *l, struct exec_package *epp) 300 { 301 int error, i; 302 struct vnode *vp; 303 struct nameidata *ndp; 304 size_t resid; 305 306 ndp = epp->ep_ndp; 307 ndp->ni_cnd.cn_nameiop = LOOKUP; 308 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME | TRYEMULROOT; 309 /* first get the vnode */ 310 if ((error = namei(ndp)) != 0) 311 return error; 312 epp->ep_vp = vp = ndp->ni_vp; 313 314 /* check access and type */ 315 if (vp->v_type != VREG) { 316 error = EACCES; 317 goto bad1; 318 } 319 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 320 goto bad1; 321 322 /* get attributes */ 323 if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred)) != 0) 324 goto bad1; 325 326 /* Check mount point */ 327 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 328 error = EACCES; 329 goto bad1; 330 } 331 if (vp->v_mount->mnt_flag & MNT_NOSUID) 332 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 333 334 /* try to open it */ 335 if ((error = VOP_OPEN(vp, FREAD, l->l_cred)) != 0) 336 goto bad1; 337 338 /* unlock vp, since we need it unlocked from here on out. */ 339 VOP_UNLOCK(vp, 0); 340 341 #if NVERIEXEC > 0 342 error = veriexec_verify(l, vp, ndp->ni_cnd.cn_pnbuf, 343 epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT, 344 NULL); 345 if (error) 346 goto bad2; 347 #endif /* NVERIEXEC > 0 */ 348 349 #ifdef PAX_SEGVGUARD 350 error = pax_segvguard(l, vp, ndp->ni_cnd.cn_pnbuf, false); 351 if (error) 352 goto bad2; 353 #endif /* PAX_SEGVGUARD */ 354 355 /* now we have the file, get the exec header */ 356 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 357 UIO_SYSSPACE, 0, l->l_cred, &resid, NULL); 358 if (error) 359 goto bad2; 360 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 361 362 /* 363 * Set up default address space limits. Can be overridden 364 * by individual exec packages. 365 * 366 * XXX probably should be all done in the exec packages. 367 */ 368 epp->ep_vm_minaddr = VM_MIN_ADDRESS; 369 epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS; 370 /* 371 * set up the vmcmds for creation of the process 372 * address space 373 */ 374 error = ENOEXEC; 375 for (i = 0; i < nexecs; i++) { 376 int newerror; 377 378 epp->ep_esch = execsw[i]; 379 newerror = (*execsw[i]->es_makecmds)(l, epp); 380 381 if (!newerror) { 382 /* Seems ok: check that entry point is sane */ 383 if (epp->ep_entry > VM_MAXUSER_ADDRESS) { 384 error = ENOEXEC; 385 break; 386 } 387 388 /* check limits */ 389 if ((epp->ep_tsize > MAXTSIZ) || 390 (epp->ep_dsize > (u_quad_t)l->l_proc->p_rlimit 391 [RLIMIT_DATA].rlim_cur)) { 392 error = ENOMEM; 393 break; 394 } 395 return 0; 396 } 397 398 if (epp->ep_emul_root != NULL) { 399 vrele(epp->ep_emul_root); 400 epp->ep_emul_root = NULL; 401 } 402 if (epp->ep_interp != NULL) { 403 vrele(epp->ep_interp); 404 epp->ep_interp = NULL; 405 } 406 407 /* make sure the first "interesting" error code is saved. */ 408 if (error == ENOEXEC) 409 error = newerror; 410 411 if (epp->ep_flags & EXEC_DESTR) 412 /* Error from "#!" code, tidied up by recursive call */ 413 return error; 414 } 415 416 /* not found, error */ 417 418 /* 419 * free any vmspace-creation commands, 420 * and release their references 421 */ 422 kill_vmcmds(&epp->ep_vmcmds); 423 424 bad2: 425 /* 426 * close and release the vnode, restore the old one, free the 427 * pathname buf, and punt. 428 */ 429 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 430 VOP_CLOSE(vp, FREAD, l->l_cred); 431 vput(vp); 432 PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); 433 return error; 434 435 bad1: 436 /* 437 * free the namei pathname buffer, and put the vnode 438 * (which we don't yet have open). 439 */ 440 vput(vp); /* was still locked */ 441 PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); 442 return error; 443 } 444 445 #ifdef __MACHINE_STACK_GROWS_UP 446 #define STACK_PTHREADSPACE NBPG 447 #else 448 #define STACK_PTHREADSPACE 0 449 #endif 450 451 static int 452 execve_fetch_element(char * const *array, size_t index, char **value) 453 { 454 return copyin(array + index, value, sizeof(*value)); 455 } 456 457 /* 458 * exec system call 459 */ 460 /* ARGSUSED */ 461 int 462 sys_execve(struct lwp *l, const struct sys_execve_args *uap, register_t *retval) 463 { 464 /* { 465 syscallarg(const char *) path; 466 syscallarg(char * const *) argp; 467 syscallarg(char * const *) envp; 468 } */ 469 470 return execve1(l, SCARG(uap, path), SCARG(uap, argp), 471 SCARG(uap, envp), execve_fetch_element); 472 } 473 474 int 475 execve1(struct lwp *l, const char *path, char * const *args, 476 char * const *envs, execve_fetch_element_t fetch_element) 477 { 478 int error; 479 struct exec_package pack; 480 struct nameidata nid; 481 struct vattr attr; 482 struct proc *p; 483 char *argp; 484 char *dp, *sp; 485 long argc, envc; 486 size_t i, len; 487 char *stack; 488 struct ps_strings arginfo; 489 struct ps_strings *aip = &arginfo; 490 struct vmspace *vm; 491 struct exec_fakearg *tmpfap; 492 int szsigcode; 493 struct exec_vmcmd *base_vcp; 494 int oldlwpflags; 495 ksiginfo_t ksi; 496 ksiginfoq_t kq; 497 char *pathbuf; 498 size_t pathbuflen; 499 500 p = l->l_proc; 501 502 /* 503 * Check if we have exceeded our number of processes limit. 504 * This is so that we handle the case where a root daemon 505 * forked, ran setuid to become the desired user and is trying 506 * to exec. The obvious place to do the reference counting check 507 * is setuid(), but we don't do the reference counting check there 508 * like other OS's do because then all the programs that use setuid() 509 * must be modified to check the return code of setuid() and exit(). 510 * It is dangerous to make setuid() fail, because it fails open and 511 * the program will continue to run as root. If we make it succeed 512 * and return an error code, again we are not enforcing the limit. 513 * The best place to enforce the limit is here, when the process tries 514 * to execute a new image, because eventually the process will need 515 * to call exec in order to do something useful. 516 */ 517 518 if ((p->p_flag & PK_SUGID) && 519 chgproccnt(kauth_cred_getuid(l->l_cred), 0) > 520 p->p_rlimit[RLIMIT_NPROC].rlim_cur) 521 return EAGAIN; 522 523 oldlwpflags = l->l_flag & (LW_SA | LW_SA_UPCALL); 524 if (l->l_flag & LW_SA) { 525 lwp_lock(l); 526 l->l_flag &= ~(LW_SA | LW_SA_UPCALL); 527 lwp_unlock(l); 528 } 529 530 /* 531 * Drain existing references and forbid new ones. The process 532 * should be left alone until we're done here. This is necessary 533 * to avoid race conditions - e.g. in ptrace() - that might allow 534 * a local user to illicitly obtain elevated privileges. 535 */ 536 rw_enter(&p->p_reflock, RW_WRITER); 537 538 base_vcp = NULL; 539 /* 540 * Init the namei data to point the file user's program name. 541 * This is done here rather than in check_exec(), so that it's 542 * possible to override this settings if any of makecmd/probe 543 * functions call check_exec() recursively - for example, 544 * see exec_script_makecmds(). 545 */ 546 pathbuf = PNBUF_GET(); 547 error = copyinstr(path, pathbuf, MAXPATHLEN, &pathbuflen); 548 if (error) { 549 DPRINTF(("execve: copyinstr path %d", error)); 550 goto clrflg; 551 } 552 553 NDINIT(&nid, LOOKUP, NOFOLLOW | TRYEMULROOT, UIO_SYSSPACE, pathbuf); 554 555 /* 556 * initialize the fields of the exec package. 557 */ 558 pack.ep_name = path; 559 pack.ep_hdr = kmem_alloc(exec_maxhdrsz, KM_SLEEP); 560 pack.ep_hdrlen = exec_maxhdrsz; 561 pack.ep_hdrvalid = 0; 562 pack.ep_ndp = &nid; 563 pack.ep_emul_arg = NULL; 564 pack.ep_vmcmds.evs_cnt = 0; 565 pack.ep_vmcmds.evs_used = 0; 566 pack.ep_vap = &attr; 567 pack.ep_flags = 0; 568 pack.ep_emul_root = NULL; 569 pack.ep_interp = NULL; 570 pack.ep_esch = NULL; 571 pack.ep_pax_flags = 0; 572 573 #ifdef LKM 574 rw_enter(&exec_lock, RW_READER); 575 #endif 576 577 /* see if we can run it. */ 578 if ((error = check_exec(l, &pack)) != 0) { 579 if (error != ENOENT) { 580 DPRINTF(("execve: check exec failed %d\n", error)); 581 } 582 goto freehdr; 583 } 584 585 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 586 587 /* allocate an argument buffer */ 588 argp = pool_get(&exec_pool, PR_WAITOK); 589 KASSERT(argp != NULL); 590 dp = argp; 591 argc = 0; 592 593 /* copy the fake args list, if there's one, freeing it as we go */ 594 if (pack.ep_flags & EXEC_HASARGL) { 595 tmpfap = pack.ep_fa; 596 while (tmpfap->fa_arg != NULL) { 597 const char *cp; 598 599 cp = tmpfap->fa_arg; 600 while (*cp) 601 *dp++ = *cp++; 602 *dp++ = '\0'; 603 604 kmem_free(tmpfap->fa_arg, tmpfap->fa_len); 605 tmpfap++; argc++; 606 } 607 kmem_free(pack.ep_fa, pack.ep_fa_len); 608 pack.ep_flags &= ~EXEC_HASARGL; 609 } 610 611 /* Now get argv & environment */ 612 if (args == NULL) { 613 DPRINTF(("execve: null args\n")); 614 error = EINVAL; 615 goto bad; 616 } 617 /* 'i' will index the argp/envp element to be retrieved */ 618 i = 0; 619 if (pack.ep_flags & EXEC_SKIPARG) 620 i++; 621 622 while (1) { 623 len = argp + ARG_MAX - dp; 624 if ((error = (*fetch_element)(args, i, &sp)) != 0) { 625 DPRINTF(("execve: fetch_element args %d\n", error)); 626 goto bad; 627 } 628 if (!sp) 629 break; 630 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 631 DPRINTF(("execve: copyinstr args %d\n", error)); 632 if (error == ENAMETOOLONG) 633 error = E2BIG; 634 goto bad; 635 } 636 ktrexecarg(dp, len - 1); 637 dp += len; 638 i++; 639 argc++; 640 } 641 642 envc = 0; 643 /* environment need not be there */ 644 if (envs != NULL) { 645 i = 0; 646 while (1) { 647 len = argp + ARG_MAX - dp; 648 if ((error = (*fetch_element)(envs, i, &sp)) != 0) { 649 DPRINTF(("execve: fetch_element env %d\n", error)); 650 goto bad; 651 } 652 if (!sp) 653 break; 654 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 655 DPRINTF(("execve: copyinstr env %d\n", error)); 656 if (error == ENAMETOOLONG) 657 error = E2BIG; 658 goto bad; 659 } 660 ktrexecenv(dp, len - 1); 661 dp += len; 662 i++; 663 envc++; 664 } 665 } 666 667 dp = (char *) ALIGN(dp); 668 669 szsigcode = pack.ep_esch->es_emul->e_esigcode - 670 pack.ep_esch->es_emul->e_sigcode; 671 672 #ifdef __MACHINE_STACK_GROWS_UP 673 /* See big comment lower down */ 674 #define RTLD_GAP 32 675 #else 676 #define RTLD_GAP 0 677 #endif 678 679 /* Now check if args & environ fit into new stack */ 680 if (pack.ep_flags & EXEC_32) 681 len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * 682 sizeof(int) + sizeof(int) + dp + RTLD_GAP + 683 szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) 684 - argp; 685 else 686 len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * 687 sizeof(char *) + sizeof(int) + dp + RTLD_GAP + 688 szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) 689 - argp; 690 691 #ifdef PAX_ASLR 692 if (pax_aslr_active(l)) 693 len += (arc4random() % PAGE_SIZE); 694 #endif /* PAX_ASLR */ 695 696 #ifdef STACKLALIGN /* arm, etc. */ 697 len = STACKALIGN(len); /* make the stack "safely" aligned */ 698 #else 699 len = ALIGN(len); /* make the stack "safely" aligned */ 700 #endif 701 702 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 703 DPRINTF(("execve: stack limit exceeded %zu\n", len)); 704 error = ENOMEM; 705 goto bad; 706 } 707 708 /* Get rid of other LWPs. */ 709 if (p->p_sa || p->p_nlwps > 1) { 710 mutex_enter(p->p_lock); 711 exit_lwps(l); 712 mutex_exit(p->p_lock); 713 } 714 KDASSERT(p->p_nlwps == 1); 715 716 /* Destroy any lwpctl info. */ 717 if (p->p_lwpctl != NULL) 718 lwp_ctl_exit(); 719 720 /* This is now LWP 1 */ 721 l->l_lid = 1; 722 p->p_nlwpid = 1; 723 724 #ifdef KERN_SA 725 /* Release any SA state. */ 726 if (p->p_sa) 727 sa_release(p); 728 #endif /* KERN_SA */ 729 730 /* Remove POSIX timers */ 731 timers_free(p, TIMERS_POSIX); 732 733 /* adjust "active stack depth" for process VSZ */ 734 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 735 736 /* 737 * Do whatever is necessary to prepare the address space 738 * for remapping. Note that this might replace the current 739 * vmspace with another! 740 */ 741 uvmspace_exec(l, pack.ep_vm_minaddr, pack.ep_vm_maxaddr); 742 743 /* record proc's vnode, for use by procfs and others */ 744 if (p->p_textvp) 745 vrele(p->p_textvp); 746 VREF(pack.ep_vp); 747 p->p_textvp = pack.ep_vp; 748 749 /* Now map address space */ 750 vm = p->p_vmspace; 751 vm->vm_taddr = (void *)pack.ep_taddr; 752 vm->vm_tsize = btoc(pack.ep_tsize); 753 vm->vm_daddr = (void*)pack.ep_daddr; 754 vm->vm_dsize = btoc(pack.ep_dsize); 755 vm->vm_ssize = btoc(pack.ep_ssize); 756 vm->vm_maxsaddr = (void *)pack.ep_maxsaddr; 757 vm->vm_minsaddr = (void *)pack.ep_minsaddr; 758 759 #ifdef PAX_ASLR 760 pax_aslr_init(l, vm); 761 #endif /* PAX_ASLR */ 762 763 /* create the new process's VM space by running the vmcmds */ 764 #ifdef DIAGNOSTIC 765 if (pack.ep_vmcmds.evs_used == 0) 766 panic("execve: no vmcmds"); 767 #endif 768 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 769 struct exec_vmcmd *vcp; 770 771 vcp = &pack.ep_vmcmds.evs_cmds[i]; 772 if (vcp->ev_flags & VMCMD_RELATIVE) { 773 #ifdef DIAGNOSTIC 774 if (base_vcp == NULL) 775 panic("execve: relative vmcmd with no base"); 776 if (vcp->ev_flags & VMCMD_BASE) 777 panic("execve: illegal base & relative vmcmd"); 778 #endif 779 vcp->ev_addr += base_vcp->ev_addr; 780 } 781 error = (*vcp->ev_proc)(l, vcp); 782 #ifdef DEBUG_EXEC 783 if (error) { 784 size_t j; 785 struct exec_vmcmd *vp = &pack.ep_vmcmds.evs_cmds[0]; 786 for (j = 0; j <= i; j++) 787 uprintf( 788 "vmcmd[%zu] = %#lx/%#lx fd@%#lx prot=0%o flags=%d\n", 789 j, vp[j].ev_addr, vp[j].ev_len, 790 vp[j].ev_offset, vp[j].ev_prot, 791 vp[j].ev_flags); 792 } 793 #endif /* DEBUG_EXEC */ 794 if (vcp->ev_flags & VMCMD_BASE) 795 base_vcp = vcp; 796 } 797 798 /* free the vmspace-creation commands, and release their references */ 799 kill_vmcmds(&pack.ep_vmcmds); 800 801 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 802 VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred); 803 vput(pack.ep_vp); 804 805 /* if an error happened, deallocate and punt */ 806 if (error) { 807 DPRINTF(("execve: vmcmd %zu failed: %d\n", i - 1, error)); 808 goto exec_abort; 809 } 810 811 /* remember information about the process */ 812 arginfo.ps_nargvstr = argc; 813 arginfo.ps_nenvstr = envc; 814 815 /* set command name & other accounting info */ 816 i = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 817 (void)memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, i); 818 p->p_comm[i] = '\0'; 819 820 dp = PNBUF_GET(); 821 /* 822 * If the path starts with /, we don't need to do any work. 823 * This handles the majority of the cases. 824 * In the future perhaps we could canonicalize it? 825 */ 826 if (pathbuf[0] == '/') 827 (void)strlcpy(pack.ep_path = dp, pathbuf, MAXPATHLEN); 828 #ifdef notyet 829 /* 830 * Although this works most of the time [since the entry was just 831 * entered in the cache] we don't use it because it theoretically 832 * can fail and it is not the cleanest interface, because there 833 * could be races. When the namei cache is re-written, this can 834 * be changed to use the appropriate function. 835 */ 836 else if (!(error = vnode_to_path(dp, MAXPATHLEN, p->p_textvp, l, p))) 837 pack.ep_path = dp; 838 #endif 839 else { 840 #ifdef notyet 841 printf("Cannot get path for pid %d [%s] (error %d)", 842 (int)p->p_pid, p->p_comm, error); 843 #endif 844 pack.ep_path = NULL; 845 PNBUF_PUT(dp); 846 } 847 848 stack = (char *)STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, 849 STACK_PTHREADSPACE + sizeof(struct ps_strings) + szsigcode), 850 len - (sizeof(struct ps_strings) + szsigcode)); 851 852 #ifdef __MACHINE_STACK_GROWS_UP 853 /* 854 * The copyargs call always copies into lower addresses 855 * first, moving towards higher addresses, starting with 856 * the stack pointer that we give. When the stack grows 857 * down, this puts argc/argv/envp very shallow on the 858 * stack, right at the first user stack pointer. 859 * When the stack grows up, the situation is reversed. 860 * 861 * Normally, this is no big deal. But the ld_elf.so _rtld() 862 * function expects to be called with a single pointer to 863 * a region that has a few words it can stash values into, 864 * followed by argc/argv/envp. When the stack grows down, 865 * it's easy to decrement the stack pointer a little bit to 866 * allocate the space for these few words and pass the new 867 * stack pointer to _rtld. When the stack grows up, however, 868 * a few words before argc is part of the signal trampoline, XXX 869 * so we have a problem. 870 * 871 * Instead of changing how _rtld works, we take the easy way 872 * out and steal 32 bytes before we call copyargs. 873 * This extra space was allowed for when 'len' was calculated. 874 */ 875 stack += RTLD_GAP; 876 #endif /* __MACHINE_STACK_GROWS_UP */ 877 878 /* Now copy argc, args & environ to new stack */ 879 error = (*pack.ep_esch->es_copyargs)(l, &pack, &arginfo, &stack, argp); 880 if (pack.ep_path) { 881 PNBUF_PUT(pack.ep_path); 882 pack.ep_path = NULL; 883 } 884 if (error) { 885 DPRINTF(("execve: copyargs failed %d\n", error)); 886 goto exec_abort; 887 } 888 /* Move the stack back to original point */ 889 stack = (char *)STACK_GROW(vm->vm_minsaddr, len); 890 891 /* fill process ps_strings info */ 892 p->p_psstr = (struct ps_strings *) 893 STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, STACK_PTHREADSPACE), 894 sizeof(struct ps_strings)); 895 p->p_psargv = offsetof(struct ps_strings, ps_argvstr); 896 p->p_psnargv = offsetof(struct ps_strings, ps_nargvstr); 897 p->p_psenv = offsetof(struct ps_strings, ps_envstr); 898 p->p_psnenv = offsetof(struct ps_strings, ps_nenvstr); 899 900 /* copy out the process's ps_strings structure */ 901 if ((error = copyout(aip, (char *)p->p_psstr, 902 sizeof(arginfo))) != 0) { 903 DPRINTF(("execve: ps_strings copyout %p->%p size %ld failed\n", 904 aip, (char *)p->p_psstr, (long)sizeof(arginfo))); 905 goto exec_abort; 906 } 907 908 fd_closeexec(); /* handle close on exec */ 909 execsigs(p); /* reset catched signals */ 910 911 l->l_ctxlink = NULL; /* reset ucontext link */ 912 913 914 p->p_acflag &= ~AFORK; 915 mutex_enter(p->p_lock); 916 p->p_flag |= PK_EXEC; 917 mutex_exit(p->p_lock); 918 919 /* 920 * Stop profiling. 921 */ 922 if ((p->p_stflag & PST_PROFIL) != 0) { 923 mutex_spin_enter(&p->p_stmutex); 924 stopprofclock(p); 925 mutex_spin_exit(&p->p_stmutex); 926 } 927 928 /* 929 * It's OK to test PL_PPWAIT unlocked here, as other LWPs have 930 * exited and exec()/exit() are the only places it will be cleared. 931 */ 932 if ((p->p_lflag & PL_PPWAIT) != 0) { 933 mutex_enter(proc_lock); 934 p->p_lflag &= ~PL_PPWAIT; 935 cv_broadcast(&p->p_pptr->p_waitcv); 936 mutex_exit(proc_lock); 937 } 938 939 /* 940 * Deal with set[ug]id. MNT_NOSUID has already been used to disable 941 * s[ug]id. It's OK to check for PSL_TRACED here as we have blocked 942 * out additional references on the process for the moment. 943 */ 944 if ((p->p_slflag & PSL_TRACED) == 0 && 945 946 (((attr.va_mode & S_ISUID) != 0 && 947 kauth_cred_geteuid(l->l_cred) != attr.va_uid) || 948 949 ((attr.va_mode & S_ISGID) != 0 && 950 kauth_cred_getegid(l->l_cred) != attr.va_gid))) { 951 /* 952 * Mark the process as SUGID before we do 953 * anything that might block. 954 */ 955 proc_crmod_enter(); 956 proc_crmod_leave(NULL, NULL, true); 957 958 /* Make sure file descriptors 0..2 are in use. */ 959 if ((error = fd_checkstd()) != 0) { 960 DPRINTF(("execve: fdcheckstd failed %d\n", error)); 961 goto exec_abort; 962 } 963 964 /* 965 * Copy the credential so other references don't see our 966 * changes. 967 */ 968 l->l_cred = kauth_cred_copy(l->l_cred); 969 #ifdef KTRACE 970 /* 971 * If the persistent trace flag isn't set, turn off. 972 */ 973 if (p->p_tracep) { 974 mutex_enter(&ktrace_lock); 975 if (!(p->p_traceflag & KTRFAC_PERSISTENT)) 976 ktrderef(p); 977 mutex_exit(&ktrace_lock); 978 } 979 #endif 980 if (attr.va_mode & S_ISUID) 981 kauth_cred_seteuid(l->l_cred, attr.va_uid); 982 if (attr.va_mode & S_ISGID) 983 kauth_cred_setegid(l->l_cred, attr.va_gid); 984 } else { 985 if (kauth_cred_geteuid(l->l_cred) == 986 kauth_cred_getuid(l->l_cred) && 987 kauth_cred_getegid(l->l_cred) == 988 kauth_cred_getgid(l->l_cred)) 989 p->p_flag &= ~PK_SUGID; 990 } 991 992 /* 993 * Copy the credential so other references don't see our changes. 994 * Test to see if this is necessary first, since in the common case 995 * we won't need a private reference. 996 */ 997 if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) || 998 kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) { 999 l->l_cred = kauth_cred_copy(l->l_cred); 1000 kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred)); 1001 kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred)); 1002 } 1003 1004 /* Update the master credentials. */ 1005 if (l->l_cred != p->p_cred) { 1006 kauth_cred_t ocred; 1007 1008 kauth_cred_hold(l->l_cred); 1009 mutex_enter(p->p_lock); 1010 ocred = p->p_cred; 1011 p->p_cred = l->l_cred; 1012 mutex_exit(p->p_lock); 1013 kauth_cred_free(ocred); 1014 } 1015 1016 #if defined(__HAVE_RAS) 1017 /* 1018 * Remove all RASs from the address space. 1019 */ 1020 ras_purgeall(); 1021 #endif 1022 1023 doexechooks(p); 1024 1025 /* setup new registers and do misc. setup. */ 1026 (*pack.ep_esch->es_emul->e_setregs)(l, &pack, (u_long) stack); 1027 if (pack.ep_esch->es_setregs) 1028 (*pack.ep_esch->es_setregs)(l, &pack, (u_long) stack); 1029 1030 /* map the process's signal trampoline code */ 1031 if (exec_sigcode_map(p, pack.ep_esch->es_emul)) { 1032 DPRINTF(("execve: map sigcode failed %d\n", error)); 1033 goto exec_abort; 1034 } 1035 1036 pool_put(&exec_pool, argp); 1037 1038 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1039 1040 /* notify others that we exec'd */ 1041 KNOTE(&p->p_klist, NOTE_EXEC); 1042 1043 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1044 1045 /* The emulation root will usually have been found when we looked 1046 * for the elf interpreter (or similar), if not look now. */ 1047 if (pack.ep_esch->es_emul->e_path != NULL && pack.ep_emul_root == NULL) 1048 emul_find_root(l, &pack); 1049 1050 /* Any old emulation root got removed by fdcloseexec */ 1051 rw_enter(&p->p_cwdi->cwdi_lock, RW_WRITER); 1052 p->p_cwdi->cwdi_edir = pack.ep_emul_root; 1053 rw_exit(&p->p_cwdi->cwdi_lock); 1054 pack.ep_emul_root = NULL; 1055 if (pack.ep_interp != NULL) 1056 vrele(pack.ep_interp); 1057 1058 /* 1059 * Call emulation specific exec hook. This can setup per-process 1060 * p->p_emuldata or do any other per-process stuff an emulation needs. 1061 * 1062 * If we are executing process of different emulation than the 1063 * original forked process, call e_proc_exit() of the old emulation 1064 * first, then e_proc_exec() of new emulation. If the emulation is 1065 * same, the exec hook code should deallocate any old emulation 1066 * resources held previously by this process. 1067 */ 1068 if (p->p_emul && p->p_emul->e_proc_exit 1069 && p->p_emul != pack.ep_esch->es_emul) 1070 (*p->p_emul->e_proc_exit)(p); 1071 1072 /* 1073 * Call exec hook. Emulation code may NOT store reference to anything 1074 * from &pack. 1075 */ 1076 if (pack.ep_esch->es_emul->e_proc_exec) 1077 (*pack.ep_esch->es_emul->e_proc_exec)(p, &pack); 1078 1079 /* update p_emul, the old value is no longer needed */ 1080 p->p_emul = pack.ep_esch->es_emul; 1081 1082 /* ...and the same for p_execsw */ 1083 p->p_execsw = pack.ep_esch; 1084 1085 #ifdef __HAVE_SYSCALL_INTERN 1086 (*p->p_emul->e_syscall_intern)(p); 1087 #endif 1088 ktremul(); 1089 1090 /* Allow new references from the debugger/procfs. */ 1091 rw_exit(&p->p_reflock); 1092 #ifdef LKM 1093 rw_exit(&exec_lock); 1094 #endif 1095 1096 mutex_enter(proc_lock); 1097 1098 if ((p->p_slflag & (PSL_TRACED|PSL_SYSCALL)) == PSL_TRACED) { 1099 KSI_INIT_EMPTY(&ksi); 1100 ksi.ksi_signo = SIGTRAP; 1101 ksi.ksi_lid = l->l_lid; 1102 kpsignal(p, &ksi, NULL); 1103 } 1104 1105 if (p->p_sflag & PS_STOPEXEC) { 1106 KERNEL_UNLOCK_ALL(l, &l->l_biglocks); 1107 p->p_pptr->p_nstopchild++; 1108 p->p_pptr->p_waited = 0; 1109 mutex_enter(p->p_lock); 1110 ksiginfo_queue_init(&kq); 1111 sigclearall(p, &contsigmask, &kq); 1112 lwp_lock(l); 1113 l->l_stat = LSSTOP; 1114 p->p_stat = SSTOP; 1115 p->p_nrlwps--; 1116 mutex_exit(p->p_lock); 1117 mutex_exit(proc_lock); 1118 mi_switch(l); 1119 ksiginfo_queue_drain(&kq); 1120 KERNEL_LOCK(l->l_biglocks, l); 1121 } else { 1122 mutex_exit(proc_lock); 1123 } 1124 1125 PNBUF_PUT(pathbuf); 1126 return (EJUSTRETURN); 1127 1128 bad: 1129 /* free the vmspace-creation commands, and release their references */ 1130 kill_vmcmds(&pack.ep_vmcmds); 1131 /* kill any opened file descriptor, if necessary */ 1132 if (pack.ep_flags & EXEC_HASFD) { 1133 pack.ep_flags &= ~EXEC_HASFD; 1134 fd_close(pack.ep_fd); 1135 } 1136 /* close and put the exec'd file */ 1137 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 1138 VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred); 1139 vput(pack.ep_vp); 1140 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1141 pool_put(&exec_pool, argp); 1142 1143 freehdr: 1144 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1145 if (pack.ep_emul_root != NULL) 1146 vrele(pack.ep_emul_root); 1147 if (pack.ep_interp != NULL) 1148 vrele(pack.ep_interp); 1149 1150 #ifdef LKM 1151 rw_exit(&exec_lock); 1152 #endif 1153 1154 clrflg: 1155 lwp_lock(l); 1156 l->l_flag |= oldlwpflags; 1157 lwp_unlock(l); 1158 PNBUF_PUT(pathbuf); 1159 rw_exit(&p->p_reflock); 1160 1161 return error; 1162 1163 exec_abort: 1164 PNBUF_PUT(pathbuf); 1165 rw_exit(&p->p_reflock); 1166 #ifdef LKM 1167 rw_exit(&exec_lock); 1168 #endif 1169 1170 /* 1171 * the old process doesn't exist anymore. exit gracefully. 1172 * get rid of the (new) address space we have created, if any, get rid 1173 * of our namei data and vnode, and exit noting failure 1174 */ 1175 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 1176 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 1177 if (pack.ep_emul_arg) 1178 FREE(pack.ep_emul_arg, M_TEMP); 1179 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1180 pool_put(&exec_pool, argp); 1181 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1182 if (pack.ep_emul_root != NULL) 1183 vrele(pack.ep_emul_root); 1184 if (pack.ep_interp != NULL) 1185 vrele(pack.ep_interp); 1186 1187 /* Acquire the sched-state mutex (exit1() will release it). */ 1188 mutex_enter(p->p_lock); 1189 exit1(l, W_EXITCODE(error, SIGABRT)); 1190 1191 /* NOTREACHED */ 1192 return 0; 1193 } 1194 1195 1196 int 1197 copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo, 1198 char **stackp, void *argp) 1199 { 1200 char **cpp, *dp, *sp; 1201 size_t len; 1202 void *nullp; 1203 long argc, envc; 1204 int error; 1205 1206 cpp = (char **)*stackp; 1207 nullp = NULL; 1208 argc = arginfo->ps_nargvstr; 1209 envc = arginfo->ps_nenvstr; 1210 if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) 1211 return error; 1212 1213 dp = (char *) (cpp + argc + envc + 2 + pack->ep_esch->es_arglen); 1214 sp = argp; 1215 1216 /* XXX don't copy them out, remap them! */ 1217 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 1218 1219 for (; --argc >= 0; sp += len, dp += len) 1220 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || 1221 (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) 1222 return error; 1223 1224 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) 1225 return error; 1226 1227 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 1228 1229 for (; --envc >= 0; sp += len, dp += len) 1230 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || 1231 (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) 1232 return error; 1233 1234 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) 1235 return error; 1236 1237 *stackp = (char *)cpp; 1238 return 0; 1239 } 1240 1241 #ifdef LKM 1242 /* 1243 * Find an emulation of given name in list of emulations. 1244 * Needs to be called with the exec_lock held. 1245 */ 1246 const struct emul * 1247 emul_search(const char *name) 1248 { 1249 struct emul_entry *it; 1250 1251 LIST_FOREACH(it, &el_head, el_list) { 1252 if (strcmp(name, it->el_emul->e_name) == 0) 1253 return it->el_emul; 1254 } 1255 1256 return NULL; 1257 } 1258 1259 /* 1260 * Add an emulation to list, if it's not there already. 1261 */ 1262 int 1263 emul_register(const struct emul *emul, int ro_entry) 1264 { 1265 struct emul_entry *ee; 1266 int error; 1267 1268 error = 0; 1269 rw_enter(&exec_lock, RW_WRITER); 1270 1271 if (emul_search(emul->e_name)) { 1272 error = EEXIST; 1273 goto out; 1274 } 1275 1276 ee = kmem_alloc(sizeof(*ee), KM_SLEEP); 1277 ee->el_emul = emul; 1278 ee->ro_entry = ro_entry; 1279 LIST_INSERT_HEAD(&el_head, ee, el_list); 1280 1281 out: 1282 rw_exit(&exec_lock); 1283 return error; 1284 } 1285 1286 /* 1287 * Remove emulation with name 'name' from list of supported emulations. 1288 */ 1289 int 1290 emul_unregister(const char *name) 1291 { 1292 const struct proclist_desc *pd; 1293 struct emul_entry *it; 1294 int i, error; 1295 struct proc *ptmp; 1296 1297 error = 0; 1298 rw_enter(&exec_lock, RW_WRITER); 1299 1300 LIST_FOREACH(it, &el_head, el_list) { 1301 if (strcmp(it->el_emul->e_name, name) == 0) 1302 break; 1303 } 1304 1305 if (!it) { 1306 error = ENOENT; 1307 goto out; 1308 } 1309 1310 if (it->ro_entry) { 1311 error = EBUSY; 1312 goto out; 1313 } 1314 1315 /* test if any execw[] entry is still using this */ 1316 for(i=0; i < nexecs; i++) { 1317 if (execsw[i]->es_emul == it->el_emul) { 1318 error = EBUSY; 1319 goto out; 1320 } 1321 } 1322 1323 /* 1324 * Test if any process is running under this emulation - since 1325 * emul_unregister() is running quite sendomly, it's better 1326 * to do expensive check here than to use any locking. 1327 */ 1328 mutex_enter(proc_lock); 1329 for (pd = proclists; pd->pd_list != NULL && !error; pd++) { 1330 PROCLIST_FOREACH(ptmp, pd->pd_list) { 1331 if (ptmp->p_emul == it->el_emul) { 1332 error = EBUSY; 1333 break; 1334 } 1335 } 1336 } 1337 mutex_exit(proc_lock); 1338 1339 if (error) 1340 goto out; 1341 1342 1343 /* entry is not used, remove it */ 1344 LIST_REMOVE(it, el_list); 1345 kmem_free(it, sizeof(*it)); 1346 1347 out: 1348 rw_exit(&exec_lock); 1349 return error; 1350 } 1351 1352 /* 1353 * Add execsw[] entry. 1354 */ 1355 int 1356 exec_add(struct execsw *esp, const char *e_name) 1357 { 1358 struct exec_entry *it; 1359 int error; 1360 1361 error = 0; 1362 rw_enter(&exec_lock, RW_WRITER); 1363 1364 if (!esp->es_emul) { 1365 esp->es_emul = emul_search(e_name); 1366 if (!esp->es_emul) { 1367 error = ENOENT; 1368 goto out; 1369 } 1370 } 1371 1372 LIST_FOREACH(it, &ex_head, ex_list) { 1373 /* assume tuple (makecmds, probe_func, emulation) is unique */ 1374 if (it->es->es_makecmds == esp->es_makecmds 1375 && it->es->u.elf_probe_func == esp->u.elf_probe_func 1376 && it->es->es_emul == esp->es_emul) { 1377 error = EEXIST; 1378 goto out; 1379 } 1380 } 1381 1382 /* if we got here, the entry doesn't exist yet */ 1383 it = kmem_alloc(sizeof(*it), KM_SLEEP); 1384 it->es = esp; 1385 LIST_INSERT_HEAD(&ex_head, it, ex_list); 1386 1387 /* update execsw[] */ 1388 exec_init(0); 1389 1390 out: 1391 rw_exit(&exec_lock); 1392 return error; 1393 } 1394 1395 /* 1396 * Remove execsw[] entry. 1397 */ 1398 int 1399 exec_remove(const struct execsw *esp) 1400 { 1401 struct exec_entry *it; 1402 int error; 1403 1404 error = 0; 1405 rw_enter(&exec_lock, RW_WRITER); 1406 1407 LIST_FOREACH(it, &ex_head, ex_list) { 1408 /* assume tuple (makecmds, probe_func, emulation) is unique */ 1409 if (it->es->es_makecmds == esp->es_makecmds 1410 && it->es->u.elf_probe_func == esp->u.elf_probe_func 1411 && it->es->es_emul == esp->es_emul) 1412 break; 1413 } 1414 if (!it) { 1415 error = ENOENT; 1416 goto out; 1417 } 1418 1419 /* remove item from list and free resources */ 1420 LIST_REMOVE(it, ex_list); 1421 kmem_free(it, sizeof(*it)); 1422 1423 /* update execsw[] */ 1424 exec_init(0); 1425 1426 out: 1427 rw_exit(&exec_lock); 1428 return error; 1429 } 1430 1431 static void 1432 link_es(struct execsw_entry **listp, const struct execsw *esp) 1433 { 1434 struct execsw_entry *et, *e1; 1435 1436 et = (struct execsw_entry *) malloc(sizeof(struct execsw_entry), 1437 M_TEMP, M_WAITOK); 1438 et->next = NULL; 1439 et->es = esp; 1440 if (*listp == NULL) { 1441 *listp = et; 1442 return; 1443 } 1444 1445 switch(et->es->es_prio) { 1446 case EXECSW_PRIO_FIRST: 1447 /* put new entry as the first */ 1448 et->next = *listp; 1449 *listp = et; 1450 break; 1451 case EXECSW_PRIO_ANY: 1452 /* put new entry after all *_FIRST and *_ANY entries */ 1453 for(e1 = *listp; e1->next 1454 && e1->next->es->es_prio != EXECSW_PRIO_LAST; 1455 e1 = e1->next); 1456 et->next = e1->next; 1457 e1->next = et; 1458 break; 1459 case EXECSW_PRIO_LAST: 1460 /* put new entry as the last one */ 1461 for(e1 = *listp; e1->next; e1 = e1->next); 1462 e1->next = et; 1463 break; 1464 default: 1465 #ifdef DIAGNOSTIC 1466 panic("execw[] entry with unknown priority %d found", 1467 et->es->es_prio); 1468 #else 1469 free(et, M_TEMP); 1470 #endif 1471 break; 1472 } 1473 } 1474 1475 /* 1476 * Initialize exec structures. If init_boot is true, also does necessary 1477 * one-time initialization (it's called from main() that way). 1478 * Once system is multiuser, this should be called with exec_lock held, 1479 * i.e. via exec_{add|remove}(). 1480 */ 1481 int 1482 exec_init(int init_boot) 1483 { 1484 const struct execsw **new_es, * const *old_es; 1485 struct execsw_entry *list, *e1; 1486 struct exec_entry *e2; 1487 int i, es_sz; 1488 1489 if (init_boot) { 1490 /* do one-time initializations */ 1491 rw_init(&exec_lock); 1492 mutex_init(&sigobject_lock, MUTEX_DEFAULT, IPL_NONE); 1493 pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, 1494 "execargs", &exec_palloc, IPL_NONE); 1495 pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); 1496 1497 /* register compiled-in emulations */ 1498 for(i=0; i < nexecs_builtin; i++) { 1499 if (execsw_builtin[i].es_emul) 1500 emul_register(execsw_builtin[i].es_emul, 1); 1501 } 1502 #ifdef DIAGNOSTIC 1503 if (i == 0) 1504 panic("no emulations found in execsw_builtin[]"); 1505 #endif 1506 } 1507 1508 /* 1509 * Build execsw[] array from builtin entries and entries added 1510 * at runtime. 1511 */ 1512 list = NULL; 1513 for(i=0; i < nexecs_builtin; i++) 1514 link_es(&list, &execsw_builtin[i]); 1515 1516 /* Add dynamically loaded entries */ 1517 es_sz = nexecs_builtin; 1518 LIST_FOREACH(e2, &ex_head, ex_list) { 1519 link_es(&list, e2->es); 1520 es_sz++; 1521 } 1522 1523 /* 1524 * Now that we have sorted all execw entries, create new execsw[] 1525 * and free no longer needed memory in the process. 1526 */ 1527 new_es = kmem_alloc(es_sz * sizeof(struct execsw *), KM_SLEEP); 1528 for(i=0; list; i++) { 1529 new_es[i] = list->es; 1530 e1 = list->next; 1531 free(list, M_TEMP); 1532 list = e1; 1533 } 1534 1535 /* 1536 * New execsw[] array built, now replace old execsw[] and free 1537 * used memory. 1538 */ 1539 old_es = execsw; 1540 if (old_es) 1541 /*XXXUNCONST*/ 1542 kmem_free(__UNCONST(old_es), nexecs * sizeof(struct execsw *)); 1543 execsw = new_es; 1544 nexecs = es_sz; 1545 1546 /* 1547 * Figure out the maximum size of an exec header. 1548 */ 1549 exec_maxhdrsz = 0; 1550 for (i = 0; i < nexecs; i++) { 1551 if (execsw[i]->es_hdrsz > exec_maxhdrsz) 1552 exec_maxhdrsz = execsw[i]->es_hdrsz; 1553 } 1554 1555 return 0; 1556 } 1557 #endif 1558 1559 #ifndef LKM 1560 /* 1561 * Simplified exec_init() for kernels without LKMs. Only initialize 1562 * exec_maxhdrsz and execsw[]. 1563 */ 1564 int 1565 exec_init(int init_boot) 1566 { 1567 int i; 1568 1569 #ifdef DIAGNOSTIC 1570 if (!init_boot) 1571 panic("exec_init(): called with init_boot == 0"); 1572 #endif 1573 1574 /* do one-time initializations */ 1575 nexecs = nexecs_builtin; 1576 execsw = kmem_alloc(nexecs * sizeof(struct execsw *), KM_SLEEP); 1577 1578 pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, 1579 "execargs", &exec_palloc, IPL_NONE); 1580 pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); 1581 1582 /* 1583 * Fill in execsw[] and figure out the maximum size of an exec header. 1584 */ 1585 exec_maxhdrsz = 0; 1586 for(i=0; i < nexecs; i++) { 1587 execsw[i] = &execsw_builtin[i]; 1588 if (execsw_builtin[i].es_hdrsz > exec_maxhdrsz) 1589 exec_maxhdrsz = execsw_builtin[i].es_hdrsz; 1590 } 1591 1592 return 0; 1593 1594 } 1595 #endif /* !LKM */ 1596 1597 static int 1598 exec_sigcode_map(struct proc *p, const struct emul *e) 1599 { 1600 vaddr_t va; 1601 vsize_t sz; 1602 int error; 1603 struct uvm_object *uobj; 1604 1605 sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; 1606 1607 if (e->e_sigobject == NULL || sz == 0) { 1608 return 0; 1609 } 1610 1611 /* 1612 * If we don't have a sigobject for this emulation, create one. 1613 * 1614 * sigobject is an anonymous memory object (just like SYSV shared 1615 * memory) that we keep a permanent reference to and that we map 1616 * in all processes that need this sigcode. The creation is simple, 1617 * we create an object, add a permanent reference to it, map it in 1618 * kernel space, copy out the sigcode to it and unmap it. 1619 * We map it with PROT_READ|PROT_EXEC into the process just 1620 * the way sys_mmap() would map it. 1621 */ 1622 1623 uobj = *e->e_sigobject; 1624 if (uobj == NULL) { 1625 mutex_enter(&sigobject_lock); 1626 if ((uobj = *e->e_sigobject) == NULL) { 1627 uobj = uao_create(sz, 0); 1628 (*uobj->pgops->pgo_reference)(uobj); 1629 va = vm_map_min(kernel_map); 1630 if ((error = uvm_map(kernel_map, &va, round_page(sz), 1631 uobj, 0, 0, 1632 UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, 1633 UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) { 1634 printf("kernel mapping failed %d\n", error); 1635 (*uobj->pgops->pgo_detach)(uobj); 1636 mutex_exit(&sigobject_lock); 1637 return (error); 1638 } 1639 memcpy((void *)va, e->e_sigcode, sz); 1640 #ifdef PMAP_NEED_PROCWR 1641 pmap_procwr(&proc0, va, sz); 1642 #endif 1643 uvm_unmap(kernel_map, va, va + round_page(sz)); 1644 *e->e_sigobject = uobj; 1645 } 1646 mutex_exit(&sigobject_lock); 1647 } 1648 1649 /* Just a hint to uvm_map where to put it. */ 1650 va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, 1651 round_page(sz)); 1652 1653 #ifdef __alpha__ 1654 /* 1655 * Tru64 puts /sbin/loader at the end of user virtual memory, 1656 * which causes the above calculation to put the sigcode at 1657 * an invalid address. Put it just below the text instead. 1658 */ 1659 if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) { 1660 va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz); 1661 } 1662 #endif 1663 1664 (*uobj->pgops->pgo_reference)(uobj); 1665 error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz), 1666 uobj, 0, 0, 1667 UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE, 1668 UVM_ADV_RANDOM, 0)); 1669 if (error) { 1670 (*uobj->pgops->pgo_detach)(uobj); 1671 return (error); 1672 } 1673 p->p_sigctx.ps_sigcode = (void *)va; 1674 return (0); 1675 } 1676