1 /* $NetBSD: kern_exec.c,v 1.522 2024/11/10 12:15:46 mlelstv Exp $ */ 2 3 /*- 4 * Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou 34 * Copyright (C) 1992 Wolfgang Solfrank. 35 * Copyright (C) 1992 TooLs GmbH. 36 * All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by TooLs GmbH. 49 * 4. The name of TooLs GmbH may not be used to endorse or promote products 50 * derived from this software without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 53 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 54 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 55 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 56 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 57 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 58 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 59 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 60 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 61 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 62 */ 63 64 #include <sys/cdefs.h> 65 __KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.522 2024/11/10 12:15:46 mlelstv Exp $"); 66 67 #include "opt_exec.h" 68 #include "opt_execfmt.h" 69 #include "opt_ktrace.h" 70 #include "opt_modular.h" 71 #include "opt_syscall_debug.h" 72 #include "veriexec.h" 73 #include "opt_pax.h" 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/filedesc.h> 78 #include <sys/kernel.h> 79 #include <sys/proc.h> 80 #include <sys/ptrace.h> 81 #include <sys/mount.h> 82 #include <sys/kmem.h> 83 #include <sys/namei.h> 84 #include <sys/vnode.h> 85 #include <sys/file.h> 86 #include <sys/filedesc.h> 87 #include <sys/acct.h> 88 #include <sys/atomic.h> 89 #include <sys/exec.h> 90 #include <sys/futex.h> 91 #include <sys/ktrace.h> 92 #include <sys/uidinfo.h> 93 #include <sys/wait.h> 94 #include <sys/mman.h> 95 #include <sys/ras.h> 96 #include <sys/signalvar.h> 97 #include <sys/stat.h> 98 #include <sys/syscall.h> 99 #include <sys/kauth.h> 100 #include <sys/lwpctl.h> 101 #include <sys/pax.h> 102 #include <sys/cpu.h> 103 #include <sys/module.h> 104 #include <sys/syscallvar.h> 105 #include <sys/syscallargs.h> 106 #include <sys/vfs_syscalls.h> 107 #if NVERIEXEC > 0 108 #include <sys/verified_exec.h> 109 #endif /* NVERIEXEC > 0 */ 110 #include <sys/sdt.h> 111 #include <sys/spawn.h> 112 #include <sys/prot.h> 113 #include <sys/cprng.h> 114 115 #include <uvm/uvm_extern.h> 116 117 #include <machine/reg.h> 118 119 #include <compat/common/compat_util.h> 120 121 #ifndef MD_TOPDOWN_INIT 122 #ifdef __USE_TOPDOWN_VM 123 #define MD_TOPDOWN_INIT(epp) (epp)->ep_flags |= EXEC_TOPDOWN_VM 124 #else 125 #define MD_TOPDOWN_INIT(epp) 126 #endif 127 #endif 128 129 struct execve_data; 130 131 extern int user_va0_disable; 132 133 static size_t calcargs(struct execve_data * restrict, const size_t); 134 static size_t calcstack(struct execve_data * restrict, const size_t); 135 static int copyoutargs(struct execve_data * restrict, struct lwp *, 136 char * const); 137 static int copyoutpsstrs(struct execve_data * restrict, struct proc *); 138 static int copyinargs(struct execve_data * restrict, char * const *, 139 char * const *, execve_fetch_element_t, char **); 140 static int copyinargstrs(struct execve_data * restrict, char * const *, 141 execve_fetch_element_t, char **, size_t *, void (*)(const void *, size_t)); 142 static int exec_sigcode_map(struct proc *, const struct emul *); 143 144 #if defined(DEBUG) && !defined(DEBUG_EXEC) 145 #define DEBUG_EXEC 146 #endif 147 #ifdef DEBUG_EXEC 148 #define DPRINTF(a) printf a 149 #define COPYPRINTF(s, a, b) printf("%s, %d: copyout%s @%p %zu\n", __func__, \ 150 __LINE__, (s), (a), (b)) 151 static void dump_vmcmds(const struct exec_package * const, size_t, int); 152 #define DUMPVMCMDS(p, x, e) do { dump_vmcmds((p), (x), (e)); } while (0) 153 #else 154 #define DPRINTF(a) 155 #define COPYPRINTF(s, a, b) 156 #define DUMPVMCMDS(p, x, e) do {} while (0) 157 #endif /* DEBUG_EXEC */ 158 159 /* 160 * DTrace SDT provider definitions 161 */ 162 SDT_PROVIDER_DECLARE(proc); 163 SDT_PROBE_DEFINE1(proc, kernel, , exec, "char *"); 164 SDT_PROBE_DEFINE1(proc, kernel, , exec__success, "char *"); 165 SDT_PROBE_DEFINE1(proc, kernel, , exec__failure, "int"); 166 167 /* 168 * Exec function switch: 169 * 170 * Note that each makecmds function is responsible for loading the 171 * exec package with the necessary functions for any exec-type-specific 172 * handling. 173 * 174 * Functions for specific exec types should be defined in their own 175 * header file. 176 */ 177 static const struct execsw **execsw = NULL; 178 static int nexecs; 179 180 u_int exec_maxhdrsz; /* must not be static - used by netbsd32 */ 181 182 /* list of dynamically loaded execsw entries */ 183 static LIST_HEAD(execlist_head, exec_entry) ex_head = 184 LIST_HEAD_INITIALIZER(ex_head); 185 struct exec_entry { 186 LIST_ENTRY(exec_entry) ex_list; 187 SLIST_ENTRY(exec_entry) ex_slist; 188 const struct execsw *ex_sw; 189 }; 190 191 #ifndef __HAVE_SYSCALL_INTERN 192 void syscall(void); 193 #endif 194 195 /* NetBSD autoloadable syscalls */ 196 #ifdef MODULAR 197 #include <kern/syscalls_autoload.c> 198 #endif 199 200 /* NetBSD emul struct */ 201 struct emul emul_netbsd = { 202 .e_name = "netbsd", 203 #ifdef EMUL_NATIVEROOT 204 .e_path = EMUL_NATIVEROOT, 205 #else 206 .e_path = NULL, 207 #endif 208 #ifndef __HAVE_MINIMAL_EMUL 209 .e_flags = EMUL_HAS_SYS___syscall, 210 .e_errno = NULL, 211 .e_nosys = SYS_syscall, 212 .e_nsysent = SYS_NSYSENT, 213 #endif 214 #ifdef MODULAR 215 .e_sc_autoload = netbsd_syscalls_autoload, 216 #endif 217 .e_sysent = sysent, 218 .e_nomodbits = sysent_nomodbits, 219 #ifdef SYSCALL_DEBUG 220 .e_syscallnames = syscallnames, 221 #else 222 .e_syscallnames = NULL, 223 #endif 224 .e_sendsig = sendsig, 225 .e_trapsignal = trapsignal, 226 .e_sigcode = NULL, 227 .e_esigcode = NULL, 228 .e_sigobject = NULL, 229 .e_setregs = setregs, 230 .e_proc_exec = NULL, 231 .e_proc_fork = NULL, 232 .e_proc_exit = NULL, 233 .e_lwp_fork = NULL, 234 .e_lwp_exit = NULL, 235 #ifdef __HAVE_SYSCALL_INTERN 236 .e_syscall_intern = syscall_intern, 237 #else 238 .e_syscall = syscall, 239 #endif 240 .e_sysctlovly = NULL, 241 .e_vm_default_addr = uvm_default_mapaddr, 242 .e_usertrap = NULL, 243 .e_ucsize = sizeof(ucontext_t), 244 .e_startlwp = startlwp 245 }; 246 247 /* 248 * Exec lock. Used to control access to execsw[] structures. 249 * This must not be static so that netbsd32 can access it, too. 250 */ 251 krwlock_t exec_lock __cacheline_aligned; 252 253 /* 254 * Data used between a loadvm and execve part of an "exec" operation 255 */ 256 struct execve_data { 257 struct exec_package ed_pack; 258 struct pathbuf *ed_pathbuf; 259 struct vattr ed_attr; 260 struct ps_strings ed_arginfo; 261 char *ed_argp; 262 const char *ed_pathstring; 263 char *ed_resolvedname; 264 size_t ed_ps_strings_sz; 265 int ed_szsigcode; 266 size_t ed_argslen; 267 long ed_argc; 268 long ed_envc; 269 }; 270 271 /* 272 * data passed from parent lwp to child during a posix_spawn() 273 */ 274 struct spawn_exec_data { 275 struct execve_data sed_exec; 276 struct posix_spawn_file_actions 277 *sed_actions; 278 struct posix_spawnattr *sed_attrs; 279 struct proc *sed_parent; 280 kcondvar_t sed_cv_child_ready; 281 kmutex_t sed_mtx_child; 282 int sed_error; 283 volatile uint32_t sed_refcnt; 284 }; 285 286 static struct vm_map *exec_map; 287 static struct pool exec_pool; 288 289 static void * 290 exec_pool_alloc(struct pool *pp, int flags) 291 { 292 293 return (void *)uvm_km_alloc(exec_map, NCARGS, 0, 294 UVM_KMF_PAGEABLE | UVM_KMF_WAITVA); 295 } 296 297 static void 298 exec_pool_free(struct pool *pp, void *addr) 299 { 300 301 uvm_km_free(exec_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE); 302 } 303 304 static struct pool_allocator exec_palloc = { 305 .pa_alloc = exec_pool_alloc, 306 .pa_free = exec_pool_free, 307 .pa_pagesz = NCARGS 308 }; 309 310 static void 311 exec_path_free(struct execve_data *data) 312 { 313 pathbuf_stringcopy_put(data->ed_pathbuf, data->ed_pathstring); 314 pathbuf_destroy(data->ed_pathbuf); 315 if (data->ed_resolvedname) 316 PNBUF_PUT(data->ed_resolvedname); 317 } 318 319 static int 320 exec_resolvename(struct lwp *l, struct exec_package *epp, struct vnode *vp, 321 char **rpath) 322 { 323 int error; 324 char *p; 325 326 KASSERT(rpath != NULL); 327 328 *rpath = PNBUF_GET(); 329 error = vnode_to_path(*rpath, MAXPATHLEN, vp, l, l->l_proc); 330 if (error) { 331 DPRINTF(("%s: can't resolve name for %s, error %d\n", 332 __func__, epp->ep_kname, error)); 333 PNBUF_PUT(*rpath); 334 *rpath = NULL; 335 return error; 336 } 337 epp->ep_resolvedname = *rpath; 338 if ((p = strrchr(*rpath, '/')) != NULL) 339 epp->ep_kname = p + 1; 340 return 0; 341 } 342 343 344 /* 345 * check exec: 346 * given an "executable" described in the exec package's namei info, 347 * see what we can do with it. 348 * 349 * ON ENTRY: 350 * exec package with appropriate namei info 351 * lwp pointer of exec'ing lwp 352 * NO SELF-LOCKED VNODES 353 * 354 * ON EXIT: 355 * error: nothing held, etc. exec header still allocated. 356 * ok: filled exec package, executable's vnode (unlocked). 357 * 358 * EXEC SWITCH ENTRY: 359 * Locked vnode to check, exec package, proc. 360 * 361 * EXEC SWITCH EXIT: 362 * ok: return 0, filled exec package, executable's vnode (unlocked). 363 * error: destructive: 364 * everything deallocated execept exec header. 365 * non-destructive: 366 * error code, executable's vnode (unlocked), 367 * exec header unmodified. 368 */ 369 int 370 /*ARGSUSED*/ 371 check_exec(struct lwp *l, struct exec_package *epp, struct pathbuf *pb, 372 char **rpath) 373 { 374 int error, i; 375 struct vnode *vp; 376 size_t resid; 377 378 if (epp->ep_resolvedname) { 379 struct nameidata nd; 380 381 // grab the absolute pathbuf here before namei() trashes it. 382 pathbuf_copystring(pb, epp->ep_resolvedname, PATH_MAX); 383 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); 384 385 /* first get the vnode */ 386 if ((error = namei(&nd)) != 0) 387 return error; 388 389 epp->ep_vp = vp = nd.ni_vp; 390 #ifdef DIAGNOSTIC 391 /* paranoia (take this out once namei stuff stabilizes) */ 392 memset(nd.ni_pnbuf, '~', PATH_MAX); 393 #endif 394 } else { 395 struct file *fp; 396 397 if ((error = fd_getvnode(epp->ep_xfd, &fp)) != 0) 398 return error; 399 epp->ep_vp = vp = fp->f_vnode; 400 vref(vp); 401 fd_putfile(epp->ep_xfd); 402 if ((error = exec_resolvename(l, epp, vp, rpath)) != 0) 403 return error; 404 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 405 } 406 407 /* check access and type */ 408 if (vp->v_type != VREG) { 409 error = EACCES; 410 goto bad1; 411 } 412 if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) 413 goto bad1; 414 415 /* get attributes */ 416 /* XXX VOP_GETATTR is the only thing that needs LK_EXCLUSIVE here */ 417 if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred)) != 0) 418 goto bad1; 419 420 /* Check mount point */ 421 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 422 error = EACCES; 423 goto bad1; 424 } 425 if (vp->v_mount->mnt_flag & MNT_NOSUID) 426 epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); 427 428 /* try to open it */ 429 if ((error = VOP_OPEN(vp, FREAD, l->l_cred)) != 0) 430 goto bad1; 431 432 /* now we have the file, get the exec header */ 433 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 434 UIO_SYSSPACE, IO_NODELOCKED, l->l_cred, &resid, NULL); 435 if (error) 436 goto bad1; 437 438 /* unlock vp, since we need it unlocked from here on out. */ 439 VOP_UNLOCK(vp); 440 441 #if NVERIEXEC > 0 442 error = veriexec_verify(l, vp, 443 epp->ep_resolvedname ? epp->ep_resolvedname : epp->ep_kname, 444 epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT, 445 NULL); 446 if (error) 447 goto bad2; 448 #endif /* NVERIEXEC > 0 */ 449 450 #ifdef PAX_SEGVGUARD 451 error = pax_segvguard(l, vp, epp->ep_resolvedname, false); 452 if (error) 453 goto bad2; 454 #endif /* PAX_SEGVGUARD */ 455 456 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 457 458 /* 459 * Set up default address space limits. Can be overridden 460 * by individual exec packages. 461 */ 462 epp->ep_vm_minaddr = exec_vm_minaddr(VM_MIN_ADDRESS); 463 epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS; 464 465 /* 466 * set up the vmcmds for creation of the process 467 * address space 468 */ 469 error = ENOEXEC; 470 for (i = 0; i < nexecs; i++) { 471 int newerror; 472 473 epp->ep_esch = execsw[i]; 474 newerror = (*execsw[i]->es_makecmds)(l, epp); 475 476 if (!newerror) { 477 /* Seems ok: check that entry point is not too high */ 478 if (epp->ep_entry >= epp->ep_vm_maxaddr) { 479 #ifdef DIAGNOSTIC 480 printf("%s: rejecting %p due to " 481 "too high entry address (>= %p)\n", 482 __func__, (void *)epp->ep_entry, 483 (void *)epp->ep_vm_maxaddr); 484 #endif 485 error = ENOEXEC; 486 break; 487 } 488 /* Seems ok: check that entry point is not too low */ 489 if (epp->ep_entry < epp->ep_vm_minaddr) { 490 #ifdef DIAGNOSTIC 491 printf("%s: rejecting %p due to " 492 "too low entry address (< %p)\n", 493 __func__, (void *)epp->ep_entry, 494 (void *)epp->ep_vm_minaddr); 495 #endif 496 error = ENOEXEC; 497 break; 498 } 499 500 /* check limits */ 501 #ifdef DIAGNOSTIC 502 #define LMSG "%s: rejecting due to %s limit (%ju > %ju)\n" 503 #endif 504 #ifdef MAXTSIZ 505 if (epp->ep_tsize > MAXTSIZ) { 506 #ifdef DIAGNOSTIC 507 printf(LMSG, __func__, "text", 508 (uintmax_t)epp->ep_tsize, 509 (uintmax_t)MAXTSIZ); 510 #endif 511 error = ENOMEM; 512 break; 513 } 514 #endif 515 vsize_t dlimit = 516 (vsize_t)l->l_proc->p_rlimit[RLIMIT_DATA].rlim_cur; 517 if (epp->ep_dsize > dlimit) { 518 #ifdef DIAGNOSTIC 519 printf(LMSG, __func__, "data", 520 (uintmax_t)epp->ep_dsize, 521 (uintmax_t)dlimit); 522 #endif 523 error = ENOMEM; 524 break; 525 } 526 return 0; 527 } 528 529 /* 530 * Reset all the fields that may have been modified by the 531 * loader. 532 */ 533 KASSERT(epp->ep_emul_arg == NULL); 534 if (epp->ep_emul_root != NULL) { 535 vrele(epp->ep_emul_root); 536 epp->ep_emul_root = NULL; 537 } 538 if (epp->ep_interp != NULL) { 539 vrele(epp->ep_interp); 540 epp->ep_interp = NULL; 541 } 542 epp->ep_pax_flags = 0; 543 544 /* make sure the first "interesting" error code is saved. */ 545 if (error == ENOEXEC) 546 error = newerror; 547 548 if (epp->ep_flags & EXEC_DESTR) 549 /* Error from "#!" code, tidied up by recursive call */ 550 return error; 551 } 552 553 /* not found, error */ 554 555 /* 556 * free any vmspace-creation commands, 557 * and release their references 558 */ 559 kill_vmcmds(&epp->ep_vmcmds); 560 561 #if NVERIEXEC > 0 || defined(PAX_SEGVGUARD) 562 bad2: 563 #endif 564 /* 565 * close and release the vnode, restore the old one, free the 566 * pathname buf, and punt. 567 */ 568 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 569 VOP_CLOSE(vp, FREAD, l->l_cred); 570 vput(vp); 571 return error; 572 573 bad1: 574 /* 575 * free the namei pathname buffer, and put the vnode 576 * (which we don't yet have open). 577 */ 578 vput(vp); /* was still locked */ 579 return error; 580 } 581 582 #ifdef __MACHINE_STACK_GROWS_UP 583 #define STACK_PTHREADSPACE NBPG 584 #else 585 #define STACK_PTHREADSPACE 0 586 #endif 587 588 static int 589 execve_fetch_element(char * const *array, size_t index, char **value) 590 { 591 return copyin(array + index, value, sizeof(*value)); 592 } 593 594 /* 595 * exec system call 596 */ 597 int 598 sys_execve(struct lwp *l, const struct sys_execve_args *uap, register_t *retval) 599 { 600 /* { 601 syscallarg(const char *) path; 602 syscallarg(char * const *) argp; 603 syscallarg(char * const *) envp; 604 } */ 605 606 return execve1(l, true, SCARG(uap, path), -1, SCARG(uap, argp), 607 SCARG(uap, envp), execve_fetch_element); 608 } 609 610 int 611 sys_fexecve(struct lwp *l, const struct sys_fexecve_args *uap, 612 register_t *retval) 613 { 614 /* { 615 syscallarg(int) fd; 616 syscallarg(char * const *) argp; 617 syscallarg(char * const *) envp; 618 } */ 619 620 return execve1(l, false, NULL, SCARG(uap, fd), SCARG(uap, argp), 621 SCARG(uap, envp), execve_fetch_element); 622 } 623 624 /* 625 * Load modules to try and execute an image that we do not understand. 626 * If no execsw entries are present, we load those likely to be needed 627 * in order to run native images only. Otherwise, we autoload all 628 * possible modules that could let us run the binary. XXX lame 629 */ 630 static void 631 exec_autoload(void) 632 { 633 #ifdef MODULAR 634 static const char * const native[] = { 635 "exec_elf32", 636 "exec_elf64", 637 "exec_script", 638 NULL 639 }; 640 static const char * const compat[] = { 641 "exec_elf32", 642 "exec_elf64", 643 "exec_script", 644 "exec_aout", 645 "exec_coff", 646 "exec_ecoff", 647 "compat_aoutm68k", 648 "compat_netbsd32", 649 #if 0 650 "compat_linux", 651 "compat_linux32", 652 #endif 653 "compat_sunos", 654 "compat_sunos32", 655 "compat_ultrix", 656 NULL 657 }; 658 char const * const *list; 659 int i; 660 661 list = nexecs == 0 ? native : compat; 662 for (i = 0; list[i] != NULL; i++) { 663 if (module_autoload(list[i], MODULE_CLASS_EXEC) != 0) { 664 continue; 665 } 666 yield(); 667 } 668 #endif 669 } 670 671 /* 672 * Copy the user or kernel supplied upath to the allocated pathbuffer pbp 673 * making it absolute in the process, by prepending the current working 674 * directory if it is not. If offs is supplied it will contain the offset 675 * where the original supplied copy of upath starts. 676 */ 677 int 678 exec_makepathbuf(struct lwp *l, const char *upath, enum uio_seg seg, 679 struct pathbuf **pbp, size_t *offs) 680 { 681 char *path, *bp; 682 size_t len, tlen; 683 int error; 684 struct cwdinfo *cwdi; 685 686 path = PNBUF_GET(); 687 if (seg == UIO_SYSSPACE) { 688 error = copystr(upath, path, MAXPATHLEN, &len); 689 } else { 690 error = copyinstr(upath, path, MAXPATHLEN, &len); 691 } 692 if (error) 693 goto err; 694 695 if (path[0] == '/') { 696 if (offs) 697 *offs = 0; 698 goto out; 699 } 700 701 len++; 702 if (len + 1 >= MAXPATHLEN) { 703 error = ENAMETOOLONG; 704 goto err; 705 } 706 bp = path + MAXPATHLEN - len; 707 memmove(bp, path, len); 708 *(--bp) = '/'; 709 710 cwdi = l->l_proc->p_cwdi; 711 rw_enter(&cwdi->cwdi_lock, RW_READER); 712 error = getcwd_common(cwdi->cwdi_cdir, NULL, &bp, path, MAXPATHLEN / 2, 713 GETCWD_CHECK_ACCESS, l); 714 rw_exit(&cwdi->cwdi_lock); 715 716 if (error) 717 goto err; 718 tlen = path + MAXPATHLEN - bp; 719 720 memmove(path, bp, tlen); 721 path[tlen - 1] = '\0'; 722 if (offs) 723 *offs = tlen - len; 724 out: 725 *pbp = pathbuf_assimilate(path); 726 return 0; 727 err: 728 PNBUF_PUT(path); 729 return error; 730 } 731 732 vaddr_t 733 exec_vm_minaddr(vaddr_t va_min) 734 { 735 /* 736 * Increase va_min if we don't want NULL to be mappable by the 737 * process. 738 */ 739 #define VM_MIN_GUARD PAGE_SIZE 740 if (user_va0_disable && (va_min < VM_MIN_GUARD)) 741 return VM_MIN_GUARD; 742 return va_min; 743 } 744 745 static int 746 execve_loadvm(struct lwp *l, bool has_path, const char *path, int fd, 747 char * const *args, char * const *envs, 748 execve_fetch_element_t fetch_element, 749 struct execve_data * restrict data) 750 { 751 struct exec_package * const epp = &data->ed_pack; 752 int error; 753 struct proc *p; 754 char *dp; 755 u_int modgen; 756 757 KASSERT(data != NULL); 758 759 p = l->l_proc; 760 modgen = 0; 761 762 SDT_PROBE(proc, kernel, , exec, path, 0, 0, 0, 0); 763 764 /* 765 * Check if we have exceeded our number of processes limit. 766 * This is so that we handle the case where a root daemon 767 * forked, ran setuid to become the desired user and is trying 768 * to exec. The obvious place to do the reference counting check 769 * is setuid(), but we don't do the reference counting check there 770 * like other OS's do because then all the programs that use setuid() 771 * must be modified to check the return code of setuid() and exit(). 772 * It is dangerous to make setuid() fail, because it fails open and 773 * the program will continue to run as root. If we make it succeed 774 * and return an error code, again we are not enforcing the limit. 775 * The best place to enforce the limit is here, when the process tries 776 * to execute a new image, because eventually the process will need 777 * to call exec in order to do something useful. 778 */ 779 retry: 780 if (p->p_flag & PK_SUGID) { 781 if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_RLIMIT, 782 p, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS), 783 &p->p_rlimit[RLIMIT_NPROC], 784 KAUTH_ARG(RLIMIT_NPROC)) != 0 && 785 chgproccnt(kauth_cred_getuid(l->l_cred), 0) > 786 p->p_rlimit[RLIMIT_NPROC].rlim_cur) 787 return EAGAIN; 788 } 789 790 /* 791 * Drain existing references and forbid new ones. The process 792 * should be left alone until we're done here. This is necessary 793 * to avoid race conditions - e.g. in ptrace() - that might allow 794 * a local user to illicitly obtain elevated privileges. 795 */ 796 rw_enter(&p->p_reflock, RW_WRITER); 797 798 if (has_path) { 799 size_t offs; 800 /* 801 * Init the namei data to point the file user's program name. 802 * This is done here rather than in check_exec(), so that it's 803 * possible to override this settings if any of makecmd/probe 804 * functions call check_exec() recursively - for example, 805 * see exec_script_makecmds(). 806 */ 807 if ((error = exec_makepathbuf(l, path, UIO_USERSPACE, 808 &data->ed_pathbuf, &offs)) != 0) 809 goto clrflg; 810 data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf); 811 epp->ep_kname = data->ed_pathstring + offs; 812 data->ed_resolvedname = PNBUF_GET(); 813 epp->ep_resolvedname = data->ed_resolvedname; 814 epp->ep_xfd = -1; 815 } else { 816 data->ed_pathbuf = pathbuf_assimilate(strcpy(PNBUF_GET(), "/")); 817 data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf); 818 epp->ep_kname = "*fexecve*"; 819 data->ed_resolvedname = NULL; 820 epp->ep_resolvedname = NULL; 821 epp->ep_xfd = fd; 822 } 823 824 825 /* 826 * initialize the fields of the exec package. 827 */ 828 epp->ep_hdr = kmem_alloc(exec_maxhdrsz, KM_SLEEP); 829 epp->ep_hdrlen = exec_maxhdrsz; 830 epp->ep_hdrvalid = 0; 831 epp->ep_emul_arg = NULL; 832 epp->ep_emul_arg_free = NULL; 833 memset(&epp->ep_vmcmds, 0, sizeof(epp->ep_vmcmds)); 834 epp->ep_vap = &data->ed_attr; 835 epp->ep_flags = (p->p_flag & PK_32) ? EXEC_FROM32 : 0; 836 MD_TOPDOWN_INIT(epp); 837 epp->ep_emul_root = NULL; 838 epp->ep_interp = NULL; 839 epp->ep_esch = NULL; 840 epp->ep_pax_flags = 0; 841 memset(epp->ep_machine_arch, 0, sizeof(epp->ep_machine_arch)); 842 843 rw_enter(&exec_lock, RW_READER); 844 845 /* see if we can run it. */ 846 if ((error = check_exec(l, epp, data->ed_pathbuf, 847 &data->ed_resolvedname)) != 0) { 848 if (error != ENOENT && error != EACCES && error != ENOEXEC) { 849 DPRINTF(("%s: check exec failed for %s, error %d\n", 850 __func__, epp->ep_kname, error)); 851 } 852 goto freehdr; 853 } 854 855 /* allocate an argument buffer */ 856 data->ed_argp = pool_get(&exec_pool, PR_WAITOK); 857 KASSERT(data->ed_argp != NULL); 858 dp = data->ed_argp; 859 860 if ((error = copyinargs(data, args, envs, fetch_element, &dp)) != 0) { 861 goto bad; 862 } 863 864 /* 865 * Calculate the new stack size. 866 */ 867 868 #ifdef __MACHINE_STACK_GROWS_UP 869 /* 870 * copyargs() fills argc/argv/envp from the lower address even on 871 * __MACHINE_STACK_GROWS_UP machines. Reserve a few words just below the SP 872 * so that _rtld() use it. 873 */ 874 #define RTLD_GAP 32 875 #else 876 #define RTLD_GAP 0 877 #endif 878 879 const size_t argenvstrlen = (char *)ALIGN(dp) - data->ed_argp; 880 881 data->ed_argslen = calcargs(data, argenvstrlen); 882 883 const size_t len = calcstack(data, pax_aslr_stack_gap(epp) + RTLD_GAP); 884 885 if (len > epp->ep_ssize) { 886 /* in effect, compare to initial limit */ 887 DPRINTF(("%s: stack limit exceeded %zu\n", __func__, len)); 888 error = ENOMEM; 889 goto bad; 890 } 891 /* adjust "active stack depth" for process VSZ */ 892 epp->ep_ssize = len; 893 894 return 0; 895 896 bad: 897 /* free the vmspace-creation commands, and release their references */ 898 kill_vmcmds(&epp->ep_vmcmds); 899 /* kill any opened file descriptor, if necessary */ 900 if (epp->ep_flags & EXEC_HASFD) { 901 epp->ep_flags &= ~EXEC_HASFD; 902 fd_close(epp->ep_fd); 903 } 904 /* close and put the exec'd file */ 905 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 906 VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred); 907 vput(epp->ep_vp); 908 pool_put(&exec_pool, data->ed_argp); 909 910 freehdr: 911 kmem_free(epp->ep_hdr, epp->ep_hdrlen); 912 if (epp->ep_emul_root != NULL) 913 vrele(epp->ep_emul_root); 914 if (epp->ep_interp != NULL) 915 vrele(epp->ep_interp); 916 917 rw_exit(&exec_lock); 918 919 exec_path_free(data); 920 921 clrflg: 922 rw_exit(&p->p_reflock); 923 924 if (modgen != module_gen && error == ENOEXEC) { 925 modgen = module_gen; 926 exec_autoload(); 927 goto retry; 928 } 929 930 SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0); 931 return error; 932 } 933 934 static int 935 execve_dovmcmds(struct lwp *l, struct execve_data * restrict data) 936 { 937 struct exec_package * const epp = &data->ed_pack; 938 struct proc *p = l->l_proc; 939 struct exec_vmcmd *base_vcp; 940 int error = 0; 941 size_t i; 942 943 /* record proc's vnode, for use by procfs and others */ 944 if (p->p_textvp) 945 vrele(p->p_textvp); 946 vref(epp->ep_vp); 947 p->p_textvp = epp->ep_vp; 948 949 /* create the new process's VM space by running the vmcmds */ 950 KASSERTMSG(epp->ep_vmcmds.evs_used != 0, "%s: no vmcmds", __func__); 951 952 #ifdef TRACE_EXEC 953 DUMPVMCMDS(epp, 0, 0); 954 #endif 955 956 base_vcp = NULL; 957 958 for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) { 959 struct exec_vmcmd *vcp; 960 961 vcp = &epp->ep_vmcmds.evs_cmds[i]; 962 if (vcp->ev_flags & VMCMD_RELATIVE) { 963 KASSERTMSG(base_vcp != NULL, 964 "%s: relative vmcmd with no base", __func__); 965 KASSERTMSG((vcp->ev_flags & VMCMD_BASE) == 0, 966 "%s: illegal base & relative vmcmd", __func__); 967 vcp->ev_addr += base_vcp->ev_addr; 968 } 969 error = (*vcp->ev_proc)(l, vcp); 970 if (error) 971 DUMPVMCMDS(epp, i, error); 972 if (vcp->ev_flags & VMCMD_BASE) 973 base_vcp = vcp; 974 } 975 976 /* free the vmspace-creation commands, and release their references */ 977 kill_vmcmds(&epp->ep_vmcmds); 978 979 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 980 VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred); 981 vput(epp->ep_vp); 982 983 /* if an error happened, deallocate and punt */ 984 if (error != 0) { 985 DPRINTF(("%s: vmcmd %zu failed: %d\n", __func__, i - 1, error)); 986 } 987 return error; 988 } 989 990 static void 991 execve_free_data(struct execve_data *data) 992 { 993 struct exec_package * const epp = &data->ed_pack; 994 995 /* free the vmspace-creation commands, and release their references */ 996 kill_vmcmds(&epp->ep_vmcmds); 997 /* kill any opened file descriptor, if necessary */ 998 if (epp->ep_flags & EXEC_HASFD) { 999 epp->ep_flags &= ~EXEC_HASFD; 1000 fd_close(epp->ep_fd); 1001 } 1002 1003 /* close and put the exec'd file */ 1004 vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); 1005 VOP_CLOSE(epp->ep_vp, FREAD, curlwp->l_cred); 1006 vput(epp->ep_vp); 1007 pool_put(&exec_pool, data->ed_argp); 1008 1009 kmem_free(epp->ep_hdr, epp->ep_hdrlen); 1010 if (epp->ep_emul_root != NULL) 1011 vrele(epp->ep_emul_root); 1012 if (epp->ep_interp != NULL) 1013 vrele(epp->ep_interp); 1014 1015 exec_path_free(data); 1016 } 1017 1018 static void 1019 pathexec(struct proc *p, const char *resolvedname) 1020 { 1021 /* set command name & other accounting info */ 1022 const char *cmdname; 1023 1024 if (resolvedname == NULL) { 1025 cmdname = "*fexecve*"; 1026 resolvedname = "/"; 1027 } else { 1028 cmdname = strrchr(resolvedname, '/') + 1; 1029 } 1030 KASSERTMSG(resolvedname[0] == '/', "bad resolvedname `%s'", 1031 resolvedname); 1032 1033 strlcpy(p->p_comm, cmdname, sizeof(p->p_comm)); 1034 1035 kmem_strfree(p->p_path); 1036 p->p_path = kmem_strdupsize(resolvedname, NULL, KM_SLEEP); 1037 } 1038 1039 /* XXX elsewhere */ 1040 static int 1041 credexec(struct lwp *l, struct execve_data *data) 1042 { 1043 struct proc *p = l->l_proc; 1044 struct vattr *attr = &data->ed_attr; 1045 int error; 1046 1047 /* 1048 * Deal with set[ug]id. MNT_NOSUID has already been used to disable 1049 * s[ug]id. It's OK to check for PSL_TRACED here as we have blocked 1050 * out additional references on the process for the moment. 1051 */ 1052 if ((p->p_slflag & PSL_TRACED) == 0 && 1053 1054 (((attr->va_mode & S_ISUID) != 0 && 1055 kauth_cred_geteuid(l->l_cred) != attr->va_uid) || 1056 1057 ((attr->va_mode & S_ISGID) != 0 && 1058 kauth_cred_getegid(l->l_cred) != attr->va_gid))) { 1059 /* 1060 * Mark the process as SUGID before we do 1061 * anything that might block. 1062 */ 1063 proc_crmod_enter(); 1064 proc_crmod_leave(NULL, NULL, true); 1065 if (data->ed_argc == 0) { 1066 DPRINTF(( 1067 "%s: not executing set[ug]id binary with no args\n", 1068 __func__)); 1069 return EINVAL; 1070 } 1071 1072 /* Make sure file descriptors 0..2 are in use. */ 1073 if ((error = fd_checkstd()) != 0) { 1074 DPRINTF(("%s: fdcheckstd failed %d\n", 1075 __func__, error)); 1076 return error; 1077 } 1078 1079 /* 1080 * Copy the credential so other references don't see our 1081 * changes. 1082 */ 1083 l->l_cred = kauth_cred_copy(l->l_cred); 1084 #ifdef KTRACE 1085 /* 1086 * If the persistent trace flag isn't set, turn off. 1087 */ 1088 if (p->p_tracep) { 1089 mutex_enter(&ktrace_lock); 1090 if (!(p->p_traceflag & KTRFAC_PERSISTENT)) 1091 ktrderef(p); 1092 mutex_exit(&ktrace_lock); 1093 } 1094 #endif 1095 if (attr->va_mode & S_ISUID) 1096 kauth_cred_seteuid(l->l_cred, attr->va_uid); 1097 if (attr->va_mode & S_ISGID) 1098 kauth_cred_setegid(l->l_cred, attr->va_gid); 1099 } else { 1100 if (kauth_cred_geteuid(l->l_cred) == 1101 kauth_cred_getuid(l->l_cred) && 1102 kauth_cred_getegid(l->l_cred) == 1103 kauth_cred_getgid(l->l_cred)) 1104 p->p_flag &= ~PK_SUGID; 1105 } 1106 1107 /* 1108 * Copy the credential so other references don't see our changes. 1109 * Test to see if this is necessary first, since in the common case 1110 * we won't need a private reference. 1111 */ 1112 if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) || 1113 kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) { 1114 l->l_cred = kauth_cred_copy(l->l_cred); 1115 kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred)); 1116 kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred)); 1117 } 1118 1119 /* Update the master credentials. */ 1120 if (l->l_cred != p->p_cred) { 1121 kauth_cred_t ocred; 1122 mutex_enter(p->p_lock); 1123 ocred = p->p_cred; 1124 p->p_cred = kauth_cred_hold(l->l_cred); 1125 mutex_exit(p->p_lock); 1126 kauth_cred_free(ocred); 1127 } 1128 1129 return 0; 1130 } 1131 1132 static void 1133 emulexec(struct lwp *l, struct exec_package *epp) 1134 { 1135 struct proc *p = l->l_proc; 1136 1137 /* The emulation root will usually have been found when we looked 1138 * for the elf interpreter (or similar), if not look now. */ 1139 if (epp->ep_esch->es_emul->e_path != NULL && 1140 epp->ep_emul_root == NULL) 1141 emul_find_root(l, epp); 1142 1143 /* Any old emulation root got removed by fdcloseexec */ 1144 rw_enter(&p->p_cwdi->cwdi_lock, RW_WRITER); 1145 p->p_cwdi->cwdi_edir = epp->ep_emul_root; 1146 rw_exit(&p->p_cwdi->cwdi_lock); 1147 epp->ep_emul_root = NULL; 1148 if (epp->ep_interp != NULL) 1149 vrele(epp->ep_interp); 1150 1151 /* 1152 * Call emulation specific exec hook. This can setup per-process 1153 * p->p_emuldata or do any other per-process stuff an emulation needs. 1154 * 1155 * If we are executing process of different emulation than the 1156 * original forked process, call e_proc_exit() of the old emulation 1157 * first, then e_proc_exec() of new emulation. If the emulation is 1158 * same, the exec hook code should deallocate any old emulation 1159 * resources held previously by this process. 1160 */ 1161 if (p->p_emul && p->p_emul->e_proc_exit 1162 && p->p_emul != epp->ep_esch->es_emul) 1163 (*p->p_emul->e_proc_exit)(p); 1164 1165 /* 1166 * Call exec hook. Emulation code may NOT store reference to anything 1167 * from &pack. 1168 */ 1169 if (epp->ep_esch->es_emul->e_proc_exec) 1170 (*epp->ep_esch->es_emul->e_proc_exec)(p, epp); 1171 1172 /* update p_emul, the old value is no longer needed */ 1173 p->p_emul = epp->ep_esch->es_emul; 1174 1175 /* ...and the same for p_execsw */ 1176 p->p_execsw = epp->ep_esch; 1177 1178 #ifdef __HAVE_SYSCALL_INTERN 1179 (*p->p_emul->e_syscall_intern)(p); 1180 #endif 1181 ktremul(); 1182 } 1183 1184 static int 1185 execve_runproc(struct lwp *l, struct execve_data * restrict data, 1186 bool no_local_exec_lock, bool is_spawn) 1187 { 1188 struct exec_package * const epp = &data->ed_pack; 1189 int error = 0; 1190 struct proc *p; 1191 struct vmspace *vm; 1192 1193 /* 1194 * In case of a posix_spawn operation, the child doing the exec 1195 * might not hold the reader lock on exec_lock, but the parent 1196 * will do this instead. 1197 */ 1198 KASSERT(no_local_exec_lock || rw_lock_held(&exec_lock)); 1199 KASSERT(!no_local_exec_lock || is_spawn); 1200 KASSERT(data != NULL); 1201 1202 p = l->l_proc; 1203 1204 /* Get rid of other LWPs. */ 1205 if (p->p_nlwps > 1) { 1206 mutex_enter(p->p_lock); 1207 exit_lwps(l); 1208 mutex_exit(p->p_lock); 1209 } 1210 KDASSERT(p->p_nlwps == 1); 1211 1212 /* 1213 * All of the other LWPs got rid of their robust futexes 1214 * when they exited above, but we might still have some 1215 * to dispose of. Do that now. 1216 */ 1217 if (__predict_false(l->l_robust_head != 0)) { 1218 futex_release_all_lwp(l); 1219 /* 1220 * Since this LWP will live on with a different 1221 * program image, we need to clear the robust 1222 * futex list pointer here. 1223 */ 1224 l->l_robust_head = 0; 1225 } 1226 1227 /* Destroy any lwpctl info. */ 1228 if (p->p_lwpctl != NULL) 1229 lwp_ctl_exit(); 1230 1231 /* Remove POSIX timers */ 1232 ptimers_free(p, TIMERS_POSIX); 1233 1234 /* Set the PaX flags. */ 1235 pax_set_flags(epp, p); 1236 1237 /* 1238 * Do whatever is necessary to prepare the address space 1239 * for remapping. Note that this might replace the current 1240 * vmspace with another! 1241 * 1242 * vfork(): do not touch any user space data in the new child 1243 * until we have awoken the parent below, or it will defeat 1244 * lazy pmap switching (on x86). 1245 */ 1246 if (is_spawn) 1247 uvmspace_spawn(l, epp->ep_vm_minaddr, 1248 epp->ep_vm_maxaddr, 1249 epp->ep_flags & EXEC_TOPDOWN_VM); 1250 else 1251 uvmspace_exec(l, epp->ep_vm_minaddr, 1252 epp->ep_vm_maxaddr, 1253 epp->ep_flags & EXEC_TOPDOWN_VM); 1254 vm = p->p_vmspace; 1255 1256 vm->vm_taddr = (void *)epp->ep_taddr; 1257 vm->vm_tsize = btoc(epp->ep_tsize); 1258 vm->vm_daddr = (void*)epp->ep_daddr; 1259 vm->vm_dsize = btoc(epp->ep_dsize); 1260 vm->vm_ssize = btoc(epp->ep_ssize); 1261 vm->vm_issize = 0; 1262 vm->vm_maxsaddr = (void *)epp->ep_maxsaddr; 1263 vm->vm_minsaddr = (void *)epp->ep_minsaddr; 1264 1265 pax_aslr_init_vm(l, vm, epp); 1266 1267 cwdexec(p); 1268 fd_closeexec(); /* handle close on exec */ 1269 1270 if (__predict_false(ktrace_on)) 1271 fd_ktrexecfd(); 1272 1273 execsigs(p); /* reset caught signals */ 1274 1275 mutex_enter(p->p_lock); 1276 l->l_ctxlink = NULL; /* reset ucontext link */ 1277 p->p_acflag &= ~AFORK; 1278 p->p_flag |= PK_EXEC; 1279 mutex_exit(p->p_lock); 1280 1281 error = credexec(l, data); 1282 if (error) 1283 goto exec_abort; 1284 1285 #if defined(__HAVE_RAS) 1286 /* 1287 * Remove all RASs from the address space. 1288 */ 1289 ras_purgeall(); 1290 #endif 1291 1292 /* 1293 * Stop profiling. 1294 */ 1295 if ((p->p_stflag & PST_PROFIL) != 0) { 1296 mutex_spin_enter(&p->p_stmutex); 1297 stopprofclock(p); 1298 mutex_spin_exit(&p->p_stmutex); 1299 } 1300 1301 /* 1302 * It's OK to test PL_PPWAIT unlocked here, as other LWPs have 1303 * exited and exec()/exit() are the only places it will be cleared. 1304 * 1305 * Once the parent has been awoken, curlwp may teleport to a new CPU 1306 * in sched_vforkexec(), and it's then OK to start messing with user 1307 * data. See comment above. 1308 */ 1309 if ((p->p_lflag & PL_PPWAIT) != 0) { 1310 bool samecpu; 1311 lwp_t *lp; 1312 1313 mutex_enter(&proc_lock); 1314 lp = p->p_vforklwp; 1315 p->p_vforklwp = NULL; 1316 l->l_lwpctl = NULL; /* was on loan from blocked parent */ 1317 1318 /* Clear flags after cv_broadcast() (scheduler needs them). */ 1319 p->p_lflag &= ~PL_PPWAIT; 1320 lp->l_vforkwaiting = false; 1321 1322 /* If parent is still on same CPU, teleport curlwp elsewhere. */ 1323 samecpu = (lp->l_cpu == curlwp->l_cpu); 1324 cv_broadcast(&lp->l_waitcv); 1325 mutex_exit(&proc_lock); 1326 1327 /* Give the parent its CPU back - find a new home. */ 1328 KASSERT(!is_spawn); 1329 sched_vforkexec(l, samecpu); 1330 } 1331 1332 /* Now map address space. */ 1333 error = execve_dovmcmds(l, data); 1334 if (error != 0) 1335 goto exec_abort; 1336 1337 pathexec(p, epp->ep_resolvedname); 1338 1339 char * const newstack = STACK_GROW(vm->vm_minsaddr, epp->ep_ssize); 1340 1341 error = copyoutargs(data, l, newstack); 1342 if (error != 0) 1343 goto exec_abort; 1344 1345 doexechooks(p); 1346 1347 /* 1348 * Set initial SP at the top of the stack. 1349 * 1350 * Note that on machines where stack grows up (e.g. hppa), SP points to 1351 * the end of arg/env strings. Userland guesses the address of argc 1352 * via ps_strings::ps_argvstr. 1353 */ 1354 1355 /* Setup new registers and do misc. setup. */ 1356 (*epp->ep_esch->es_emul->e_setregs)(l, epp, (vaddr_t)newstack); 1357 if (epp->ep_esch->es_setregs) 1358 (*epp->ep_esch->es_setregs)(l, epp, (vaddr_t)newstack); 1359 1360 /* Provide a consistent LWP private setting */ 1361 (void)lwp_setprivate(l, NULL); 1362 1363 /* Discard all PCU state; need to start fresh */ 1364 pcu_discard_all(l); 1365 1366 /* map the process's signal trampoline code */ 1367 if ((error = exec_sigcode_map(p, epp->ep_esch->es_emul)) != 0) { 1368 DPRINTF(("%s: map sigcode failed %d\n", __func__, error)); 1369 goto exec_abort; 1370 } 1371 1372 pool_put(&exec_pool, data->ed_argp); 1373 1374 /* 1375 * Notify anyone who might care that we've exec'd. 1376 * 1377 * This is slightly racy; someone could sneak in and 1378 * attach a knote after we've decided not to notify, 1379 * or vice-versa, but that's not particularly bothersome. 1380 * knote_proc_exec() will acquire p->p_lock as needed. 1381 */ 1382 if (!SLIST_EMPTY(&p->p_klist)) { 1383 knote_proc_exec(p); 1384 } 1385 1386 kmem_free(epp->ep_hdr, epp->ep_hdrlen); 1387 1388 SDT_PROBE(proc, kernel, , exec__success, epp->ep_kname, 0, 0, 0, 0); 1389 1390 emulexec(l, epp); 1391 1392 /* Allow new references from the debugger/procfs. */ 1393 rw_exit(&p->p_reflock); 1394 if (!no_local_exec_lock) 1395 rw_exit(&exec_lock); 1396 1397 mutex_enter(&proc_lock); 1398 1399 /* posix_spawn(3) reports a single event with implied exec(3) */ 1400 if ((p->p_slflag & PSL_TRACED) && !is_spawn) { 1401 mutex_enter(p->p_lock); 1402 eventswitch(TRAP_EXEC, 0, 0); 1403 mutex_enter(&proc_lock); 1404 } 1405 1406 if (p->p_sflag & PS_STOPEXEC) { 1407 ksiginfoq_t kq; 1408 1409 KASSERT(l->l_blcnt == 0); 1410 p->p_pptr->p_nstopchild++; 1411 p->p_waited = 0; 1412 mutex_enter(p->p_lock); 1413 ksiginfo_queue_init(&kq); 1414 sigclearall(p, &contsigmask, &kq); 1415 lwp_lock(l); 1416 l->l_stat = LSSTOP; 1417 p->p_stat = SSTOP; 1418 p->p_nrlwps--; 1419 lwp_unlock(l); 1420 mutex_exit(p->p_lock); 1421 mutex_exit(&proc_lock); 1422 lwp_lock(l); 1423 spc_lock(l->l_cpu); 1424 mi_switch(l); 1425 ksiginfo_queue_drain(&kq); 1426 } else { 1427 mutex_exit(&proc_lock); 1428 } 1429 1430 exec_path_free(data); 1431 #ifdef TRACE_EXEC 1432 DPRINTF(("%s finished\n", __func__)); 1433 #endif 1434 return EJUSTRETURN; 1435 1436 exec_abort: 1437 SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0); 1438 rw_exit(&p->p_reflock); 1439 if (!no_local_exec_lock) 1440 rw_exit(&exec_lock); 1441 1442 exec_path_free(data); 1443 1444 /* 1445 * the old process doesn't exist anymore. exit gracefully. 1446 * get rid of the (new) address space we have created, if any, get rid 1447 * of our namei data and vnode, and exit noting failure 1448 */ 1449 if (vm != NULL) { 1450 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 1451 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 1452 } 1453 1454 exec_free_emul_arg(epp); 1455 pool_put(&exec_pool, data->ed_argp); 1456 kmem_free(epp->ep_hdr, epp->ep_hdrlen); 1457 if (epp->ep_emul_root != NULL) 1458 vrele(epp->ep_emul_root); 1459 if (epp->ep_interp != NULL) 1460 vrele(epp->ep_interp); 1461 1462 /* Acquire the sched-state mutex (exit1() will release it). */ 1463 if (!is_spawn) { 1464 mutex_enter(p->p_lock); 1465 exit1(l, error, SIGABRT); 1466 } 1467 1468 return error; 1469 } 1470 1471 int 1472 execve1(struct lwp *l, bool has_path, const char *path, int fd, 1473 char * const *args, char * const *envs, 1474 execve_fetch_element_t fetch_element) 1475 { 1476 struct execve_data data; 1477 int error; 1478 1479 error = execve_loadvm(l, has_path, path, fd, args, envs, fetch_element, 1480 &data); 1481 if (error) 1482 return error; 1483 error = execve_runproc(l, &data, false, false); 1484 return error; 1485 } 1486 1487 static size_t 1488 fromptrsz(const struct exec_package *epp) 1489 { 1490 return (epp->ep_flags & EXEC_FROM32) ? sizeof(int) : sizeof(char *); 1491 } 1492 1493 static size_t 1494 ptrsz(const struct exec_package *epp) 1495 { 1496 return (epp->ep_flags & EXEC_32) ? sizeof(int) : sizeof(char *); 1497 } 1498 1499 static size_t 1500 calcargs(struct execve_data * restrict data, const size_t argenvstrlen) 1501 { 1502 struct exec_package * const epp = &data->ed_pack; 1503 1504 const size_t nargenvptrs = 1505 1 + /* long argc */ 1506 data->ed_argc + /* char *argv[] */ 1507 1 + /* \0 */ 1508 data->ed_envc + /* char *env[] */ 1509 1; /* \0 */ 1510 1511 return (nargenvptrs * ptrsz(epp)) /* pointers */ 1512 + argenvstrlen /* strings */ 1513 + epp->ep_esch->es_arglen; /* auxinfo */ 1514 } 1515 1516 static size_t 1517 calcstack(struct execve_data * restrict data, const size_t gaplen) 1518 { 1519 struct exec_package * const epp = &data->ed_pack; 1520 1521 data->ed_szsigcode = epp->ep_esch->es_emul->e_esigcode - 1522 epp->ep_esch->es_emul->e_sigcode; 1523 1524 data->ed_ps_strings_sz = (epp->ep_flags & EXEC_32) ? 1525 sizeof(struct ps_strings32) : sizeof(struct ps_strings); 1526 1527 const size_t sigcode_psstr_sz = 1528 data->ed_szsigcode + /* sigcode */ 1529 data->ed_ps_strings_sz + /* ps_strings */ 1530 STACK_PTHREADSPACE; /* pthread space */ 1531 1532 const size_t stacklen = 1533 data->ed_argslen + 1534 gaplen + 1535 sigcode_psstr_sz; 1536 1537 /* make the stack "safely" aligned */ 1538 return STACK_LEN_ALIGN(stacklen, STACK_ALIGNBYTES); 1539 } 1540 1541 static int 1542 copyoutargs(struct execve_data * restrict data, struct lwp *l, 1543 char * const newstack) 1544 { 1545 struct exec_package * const epp = &data->ed_pack; 1546 struct proc *p = l->l_proc; 1547 int error; 1548 1549 memset(&data->ed_arginfo, 0, sizeof(data->ed_arginfo)); 1550 1551 /* remember information about the process */ 1552 data->ed_arginfo.ps_nargvstr = data->ed_argc; 1553 data->ed_arginfo.ps_nenvstr = data->ed_envc; 1554 1555 /* 1556 * Allocate the stack address passed to the newly execve()'ed process. 1557 * 1558 * The new stack address will be set to the SP (stack pointer) register 1559 * in setregs(). 1560 */ 1561 1562 char *newargs = STACK_ALLOC( 1563 STACK_SHRINK(newstack, data->ed_argslen), data->ed_argslen); 1564 1565 error = (*epp->ep_esch->es_copyargs)(l, epp, 1566 &data->ed_arginfo, &newargs, data->ed_argp); 1567 1568 if (error) { 1569 DPRINTF(("%s: copyargs failed %d\n", __func__, error)); 1570 return error; 1571 } 1572 1573 error = copyoutpsstrs(data, p); 1574 if (error != 0) 1575 return error; 1576 1577 return 0; 1578 } 1579 1580 static int 1581 copyoutpsstrs(struct execve_data * restrict data, struct proc *p) 1582 { 1583 struct exec_package * const epp = &data->ed_pack; 1584 struct ps_strings32 arginfo32; 1585 void *aip; 1586 int error; 1587 1588 /* fill process ps_strings info */ 1589 p->p_psstrp = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, 1590 STACK_PTHREADSPACE), data->ed_ps_strings_sz); 1591 1592 if (epp->ep_flags & EXEC_32) { 1593 aip = &arginfo32; 1594 arginfo32.ps_argvstr = (vaddr_t)data->ed_arginfo.ps_argvstr; 1595 arginfo32.ps_nargvstr = data->ed_arginfo.ps_nargvstr; 1596 arginfo32.ps_envstr = (vaddr_t)data->ed_arginfo.ps_envstr; 1597 arginfo32.ps_nenvstr = data->ed_arginfo.ps_nenvstr; 1598 } else 1599 aip = &data->ed_arginfo; 1600 1601 /* copy out the process's ps_strings structure */ 1602 if ((error = copyout(aip, (void *)p->p_psstrp, data->ed_ps_strings_sz)) 1603 != 0) { 1604 DPRINTF(("%s: ps_strings copyout %p->%p size %zu failed\n", 1605 __func__, aip, (void *)p->p_psstrp, data->ed_ps_strings_sz)); 1606 return error; 1607 } 1608 1609 return 0; 1610 } 1611 1612 static int 1613 copyinargs(struct execve_data * restrict data, char * const *args, 1614 char * const *envs, execve_fetch_element_t fetch_element, char **dpp) 1615 { 1616 struct exec_package * const epp = &data->ed_pack; 1617 char *dp; 1618 size_t i; 1619 int error; 1620 1621 dp = *dpp; 1622 1623 data->ed_argc = 0; 1624 1625 /* copy the fake args list, if there's one, freeing it as we go */ 1626 if (epp->ep_flags & EXEC_HASARGL) { 1627 struct exec_fakearg *fa = epp->ep_fa; 1628 1629 while (fa->fa_arg != NULL) { 1630 const size_t maxlen = ARG_MAX - (dp - data->ed_argp); 1631 size_t len; 1632 1633 len = strlcpy(dp, fa->fa_arg, maxlen); 1634 /* Count NUL into len. */ 1635 if (len < maxlen) 1636 len++; 1637 else { 1638 while (fa->fa_arg != NULL) { 1639 kmem_free(fa->fa_arg, fa->fa_len); 1640 fa++; 1641 } 1642 kmem_free(epp->ep_fa, epp->ep_fa_len); 1643 epp->ep_flags &= ~EXEC_HASARGL; 1644 return E2BIG; 1645 } 1646 ktrexecarg(fa->fa_arg, len - 1); 1647 dp += len; 1648 1649 kmem_free(fa->fa_arg, fa->fa_len); 1650 fa++; 1651 data->ed_argc++; 1652 } 1653 kmem_free(epp->ep_fa, epp->ep_fa_len); 1654 epp->ep_flags &= ~EXEC_HASARGL; 1655 } 1656 1657 /* 1658 * Read and count argument strings from user. 1659 */ 1660 1661 if (args == NULL) { 1662 DPRINTF(("%s: null args\n", __func__)); 1663 return EINVAL; 1664 } 1665 if (epp->ep_flags & EXEC_SKIPARG) 1666 args = (const void *)((const char *)args + fromptrsz(epp)); 1667 i = 0; 1668 error = copyinargstrs(data, args, fetch_element, &dp, &i, ktr_execarg); 1669 if (error != 0) { 1670 DPRINTF(("%s: copyin arg %d\n", __func__, error)); 1671 return error; 1672 } 1673 data->ed_argc += i; 1674 1675 /* 1676 * Read and count environment strings from user. 1677 */ 1678 1679 data->ed_envc = 0; 1680 /* environment need not be there */ 1681 if (envs == NULL) 1682 goto done; 1683 i = 0; 1684 error = copyinargstrs(data, envs, fetch_element, &dp, &i, ktr_execenv); 1685 if (error != 0) { 1686 DPRINTF(("%s: copyin env %d\n", __func__, error)); 1687 return error; 1688 } 1689 data->ed_envc += i; 1690 1691 done: 1692 *dpp = dp; 1693 1694 return 0; 1695 } 1696 1697 static int 1698 copyinargstrs(struct execve_data * restrict data, char * const *strs, 1699 execve_fetch_element_t fetch_element, char **dpp, size_t *ip, 1700 void (*ktr)(const void *, size_t)) 1701 { 1702 char *dp, *sp; 1703 size_t i; 1704 int error; 1705 1706 dp = *dpp; 1707 1708 i = 0; 1709 while (1) { 1710 const size_t maxlen = ARG_MAX - (dp - data->ed_argp); 1711 size_t len; 1712 1713 if ((error = (*fetch_element)(strs, i, &sp)) != 0) { 1714 return error; 1715 } 1716 if (!sp) 1717 break; 1718 if ((error = copyinstr(sp, dp, maxlen, &len)) != 0) { 1719 if (error == ENAMETOOLONG) 1720 error = E2BIG; 1721 return error; 1722 } 1723 if (__predict_false(ktrace_on)) 1724 (*ktr)(dp, len - 1); 1725 dp += len; 1726 i++; 1727 } 1728 1729 *dpp = dp; 1730 *ip = i; 1731 1732 return 0; 1733 } 1734 1735 /* 1736 * Copy argv and env strings from kernel buffer (argp) to the new stack. 1737 * Those strings are located just after auxinfo. 1738 */ 1739 int 1740 copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo, 1741 char **stackp, void *argp) 1742 { 1743 char **cpp, *dp, *sp; 1744 size_t len; 1745 void *nullp; 1746 long argc, envc; 1747 int error; 1748 1749 cpp = (char **)*stackp; 1750 nullp = NULL; 1751 argc = arginfo->ps_nargvstr; 1752 envc = arginfo->ps_nenvstr; 1753 1754 /* argc on stack is long */ 1755 CTASSERT(sizeof(*cpp) == sizeof(argc)); 1756 1757 dp = (char *)(cpp + 1758 1 + /* long argc */ 1759 argc + /* char *argv[] */ 1760 1 + /* \0 */ 1761 envc + /* char *env[] */ 1762 1) + /* \0 */ 1763 pack->ep_esch->es_arglen; /* auxinfo */ 1764 sp = argp; 1765 1766 if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) { 1767 COPYPRINTF("", cpp - 1, sizeof(argc)); 1768 return error; 1769 } 1770 1771 /* XXX don't copy them out, remap them! */ 1772 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 1773 1774 for (; --argc >= 0; sp += len, dp += len) { 1775 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) { 1776 COPYPRINTF("", cpp - 1, sizeof(dp)); 1777 return error; 1778 } 1779 if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) { 1780 COPYPRINTF("str", dp, (size_t)ARG_MAX); 1781 return error; 1782 } 1783 } 1784 1785 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) { 1786 COPYPRINTF("", cpp - 1, sizeof(nullp)); 1787 return error; 1788 } 1789 1790 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 1791 1792 for (; --envc >= 0; sp += len, dp += len) { 1793 if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) { 1794 COPYPRINTF("", cpp - 1, sizeof(dp)); 1795 return error; 1796 } 1797 if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) { 1798 COPYPRINTF("str", dp, (size_t)ARG_MAX); 1799 return error; 1800 } 1801 1802 } 1803 1804 if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) { 1805 COPYPRINTF("", cpp - 1, sizeof(nullp)); 1806 return error; 1807 } 1808 1809 *stackp = (char *)cpp; 1810 return 0; 1811 } 1812 1813 1814 /* 1815 * Add execsw[] entries. 1816 */ 1817 int 1818 exec_add(struct execsw *esp, int count) 1819 { 1820 struct exec_entry *it; 1821 int i, error = 0; 1822 1823 if (count == 0) { 1824 return 0; 1825 } 1826 1827 /* Check for duplicates. */ 1828 rw_enter(&exec_lock, RW_WRITER); 1829 for (i = 0; i < count; i++) { 1830 LIST_FOREACH(it, &ex_head, ex_list) { 1831 /* assume unique (makecmds, probe_func, emulation) */ 1832 if (it->ex_sw->es_makecmds == esp[i].es_makecmds && 1833 it->ex_sw->u.elf_probe_func == 1834 esp[i].u.elf_probe_func && 1835 it->ex_sw->es_emul == esp[i].es_emul) { 1836 rw_exit(&exec_lock); 1837 return EEXIST; 1838 } 1839 } 1840 } 1841 1842 /* Allocate new entries. */ 1843 for (i = 0; i < count; i++) { 1844 it = kmem_alloc(sizeof(*it), KM_SLEEP); 1845 it->ex_sw = &esp[i]; 1846 error = exec_sigcode_alloc(it->ex_sw->es_emul); 1847 if (error != 0) { 1848 kmem_free(it, sizeof(*it)); 1849 break; 1850 } 1851 LIST_INSERT_HEAD(&ex_head, it, ex_list); 1852 } 1853 /* If even one fails, remove them all back. */ 1854 if (error != 0) { 1855 for (i--; i >= 0; i--) { 1856 it = LIST_FIRST(&ex_head); 1857 LIST_REMOVE(it, ex_list); 1858 exec_sigcode_free(it->ex_sw->es_emul); 1859 kmem_free(it, sizeof(*it)); 1860 } 1861 rw_exit(&exec_lock); 1862 return error; 1863 } 1864 1865 /* update execsw[] */ 1866 exec_init(0); 1867 rw_exit(&exec_lock); 1868 return 0; 1869 } 1870 1871 /* 1872 * Remove execsw[] entry. 1873 */ 1874 int 1875 exec_remove(struct execsw *esp, int count) 1876 { 1877 struct exec_entry *it, *next; 1878 int i; 1879 const struct proclist_desc *pd; 1880 proc_t *p; 1881 1882 if (count == 0) { 1883 return 0; 1884 } 1885 1886 /* Abort if any are busy. */ 1887 rw_enter(&exec_lock, RW_WRITER); 1888 for (i = 0; i < count; i++) { 1889 mutex_enter(&proc_lock); 1890 for (pd = proclists; pd->pd_list != NULL; pd++) { 1891 PROCLIST_FOREACH(p, pd->pd_list) { 1892 if (p->p_execsw == &esp[i]) { 1893 mutex_exit(&proc_lock); 1894 rw_exit(&exec_lock); 1895 return EBUSY; 1896 } 1897 } 1898 } 1899 mutex_exit(&proc_lock); 1900 } 1901 1902 /* None are busy, so remove them all. */ 1903 for (i = 0; i < count; i++) { 1904 for (it = LIST_FIRST(&ex_head); it != NULL; it = next) { 1905 next = LIST_NEXT(it, ex_list); 1906 if (it->ex_sw == &esp[i]) { 1907 LIST_REMOVE(it, ex_list); 1908 exec_sigcode_free(it->ex_sw->es_emul); 1909 kmem_free(it, sizeof(*it)); 1910 break; 1911 } 1912 } 1913 } 1914 1915 /* update execsw[] */ 1916 exec_init(0); 1917 rw_exit(&exec_lock); 1918 return 0; 1919 } 1920 1921 /* 1922 * Initialize exec structures. If init_boot is true, also does necessary 1923 * one-time initialization (it's called from main() that way). 1924 * Once system is multiuser, this should be called with exec_lock held, 1925 * i.e. via exec_{add|remove}(). 1926 */ 1927 int 1928 exec_init(int init_boot) 1929 { 1930 const struct execsw **sw; 1931 struct exec_entry *ex; 1932 SLIST_HEAD(,exec_entry) first; 1933 SLIST_HEAD(,exec_entry) any; 1934 SLIST_HEAD(,exec_entry) last; 1935 int i, sz; 1936 1937 if (init_boot) { 1938 /* do one-time initializations */ 1939 vaddr_t vmin = 0, vmax; 1940 1941 rw_init(&exec_lock); 1942 exec_map = uvm_km_suballoc(kernel_map, &vmin, &vmax, 1943 maxexec*NCARGS, VM_MAP_PAGEABLE, false, NULL); 1944 pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, 1945 "execargs", &exec_palloc, IPL_NONE); 1946 pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); 1947 } else { 1948 KASSERT(rw_write_held(&exec_lock)); 1949 } 1950 1951 /* Sort each entry onto the appropriate queue. */ 1952 SLIST_INIT(&first); 1953 SLIST_INIT(&any); 1954 SLIST_INIT(&last); 1955 sz = 0; 1956 LIST_FOREACH(ex, &ex_head, ex_list) { 1957 switch(ex->ex_sw->es_prio) { 1958 case EXECSW_PRIO_FIRST: 1959 SLIST_INSERT_HEAD(&first, ex, ex_slist); 1960 break; 1961 case EXECSW_PRIO_ANY: 1962 SLIST_INSERT_HEAD(&any, ex, ex_slist); 1963 break; 1964 case EXECSW_PRIO_LAST: 1965 SLIST_INSERT_HEAD(&last, ex, ex_slist); 1966 break; 1967 default: 1968 panic("%s", __func__); 1969 break; 1970 } 1971 sz++; 1972 } 1973 1974 /* 1975 * Create new execsw[]. Ensure we do not try a zero-sized 1976 * allocation. 1977 */ 1978 sw = kmem_alloc(sz * sizeof(struct execsw *) + 1, KM_SLEEP); 1979 i = 0; 1980 SLIST_FOREACH(ex, &first, ex_slist) { 1981 sw[i++] = ex->ex_sw; 1982 } 1983 SLIST_FOREACH(ex, &any, ex_slist) { 1984 sw[i++] = ex->ex_sw; 1985 } 1986 SLIST_FOREACH(ex, &last, ex_slist) { 1987 sw[i++] = ex->ex_sw; 1988 } 1989 1990 /* Replace old execsw[] and free used memory. */ 1991 if (execsw != NULL) { 1992 kmem_free(__UNCONST(execsw), 1993 nexecs * sizeof(struct execsw *) + 1); 1994 } 1995 execsw = sw; 1996 nexecs = sz; 1997 1998 /* Figure out the maximum size of an exec header. */ 1999 exec_maxhdrsz = sizeof(int); 2000 for (i = 0; i < nexecs; i++) { 2001 if (execsw[i]->es_hdrsz > exec_maxhdrsz) 2002 exec_maxhdrsz = execsw[i]->es_hdrsz; 2003 } 2004 2005 return 0; 2006 } 2007 2008 int 2009 exec_sigcode_alloc(const struct emul *e) 2010 { 2011 vaddr_t va; 2012 vsize_t sz; 2013 int error; 2014 struct uvm_object *uobj; 2015 2016 KASSERT(rw_lock_held(&exec_lock)); 2017 2018 if (e == NULL || e->e_sigobject == NULL) 2019 return 0; 2020 2021 sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; 2022 if (sz == 0) 2023 return 0; 2024 2025 /* 2026 * Create a sigobject for this emulation. 2027 * 2028 * sigobject is an anonymous memory object (just like SYSV shared 2029 * memory) that we keep a permanent reference to and that we map 2030 * in all processes that need this sigcode. The creation is simple, 2031 * we create an object, add a permanent reference to it, map it in 2032 * kernel space, copy out the sigcode to it and unmap it. 2033 * We map it with PROT_READ|PROT_EXEC into the process just 2034 * the way sys_mmap() would map it. 2035 */ 2036 if (*e->e_sigobject == NULL) { 2037 uobj = uao_create(sz, 0); 2038 (*uobj->pgops->pgo_reference)(uobj); 2039 va = vm_map_min(kernel_map); 2040 if ((error = uvm_map(kernel_map, &va, round_page(sz), 2041 uobj, 0, 0, 2042 UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, 2043 UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) { 2044 printf("sigcode kernel mapping failed %d\n", error); 2045 (*uobj->pgops->pgo_detach)(uobj); 2046 return error; 2047 } 2048 memcpy((void *)va, e->e_sigcode, sz); 2049 #ifdef PMAP_NEED_PROCWR 2050 pmap_procwr(&proc0, va, sz); 2051 #endif 2052 uvm_unmap(kernel_map, va, va + round_page(sz)); 2053 *e->e_sigobject = uobj; 2054 KASSERT(uobj->uo_refs == 1); 2055 } else { 2056 /* if already created, reference++ */ 2057 uobj = *e->e_sigobject; 2058 (*uobj->pgops->pgo_reference)(uobj); 2059 } 2060 2061 return 0; 2062 } 2063 2064 void 2065 exec_sigcode_free(const struct emul *e) 2066 { 2067 struct uvm_object *uobj; 2068 2069 KASSERT(rw_lock_held(&exec_lock)); 2070 2071 if (e == NULL || e->e_sigobject == NULL) 2072 return; 2073 2074 uobj = *e->e_sigobject; 2075 if (uobj == NULL) 2076 return; 2077 2078 if (uobj->uo_refs == 1) 2079 *e->e_sigobject = NULL; /* I'm the last person to reference. */ 2080 (*uobj->pgops->pgo_detach)(uobj); 2081 } 2082 2083 static int 2084 exec_sigcode_map(struct proc *p, const struct emul *e) 2085 { 2086 vaddr_t va; 2087 vsize_t sz; 2088 int error; 2089 struct uvm_object *uobj; 2090 2091 sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; 2092 if (e->e_sigobject == NULL || sz == 0) 2093 return 0; 2094 2095 uobj = *e->e_sigobject; 2096 if (uobj == NULL) 2097 return 0; 2098 2099 /* Just a hint to uvm_map where to put it. */ 2100 va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, 2101 round_page(sz), p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN); 2102 2103 #ifdef __alpha__ 2104 /* 2105 * Tru64 puts /sbin/loader at the end of user virtual memory, 2106 * which causes the above calculation to put the sigcode at 2107 * an invalid address. Put it just below the text instead. 2108 */ 2109 if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) { 2110 va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz); 2111 } 2112 #endif 2113 2114 (*uobj->pgops->pgo_reference)(uobj); 2115 error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz), 2116 uobj, 0, 0, 2117 UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE, 2118 UVM_ADV_RANDOM, 0)); 2119 if (error) { 2120 DPRINTF(("%s, %d: map %p " 2121 "uvm_map %#"PRIxVSIZE"@%#"PRIxVADDR" failed %d\n", 2122 __func__, __LINE__, &p->p_vmspace->vm_map, round_page(sz), 2123 va, error)); 2124 (*uobj->pgops->pgo_detach)(uobj); 2125 return error; 2126 } 2127 p->p_sigctx.ps_sigcode = (void *)va; 2128 return 0; 2129 } 2130 2131 /* 2132 * Release a refcount on spawn_exec_data and destroy memory, if this 2133 * was the last one. 2134 */ 2135 static void 2136 spawn_exec_data_release(struct spawn_exec_data *data) 2137 { 2138 2139 membar_release(); 2140 if (atomic_dec_32_nv(&data->sed_refcnt) != 0) 2141 return; 2142 membar_acquire(); 2143 2144 cv_destroy(&data->sed_cv_child_ready); 2145 mutex_destroy(&data->sed_mtx_child); 2146 2147 if (data->sed_actions) 2148 posix_spawn_fa_free(data->sed_actions, 2149 data->sed_actions->len); 2150 if (data->sed_attrs) 2151 kmem_free(data->sed_attrs, 2152 sizeof(*data->sed_attrs)); 2153 kmem_free(data, sizeof(*data)); 2154 } 2155 2156 static int 2157 handle_posix_spawn_file_actions(struct posix_spawn_file_actions *actions) 2158 { 2159 struct lwp *l = curlwp; 2160 register_t retval; 2161 int error, newfd; 2162 2163 if (actions == NULL) 2164 return 0; 2165 2166 for (size_t i = 0; i < actions->len; i++) { 2167 const struct posix_spawn_file_actions_entry *fae = 2168 &actions->fae[i]; 2169 switch (fae->fae_action) { 2170 case FAE_OPEN: 2171 if (fd_getfile(fae->fae_fildes) != NULL) { 2172 error = fd_close(fae->fae_fildes); 2173 if (error) 2174 return error; 2175 } 2176 error = fd_open(fae->fae_path, fae->fae_oflag, 2177 fae->fae_mode, &newfd); 2178 if (error) 2179 return error; 2180 if (newfd != fae->fae_fildes) { 2181 error = dodup(l, newfd, 2182 fae->fae_fildes, 0, &retval); 2183 if (fd_getfile(newfd) != NULL) 2184 fd_close(newfd); 2185 } 2186 break; 2187 case FAE_DUP2: 2188 error = dodup(l, fae->fae_fildes, 2189 fae->fae_newfildes, 0, &retval); 2190 break; 2191 case FAE_CLOSE: 2192 if (fd_getfile(fae->fae_fildes) == NULL) { 2193 return EBADF; 2194 } 2195 error = fd_close(fae->fae_fildes); 2196 break; 2197 case FAE_CHDIR: 2198 error = do_sys_chdir(l, fae->fae_chdir_path, 2199 UIO_SYSSPACE, &retval); 2200 break; 2201 case FAE_FCHDIR: 2202 error = do_sys_fchdir(l, fae->fae_fildes, &retval); 2203 break; 2204 } 2205 if (error) 2206 return error; 2207 } 2208 return 0; 2209 } 2210 2211 static int 2212 handle_posix_spawn_attrs(struct posix_spawnattr *attrs, struct proc *parent) 2213 { 2214 struct sigaction sigact; 2215 int error; 2216 struct proc *p = curproc; 2217 struct lwp *l = curlwp; 2218 2219 if (attrs == NULL) 2220 return 0; 2221 2222 memset(&sigact, 0, sizeof(sigact)); 2223 sigact._sa_u._sa_handler = SIG_DFL; 2224 sigact.sa_flags = 0; 2225 2226 /* 2227 * set state to SSTOP so that this proc can be found by pid. 2228 * see proc_enterprp, do_sched_setparam below 2229 */ 2230 mutex_enter(&proc_lock); 2231 /* 2232 * p_stat should be SACTIVE, so we need to adjust the 2233 * parent's p_nstopchild here. For safety, just make 2234 * we're on the good side of SDEAD before we adjust. 2235 */ 2236 int ostat = p->p_stat; 2237 KASSERT(ostat < SSTOP); 2238 p->p_stat = SSTOP; 2239 p->p_waited = 0; 2240 p->p_pptr->p_nstopchild++; 2241 mutex_exit(&proc_lock); 2242 2243 /* Set process group */ 2244 if (attrs->sa_flags & POSIX_SPAWN_SETPGROUP) { 2245 pid_t mypid = p->p_pid; 2246 pid_t pgrp = attrs->sa_pgroup; 2247 2248 if (pgrp == 0) 2249 pgrp = mypid; 2250 2251 error = proc_enterpgrp(parent, mypid, pgrp, false); 2252 if (error) 2253 goto out; 2254 } 2255 2256 /* Set scheduler policy */ 2257 if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDULER) 2258 error = do_sched_setparam(p->p_pid, 0, attrs->sa_schedpolicy, 2259 &attrs->sa_schedparam); 2260 else if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) { 2261 error = do_sched_setparam(parent->p_pid, 0, 2262 SCHED_NONE, &attrs->sa_schedparam); 2263 } 2264 if (error) 2265 goto out; 2266 2267 /* Reset user ID's */ 2268 if (attrs->sa_flags & POSIX_SPAWN_RESETIDS) { 2269 error = do_setresgid(l, -1, kauth_cred_getgid(l->l_cred), -1, 2270 ID_E_EQ_R | ID_E_EQ_S); 2271 if (error) 2272 return error; 2273 error = do_setresuid(l, -1, kauth_cred_getuid(l->l_cred), -1, 2274 ID_E_EQ_R | ID_E_EQ_S); 2275 if (error) 2276 goto out; 2277 } 2278 2279 /* Set signal masks/defaults */ 2280 if (attrs->sa_flags & POSIX_SPAWN_SETSIGMASK) { 2281 mutex_enter(p->p_lock); 2282 error = sigprocmask1(l, SIG_SETMASK, &attrs->sa_sigmask, NULL); 2283 mutex_exit(p->p_lock); 2284 if (error) 2285 goto out; 2286 } 2287 2288 if (attrs->sa_flags & POSIX_SPAWN_SETSIGDEF) { 2289 /* 2290 * The following sigaction call is using a sigaction 2291 * version 0 trampoline which is in the compatibility 2292 * code only. This is not a problem because for SIG_DFL 2293 * and SIG_IGN, the trampolines are now ignored. If they 2294 * were not, this would be a problem because we are 2295 * holding the exec_lock, and the compat code needs 2296 * to do the same in order to replace the trampoline 2297 * code of the process. 2298 */ 2299 for (int i = 1; i <= NSIG; i++) { 2300 if (sigismember(&attrs->sa_sigdefault, i)) 2301 sigaction1(l, i, &sigact, NULL, NULL, 0); 2302 } 2303 } 2304 error = 0; 2305 out: 2306 mutex_enter(&proc_lock); 2307 p->p_stat = ostat; 2308 p->p_pptr->p_nstopchild--; 2309 mutex_exit(&proc_lock); 2310 return error; 2311 } 2312 2313 /* 2314 * A child lwp of a posix_spawn operation starts here and ends up in 2315 * cpu_spawn_return, dealing with all filedescriptor and scheduler 2316 * manipulations in between. 2317 * The parent waits for the child, as it is not clear whether the child 2318 * will be able to acquire its own exec_lock. If it can, the parent can 2319 * be released early and continue running in parallel. If not (or if the 2320 * magic debug flag is passed in the scheduler attribute struct), the 2321 * child rides on the parent's exec lock until it is ready to return to 2322 * to userland - and only then releases the parent. This method loses 2323 * concurrency, but improves error reporting. 2324 */ 2325 static void 2326 spawn_return(void *arg) 2327 { 2328 struct spawn_exec_data *spawn_data = arg; 2329 struct lwp *l = curlwp; 2330 struct proc *p = l->l_proc; 2331 int error; 2332 bool have_reflock; 2333 bool parent_is_waiting = true; 2334 2335 /* 2336 * Check if we can release parent early. 2337 * We either need to have no sed_attrs, or sed_attrs does not 2338 * have POSIX_SPAWN_RETURNERROR or one of the flags, that require 2339 * safe access to the parent proc (passed in sed_parent). 2340 * We then try to get the exec_lock, and only if that works, we can 2341 * release the parent here already. 2342 */ 2343 struct posix_spawnattr *attrs = spawn_data->sed_attrs; 2344 if ((!attrs || (attrs->sa_flags 2345 & (POSIX_SPAWN_RETURNERROR|POSIX_SPAWN_SETPGROUP)) == 0) 2346 && rw_tryenter(&exec_lock, RW_READER)) { 2347 parent_is_waiting = false; 2348 mutex_enter(&spawn_data->sed_mtx_child); 2349 cv_signal(&spawn_data->sed_cv_child_ready); 2350 mutex_exit(&spawn_data->sed_mtx_child); 2351 } 2352 2353 /* don't allow debugger access yet */ 2354 rw_enter(&p->p_reflock, RW_WRITER); 2355 have_reflock = true; 2356 2357 /* handle posix_spawnattr */ 2358 error = handle_posix_spawn_attrs(attrs, spawn_data->sed_parent); 2359 if (error) 2360 goto report_error; 2361 2362 /* handle posix_spawn_file_actions */ 2363 error = handle_posix_spawn_file_actions(spawn_data->sed_actions); 2364 if (error) 2365 goto report_error; 2366 2367 /* now do the real exec */ 2368 error = execve_runproc(l, &spawn_data->sed_exec, parent_is_waiting, 2369 true); 2370 have_reflock = false; 2371 if (error == EJUSTRETURN) 2372 error = 0; 2373 else if (error) 2374 goto report_error; 2375 2376 if (parent_is_waiting) { 2377 mutex_enter(&spawn_data->sed_mtx_child); 2378 cv_signal(&spawn_data->sed_cv_child_ready); 2379 mutex_exit(&spawn_data->sed_mtx_child); 2380 } 2381 2382 /* release our refcount on the data */ 2383 spawn_exec_data_release(spawn_data); 2384 2385 if ((p->p_slflag & (PSL_TRACED|PSL_TRACEDCHILD)) == 2386 (PSL_TRACED|PSL_TRACEDCHILD)) { 2387 eventswitchchild(p, TRAP_CHLD, PTRACE_POSIX_SPAWN); 2388 } 2389 2390 /* and finally: leave to userland for the first time */ 2391 cpu_spawn_return(l); 2392 2393 /* NOTREACHED */ 2394 return; 2395 2396 report_error: 2397 if (have_reflock) { 2398 /* 2399 * We have not passed through execve_runproc(), 2400 * which would have released the p_reflock and also 2401 * taken ownership of the sed_exec part of spawn_data, 2402 * so release/free both here. 2403 */ 2404 rw_exit(&p->p_reflock); 2405 execve_free_data(&spawn_data->sed_exec); 2406 } 2407 2408 if (parent_is_waiting) { 2409 /* pass error to parent */ 2410 mutex_enter(&spawn_data->sed_mtx_child); 2411 spawn_data->sed_error = error; 2412 cv_signal(&spawn_data->sed_cv_child_ready); 2413 mutex_exit(&spawn_data->sed_mtx_child); 2414 } else { 2415 rw_exit(&exec_lock); 2416 } 2417 2418 /* release our refcount on the data */ 2419 spawn_exec_data_release(spawn_data); 2420 2421 /* done, exit */ 2422 mutex_enter(p->p_lock); 2423 /* 2424 * Posix explicitly asks for an exit code of 127 if we report 2425 * errors from the child process - so, unfortunately, there 2426 * is no way to report a more exact error code. 2427 * A NetBSD specific workaround is POSIX_SPAWN_RETURNERROR as 2428 * flag bit in the attrp argument to posix_spawn(2), see above. 2429 */ 2430 exit1(l, 127, 0); 2431 } 2432 2433 static __inline char ** 2434 posix_spawn_fae_path(struct posix_spawn_file_actions_entry *fae) 2435 { 2436 switch (fae->fae_action) { 2437 case FAE_OPEN: 2438 return &fae->fae_path; 2439 case FAE_CHDIR: 2440 return &fae->fae_chdir_path; 2441 default: 2442 return NULL; 2443 } 2444 } 2445 2446 void 2447 posix_spawn_fa_free(struct posix_spawn_file_actions *fa, size_t len) 2448 { 2449 2450 for (size_t i = 0; i < len; i++) { 2451 char **pathp = posix_spawn_fae_path(&fa->fae[i]); 2452 if (pathp) 2453 kmem_strfree(*pathp); 2454 } 2455 if (fa->len > 0) 2456 kmem_free(fa->fae, sizeof(*fa->fae) * fa->len); 2457 kmem_free(fa, sizeof(*fa)); 2458 } 2459 2460 static int 2461 posix_spawn_fa_alloc(struct posix_spawn_file_actions **fap, 2462 const struct posix_spawn_file_actions *ufa, rlim_t lim) 2463 { 2464 struct posix_spawn_file_actions *fa; 2465 struct posix_spawn_file_actions_entry *fae; 2466 char *pbuf = NULL; 2467 int error; 2468 size_t i = 0; 2469 2470 fa = kmem_alloc(sizeof(*fa), KM_SLEEP); 2471 error = copyin(ufa, fa, sizeof(*fa)); 2472 if (error || fa->len == 0) { 2473 kmem_free(fa, sizeof(*fa)); 2474 return error; /* 0 if not an error, and len == 0 */ 2475 } 2476 2477 if (fa->len > lim) { 2478 kmem_free(fa, sizeof(*fa)); 2479 return EINVAL; 2480 } 2481 2482 fa->size = fa->len; 2483 size_t fal = fa->len * sizeof(*fae); 2484 fae = fa->fae; 2485 fa->fae = kmem_alloc(fal, KM_SLEEP); 2486 error = copyin(fae, fa->fae, fal); 2487 if (error) 2488 goto out; 2489 2490 pbuf = PNBUF_GET(); 2491 for (; i < fa->len; i++) { 2492 char **pathp = posix_spawn_fae_path(&fa->fae[i]); 2493 if (pathp == NULL) 2494 continue; 2495 error = copyinstr(*pathp, pbuf, MAXPATHLEN, &fal); 2496 if (error) 2497 goto out; 2498 *pathp = kmem_alloc(fal, KM_SLEEP); 2499 memcpy(*pathp, pbuf, fal); 2500 } 2501 PNBUF_PUT(pbuf); 2502 2503 *fap = fa; 2504 return 0; 2505 out: 2506 if (pbuf) 2507 PNBUF_PUT(pbuf); 2508 posix_spawn_fa_free(fa, i); 2509 return error; 2510 } 2511 2512 /* 2513 * N.B. increments nprocs upon success. Callers need to drop nprocs if 2514 * they fail for some other reason. 2515 */ 2516 int 2517 check_posix_spawn(struct lwp *l1) 2518 { 2519 int error, tnprocs, count; 2520 uid_t uid; 2521 struct proc *p1; 2522 2523 p1 = l1->l_proc; 2524 uid = kauth_cred_getuid(l1->l_cred); 2525 tnprocs = atomic_inc_uint_nv(&nprocs); 2526 2527 /* 2528 * Although process entries are dynamically created, we still keep 2529 * a global limit on the maximum number we will create. 2530 */ 2531 if (__predict_false(tnprocs >= maxproc)) 2532 error = -1; 2533 else 2534 error = kauth_authorize_process(l1->l_cred, 2535 KAUTH_PROCESS_FORK, p1, KAUTH_ARG(tnprocs), NULL, NULL); 2536 2537 if (error) { 2538 atomic_dec_uint(&nprocs); 2539 return EAGAIN; 2540 } 2541 2542 /* 2543 * Enforce limits. 2544 */ 2545 count = chgproccnt(uid, 1); 2546 if (kauth_authorize_process(l1->l_cred, KAUTH_PROCESS_RLIMIT, 2547 p1, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS), 2548 &p1->p_rlimit[RLIMIT_NPROC], KAUTH_ARG(RLIMIT_NPROC)) != 0 && 2549 __predict_false(count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur)) { 2550 (void)chgproccnt(uid, -1); 2551 atomic_dec_uint(&nprocs); 2552 return EAGAIN; 2553 } 2554 2555 return 0; 2556 } 2557 2558 int 2559 do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path, 2560 struct posix_spawn_file_actions *fa, 2561 struct posix_spawnattr *sa, 2562 char *const *argv, char *const *envp, 2563 execve_fetch_element_t fetch) 2564 { 2565 2566 struct proc *p1, *p2; 2567 struct lwp *l2; 2568 int error; 2569 struct spawn_exec_data *spawn_data; 2570 vaddr_t uaddr = 0; 2571 pid_t pid; 2572 bool have_exec_lock = false; 2573 2574 p1 = l1->l_proc; 2575 2576 /* Allocate and init spawn_data */ 2577 spawn_data = kmem_zalloc(sizeof(*spawn_data), KM_SLEEP); 2578 spawn_data->sed_refcnt = 1; /* only parent so far */ 2579 cv_init(&spawn_data->sed_cv_child_ready, "pspawn"); 2580 mutex_init(&spawn_data->sed_mtx_child, MUTEX_DEFAULT, IPL_NONE); 2581 mutex_enter(&spawn_data->sed_mtx_child); 2582 2583 /* 2584 * Do the first part of the exec now, collect state 2585 * in spawn_data. 2586 */ 2587 error = execve_loadvm(l1, true, path, -1, argv, 2588 envp, fetch, &spawn_data->sed_exec); 2589 if (error == EJUSTRETURN) 2590 error = 0; 2591 else if (error) 2592 goto error_exit; 2593 2594 have_exec_lock = true; 2595 2596 /* 2597 * Allocate virtual address space for the U-area now, while it 2598 * is still easy to abort the fork operation if we're out of 2599 * kernel virtual address space. 2600 */ 2601 uaddr = uvm_uarea_alloc(); 2602 if (__predict_false(uaddr == 0)) { 2603 error = ENOMEM; 2604 goto error_exit; 2605 } 2606 2607 /* 2608 * Allocate new proc. Borrow proc0 vmspace for it, we will 2609 * replace it with its own before returning to userland 2610 * in the child. 2611 */ 2612 p2 = proc_alloc(); 2613 if (p2 == NULL) { 2614 /* We were unable to allocate a process ID. */ 2615 error = EAGAIN; 2616 goto error_exit; 2617 } 2618 2619 /* 2620 * This is a point of no return, we will have to go through 2621 * the child proc to properly clean it up past this point. 2622 */ 2623 pid = p2->p_pid; 2624 2625 /* 2626 * Make a proc table entry for the new process. 2627 * Start by zeroing the section of proc that is zero-initialized, 2628 * then copy the section that is copied directly from the parent. 2629 */ 2630 memset(&p2->p_startzero, 0, 2631 (unsigned) ((char *)&p2->p_endzero - (char *)&p2->p_startzero)); 2632 memcpy(&p2->p_startcopy, &p1->p_startcopy, 2633 (unsigned) ((char *)&p2->p_endcopy - (char *)&p2->p_startcopy)); 2634 p2->p_vmspace = proc0.p_vmspace; 2635 2636 TAILQ_INIT(&p2->p_sigpend.sp_info); 2637 2638 LIST_INIT(&p2->p_lwps); 2639 LIST_INIT(&p2->p_sigwaiters); 2640 2641 /* 2642 * Duplicate sub-structures as needed. 2643 * Increase reference counts on shared objects. 2644 * Inherit flags we want to keep. The flags related to SIGCHLD 2645 * handling are important in order to keep a consistent behaviour 2646 * for the child after the fork. If we are a 32-bit process, the 2647 * child will be too. 2648 */ 2649 p2->p_flag = 2650 p1->p_flag & (PK_SUGID | PK_NOCLDWAIT | PK_CLDSIGIGN | PK_32); 2651 p2->p_emul = p1->p_emul; 2652 p2->p_execsw = p1->p_execsw; 2653 2654 mutex_init(&p2->p_stmutex, MUTEX_DEFAULT, IPL_HIGH); 2655 mutex_init(&p2->p_auxlock, MUTEX_DEFAULT, IPL_NONE); 2656 rw_init(&p2->p_reflock); 2657 cv_init(&p2->p_waitcv, "wait"); 2658 cv_init(&p2->p_lwpcv, "lwpwait"); 2659 2660 p2->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 2661 2662 kauth_proc_fork(p1, p2); 2663 2664 p2->p_raslist = NULL; 2665 p2->p_fd = fd_copy(); 2666 2667 /* XXX racy */ 2668 p2->p_mqueue_cnt = p1->p_mqueue_cnt; 2669 2670 p2->p_cwdi = cwdinit(); 2671 2672 /* 2673 * Note: p_limit (rlimit stuff) is copy-on-write, so normally 2674 * we just need increase pl_refcnt. 2675 */ 2676 if (!p1->p_limit->pl_writeable) { 2677 lim_addref(p1->p_limit); 2678 p2->p_limit = p1->p_limit; 2679 } else { 2680 p2->p_limit = lim_copy(p1->p_limit); 2681 } 2682 2683 p2->p_lflag = 0; 2684 l1->l_vforkwaiting = false; 2685 p2->p_sflag = 0; 2686 p2->p_slflag = 0; 2687 p2->p_pptr = p1; 2688 p2->p_ppid = p1->p_pid; 2689 LIST_INIT(&p2->p_children); 2690 2691 p2->p_aio = NULL; 2692 2693 #ifdef KTRACE 2694 /* 2695 * Copy traceflag and tracefile if enabled. 2696 * If not inherited, these were zeroed above. 2697 */ 2698 if (p1->p_traceflag & KTRFAC_INHERIT) { 2699 mutex_enter(&ktrace_lock); 2700 p2->p_traceflag = p1->p_traceflag; 2701 if ((p2->p_tracep = p1->p_tracep) != NULL) 2702 ktradref(p2); 2703 mutex_exit(&ktrace_lock); 2704 } 2705 #endif 2706 2707 /* 2708 * Create signal actions for the child process. 2709 */ 2710 p2->p_sigacts = sigactsinit(p1, 0); 2711 mutex_enter(p1->p_lock); 2712 p2->p_sflag |= 2713 (p1->p_sflag & (PS_STOPFORK | PS_STOPEXEC | PS_NOCLDSTOP)); 2714 sched_proc_fork(p1, p2); 2715 mutex_exit(p1->p_lock); 2716 2717 p2->p_stflag = p1->p_stflag; 2718 2719 /* 2720 * p_stats. 2721 * Copy parts of p_stats, and zero out the rest. 2722 */ 2723 p2->p_stats = pstatscopy(p1->p_stats); 2724 2725 /* copy over machdep flags to the new proc */ 2726 cpu_proc_fork(p1, p2); 2727 2728 /* 2729 * Prepare remaining parts of spawn data 2730 */ 2731 spawn_data->sed_actions = fa; 2732 spawn_data->sed_attrs = sa; 2733 2734 spawn_data->sed_parent = p1; 2735 2736 /* create LWP */ 2737 lwp_create(l1, p2, uaddr, 0, NULL, 0, spawn_return, spawn_data, 2738 &l2, l1->l_class, &l1->l_sigmask, &l1->l_sigstk); 2739 l2->l_ctxlink = NULL; /* reset ucontext link */ 2740 2741 /* 2742 * Copy the credential so other references don't see our changes. 2743 * Test to see if this is necessary first, since in the common case 2744 * we won't need a private reference. 2745 */ 2746 if (kauth_cred_geteuid(l2->l_cred) != kauth_cred_getsvuid(l2->l_cred) || 2747 kauth_cred_getegid(l2->l_cred) != kauth_cred_getsvgid(l2->l_cred)) { 2748 l2->l_cred = kauth_cred_copy(l2->l_cred); 2749 kauth_cred_setsvuid(l2->l_cred, kauth_cred_geteuid(l2->l_cred)); 2750 kauth_cred_setsvgid(l2->l_cred, kauth_cred_getegid(l2->l_cred)); 2751 } 2752 2753 /* Update the master credentials. */ 2754 if (l2->l_cred != p2->p_cred) { 2755 kauth_cred_t ocred; 2756 mutex_enter(p2->p_lock); 2757 ocred = p2->p_cred; 2758 p2->p_cred = kauth_cred_hold(l2->l_cred); 2759 mutex_exit(p2->p_lock); 2760 kauth_cred_free(ocred); 2761 } 2762 2763 *child_ok = true; 2764 spawn_data->sed_refcnt = 2; /* child gets it as well */ 2765 #if 0 2766 l2->l_nopreempt = 1; /* start it non-preemptable */ 2767 #endif 2768 2769 /* 2770 * It's now safe for the scheduler and other processes to see the 2771 * child process. 2772 */ 2773 mutex_enter(&proc_lock); 2774 2775 if (p1->p_session->s_ttyvp != NULL && p1->p_lflag & PL_CONTROLT) 2776 p2->p_lflag |= PL_CONTROLT; 2777 2778 LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling); 2779 p2->p_exitsig = SIGCHLD; /* signal for parent on exit */ 2780 2781 if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) == 2782 (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) { 2783 proc_changeparent(p2, p1->p_pptr); 2784 SET(p2->p_slflag, PSL_TRACEDCHILD); 2785 } 2786 2787 p2->p_oppid = p1->p_pid; /* Remember the original parent id. */ 2788 2789 LIST_INSERT_AFTER(p1, p2, p_pglist); 2790 LIST_INSERT_HEAD(&allproc, p2, p_list); 2791 2792 p2->p_trace_enabled = trace_is_enabled(p2); 2793 #ifdef __HAVE_SYSCALL_INTERN 2794 (*p2->p_emul->e_syscall_intern)(p2); 2795 #endif 2796 2797 /* 2798 * Make child runnable, set start time, and add to run queue except 2799 * if the parent requested the child to start in SSTOP state. 2800 */ 2801 mutex_enter(p2->p_lock); 2802 2803 getmicrotime(&p2->p_stats->p_start); 2804 2805 lwp_lock(l2); 2806 KASSERT(p2->p_nrlwps == 1); 2807 KASSERT(l2->l_stat == LSIDL); 2808 p2->p_nrlwps = 1; 2809 p2->p_stat = SACTIVE; 2810 setrunnable(l2); 2811 /* LWP now unlocked */ 2812 2813 mutex_exit(p2->p_lock); 2814 mutex_exit(&proc_lock); 2815 2816 cv_wait(&spawn_data->sed_cv_child_ready, &spawn_data->sed_mtx_child); 2817 error = spawn_data->sed_error; 2818 mutex_exit(&spawn_data->sed_mtx_child); 2819 spawn_exec_data_release(spawn_data); 2820 2821 rw_exit(&p1->p_reflock); 2822 rw_exit(&exec_lock); 2823 have_exec_lock = false; 2824 2825 *pid_res = pid; 2826 2827 if (error) 2828 return error; 2829 2830 if (p1->p_slflag & PSL_TRACED) { 2831 /* Paranoid check */ 2832 mutex_enter(&proc_lock); 2833 if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) != 2834 (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) { 2835 mutex_exit(&proc_lock); 2836 return 0; 2837 } 2838 2839 mutex_enter(p1->p_lock); 2840 eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, pid); 2841 } 2842 return 0; 2843 2844 error_exit: 2845 if (have_exec_lock) { 2846 execve_free_data(&spawn_data->sed_exec); 2847 rw_exit(&p1->p_reflock); 2848 rw_exit(&exec_lock); 2849 } 2850 mutex_exit(&spawn_data->sed_mtx_child); 2851 spawn_exec_data_release(spawn_data); 2852 if (uaddr != 0) 2853 uvm_uarea_free(uaddr); 2854 2855 return error; 2856 } 2857 2858 int 2859 sys_posix_spawn(struct lwp *l1, const struct sys_posix_spawn_args *uap, 2860 register_t *retval) 2861 { 2862 /* { 2863 syscallarg(pid_t *) pid; 2864 syscallarg(const char *) path; 2865 syscallarg(const struct posix_spawn_file_actions *) file_actions; 2866 syscallarg(const struct posix_spawnattr *) attrp; 2867 syscallarg(char *const *) argv; 2868 syscallarg(char *const *) envp; 2869 } */ 2870 2871 int error; 2872 struct posix_spawn_file_actions *fa = NULL; 2873 struct posix_spawnattr *sa = NULL; 2874 pid_t pid; 2875 bool child_ok = false; 2876 rlim_t max_fileactions; 2877 proc_t *p = l1->l_proc; 2878 2879 /* check_posix_spawn() increments nprocs for us. */ 2880 error = check_posix_spawn(l1); 2881 if (error) { 2882 *retval = error; 2883 return 0; 2884 } 2885 2886 /* copy in file_actions struct */ 2887 if (SCARG(uap, file_actions) != NULL) { 2888 max_fileactions = 2 * uimin(p->p_rlimit[RLIMIT_NOFILE].rlim_cur, 2889 maxfiles); 2890 error = posix_spawn_fa_alloc(&fa, SCARG(uap, file_actions), 2891 max_fileactions); 2892 if (error) 2893 goto error_exit; 2894 } 2895 2896 /* copyin posix_spawnattr struct */ 2897 if (SCARG(uap, attrp) != NULL) { 2898 sa = kmem_alloc(sizeof(*sa), KM_SLEEP); 2899 error = copyin(SCARG(uap, attrp), sa, sizeof(*sa)); 2900 if (error) 2901 goto error_exit; 2902 } 2903 2904 /* 2905 * Do the spawn 2906 */ 2907 error = do_posix_spawn(l1, &pid, &child_ok, SCARG(uap, path), fa, sa, 2908 SCARG(uap, argv), SCARG(uap, envp), execve_fetch_element); 2909 if (error) 2910 goto error_exit; 2911 2912 if (error == 0 && SCARG(uap, pid) != NULL) 2913 error = copyout(&pid, SCARG(uap, pid), sizeof(pid)); 2914 2915 *retval = error; 2916 return 0; 2917 2918 error_exit: 2919 if (!child_ok) { 2920 (void)chgproccnt(kauth_cred_getuid(l1->l_cred), -1); 2921 atomic_dec_uint(&nprocs); 2922 2923 if (sa) 2924 kmem_free(sa, sizeof(*sa)); 2925 if (fa) 2926 posix_spawn_fa_free(fa, fa->len); 2927 } 2928 2929 *retval = error; 2930 return 0; 2931 } 2932 2933 void 2934 exec_free_emul_arg(struct exec_package *epp) 2935 { 2936 if (epp->ep_emul_arg_free != NULL) { 2937 KASSERT(epp->ep_emul_arg != NULL); 2938 (*epp->ep_emul_arg_free)(epp->ep_emul_arg); 2939 epp->ep_emul_arg_free = NULL; 2940 epp->ep_emul_arg = NULL; 2941 } else { 2942 KASSERT(epp->ep_emul_arg == NULL); 2943 } 2944 } 2945 2946 #ifdef DEBUG_EXEC 2947 static void 2948 dump_vmcmds(const struct exec_package * const epp, size_t x, int error) 2949 { 2950 struct exec_vmcmd *vp = &epp->ep_vmcmds.evs_cmds[0]; 2951 size_t j; 2952 2953 if (error == 0) 2954 DPRINTF(("vmcmds %u\n", epp->ep_vmcmds.evs_used)); 2955 else 2956 DPRINTF(("vmcmds %zu/%u, error %d\n", x, 2957 epp->ep_vmcmds.evs_used, error)); 2958 2959 for (j = 0; j < epp->ep_vmcmds.evs_used; j++) { 2960 DPRINTF(("vmcmd[%zu] = vmcmd_map_%s %#" 2961 PRIxVADDR"/%#"PRIxVSIZE" fd@%#" 2962 PRIxVSIZE" prot=0%o flags=%d\n", j, 2963 vp[j].ev_proc == vmcmd_map_pagedvn ? 2964 "pagedvn" : 2965 vp[j].ev_proc == vmcmd_map_readvn ? 2966 "readvn" : 2967 vp[j].ev_proc == vmcmd_map_zero ? 2968 "zero" : "*unknown*", 2969 vp[j].ev_addr, vp[j].ev_len, 2970 vp[j].ev_offset, vp[j].ev_prot, 2971 vp[j].ev_flags)); 2972 if (error != 0 && j == x) 2973 DPRINTF((" ^--- failed\n")); 2974 } 2975 } 2976 #endif 2977