1 /* $NetBSD: kern_exec.c,v 1.277 2008/07/02 17:28:57 ad 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 1.277 2008/07/02 17:28:57 ad 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 70 #include <sys/param.h> 71 #include <sys/systm.h> 72 #include <sys/filedesc.h> 73 #include <sys/kernel.h> 74 #include <sys/proc.h> 75 #include <sys/mount.h> 76 #include <sys/malloc.h> 77 #include <sys/kmem.h> 78 #include <sys/namei.h> 79 #include <sys/vnode.h> 80 #include <sys/file.h> 81 #include <sys/acct.h> 82 #include <sys/exec.h> 83 #include <sys/ktrace.h> 84 #include <sys/resourcevar.h> 85 #include <sys/wait.h> 86 #include <sys/mman.h> 87 #include <sys/ras.h> 88 #include <sys/signalvar.h> 89 #include <sys/stat.h> 90 #include <sys/syscall.h> 91 #include <sys/kauth.h> 92 #include <sys/lwpctl.h> 93 #include <sys/pax.h> 94 #include <sys/cpu.h> 95 96 #include <sys/syscallargs.h> 97 #if NVERIEXEC > 0 98 #include <sys/verified_exec.h> 99 #endif /* NVERIEXEC > 0 */ 100 101 #include <uvm/uvm_extern.h> 102 103 #include <machine/reg.h> 104 105 #include <compat/common/compat_util.h> 106 107 static int exec_sigcode_map(struct proc *, const struct emul *); 108 109 #ifdef DEBUG_EXEC 110 #define DPRINTF(a) uprintf a 111 #else 112 #define DPRINTF(a) 113 #endif /* DEBUG_EXEC */ 114 115 /* 116 * Exec function switch: 117 * 118 * Note that each makecmds function is responsible for loading the 119 * exec package with the necessary functions for any exec-type-specific 120 * handling. 121 * 122 * Functions for specific exec types should be defined in their own 123 * header file. 124 */ 125 extern const struct execsw execsw_builtin[]; 126 extern int nexecs_builtin; 127 static const struct execsw **execsw = NULL; 128 static int nexecs; 129 130 u_int exec_maxhdrsz; /* must not be static - netbsd32 needs it */ 131 132 #ifdef LKM 133 /* list of supported emulations */ 134 static 135 LIST_HEAD(emlist_head, emul_entry) el_head = LIST_HEAD_INITIALIZER(el_head); 136 struct emul_entry { 137 LIST_ENTRY(emul_entry) el_list; 138 const struct emul *el_emul; 139 int ro_entry; 140 }; 141 142 /* list of dynamically loaded execsw entries */ 143 static 144 LIST_HEAD(execlist_head, exec_entry) ex_head = LIST_HEAD_INITIALIZER(ex_head); 145 struct exec_entry { 146 LIST_ENTRY(exec_entry) ex_list; 147 const struct execsw *es; 148 }; 149 150 /* structure used for building execw[] */ 151 struct execsw_entry { 152 struct execsw_entry *next; 153 const struct execsw *es; 154 }; 155 #endif /* LKM */ 156 157 #ifdef SYSCALL_DEBUG 158 extern const char * const syscallnames[]; 159 #endif 160 161 #ifdef COMPAT_16 162 extern char sigcode[], esigcode[]; 163 struct uvm_object *emul_netbsd_object; 164 #endif 165 166 #ifndef __HAVE_SYSCALL_INTERN 167 void syscall(void); 168 #endif 169 170 /* NetBSD emul struct */ 171 const struct emul emul_netbsd = { 172 "netbsd", 173 NULL, /* emulation path */ 174 #ifndef __HAVE_MINIMAL_EMUL 175 EMUL_HAS_SYS___syscall, 176 NULL, 177 SYS_syscall, 178 SYS_NSYSENT, 179 #endif 180 sysent, 181 #ifdef SYSCALL_DEBUG 182 syscallnames, 183 #else 184 NULL, 185 #endif 186 sendsig, 187 trapsignal, 188 NULL, 189 #ifdef COMPAT_16 190 sigcode, 191 esigcode, 192 &emul_netbsd_object, 193 #else 194 NULL, 195 NULL, 196 NULL, 197 #endif 198 setregs, 199 NULL, 200 NULL, 201 NULL, 202 NULL, 203 NULL, 204 #ifdef __HAVE_SYSCALL_INTERN 205 syscall_intern, 206 #else 207 syscall, 208 #endif 209 NULL, 210 NULL, 211 212 uvm_default_mapaddr, 213 NULL, 214 sizeof(ucontext_t), 215 startlwp, 216 }; 217 218 #ifdef LKM 219 /* 220 * Exec lock. Used to control access to execsw[] structures. 221 * This must not be static so that netbsd32 can access it, too. 222 */ 223 krwlock_t exec_lock; 224 225 static void link_es(struct execsw_entry **, const struct execsw *); 226 #endif /* LKM */ 227 228 static kmutex_t sigobject_lock; 229 230 static void * 231 exec_pool_alloc(struct pool *pp, int flags) 232 { 233 234 return (void *)uvm_km_alloc(kernel_map, NCARGS, 0, 235 UVM_KMF_PAGEABLE | UVM_KMF_WAITVA); 236 } 237 238 static void 239 exec_pool_free(struct pool *pp, void *addr) 240 { 241 242 uvm_km_free(kernel_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE); 243 } 244 245 static struct pool exec_pool; 246 247 static struct pool_allocator exec_palloc = { 248 .pa_alloc = exec_pool_alloc, 249 .pa_free = exec_pool_free, 250 .pa_pagesz = NCARGS 251 }; 252 253 /* 254 * check exec: 255 * given an "executable" described in the exec package's namei info, 256 * see what we can do with it. 257 * 258 * ON ENTRY: 259 * exec package with appropriate namei info 260 * lwp pointer of exec'ing lwp 261 * NO SELF-LOCKED VNODES 262 * 263 * ON EXIT: 264 * error: nothing held, etc. exec header still allocated. 265 * ok: filled exec package, executable's vnode (unlocked). 266 * 267 * EXEC SWITCH ENTRY: 268 * Locked vnode to check, exec package, proc. 269 * 270 * EXEC SWITCH EXIT: 271 * ok: return 0, filled exec package, executable's vnode (unlocked). 272 * error: destructive: 273 * everything deallocated execept exec header. 274 * non-destructive: 275 * error code, executable's vnode (unlocked), 276 * exec header unmodified. 277 */ 278 int 279 /*ARGSUSED*/ 280 check_exec(struct lwp *l, struct exec_package *epp) 281 { 282 int error, i; 283 struct vnode *vp; 284 struct nameidata *ndp; 285 size_t resid; 286 287 ndp = epp->ep_ndp; 288 ndp->ni_cnd.cn_nameiop = LOOKUP; 289 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME | TRYEMULROOT; 290 /* first get the vnode */ 291 if ((error = namei(ndp)) != 0) 292 return error; 293 epp->ep_vp = vp = ndp->ni_vp; 294 295 /* check access and type */ 296 if (vp->v_type != VREG) { 297 error = EACCES; 298 goto bad1; 299 } 300 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 301 goto bad1; 302 303 /* get attributes */ 304 if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred)) != 0) 305 goto bad1; 306 307 /* Check mount point */ 308 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 309 error = EACCES; 310 goto bad1; 311 } 312 if (vp->v_mount->mnt_flag & MNT_NOSUID) 313 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 314 315 /* try to open it */ 316 if ((error = VOP_OPEN(vp, FREAD, l->l_cred)) != 0) 317 goto bad1; 318 319 /* unlock vp, since we need it unlocked from here on out. */ 320 VOP_UNLOCK(vp, 0); 321 322 #if NVERIEXEC > 0 323 error = veriexec_verify(l, vp, ndp->ni_cnd.cn_pnbuf, 324 epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT, 325 NULL); 326 if (error) 327 goto bad2; 328 #endif /* NVERIEXEC > 0 */ 329 330 #ifdef PAX_SEGVGUARD 331 error = pax_segvguard(l, vp, ndp->ni_cnd.cn_pnbuf, false); 332 if (error) 333 goto bad2; 334 #endif /* PAX_SEGVGUARD */ 335 336 /* now we have the file, get the exec header */ 337 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 338 UIO_SYSSPACE, 0, l->l_cred, &resid, NULL); 339 if (error) 340 goto bad2; 341 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 342 343 /* 344 * Set up default address space limits. Can be overridden 345 * by individual exec packages. 346 * 347 * XXX probably should be all done in the exec packages. 348 */ 349 epp->ep_vm_minaddr = VM_MIN_ADDRESS; 350 epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS; 351 /* 352 * set up the vmcmds for creation of the process 353 * address space 354 */ 355 error = ENOEXEC; 356 for (i = 0; i < nexecs; i++) { 357 int newerror; 358 359 epp->ep_esch = execsw[i]; 360 newerror = (*execsw[i]->es_makecmds)(l, epp); 361 362 if (!newerror) { 363 /* Seems ok: check that entry point is sane */ 364 if (epp->ep_entry > VM_MAXUSER_ADDRESS) { 365 error = ENOEXEC; 366 break; 367 } 368 369 /* check limits */ 370 if ((epp->ep_tsize > MAXTSIZ) || 371 (epp->ep_dsize > (u_quad_t)l->l_proc->p_rlimit 372 [RLIMIT_DATA].rlim_cur)) { 373 error = ENOMEM; 374 break; 375 } 376 return 0; 377 } 378 379 if (epp->ep_emul_root != NULL) { 380 vrele(epp->ep_emul_root); 381 epp->ep_emul_root = NULL; 382 } 383 if (epp->ep_interp != NULL) { 384 vrele(epp->ep_interp); 385 epp->ep_interp = NULL; 386 } 387 388 /* make sure the first "interesting" error code is saved. */ 389 if (error == ENOEXEC) 390 error = newerror; 391 392 if (epp->ep_flags & EXEC_DESTR) 393 /* Error from "#!" code, tidied up by recursive call */ 394 return error; 395 } 396 397 /* not found, error */ 398 399 /* 400 * free any vmspace-creation commands, 401 * and release their references 402 */ 403 kill_vmcmds(&epp->ep_vmcmds); 404 405 bad2: 406 /* 407 * close and release the vnode, restore the old one, free the 408 * pathname buf, and punt. 409 */ 410 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 411 VOP_CLOSE(vp, FREAD, l->l_cred); 412 vput(vp); 413 PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); 414 return error; 415 416 bad1: 417 /* 418 * free the namei pathname buffer, and put the vnode 419 * (which we don't yet have open). 420 */ 421 vput(vp); /* was still locked */ 422 PNBUF_PUT(ndp->ni_cnd.cn_pnbuf); 423 return error; 424 } 425 426 #ifdef __MACHINE_STACK_GROWS_UP 427 #define STACK_PTHREADSPACE NBPG 428 #else 429 #define STACK_PTHREADSPACE 0 430 #endif 431 432 static int 433 execve_fetch_element(char * const *array, size_t index, char **value) 434 { 435 return copyin(array + index, value, sizeof(*value)); 436 } 437 438 /* 439 * exec system call 440 */ 441 /* ARGSUSED */ 442 int 443 sys_execve(struct lwp *l, const struct sys_execve_args *uap, register_t *retval) 444 { 445 /* { 446 syscallarg(const char *) path; 447 syscallarg(char * const *) argp; 448 syscallarg(char * const *) envp; 449 } */ 450 451 return execve1(l, SCARG(uap, path), SCARG(uap, argp), 452 SCARG(uap, envp), execve_fetch_element); 453 } 454 455 int 456 execve1(struct lwp *l, const char *path, char * const *args, 457 char * const *envs, execve_fetch_element_t fetch_element) 458 { 459 int error; 460 struct exec_package pack; 461 struct nameidata nid; 462 struct vattr attr; 463 struct proc *p; 464 char *argp; 465 char *dp, *sp; 466 long argc, envc; 467 size_t i, len; 468 char *stack; 469 struct ps_strings arginfo; 470 struct ps_strings *aip = &arginfo; 471 struct vmspace *vm; 472 struct exec_fakearg *tmpfap; 473 int szsigcode; 474 struct exec_vmcmd *base_vcp; 475 ksiginfo_t ksi; 476 ksiginfoq_t kq; 477 char *pathbuf; 478 size_t pathbuflen; 479 480 p = l->l_proc; 481 482 /* 483 * Check if we have exceeded our number of processes limit. 484 * This is so that we handle the case where a root daemon 485 * forked, ran setuid to become the desired user and is trying 486 * to exec. The obvious place to do the reference counting check 487 * is setuid(), but we don't do the reference counting check there 488 * like other OS's do because then all the programs that use setuid() 489 * must be modified to check the return code of setuid() and exit(). 490 * It is dangerous to make setuid() fail, because it fails open and 491 * the program will continue to run as root. If we make it succeed 492 * and return an error code, again we are not enforcing the limit. 493 * The best place to enforce the limit is here, when the process tries 494 * to execute a new image, because eventually the process will need 495 * to call exec in order to do something useful. 496 */ 497 498 if ((p->p_flag & PK_SUGID) && 499 chgproccnt(kauth_cred_getuid(l->l_cred), 0) > 500 p->p_rlimit[RLIMIT_NPROC].rlim_cur) 501 return EAGAIN; 502 503 /* 504 * Drain existing references and forbid new ones. The process 505 * should be left alone until we're done here. This is necessary 506 * to avoid race conditions - e.g. in ptrace() - that might allow 507 * a local user to illicitly obtain elevated privileges. 508 */ 509 rw_enter(&p->p_reflock, RW_WRITER); 510 511 base_vcp = NULL; 512 /* 513 * Init the namei data to point the file user's program name. 514 * This is done here rather than in check_exec(), so that it's 515 * possible to override this settings if any of makecmd/probe 516 * functions call check_exec() recursively - for example, 517 * see exec_script_makecmds(). 518 */ 519 pathbuf = PNBUF_GET(); 520 error = copyinstr(path, pathbuf, MAXPATHLEN, &pathbuflen); 521 if (error) { 522 DPRINTF(("execve: copyinstr path %d", error)); 523 goto clrflg; 524 } 525 526 NDINIT(&nid, LOOKUP, NOFOLLOW | TRYEMULROOT, UIO_SYSSPACE, pathbuf); 527 528 /* 529 * initialize the fields of the exec package. 530 */ 531 pack.ep_name = path; 532 pack.ep_hdr = kmem_alloc(exec_maxhdrsz, KM_SLEEP); 533 pack.ep_hdrlen = exec_maxhdrsz; 534 pack.ep_hdrvalid = 0; 535 pack.ep_ndp = &nid; 536 pack.ep_emul_arg = NULL; 537 pack.ep_vmcmds.evs_cnt = 0; 538 pack.ep_vmcmds.evs_used = 0; 539 pack.ep_vap = &attr; 540 pack.ep_flags = 0; 541 pack.ep_emul_root = NULL; 542 pack.ep_interp = NULL; 543 pack.ep_esch = NULL; 544 pack.ep_pax_flags = 0; 545 546 #ifdef LKM 547 rw_enter(&exec_lock, RW_READER); 548 #endif 549 550 /* see if we can run it. */ 551 if ((error = check_exec(l, &pack)) != 0) { 552 if (error != ENOENT) { 553 DPRINTF(("execve: check exec failed %d\n", error)); 554 } 555 goto freehdr; 556 } 557 558 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 559 560 /* allocate an argument buffer */ 561 argp = pool_get(&exec_pool, PR_WAITOK); 562 KASSERT(argp != NULL); 563 dp = argp; 564 argc = 0; 565 566 /* copy the fake args list, if there's one, freeing it as we go */ 567 if (pack.ep_flags & EXEC_HASARGL) { 568 tmpfap = pack.ep_fa; 569 while (tmpfap->fa_arg != NULL) { 570 const char *cp; 571 572 cp = tmpfap->fa_arg; 573 while (*cp) 574 *dp++ = *cp++; 575 *dp++ = '\0'; 576 577 kmem_free(tmpfap->fa_arg, tmpfap->fa_len); 578 tmpfap++; argc++; 579 } 580 kmem_free(pack.ep_fa, pack.ep_fa_len); 581 pack.ep_flags &= ~EXEC_HASARGL; 582 } 583 584 /* Now get argv & environment */ 585 if (args == NULL) { 586 DPRINTF(("execve: null args\n")); 587 error = EINVAL; 588 goto bad; 589 } 590 /* 'i' will index the argp/envp element to be retrieved */ 591 i = 0; 592 if (pack.ep_flags & EXEC_SKIPARG) 593 i++; 594 595 while (1) { 596 len = argp + ARG_MAX - dp; 597 if ((error = (*fetch_element)(args, i, &sp)) != 0) { 598 DPRINTF(("execve: fetch_element args %d\n", error)); 599 goto bad; 600 } 601 if (!sp) 602 break; 603 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 604 DPRINTF(("execve: copyinstr args %d\n", error)); 605 if (error == ENAMETOOLONG) 606 error = E2BIG; 607 goto bad; 608 } 609 ktrexecarg(dp, len - 1); 610 dp += len; 611 i++; 612 argc++; 613 } 614 615 envc = 0; 616 /* environment need not be there */ 617 if (envs != NULL) { 618 i = 0; 619 while (1) { 620 len = argp + ARG_MAX - dp; 621 if ((error = (*fetch_element)(envs, i, &sp)) != 0) { 622 DPRINTF(("execve: fetch_element env %d\n", error)); 623 goto bad; 624 } 625 if (!sp) 626 break; 627 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 628 DPRINTF(("execve: copyinstr env %d\n", error)); 629 if (error == ENAMETOOLONG) 630 error = E2BIG; 631 goto bad; 632 } 633 ktrexecenv(dp, len - 1); 634 dp += len; 635 i++; 636 envc++; 637 } 638 } 639 640 dp = (char *) ALIGN(dp); 641 642 szsigcode = pack.ep_esch->es_emul->e_esigcode - 643 pack.ep_esch->es_emul->e_sigcode; 644 645 #ifdef __MACHINE_STACK_GROWS_UP 646 /* See big comment lower down */ 647 #define RTLD_GAP 32 648 #else 649 #define RTLD_GAP 0 650 #endif 651 652 /* Now check if args & environ fit into new stack */ 653 if (pack.ep_flags & EXEC_32) 654 len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * 655 sizeof(int) + sizeof(int) + dp + RTLD_GAP + 656 szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) 657 - argp; 658 else 659 len = ((argc + envc + 2 + pack.ep_esch->es_arglen) * 660 sizeof(char *) + sizeof(int) + dp + RTLD_GAP + 661 szsigcode + sizeof(struct ps_strings) + STACK_PTHREADSPACE) 662 - argp; 663 664 #ifdef PAX_ASLR 665 if (pax_aslr_active(l)) 666 len += (arc4random() % PAGE_SIZE); 667 #endif /* PAX_ASLR */ 668 669 #ifdef STACKLALIGN /* arm, etc. */ 670 len = STACKALIGN(len); /* make the stack "safely" aligned */ 671 #else 672 len = ALIGN(len); /* make the stack "safely" aligned */ 673 #endif 674 675 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 676 DPRINTF(("execve: stack limit exceeded %zu\n", len)); 677 error = ENOMEM; 678 goto bad; 679 } 680 681 /* Get rid of other LWPs. */ 682 if (p->p_nlwps > 1) { 683 mutex_enter(p->p_lock); 684 exit_lwps(l); 685 mutex_exit(p->p_lock); 686 } 687 KDASSERT(p->p_nlwps == 1); 688 689 /* Destroy any lwpctl info. */ 690 if (p->p_lwpctl != NULL) 691 lwp_ctl_exit(); 692 693 /* This is now LWP 1 */ 694 l->l_lid = 1; 695 p->p_nlwpid = 1; 696 697 /* Remove POSIX timers */ 698 timers_free(p, TIMERS_POSIX); 699 700 /* adjust "active stack depth" for process VSZ */ 701 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 702 703 /* 704 * Do whatever is necessary to prepare the address space 705 * for remapping. Note that this might replace the current 706 * vmspace with another! 707 */ 708 uvmspace_exec(l, pack.ep_vm_minaddr, pack.ep_vm_maxaddr); 709 710 /* record proc's vnode, for use by procfs and others */ 711 if (p->p_textvp) 712 vrele(p->p_textvp); 713 VREF(pack.ep_vp); 714 p->p_textvp = pack.ep_vp; 715 716 /* Now map address space */ 717 vm = p->p_vmspace; 718 vm->vm_taddr = (void *)pack.ep_taddr; 719 vm->vm_tsize = btoc(pack.ep_tsize); 720 vm->vm_daddr = (void*)pack.ep_daddr; 721 vm->vm_dsize = btoc(pack.ep_dsize); 722 vm->vm_ssize = btoc(pack.ep_ssize); 723 vm->vm_maxsaddr = (void *)pack.ep_maxsaddr; 724 vm->vm_minsaddr = (void *)pack.ep_minsaddr; 725 726 #ifdef PAX_ASLR 727 pax_aslr_init(l, vm); 728 #endif /* PAX_ASLR */ 729 730 /* create the new process's VM space by running the vmcmds */ 731 #ifdef DIAGNOSTIC 732 if (pack.ep_vmcmds.evs_used == 0) 733 panic("execve: no vmcmds"); 734 #endif 735 for (i = 0; i < pack.ep_vmcmds.evs_used && !error; i++) { 736 struct exec_vmcmd *vcp; 737 738 vcp = &pack.ep_vmcmds.evs_cmds[i]; 739 if (vcp->ev_flags & VMCMD_RELATIVE) { 740 #ifdef DIAGNOSTIC 741 if (base_vcp == NULL) 742 panic("execve: relative vmcmd with no base"); 743 if (vcp->ev_flags & VMCMD_BASE) 744 panic("execve: illegal base & relative vmcmd"); 745 #endif 746 vcp->ev_addr += base_vcp->ev_addr; 747 } 748 error = (*vcp->ev_proc)(l, vcp); 749 #ifdef DEBUG_EXEC 750 if (error) { 751 size_t j; 752 struct exec_vmcmd *vp = &pack.ep_vmcmds.evs_cmds[0]; 753 for (j = 0; j <= i; j++) 754 uprintf( 755 "vmcmd[%zu] = %#lx/%#lx fd@%#lx prot=0%o flags=%d\n", 756 j, vp[j].ev_addr, vp[j].ev_len, 757 vp[j].ev_offset, vp[j].ev_prot, 758 vp[j].ev_flags); 759 } 760 #endif /* DEBUG_EXEC */ 761 if (vcp->ev_flags & VMCMD_BASE) 762 base_vcp = vcp; 763 } 764 765 /* free the vmspace-creation commands, and release their references */ 766 kill_vmcmds(&pack.ep_vmcmds); 767 768 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 769 VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred); 770 vput(pack.ep_vp); 771 772 /* if an error happened, deallocate and punt */ 773 if (error) { 774 DPRINTF(("execve: vmcmd %zu failed: %d\n", i - 1, error)); 775 goto exec_abort; 776 } 777 778 /* remember information about the process */ 779 arginfo.ps_nargvstr = argc; 780 arginfo.ps_nenvstr = envc; 781 782 /* set command name & other accounting info */ 783 i = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 784 (void)memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, i); 785 p->p_comm[i] = '\0'; 786 787 dp = PNBUF_GET(); 788 /* 789 * If the path starts with /, we don't need to do any work. 790 * This handles the majority of the cases. 791 * In the future perhaps we could canonicalize it? 792 */ 793 if (pathbuf[0] == '/') 794 (void)strlcpy(pack.ep_path = dp, pathbuf, MAXPATHLEN); 795 #ifdef notyet 796 /* 797 * Although this works most of the time [since the entry was just 798 * entered in the cache] we don't use it because it theoretically 799 * can fail and it is not the cleanest interface, because there 800 * could be races. When the namei cache is re-written, this can 801 * be changed to use the appropriate function. 802 */ 803 else if (!(error = vnode_to_path(dp, MAXPATHLEN, p->p_textvp, l, p))) 804 pack.ep_path = dp; 805 #endif 806 else { 807 #ifdef notyet 808 printf("Cannot get path for pid %d [%s] (error %d)", 809 (int)p->p_pid, p->p_comm, error); 810 #endif 811 pack.ep_path = NULL; 812 PNBUF_PUT(dp); 813 } 814 815 stack = (char *)STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, 816 STACK_PTHREADSPACE + sizeof(struct ps_strings) + szsigcode), 817 len - (sizeof(struct ps_strings) + szsigcode)); 818 819 #ifdef __MACHINE_STACK_GROWS_UP 820 /* 821 * The copyargs call always copies into lower addresses 822 * first, moving towards higher addresses, starting with 823 * the stack pointer that we give. When the stack grows 824 * down, this puts argc/argv/envp very shallow on the 825 * stack, right at the first user stack pointer. 826 * When the stack grows up, the situation is reversed. 827 * 828 * Normally, this is no big deal. But the ld_elf.so _rtld() 829 * function expects to be called with a single pointer to 830 * a region that has a few words it can stash values into, 831 * followed by argc/argv/envp. When the stack grows down, 832 * it's easy to decrement the stack pointer a little bit to 833 * allocate the space for these few words and pass the new 834 * stack pointer to _rtld. When the stack grows up, however, 835 * a few words before argc is part of the signal trampoline, XXX 836 * so we have a problem. 837 * 838 * Instead of changing how _rtld works, we take the easy way 839 * out and steal 32 bytes before we call copyargs. 840 * This extra space was allowed for when 'len' was calculated. 841 */ 842 stack += RTLD_GAP; 843 #endif /* __MACHINE_STACK_GROWS_UP */ 844 845 /* Now copy argc, args & environ to new stack */ 846 error = (*pack.ep_esch->es_copyargs)(l, &pack, &arginfo, &stack, argp); 847 if (pack.ep_path) { 848 PNBUF_PUT(pack.ep_path); 849 pack.ep_path = NULL; 850 } 851 if (error) { 852 DPRINTF(("execve: copyargs failed %d\n", error)); 853 goto exec_abort; 854 } 855 /* Move the stack back to original point */ 856 stack = (char *)STACK_GROW(vm->vm_minsaddr, len); 857 858 /* fill process ps_strings info */ 859 p->p_psstr = (struct ps_strings *) 860 STACK_ALLOC(STACK_GROW(vm->vm_minsaddr, STACK_PTHREADSPACE), 861 sizeof(struct ps_strings)); 862 p->p_psargv = offsetof(struct ps_strings, ps_argvstr); 863 p->p_psnargv = offsetof(struct ps_strings, ps_nargvstr); 864 p->p_psenv = offsetof(struct ps_strings, ps_envstr); 865 p->p_psnenv = offsetof(struct ps_strings, ps_nenvstr); 866 867 /* copy out the process's ps_strings structure */ 868 if ((error = copyout(aip, (char *)p->p_psstr, 869 sizeof(arginfo))) != 0) { 870 DPRINTF(("execve: ps_strings copyout %p->%p size %ld failed\n", 871 aip, (char *)p->p_psstr, (long)sizeof(arginfo))); 872 goto exec_abort; 873 } 874 875 fd_closeexec(); /* handle close on exec */ 876 execsigs(p); /* reset catched signals */ 877 878 l->l_ctxlink = NULL; /* reset ucontext link */ 879 880 881 p->p_acflag &= ~AFORK; 882 mutex_enter(p->p_lock); 883 p->p_flag |= PK_EXEC; 884 mutex_exit(p->p_lock); 885 886 /* 887 * Stop profiling. 888 */ 889 if ((p->p_stflag & PST_PROFIL) != 0) { 890 mutex_spin_enter(&p->p_stmutex); 891 stopprofclock(p); 892 mutex_spin_exit(&p->p_stmutex); 893 } 894 895 /* 896 * It's OK to test PL_PPWAIT unlocked here, as other LWPs have 897 * exited and exec()/exit() are the only places it will be cleared. 898 */ 899 if ((p->p_lflag & PL_PPWAIT) != 0) { 900 mutex_enter(proc_lock); 901 p->p_lflag &= ~PL_PPWAIT; 902 cv_broadcast(&p->p_pptr->p_waitcv); 903 mutex_exit(proc_lock); 904 } 905 906 /* 907 * Deal with set[ug]id. MNT_NOSUID has already been used to disable 908 * s[ug]id. It's OK to check for PSL_TRACED here as we have blocked 909 * out additional references on the process for the moment. 910 */ 911 if ((p->p_slflag & PSL_TRACED) == 0 && 912 913 (((attr.va_mode & S_ISUID) != 0 && 914 kauth_cred_geteuid(l->l_cred) != attr.va_uid) || 915 916 ((attr.va_mode & S_ISGID) != 0 && 917 kauth_cred_getegid(l->l_cred) != attr.va_gid))) { 918 /* 919 * Mark the process as SUGID before we do 920 * anything that might block. 921 */ 922 proc_crmod_enter(); 923 proc_crmod_leave(NULL, NULL, true); 924 925 /* Make sure file descriptors 0..2 are in use. */ 926 if ((error = fd_checkstd()) != 0) { 927 DPRINTF(("execve: fdcheckstd failed %d\n", error)); 928 goto exec_abort; 929 } 930 931 /* 932 * Copy the credential so other references don't see our 933 * changes. 934 */ 935 l->l_cred = kauth_cred_copy(l->l_cred); 936 #ifdef KTRACE 937 /* 938 * If the persistent trace flag isn't set, turn off. 939 */ 940 if (p->p_tracep) { 941 mutex_enter(&ktrace_lock); 942 if (!(p->p_traceflag & KTRFAC_PERSISTENT)) 943 ktrderef(p); 944 mutex_exit(&ktrace_lock); 945 } 946 #endif 947 if (attr.va_mode & S_ISUID) 948 kauth_cred_seteuid(l->l_cred, attr.va_uid); 949 if (attr.va_mode & S_ISGID) 950 kauth_cred_setegid(l->l_cred, attr.va_gid); 951 } else { 952 if (kauth_cred_geteuid(l->l_cred) == 953 kauth_cred_getuid(l->l_cred) && 954 kauth_cred_getegid(l->l_cred) == 955 kauth_cred_getgid(l->l_cred)) 956 p->p_flag &= ~PK_SUGID; 957 } 958 959 /* 960 * Copy the credential so other references don't see our changes. 961 * Test to see if this is necessary first, since in the common case 962 * we won't need a private reference. 963 */ 964 if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) || 965 kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) { 966 l->l_cred = kauth_cred_copy(l->l_cred); 967 kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred)); 968 kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred)); 969 } 970 971 /* Update the master credentials. */ 972 if (l->l_cred != p->p_cred) { 973 kauth_cred_t ocred; 974 975 kauth_cred_hold(l->l_cred); 976 mutex_enter(p->p_lock); 977 ocred = p->p_cred; 978 p->p_cred = l->l_cred; 979 mutex_exit(p->p_lock); 980 kauth_cred_free(ocred); 981 } 982 983 #if defined(__HAVE_RAS) 984 /* 985 * Remove all RASs from the address space. 986 */ 987 ras_purgeall(); 988 #endif 989 990 doexechooks(p); 991 992 /* setup new registers and do misc. setup. */ 993 (*pack.ep_esch->es_emul->e_setregs)(l, &pack, (u_long) stack); 994 if (pack.ep_esch->es_setregs) 995 (*pack.ep_esch->es_setregs)(l, &pack, (u_long) stack); 996 997 /* map the process's signal trampoline code */ 998 if (exec_sigcode_map(p, pack.ep_esch->es_emul)) { 999 DPRINTF(("execve: map sigcode failed %d\n", error)); 1000 goto exec_abort; 1001 } 1002 1003 pool_put(&exec_pool, argp); 1004 1005 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1006 1007 /* notify others that we exec'd */ 1008 KNOTE(&p->p_klist, NOTE_EXEC); 1009 1010 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1011 1012 /* The emulation root will usually have been found when we looked 1013 * for the elf interpreter (or similar), if not look now. */ 1014 if (pack.ep_esch->es_emul->e_path != NULL && pack.ep_emul_root == NULL) 1015 emul_find_root(l, &pack); 1016 1017 /* Any old emulation root got removed by fdcloseexec */ 1018 rw_enter(&p->p_cwdi->cwdi_lock, RW_WRITER); 1019 p->p_cwdi->cwdi_edir = pack.ep_emul_root; 1020 rw_exit(&p->p_cwdi->cwdi_lock); 1021 pack.ep_emul_root = NULL; 1022 if (pack.ep_interp != NULL) 1023 vrele(pack.ep_interp); 1024 1025 /* 1026 * Call emulation specific exec hook. This can setup per-process 1027 * p->p_emuldata or do any other per-process stuff an emulation needs. 1028 * 1029 * If we are executing process of different emulation than the 1030 * original forked process, call e_proc_exit() of the old emulation 1031 * first, then e_proc_exec() of new emulation. If the emulation is 1032 * same, the exec hook code should deallocate any old emulation 1033 * resources held previously by this process. 1034 */ 1035 if (p->p_emul && p->p_emul->e_proc_exit 1036 && p->p_emul != pack.ep_esch->es_emul) 1037 (*p->p_emul->e_proc_exit)(p); 1038 1039 /* 1040 * Call exec hook. Emulation code may NOT store reference to anything 1041 * from &pack. 1042 */ 1043 if (pack.ep_esch->es_emul->e_proc_exec) 1044 (*pack.ep_esch->es_emul->e_proc_exec)(p, &pack); 1045 1046 /* update p_emul, the old value is no longer needed */ 1047 p->p_emul = pack.ep_esch->es_emul; 1048 1049 /* ...and the same for p_execsw */ 1050 p->p_execsw = pack.ep_esch; 1051 1052 #ifdef __HAVE_SYSCALL_INTERN 1053 (*p->p_emul->e_syscall_intern)(p); 1054 #endif 1055 ktremul(); 1056 1057 /* Allow new references from the debugger/procfs. */ 1058 rw_exit(&p->p_reflock); 1059 #ifdef LKM 1060 rw_exit(&exec_lock); 1061 #endif 1062 1063 mutex_enter(proc_lock); 1064 1065 if ((p->p_slflag & (PSL_TRACED|PSL_SYSCALL)) == PSL_TRACED) { 1066 KSI_INIT_EMPTY(&ksi); 1067 ksi.ksi_signo = SIGTRAP; 1068 ksi.ksi_lid = l->l_lid; 1069 kpsignal(p, &ksi, NULL); 1070 } 1071 1072 if (p->p_sflag & PS_STOPEXEC) { 1073 KERNEL_UNLOCK_ALL(l, &l->l_biglocks); 1074 p->p_pptr->p_nstopchild++; 1075 p->p_pptr->p_waited = 0; 1076 mutex_enter(p->p_lock); 1077 ksiginfo_queue_init(&kq); 1078 sigclearall(p, &contsigmask, &kq); 1079 lwp_lock(l); 1080 l->l_stat = LSSTOP; 1081 p->p_stat = SSTOP; 1082 p->p_nrlwps--; 1083 mutex_exit(p->p_lock); 1084 mutex_exit(proc_lock); 1085 mi_switch(l); 1086 ksiginfo_queue_drain(&kq); 1087 KERNEL_LOCK(l->l_biglocks, l); 1088 } else { 1089 mutex_exit(proc_lock); 1090 } 1091 1092 PNBUF_PUT(pathbuf); 1093 return (EJUSTRETURN); 1094 1095 bad: 1096 /* free the vmspace-creation commands, and release their references */ 1097 kill_vmcmds(&pack.ep_vmcmds); 1098 /* kill any opened file descriptor, if necessary */ 1099 if (pack.ep_flags & EXEC_HASFD) { 1100 pack.ep_flags &= ~EXEC_HASFD; 1101 fd_close(pack.ep_fd); 1102 } 1103 /* close and put the exec'd file */ 1104 vn_lock(pack.ep_vp, LK_EXCLUSIVE | LK_RETRY); 1105 VOP_CLOSE(pack.ep_vp, FREAD, l->l_cred); 1106 vput(pack.ep_vp); 1107 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1108 pool_put(&exec_pool, argp); 1109 1110 freehdr: 1111 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1112 if (pack.ep_emul_root != NULL) 1113 vrele(pack.ep_emul_root); 1114 if (pack.ep_interp != NULL) 1115 vrele(pack.ep_interp); 1116 1117 #ifdef LKM 1118 rw_exit(&exec_lock); 1119 #endif 1120 1121 clrflg: 1122 PNBUF_PUT(pathbuf); 1123 rw_exit(&p->p_reflock); 1124 1125 return error; 1126 1127 exec_abort: 1128 PNBUF_PUT(pathbuf); 1129 rw_exit(&p->p_reflock); 1130 #ifdef LKM 1131 rw_exit(&exec_lock); 1132 #endif 1133 1134 /* 1135 * the old process doesn't exist anymore. exit gracefully. 1136 * get rid of the (new) address space we have created, if any, get rid 1137 * of our namei data and vnode, and exit noting failure 1138 */ 1139 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 1140 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 1141 if (pack.ep_emul_arg) 1142 FREE(pack.ep_emul_arg, M_TEMP); 1143 PNBUF_PUT(nid.ni_cnd.cn_pnbuf); 1144 pool_put(&exec_pool, argp); 1145 kmem_free(pack.ep_hdr, pack.ep_hdrlen); 1146 if (pack.ep_emul_root != NULL) 1147 vrele(pack.ep_emul_root); 1148 if (pack.ep_interp != NULL) 1149 vrele(pack.ep_interp); 1150 1151 /* Acquire the sched-state mutex (exit1() will release it). */ 1152 mutex_enter(p->p_lock); 1153 exit1(l, W_EXITCODE(error, SIGABRT)); 1154 1155 /* NOTREACHED */ 1156 return 0; 1157 } 1158 1159 1160 int 1161 copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo, 1162 char **stackp, void *argp) 1163 { 1164 char **cpp, *dp, *sp; 1165 size_t len; 1166 void *nullp; 1167 long argc, envc; 1168 int error; 1169 1170 cpp = (char **)*stackp; 1171 nullp = NULL; 1172 argc = arginfo->ps_nargvstr; 1173 envc = arginfo->ps_nenvstr; 1174 if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) 1175 return error; 1176 1177 dp = (char *) (cpp + argc + envc + 2 + pack->ep_esch->es_arglen); 1178 sp = argp; 1179 1180 /* XXX don't copy them out, remap them! */ 1181 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 1182 1183 for (; --argc >= 0; sp += len, dp += len) 1184 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || 1185 (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) 1186 return error; 1187 1188 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) 1189 return error; 1190 1191 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 1192 1193 for (; --envc >= 0; sp += len, dp += len) 1194 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 || 1195 (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) 1196 return error; 1197 1198 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) 1199 return error; 1200 1201 *stackp = (char *)cpp; 1202 return 0; 1203 } 1204 1205 #ifdef LKM 1206 /* 1207 * Find an emulation of given name in list of emulations. 1208 * Needs to be called with the exec_lock held. 1209 */ 1210 const struct emul * 1211 emul_search(const char *name) 1212 { 1213 struct emul_entry *it; 1214 1215 LIST_FOREACH(it, &el_head, el_list) { 1216 if (strcmp(name, it->el_emul->e_name) == 0) 1217 return it->el_emul; 1218 } 1219 1220 return NULL; 1221 } 1222 1223 /* 1224 * Add an emulation to list, if it's not there already. 1225 */ 1226 int 1227 emul_register(const struct emul *emul, int ro_entry) 1228 { 1229 struct emul_entry *ee; 1230 int error; 1231 1232 error = 0; 1233 rw_enter(&exec_lock, RW_WRITER); 1234 1235 if (emul_search(emul->e_name)) { 1236 error = EEXIST; 1237 goto out; 1238 } 1239 1240 ee = kmem_alloc(sizeof(*ee), KM_SLEEP); 1241 ee->el_emul = emul; 1242 ee->ro_entry = ro_entry; 1243 LIST_INSERT_HEAD(&el_head, ee, el_list); 1244 1245 out: 1246 rw_exit(&exec_lock); 1247 return error; 1248 } 1249 1250 /* 1251 * Remove emulation with name 'name' from list of supported emulations. 1252 */ 1253 int 1254 emul_unregister(const char *name) 1255 { 1256 const struct proclist_desc *pd; 1257 struct emul_entry *it; 1258 int i, error; 1259 struct proc *ptmp; 1260 1261 error = 0; 1262 rw_enter(&exec_lock, RW_WRITER); 1263 1264 LIST_FOREACH(it, &el_head, el_list) { 1265 if (strcmp(it->el_emul->e_name, name) == 0) 1266 break; 1267 } 1268 1269 if (!it) { 1270 error = ENOENT; 1271 goto out; 1272 } 1273 1274 if (it->ro_entry) { 1275 error = EBUSY; 1276 goto out; 1277 } 1278 1279 /* test if any execw[] entry is still using this */ 1280 for(i=0; i < nexecs; i++) { 1281 if (execsw[i]->es_emul == it->el_emul) { 1282 error = EBUSY; 1283 goto out; 1284 } 1285 } 1286 1287 /* 1288 * Test if any process is running under this emulation - since 1289 * emul_unregister() is running quite sendomly, it's better 1290 * to do expensive check here than to use any locking. 1291 */ 1292 mutex_enter(proc_lock); 1293 for (pd = proclists; pd->pd_list != NULL && !error; pd++) { 1294 PROCLIST_FOREACH(ptmp, pd->pd_list) { 1295 if (ptmp->p_emul == it->el_emul) { 1296 error = EBUSY; 1297 break; 1298 } 1299 } 1300 } 1301 mutex_exit(proc_lock); 1302 1303 if (error) 1304 goto out; 1305 1306 1307 /* entry is not used, remove it */ 1308 LIST_REMOVE(it, el_list); 1309 kmem_free(it, sizeof(*it)); 1310 1311 out: 1312 rw_exit(&exec_lock); 1313 return error; 1314 } 1315 1316 /* 1317 * Add execsw[] entry. 1318 */ 1319 int 1320 exec_add(struct execsw *esp, const char *e_name) 1321 { 1322 struct exec_entry *it; 1323 int error; 1324 1325 error = 0; 1326 rw_enter(&exec_lock, RW_WRITER); 1327 1328 if (!esp->es_emul) { 1329 esp->es_emul = emul_search(e_name); 1330 if (!esp->es_emul) { 1331 error = ENOENT; 1332 goto out; 1333 } 1334 } 1335 1336 LIST_FOREACH(it, &ex_head, ex_list) { 1337 /* assume tuple (makecmds, probe_func, emulation) is unique */ 1338 if (it->es->es_makecmds == esp->es_makecmds 1339 && it->es->u.elf_probe_func == esp->u.elf_probe_func 1340 && it->es->es_emul == esp->es_emul) { 1341 error = EEXIST; 1342 goto out; 1343 } 1344 } 1345 1346 /* if we got here, the entry doesn't exist yet */ 1347 it = kmem_alloc(sizeof(*it), KM_SLEEP); 1348 it->es = esp; 1349 LIST_INSERT_HEAD(&ex_head, it, ex_list); 1350 1351 /* update execsw[] */ 1352 exec_init(0); 1353 1354 out: 1355 rw_exit(&exec_lock); 1356 return error; 1357 } 1358 1359 /* 1360 * Remove execsw[] entry. 1361 */ 1362 int 1363 exec_remove(const struct execsw *esp) 1364 { 1365 struct exec_entry *it; 1366 int error; 1367 1368 error = 0; 1369 rw_enter(&exec_lock, RW_WRITER); 1370 1371 LIST_FOREACH(it, &ex_head, ex_list) { 1372 /* assume tuple (makecmds, probe_func, emulation) is unique */ 1373 if (it->es->es_makecmds == esp->es_makecmds 1374 && it->es->u.elf_probe_func == esp->u.elf_probe_func 1375 && it->es->es_emul == esp->es_emul) 1376 break; 1377 } 1378 if (!it) { 1379 error = ENOENT; 1380 goto out; 1381 } 1382 1383 /* remove item from list and free resources */ 1384 LIST_REMOVE(it, ex_list); 1385 kmem_free(it, sizeof(*it)); 1386 1387 /* update execsw[] */ 1388 exec_init(0); 1389 1390 out: 1391 rw_exit(&exec_lock); 1392 return error; 1393 } 1394 1395 static void 1396 link_es(struct execsw_entry **listp, const struct execsw *esp) 1397 { 1398 struct execsw_entry *et, *e1; 1399 1400 et = (struct execsw_entry *) malloc(sizeof(struct execsw_entry), 1401 M_TEMP, M_WAITOK); 1402 et->next = NULL; 1403 et->es = esp; 1404 if (*listp == NULL) { 1405 *listp = et; 1406 return; 1407 } 1408 1409 switch(et->es->es_prio) { 1410 case EXECSW_PRIO_FIRST: 1411 /* put new entry as the first */ 1412 et->next = *listp; 1413 *listp = et; 1414 break; 1415 case EXECSW_PRIO_ANY: 1416 /* put new entry after all *_FIRST and *_ANY entries */ 1417 for(e1 = *listp; e1->next 1418 && e1->next->es->es_prio != EXECSW_PRIO_LAST; 1419 e1 = e1->next); 1420 et->next = e1->next; 1421 e1->next = et; 1422 break; 1423 case EXECSW_PRIO_LAST: 1424 /* put new entry as the last one */ 1425 for(e1 = *listp; e1->next; e1 = e1->next); 1426 e1->next = et; 1427 break; 1428 default: 1429 #ifdef DIAGNOSTIC 1430 panic("execw[] entry with unknown priority %d found", 1431 et->es->es_prio); 1432 #else 1433 free(et, M_TEMP); 1434 #endif 1435 break; 1436 } 1437 } 1438 1439 /* 1440 * Initialize exec structures. If init_boot is true, also does necessary 1441 * one-time initialization (it's called from main() that way). 1442 * Once system is multiuser, this should be called with exec_lock held, 1443 * i.e. via exec_{add|remove}(). 1444 */ 1445 int 1446 exec_init(int init_boot) 1447 { 1448 const struct execsw **new_es, * const *old_es; 1449 struct execsw_entry *list, *e1; 1450 struct exec_entry *e2; 1451 int i, es_sz; 1452 1453 if (init_boot) { 1454 /* do one-time initializations */ 1455 rw_init(&exec_lock); 1456 mutex_init(&sigobject_lock, MUTEX_DEFAULT, IPL_NONE); 1457 pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, 1458 "execargs", &exec_palloc, IPL_NONE); 1459 pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); 1460 1461 /* register compiled-in emulations */ 1462 for(i=0; i < nexecs_builtin; i++) { 1463 if (execsw_builtin[i].es_emul) 1464 emul_register(execsw_builtin[i].es_emul, 1); 1465 } 1466 #ifdef DIAGNOSTIC 1467 if (i == 0) 1468 panic("no emulations found in execsw_builtin[]"); 1469 #endif 1470 } 1471 1472 /* 1473 * Build execsw[] array from builtin entries and entries added 1474 * at runtime. 1475 */ 1476 list = NULL; 1477 for(i=0; i < nexecs_builtin; i++) 1478 link_es(&list, &execsw_builtin[i]); 1479 1480 /* Add dynamically loaded entries */ 1481 es_sz = nexecs_builtin; 1482 LIST_FOREACH(e2, &ex_head, ex_list) { 1483 link_es(&list, e2->es); 1484 es_sz++; 1485 } 1486 1487 /* 1488 * Now that we have sorted all execw entries, create new execsw[] 1489 * and free no longer needed memory in the process. 1490 */ 1491 new_es = kmem_alloc(es_sz * sizeof(struct execsw *), KM_SLEEP); 1492 for(i=0; list; i++) { 1493 new_es[i] = list->es; 1494 e1 = list->next; 1495 free(list, M_TEMP); 1496 list = e1; 1497 } 1498 1499 /* 1500 * New execsw[] array built, now replace old execsw[] and free 1501 * used memory. 1502 */ 1503 old_es = execsw; 1504 if (old_es) 1505 /*XXXUNCONST*/ 1506 kmem_free(__UNCONST(old_es), nexecs * sizeof(struct execsw *)); 1507 execsw = new_es; 1508 nexecs = es_sz; 1509 1510 /* 1511 * Figure out the maximum size of an exec header. 1512 */ 1513 exec_maxhdrsz = 0; 1514 for (i = 0; i < nexecs; i++) { 1515 if (execsw[i]->es_hdrsz > exec_maxhdrsz) 1516 exec_maxhdrsz = execsw[i]->es_hdrsz; 1517 } 1518 1519 return 0; 1520 } 1521 #endif 1522 1523 #ifndef LKM 1524 /* 1525 * Simplified exec_init() for kernels without LKMs. Only initialize 1526 * exec_maxhdrsz and execsw[]. 1527 */ 1528 int 1529 exec_init(int init_boot) 1530 { 1531 int i; 1532 1533 #ifdef DIAGNOSTIC 1534 if (!init_boot) 1535 panic("exec_init(): called with init_boot == 0"); 1536 #endif 1537 1538 /* do one-time initializations */ 1539 nexecs = nexecs_builtin; 1540 execsw = kmem_alloc(nexecs * sizeof(struct execsw *), KM_SLEEP); 1541 1542 pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, 1543 "execargs", &exec_palloc, IPL_NONE); 1544 pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); 1545 1546 /* 1547 * Fill in execsw[] and figure out the maximum size of an exec header. 1548 */ 1549 exec_maxhdrsz = 0; 1550 for(i=0; i < nexecs; i++) { 1551 execsw[i] = &execsw_builtin[i]; 1552 if (execsw_builtin[i].es_hdrsz > exec_maxhdrsz) 1553 exec_maxhdrsz = execsw_builtin[i].es_hdrsz; 1554 } 1555 1556 return 0; 1557 1558 } 1559 #endif /* !LKM */ 1560 1561 static int 1562 exec_sigcode_map(struct proc *p, const struct emul *e) 1563 { 1564 vaddr_t va; 1565 vsize_t sz; 1566 int error; 1567 struct uvm_object *uobj; 1568 1569 sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; 1570 1571 if (e->e_sigobject == NULL || sz == 0) { 1572 return 0; 1573 } 1574 1575 /* 1576 * If we don't have a sigobject for this emulation, create one. 1577 * 1578 * sigobject is an anonymous memory object (just like SYSV shared 1579 * memory) that we keep a permanent reference to and that we map 1580 * in all processes that need this sigcode. The creation is simple, 1581 * we create an object, add a permanent reference to it, map it in 1582 * kernel space, copy out the sigcode to it and unmap it. 1583 * We map it with PROT_READ|PROT_EXEC into the process just 1584 * the way sys_mmap() would map it. 1585 */ 1586 1587 uobj = *e->e_sigobject; 1588 if (uobj == NULL) { 1589 mutex_enter(&sigobject_lock); 1590 if ((uobj = *e->e_sigobject) == NULL) { 1591 uobj = uao_create(sz, 0); 1592 (*uobj->pgops->pgo_reference)(uobj); 1593 va = vm_map_min(kernel_map); 1594 if ((error = uvm_map(kernel_map, &va, round_page(sz), 1595 uobj, 0, 0, 1596 UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, 1597 UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) { 1598 printf("kernel mapping failed %d\n", error); 1599 (*uobj->pgops->pgo_detach)(uobj); 1600 mutex_exit(&sigobject_lock); 1601 return (error); 1602 } 1603 memcpy((void *)va, e->e_sigcode, sz); 1604 #ifdef PMAP_NEED_PROCWR 1605 pmap_procwr(&proc0, va, sz); 1606 #endif 1607 uvm_unmap(kernel_map, va, va + round_page(sz)); 1608 *e->e_sigobject = uobj; 1609 } 1610 mutex_exit(&sigobject_lock); 1611 } 1612 1613 /* Just a hint to uvm_map where to put it. */ 1614 va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, 1615 round_page(sz)); 1616 1617 #ifdef __alpha__ 1618 /* 1619 * Tru64 puts /sbin/loader at the end of user virtual memory, 1620 * which causes the above calculation to put the sigcode at 1621 * an invalid address. Put it just below the text instead. 1622 */ 1623 if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) { 1624 va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz); 1625 } 1626 #endif 1627 1628 (*uobj->pgops->pgo_reference)(uobj); 1629 error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz), 1630 uobj, 0, 0, 1631 UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE, 1632 UVM_ADV_RANDOM, 0)); 1633 if (error) { 1634 (*uobj->pgops->pgo_detach)(uobj); 1635 return (error); 1636 } 1637 p->p_sigctx.ps_sigcode = (void *)va; 1638 return (0); 1639 } 1640