1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1993, David Greenman 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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD$"); 31 32#include "opt_capsicum.h" 33#include "opt_hwpmc_hooks.h" 34#include "opt_ktrace.h" 35#include "opt_vm.h" 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/acct.h> 40#include <sys/capsicum.h> 41#include <sys/eventhandler.h> 42#include <sys/exec.h> 43#include <sys/fcntl.h> 44#include <sys/filedesc.h> 45#include <sys/imgact.h> 46#include <sys/imgact_elf.h> 47#include <sys/kernel.h> 48#include <sys/lock.h> 49#include <sys/malloc.h> 50#include <sys/mman.h> 51#include <sys/mount.h> 52#include <sys/mutex.h> 53#include <sys/namei.h> 54#include <sys/priv.h> 55#include <sys/proc.h> 56#include <sys/ptrace.h> 57#include <sys/resourcevar.h> 58#include <sys/rwlock.h> 59#include <sys/sched.h> 60#include <sys/sdt.h> 61#include <sys/sf_buf.h> 62#include <sys/shm.h> 63#include <sys/signalvar.h> 64#include <sys/smp.h> 65#include <sys/stat.h> 66#include <sys/syscallsubr.h> 67#include <sys/sysctl.h> 68#include <sys/sysent.h> 69#include <sys/sysproto.h> 70#include <sys/timers.h> 71#include <sys/umtx.h> 72#include <sys/vnode.h> 73#include <sys/wait.h> 74#ifdef KTRACE 75#include <sys/ktrace.h> 76#endif 77 78#include <vm/vm.h> 79#include <vm/vm_param.h> 80#include <vm/pmap.h> 81#include <vm/vm_page.h> 82#include <vm/vm_map.h> 83#include <vm/vm_kern.h> 84#include <vm/vm_extern.h> 85#include <vm/vm_object.h> 86#include <vm/vm_pager.h> 87 88#ifdef HWPMC_HOOKS 89#include <sys/pmckern.h> 90#endif 91 92#include <machine/reg.h> 93 94#include <security/audit/audit.h> 95#include <security/mac/mac_framework.h> 96 97#ifdef KDTRACE_HOOKS 98#include <sys/dtrace_bsd.h> 99dtrace_execexit_func_t dtrace_fasttrap_exec; 100#endif 101 102SDT_PROVIDER_DECLARE(proc); 103SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 104SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 105SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 106 107MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 108 109int coredump_pack_fileinfo = 1; 110SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 111 &coredump_pack_fileinfo, 0, 112 "Enable file path packing in 'procstat -f' coredump notes"); 113 114int coredump_pack_vmmapinfo = 1; 115SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 116 &coredump_pack_vmmapinfo, 0, 117 "Enable file path packing in 'procstat -v' coredump notes"); 118 119static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 120static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 121static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 122static int do_execve(struct thread *td, struct image_args *args, 123 struct mac *mac_p, struct vmspace *oldvmspace); 124 125/* XXX This should be vm_size_t. */ 126SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD| 127 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU", 128 "Location of process' ps_strings structure"); 129 130/* XXX This should be vm_size_t. */ 131SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 132 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", 133 "Top of process stack"); 134 135SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, 136 NULL, 0, sysctl_kern_stackprot, "I", 137 "Stack memory permissions"); 138 139u_long ps_arg_cache_limit = PAGE_SIZE / 16; 140SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 141 &ps_arg_cache_limit, 0, 142 "Process' command line characters cache limit"); 143 144static int disallow_high_osrel; 145SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 146 &disallow_high_osrel, 0, 147 "Disallow execution of binaries built for higher version of the world"); 148 149static int map_at_zero = 0; 150SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0, 151 "Permit processes to map an object at virtual address 0."); 152 153static int 154sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 155{ 156 struct proc *p; 157 int error; 158 159 p = curproc; 160#ifdef SCTL_MASK32 161 if (req->flags & SCTL_MASK32) { 162 unsigned int val; 163 val = (unsigned int)p->p_sysent->sv_psstrings; 164 error = SYSCTL_OUT(req, &val, sizeof(val)); 165 } else 166#endif 167 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 168 sizeof(p->p_sysent->sv_psstrings)); 169 return error; 170} 171 172static int 173sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 174{ 175 struct proc *p; 176 int error; 177 178 p = curproc; 179#ifdef SCTL_MASK32 180 if (req->flags & SCTL_MASK32) { 181 unsigned int val; 182 val = (unsigned int)p->p_sysent->sv_usrstack; 183 error = SYSCTL_OUT(req, &val, sizeof(val)); 184 } else 185#endif 186 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 187 sizeof(p->p_sysent->sv_usrstack)); 188 return error; 189} 190 191static int 192sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 193{ 194 struct proc *p; 195 196 p = curproc; 197 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 198 sizeof(p->p_sysent->sv_stackprot))); 199} 200 201/* 202 * Each of the items is a pointer to a `const struct execsw', hence the 203 * double pointer here. 204 */ 205static const struct execsw **execsw; 206 207#ifndef _SYS_SYSPROTO_H_ 208struct execve_args { 209 char *fname; 210 char **argv; 211 char **envv; 212}; 213#endif 214 215int 216sys_execve(struct thread *td, struct execve_args *uap) 217{ 218 struct image_args args; 219 struct vmspace *oldvmspace; 220 int error; 221 222 error = pre_execve(td, &oldvmspace); 223 if (error != 0) 224 return (error); 225 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 226 uap->argv, uap->envv); 227 if (error == 0) 228 error = kern_execve(td, &args, NULL, oldvmspace); 229 post_execve(td, error, oldvmspace); 230 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 231 return (error); 232} 233 234#ifndef _SYS_SYSPROTO_H_ 235struct fexecve_args { 236 int fd; 237 char **argv; 238 char **envv; 239}; 240#endif 241int 242sys_fexecve(struct thread *td, struct fexecve_args *uap) 243{ 244 struct image_args args; 245 struct vmspace *oldvmspace; 246 int error; 247 248 error = pre_execve(td, &oldvmspace); 249 if (error != 0) 250 return (error); 251 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 252 uap->argv, uap->envv); 253 if (error == 0) { 254 args.fd = uap->fd; 255 error = kern_execve(td, &args, NULL, oldvmspace); 256 } 257 post_execve(td, error, oldvmspace); 258 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 259 return (error); 260} 261 262#ifndef _SYS_SYSPROTO_H_ 263struct __mac_execve_args { 264 char *fname; 265 char **argv; 266 char **envv; 267 struct mac *mac_p; 268}; 269#endif 270 271int 272sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 273{ 274#ifdef MAC 275 struct image_args args; 276 struct vmspace *oldvmspace; 277 int error; 278 279 error = pre_execve(td, &oldvmspace); 280 if (error != 0) 281 return (error); 282 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 283 uap->argv, uap->envv); 284 if (error == 0) 285 error = kern_execve(td, &args, uap->mac_p, oldvmspace); 286 post_execve(td, error, oldvmspace); 287 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 288 return (error); 289#else 290 return (ENOSYS); 291#endif 292} 293 294int 295pre_execve(struct thread *td, struct vmspace **oldvmspace) 296{ 297 struct proc *p; 298 int error; 299 300 KASSERT(td == curthread, ("non-current thread %p", td)); 301 error = 0; 302 p = td->td_proc; 303 if ((p->p_flag & P_HADTHREADS) != 0) { 304 PROC_LOCK(p); 305 if (thread_single(p, SINGLE_BOUNDARY) != 0) 306 error = ERESTART; 307 PROC_UNLOCK(p); 308 } 309 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 310 ("nested execve")); 311 *oldvmspace = p->p_vmspace; 312 return (error); 313} 314 315void 316post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 317{ 318 struct proc *p; 319 320 KASSERT(td == curthread, ("non-current thread %p", td)); 321 p = td->td_proc; 322 if ((p->p_flag & P_HADTHREADS) != 0) { 323 PROC_LOCK(p); 324 /* 325 * If success, we upgrade to SINGLE_EXIT state to 326 * force other threads to suicide. 327 */ 328 if (error == EJUSTRETURN) 329 thread_single(p, SINGLE_EXIT); 330 else 331 thread_single_end(p, SINGLE_BOUNDARY); 332 PROC_UNLOCK(p); 333 } 334 exec_cleanup(td, oldvmspace); 335} 336 337/* 338 * kern_execve() has the astonishing property of not always returning to 339 * the caller. If sufficiently bad things happen during the call to 340 * do_execve(), it can end up calling exit1(); as a result, callers must 341 * avoid doing anything which they might need to undo (e.g., allocating 342 * memory). 343 */ 344int 345kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p, 346 struct vmspace *oldvmspace) 347{ 348 349 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 350 exec_args_get_begin_envv(args) - args->begin_argv); 351 AUDIT_ARG_ENVV(exec_args_get_begin_envv(args), args->envc, 352 args->endp - exec_args_get_begin_envv(args)); 353 return (do_execve(td, args, mac_p, oldvmspace)); 354} 355 356static void 357execve_nosetid(struct image_params *imgp) 358{ 359 imgp->credential_setid = false; 360 if (imgp->newcred != NULL) { 361 crfree(imgp->newcred); 362 imgp->newcred = NULL; 363 } 364} 365 366/* 367 * In-kernel implementation of execve(). All arguments are assumed to be 368 * userspace pointers from the passed thread. 369 */ 370static int 371do_execve(struct thread *td, struct image_args *args, struct mac *mac_p, 372 struct vmspace *oldvmspace) 373{ 374 struct proc *p = td->td_proc; 375 struct nameidata nd; 376 struct ucred *oldcred; 377 struct uidinfo *euip = NULL; 378 uintptr_t stack_base; 379 struct image_params image_params, *imgp; 380 struct vattr attr; 381 int (*img_first)(struct image_params *); 382 struct pargs *oldargs = NULL, *newargs = NULL; 383 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 384#ifdef KTRACE 385 struct ktr_io_params *kiop; 386#endif 387 struct vnode *oldtextvp = NULL, *newtextvp; 388 int credential_changing; 389#ifdef MAC 390 struct label *interpvplabel = NULL; 391 int will_transition; 392#endif 393#ifdef HWPMC_HOOKS 394 struct pmckern_procexec pe; 395#endif 396 int error, i, orig_osrel; 397 uint32_t orig_fctl0; 398 static const char fexecv_proc_title[] = "(fexecv)"; 399 400 imgp = &image_params; 401#ifdef KTRACE 402 kiop = NULL; 403#endif 404 405 /* 406 * Lock the process and set the P_INEXEC flag to indicate that 407 * it should be left alone until we're done here. This is 408 * necessary to avoid race conditions - e.g. in ptrace() - 409 * that might allow a local user to illicitly obtain elevated 410 * privileges. 411 */ 412 PROC_LOCK(p); 413 KASSERT((p->p_flag & P_INEXEC) == 0, 414 ("%s(): process already has P_INEXEC flag", __func__)); 415 p->p_flag |= P_INEXEC; 416 PROC_UNLOCK(p); 417 418 /* 419 * Initialize part of the common data 420 */ 421 bzero(imgp, sizeof(*imgp)); 422 imgp->proc = p; 423 imgp->attr = &attr; 424 imgp->args = args; 425 oldcred = p->p_ucred; 426 orig_osrel = p->p_osrel; 427 orig_fctl0 = p->p_fctl0; 428 429#ifdef MAC 430 error = mac_execve_enter(imgp, mac_p); 431 if (error) 432 goto exec_fail; 433#endif 434 435 /* 436 * Translate the file name. namei() returns a vnode pointer 437 * in ni_vp among other things. 438 * 439 * XXXAUDIT: It would be desirable to also audit the name of the 440 * interpreter if this is an interpreted binary. 441 */ 442 if (args->fname != NULL) { 443 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 444 SAVENAME | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 445 } 446 447 SDT_PROBE1(proc, , , exec, args->fname); 448 449interpret: 450 if (args->fname != NULL) { 451#ifdef CAPABILITY_MODE 452 /* 453 * While capability mode can't reach this point via direct 454 * path arguments to execve(), we also don't allow 455 * interpreters to be used in capability mode (for now). 456 * Catch indirect lookups and return a permissions error. 457 */ 458 if (IN_CAPABILITY_MODE(td)) { 459 error = ECAPMODE; 460 goto exec_fail; 461 } 462#endif 463 error = namei(&nd); 464 if (error) 465 goto exec_fail; 466 467 newtextvp = nd.ni_vp; 468 imgp->vp = newtextvp; 469 } else { 470 AUDIT_ARG_FD(args->fd); 471 /* 472 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 473 */ 474 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights, &newtextvp); 475 if (error) 476 goto exec_fail; 477 vn_lock(newtextvp, LK_SHARED | LK_RETRY); 478 AUDIT_ARG_VNODE1(newtextvp); 479 imgp->vp = newtextvp; 480 } 481 482 /* 483 * Check file permissions. Also 'opens' file and sets its vnode to 484 * text mode. 485 */ 486 error = exec_check_permissions(imgp); 487 if (error) 488 goto exec_fail_dealloc; 489 490 imgp->object = imgp->vp->v_object; 491 if (imgp->object != NULL) 492 vm_object_reference(imgp->object); 493 494 error = exec_map_first_page(imgp); 495 if (error) 496 goto exec_fail_dealloc; 497 498 imgp->proc->p_osrel = 0; 499 imgp->proc->p_fctl0 = 0; 500 501 /* 502 * Implement image setuid/setgid. 503 * 504 * Determine new credentials before attempting image activators 505 * so that it can be used by process_exec handlers to determine 506 * credential/setid changes. 507 * 508 * Don't honor setuid/setgid if the filesystem prohibits it or if 509 * the process is being traced. 510 * 511 * We disable setuid/setgid/etc in capability mode on the basis 512 * that most setugid applications are not written with that 513 * environment in mind, and will therefore almost certainly operate 514 * incorrectly. In principle there's no reason that setugid 515 * applications might not be useful in capability mode, so we may want 516 * to reconsider this conservative design choice in the future. 517 * 518 * XXXMAC: For the time being, use NOSUID to also prohibit 519 * transitions on the file system. 520 */ 521 credential_changing = 0; 522 credential_changing |= (attr.va_mode & S_ISUID) && 523 oldcred->cr_uid != attr.va_uid; 524 credential_changing |= (attr.va_mode & S_ISGID) && 525 oldcred->cr_gid != attr.va_gid; 526#ifdef MAC 527 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 528 interpvplabel, imgp); 529 credential_changing |= will_transition; 530#endif 531 532 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */ 533 if (credential_changing) 534 imgp->proc->p_pdeathsig = 0; 535 536 if (credential_changing && 537#ifdef CAPABILITY_MODE 538 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 539#endif 540 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 541 (p->p_flag & P_TRACED) == 0) { 542 imgp->credential_setid = true; 543 VOP_UNLOCK(imgp->vp); 544 imgp->newcred = crdup(oldcred); 545 if (attr.va_mode & S_ISUID) { 546 euip = uifind(attr.va_uid); 547 change_euid(imgp->newcred, euip); 548 } 549 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 550 if (attr.va_mode & S_ISGID) 551 change_egid(imgp->newcred, attr.va_gid); 552 /* 553 * Implement correct POSIX saved-id behavior. 554 * 555 * XXXMAC: Note that the current logic will save the 556 * uid and gid if a MAC domain transition occurs, even 557 * though maybe it shouldn't. 558 */ 559 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 560 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 561 } else { 562 /* 563 * Implement correct POSIX saved-id behavior. 564 * 565 * XXX: It's not clear that the existing behavior is 566 * POSIX-compliant. A number of sources indicate that the 567 * saved uid/gid should only be updated if the new ruid is 568 * not equal to the old ruid, or the new euid is not equal 569 * to the old euid and the new euid is not equal to the old 570 * ruid. The FreeBSD code always updates the saved uid/gid. 571 * Also, this code uses the new (replaced) euid and egid as 572 * the source, which may or may not be the right ones to use. 573 */ 574 if (oldcred->cr_svuid != oldcred->cr_uid || 575 oldcred->cr_svgid != oldcred->cr_gid) { 576 VOP_UNLOCK(imgp->vp); 577 imgp->newcred = crdup(oldcred); 578 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 579 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 580 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 581 } 582 } 583 /* The new credentials are installed into the process later. */ 584 585 /* 586 * Do the best to calculate the full path to the image file. 587 */ 588 if (args->fname != NULL && args->fname[0] == '/') 589 imgp->execpath = args->fname; 590 else { 591 VOP_UNLOCK(imgp->vp); 592 if (vn_fullpath(imgp->vp, &imgp->execpath, &imgp->freepath) != 0) 593 imgp->execpath = args->fname; 594 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 595 } 596 597 /* 598 * If the current process has a special image activator it 599 * wants to try first, call it. For example, emulating shell 600 * scripts differently. 601 */ 602 error = -1; 603 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 604 error = img_first(imgp); 605 606 /* 607 * Loop through the list of image activators, calling each one. 608 * An activator returns -1 if there is no match, 0 on success, 609 * and an error otherwise. 610 */ 611 for (i = 0; error == -1 && execsw[i]; ++i) { 612 if (execsw[i]->ex_imgact == NULL || 613 execsw[i]->ex_imgact == img_first) { 614 continue; 615 } 616 error = (*execsw[i]->ex_imgact)(imgp); 617 } 618 619 if (error) { 620 if (error == -1) 621 error = ENOEXEC; 622 goto exec_fail_dealloc; 623 } 624 625 /* 626 * Special interpreter operation, cleanup and loop up to try to 627 * activate the interpreter. 628 */ 629 if (imgp->interpreted) { 630 exec_unmap_first_page(imgp); 631 /* 632 * The text reference needs to be removed for scripts. 633 * There is a short period before we determine that 634 * something is a script where text reference is active. 635 * The vnode lock is held over this entire period 636 * so nothing should illegitimately be blocked. 637 */ 638 MPASS(imgp->textset); 639 VOP_UNSET_TEXT_CHECKED(newtextvp); 640 imgp->textset = false; 641 /* free name buffer and old vnode */ 642 if (args->fname != NULL) 643 NDFREE(&nd, NDF_ONLY_PNBUF); 644#ifdef MAC 645 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 646#endif 647 if (imgp->opened) { 648 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 649 imgp->opened = 0; 650 } 651 vput(newtextvp); 652 vm_object_deallocate(imgp->object); 653 imgp->object = NULL; 654 execve_nosetid(imgp); 655 imgp->execpath = NULL; 656 free(imgp->freepath, M_TEMP); 657 imgp->freepath = NULL; 658 /* set new name to that of the interpreter */ 659 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 660 SAVENAME, UIO_SYSSPACE, imgp->interpreter_name, td); 661 args->fname = imgp->interpreter_name; 662 goto interpret; 663 } 664 665 /* 666 * NB: We unlock the vnode here because it is believed that none 667 * of the sv_copyout_strings/sv_fixup operations require the vnode. 668 */ 669 VOP_UNLOCK(imgp->vp); 670 671 if (disallow_high_osrel && 672 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 673 error = ENOEXEC; 674 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 675 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 676 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 677 goto exec_fail_dealloc; 678 } 679 680 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 681 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 682 sys_cap_enter(td, NULL); 683 684 /* 685 * Copy out strings (args and env) and initialize stack base. 686 */ 687 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base); 688 if (error != 0) { 689 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 690 goto exec_fail_dealloc; 691 } 692 693 /* 694 * Stack setup. 695 */ 696 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp); 697 if (error != 0) { 698 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 699 goto exec_fail_dealloc; 700 } 701 702 if (args->fdp != NULL) { 703 /* Install a brand new file descriptor table. */ 704 fdinstall_remapped(td, args->fdp); 705 args->fdp = NULL; 706 } else { 707 /* 708 * Keep on using the existing file descriptor table. For 709 * security and other reasons, the file descriptor table 710 * cannot be shared after an exec. 711 */ 712 fdunshare(td); 713 pdunshare(td); 714 /* close files on exec */ 715 fdcloseexec(td); 716 } 717 718 /* 719 * Malloc things before we need locks. 720 */ 721 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv; 722 /* Cache arguments if they fit inside our allowance */ 723 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 724 newargs = pargs_alloc(i); 725 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 726 } 727 728 /* 729 * For security and other reasons, signal handlers cannot 730 * be shared after an exec. The new process gets a copy of the old 731 * handlers. In execsigs(), the new process will have its signals 732 * reset. 733 */ 734 if (sigacts_shared(p->p_sigacts)) { 735 oldsigacts = p->p_sigacts; 736 newsigacts = sigacts_alloc(); 737 sigacts_copy(newsigacts, oldsigacts); 738 } 739 740 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 741 742 PROC_LOCK(p); 743 if (oldsigacts) 744 p->p_sigacts = newsigacts; 745 /* Stop profiling */ 746 stopprofclock(p); 747 748 /* reset caught signals */ 749 execsigs(p); 750 751 /* name this process - nameiexec(p, ndp) */ 752 bzero(p->p_comm, sizeof(p->p_comm)); 753 if (args->fname) 754 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 755 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 756 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 757 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 758 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 759#ifdef KTR 760 sched_clear_tdname(td); 761#endif 762 763 /* 764 * mark as execed, wakeup the process that vforked (if any) and tell 765 * it that it now has its own resources back 766 */ 767 p->p_flag |= P_EXEC; 768 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 769 p->p_flag2 &= ~P2_NOTRACE; 770 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0) 771 p->p_flag2 &= ~P2_STKGAP_DISABLE; 772 if (p->p_flag & P_PPWAIT) { 773 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 774 cv_broadcast(&p->p_pwait); 775 /* STOPs are no longer ignored, arrange for AST */ 776 signotify(td); 777 } 778 779 if (imgp->sysent->sv_setid_allowed != NULL && 780 !(*imgp->sysent->sv_setid_allowed)(td, imgp)) 781 execve_nosetid(imgp); 782 783 /* 784 * Implement image setuid/setgid installation. 785 */ 786 if (imgp->credential_setid) { 787 /* 788 * Turn off syscall tracing for set-id programs, except for 789 * root. Record any set-id flags first to make sure that 790 * we do not regain any tracing during a possible block. 791 */ 792 setsugid(p); 793#ifdef KTRACE 794 kiop = ktrprocexec(p); 795#endif 796 /* 797 * Close any file descriptors 0..2 that reference procfs, 798 * then make sure file descriptors 0..2 are in use. 799 * 800 * Both fdsetugidsafety() and fdcheckstd() may call functions 801 * taking sleepable locks, so temporarily drop our locks. 802 */ 803 PROC_UNLOCK(p); 804 VOP_UNLOCK(imgp->vp); 805 fdsetugidsafety(td); 806 error = fdcheckstd(td); 807 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 808 if (error != 0) 809 goto exec_fail_dealloc; 810 PROC_LOCK(p); 811#ifdef MAC 812 if (will_transition) { 813 mac_vnode_execve_transition(oldcred, imgp->newcred, 814 imgp->vp, interpvplabel, imgp); 815 } 816#endif 817 } else { 818 if (oldcred->cr_uid == oldcred->cr_ruid && 819 oldcred->cr_gid == oldcred->cr_rgid) 820 p->p_flag &= ~P_SUGID; 821 } 822 /* 823 * Set the new credentials. 824 */ 825 if (imgp->newcred != NULL) { 826 proc_set_cred(p, imgp->newcred); 827 crfree(oldcred); 828 oldcred = NULL; 829 } 830 831 /* 832 * Store the vp for use in procfs. This vnode was referenced by namei 833 * or fgetvp_exec. 834 */ 835 oldtextvp = p->p_textvp; 836 p->p_textvp = newtextvp; 837 838#ifdef KDTRACE_HOOKS 839 /* 840 * Tell the DTrace fasttrap provider about the exec if it 841 * has declared an interest. 842 */ 843 if (dtrace_fasttrap_exec) 844 dtrace_fasttrap_exec(p); 845#endif 846 847 /* 848 * Notify others that we exec'd, and clear the P_INEXEC flag 849 * as we're now a bona fide freshly-execed process. 850 */ 851 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 852 p->p_flag &= ~P_INEXEC; 853 854 /* clear "fork but no exec" flag, as we _are_ execing */ 855 p->p_acflag &= ~AFORK; 856 857 /* 858 * Free any previous argument cache and replace it with 859 * the new argument cache, if any. 860 */ 861 oldargs = p->p_args; 862 p->p_args = newargs; 863 newargs = NULL; 864 865 PROC_UNLOCK(p); 866 867#ifdef HWPMC_HOOKS 868 /* 869 * Check if system-wide sampling is in effect or if the 870 * current process is using PMCs. If so, do exec() time 871 * processing. This processing needs to happen AFTER the 872 * P_INEXEC flag is cleared. 873 */ 874 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 875 VOP_UNLOCK(imgp->vp); 876 pe.pm_credentialschanged = credential_changing; 877 pe.pm_entryaddr = imgp->entry_addr; 878 879 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 880 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 881 } 882#endif 883 884 /* Set values passed into the program in registers. */ 885 (*p->p_sysent->sv_setregs)(td, imgp, stack_base); 886 887 VOP_MMAPPED(imgp->vp); 888 889 SDT_PROBE1(proc, , , exec__success, args->fname); 890 891exec_fail_dealloc: 892 if (error != 0) { 893 p->p_osrel = orig_osrel; 894 p->p_fctl0 = orig_fctl0; 895 } 896 897 if (imgp->firstpage != NULL) 898 exec_unmap_first_page(imgp); 899 900 if (imgp->vp != NULL) { 901 if (args->fname) 902 NDFREE(&nd, NDF_ONLY_PNBUF); 903 if (imgp->opened) 904 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 905 if (imgp->textset) 906 VOP_UNSET_TEXT_CHECKED(imgp->vp); 907 if (error != 0) 908 vput(imgp->vp); 909 else 910 VOP_UNLOCK(imgp->vp); 911 } 912 913 if (imgp->object != NULL) 914 vm_object_deallocate(imgp->object); 915 916 free(imgp->freepath, M_TEMP); 917 918 if (error == 0) { 919 if (p->p_ptevents & PTRACE_EXEC) { 920 PROC_LOCK(p); 921 if (p->p_ptevents & PTRACE_EXEC) 922 td->td_dbgflags |= TDB_EXEC; 923 PROC_UNLOCK(p); 924 } 925 } else { 926exec_fail: 927 /* we're done here, clear P_INEXEC */ 928 PROC_LOCK(p); 929 p->p_flag &= ~P_INEXEC; 930 PROC_UNLOCK(p); 931 932 SDT_PROBE1(proc, , , exec__failure, error); 933 } 934 935 if (imgp->newcred != NULL && oldcred != NULL) 936 crfree(imgp->newcred); 937 938#ifdef MAC 939 mac_execve_exit(imgp); 940 mac_execve_interpreter_exit(interpvplabel); 941#endif 942 exec_free_args(args); 943 944 /* 945 * Handle deferred decrement of ref counts. 946 */ 947 if (oldtextvp != NULL) 948 vrele(oldtextvp); 949#ifdef KTRACE 950 ktr_io_params_free(kiop); 951#endif 952 pargs_drop(oldargs); 953 pargs_drop(newargs); 954 if (oldsigacts != NULL) 955 sigacts_free(oldsigacts); 956 if (euip != NULL) 957 uifree(euip); 958 959 if (error && imgp->vmspace_destroyed) { 960 /* sorry, no more process anymore. exit gracefully */ 961 exec_cleanup(td, oldvmspace); 962 exit1(td, 0, SIGABRT); 963 /* NOT REACHED */ 964 } 965 966#ifdef KTRACE 967 if (error == 0) 968 ktrprocctor(p); 969#endif 970 971 /* 972 * We don't want cpu_set_syscall_retval() to overwrite any of 973 * the register values put in place by exec_setregs(). 974 * Implementations of cpu_set_syscall_retval() will leave 975 * registers unmodified when returning EJUSTRETURN. 976 */ 977 return (error == 0 ? EJUSTRETURN : error); 978} 979 980void 981exec_cleanup(struct thread *td, struct vmspace *oldvmspace) 982{ 983 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 984 KASSERT(td->td_proc->p_vmspace != oldvmspace, 985 ("oldvmspace still used")); 986 vmspace_free(oldvmspace); 987 td->td_pflags &= ~TDP_EXECVMSPC; 988 } 989} 990 991int 992exec_map_first_page(struct image_params *imgp) 993{ 994 vm_object_t object; 995 vm_page_t m; 996 int error; 997 998 if (imgp->firstpage != NULL) 999 exec_unmap_first_page(imgp); 1000 1001 object = imgp->vp->v_object; 1002 if (object == NULL) 1003 return (EACCES); 1004#if VM_NRESERVLEVEL > 0 1005 if ((object->flags & OBJ_COLORED) == 0) { 1006 VM_OBJECT_WLOCK(object); 1007 vm_object_color(object, 0); 1008 VM_OBJECT_WUNLOCK(object); 1009 } 1010#endif 1011 error = vm_page_grab_valid_unlocked(&m, object, 0, 1012 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) | 1013 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED); 1014 1015 if (error != VM_PAGER_OK) 1016 return (EIO); 1017 imgp->firstpage = sf_buf_alloc(m, 0); 1018 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1019 1020 return (0); 1021} 1022 1023void 1024exec_unmap_first_page(struct image_params *imgp) 1025{ 1026 vm_page_t m; 1027 1028 if (imgp->firstpage != NULL) { 1029 m = sf_buf_page(imgp->firstpage); 1030 sf_buf_free(imgp->firstpage); 1031 imgp->firstpage = NULL; 1032 vm_page_unwire(m, PQ_ACTIVE); 1033 } 1034} 1035 1036/* 1037 * Destroy old address space, and allocate a new stack. 1038 * The new stack is only sgrowsiz large because it is grown 1039 * automatically on a page fault. 1040 */ 1041int 1042exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1043{ 1044 int error; 1045 struct proc *p = imgp->proc; 1046 struct vmspace *vmspace = p->p_vmspace; 1047 struct thread *td = curthread; 1048 vm_object_t obj; 1049 struct rlimit rlim_stack; 1050 vm_offset_t sv_minuser, stack_addr; 1051 vm_map_t map; 1052 vm_prot_t stack_prot; 1053 u_long ssiz; 1054 1055 imgp->vmspace_destroyed = 1; 1056 imgp->sysent = sv; 1057 1058 sigfastblock_clear(td); 1059 umtx_exec(p); 1060 itimers_exec(p); 1061 if (sv->sv_onexec != NULL) 1062 sv->sv_onexec(p, imgp); 1063 1064 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp); 1065 1066 /* 1067 * Blow away entire process VM, if address space not shared, 1068 * otherwise, create a new VM space so that other threads are 1069 * not disrupted 1070 */ 1071 map = &vmspace->vm_map; 1072 if (map_at_zero) 1073 sv_minuser = sv->sv_minuser; 1074 else 1075 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1076 if (refcount_load(&vmspace->vm_refcnt) == 1 && 1077 vm_map_min(map) == sv_minuser && 1078 vm_map_max(map) == sv->sv_maxuser && 1079 cpu_exec_vmspace_reuse(p, map)) { 1080 shmexit(vmspace); 1081 pmap_remove_pages(vmspace_pmap(vmspace)); 1082 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1083 /* 1084 * An exec terminates mlockall(MCL_FUTURE). 1085 * ASLR and W^X states must be re-evaluated. 1086 */ 1087 vm_map_lock(map); 1088 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR | 1089 MAP_ASLR_IGNSTART | MAP_WXORX); 1090 vm_map_unlock(map); 1091 } else { 1092 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1093 if (error) 1094 return (error); 1095 vmspace = p->p_vmspace; 1096 map = &vmspace->vm_map; 1097 } 1098 map->flags |= imgp->map_flags; 1099 1100 /* Map a shared page */ 1101 obj = sv->sv_shared_page_obj; 1102 if (obj != NULL) { 1103 vm_object_reference(obj); 1104 error = vm_map_fixed(map, obj, 0, 1105 sv->sv_shared_page_base, sv->sv_shared_page_len, 1106 VM_PROT_READ | VM_PROT_EXECUTE, 1107 VM_PROT_READ | VM_PROT_EXECUTE, 1108 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1109 if (error != KERN_SUCCESS) { 1110 vm_object_deallocate(obj); 1111 return (vm_mmap_to_errno(error)); 1112 } 1113 } 1114 1115 /* Allocate a new stack */ 1116 if (imgp->stack_sz != 0) { 1117 ssiz = trunc_page(imgp->stack_sz); 1118 PROC_LOCK(p); 1119 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1120 PROC_UNLOCK(p); 1121 if (ssiz > rlim_stack.rlim_max) 1122 ssiz = rlim_stack.rlim_max; 1123 if (ssiz > rlim_stack.rlim_cur) { 1124 rlim_stack.rlim_cur = ssiz; 1125 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1126 } 1127 } else if (sv->sv_maxssiz != NULL) { 1128 ssiz = *sv->sv_maxssiz; 1129 } else { 1130 ssiz = maxssiz; 1131 } 1132 imgp->eff_stack_sz = lim_cur(curthread, RLIMIT_STACK); 1133 if (ssiz < imgp->eff_stack_sz) 1134 imgp->eff_stack_sz = ssiz; 1135 stack_addr = sv->sv_usrstack - ssiz; 1136 stack_prot = obj != NULL && imgp->stack_prot != 0 ? 1137 imgp->stack_prot : sv->sv_stackprot; 1138 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, stack_prot, 1139 VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1140 if (error != KERN_SUCCESS) { 1141 uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x " 1142 "failed mach error %d errno %d\n", (uintmax_t)ssiz, 1143 stack_prot, error, vm_mmap_to_errno(error)); 1144 return (vm_mmap_to_errno(error)); 1145 } 1146 1147 /* 1148 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1149 * are still used to enforce the stack rlimit on the process stack. 1150 */ 1151 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1152 vmspace->vm_maxsaddr = (char *)stack_addr; 1153 1154 return (0); 1155} 1156 1157/* 1158 * Copy out argument and environment strings from the old process address 1159 * space into the temporary string buffer. 1160 */ 1161int 1162exec_copyin_args(struct image_args *args, const char *fname, 1163 enum uio_seg segflg, char **argv, char **envv) 1164{ 1165 u_long arg, env; 1166 int error; 1167 1168 bzero(args, sizeof(*args)); 1169 if (argv == NULL) 1170 return (EFAULT); 1171 1172 /* 1173 * Allocate demand-paged memory for the file name, argument, and 1174 * environment strings. 1175 */ 1176 error = exec_alloc_args(args); 1177 if (error != 0) 1178 return (error); 1179 1180 /* 1181 * Copy the file name. 1182 */ 1183 error = exec_args_add_fname(args, fname, segflg); 1184 if (error != 0) 1185 goto err_exit; 1186 1187 /* 1188 * extract arguments first 1189 */ 1190 for (;;) { 1191 error = fueword(argv++, &arg); 1192 if (error == -1) { 1193 error = EFAULT; 1194 goto err_exit; 1195 } 1196 if (arg == 0) 1197 break; 1198 error = exec_args_add_arg(args, (char *)(uintptr_t)arg, 1199 UIO_USERSPACE); 1200 if (error != 0) 1201 goto err_exit; 1202 } 1203 1204 /* 1205 * extract environment strings 1206 */ 1207 if (envv) { 1208 for (;;) { 1209 error = fueword(envv++, &env); 1210 if (error == -1) { 1211 error = EFAULT; 1212 goto err_exit; 1213 } 1214 if (env == 0) 1215 break; 1216 error = exec_args_add_env(args, 1217 (char *)(uintptr_t)env, UIO_USERSPACE); 1218 if (error != 0) 1219 goto err_exit; 1220 } 1221 } 1222 1223 return (0); 1224 1225err_exit: 1226 exec_free_args(args); 1227 return (error); 1228} 1229 1230int 1231exec_copyin_data_fds(struct thread *td, struct image_args *args, 1232 const void *data, size_t datalen, const int *fds, size_t fdslen) 1233{ 1234 struct filedesc *ofdp; 1235 const char *p; 1236 int *kfds; 1237 int error; 1238 1239 memset(args, '\0', sizeof(*args)); 1240 ofdp = td->td_proc->p_fd; 1241 if (datalen >= ARG_MAX || fdslen >= ofdp->fd_nfiles) 1242 return (E2BIG); 1243 error = exec_alloc_args(args); 1244 if (error != 0) 1245 return (error); 1246 1247 args->begin_argv = args->buf; 1248 args->stringspace = ARG_MAX; 1249 1250 if (datalen > 0) { 1251 /* 1252 * Argument buffer has been provided. Copy it into the 1253 * kernel as a single string and add a terminating null 1254 * byte. 1255 */ 1256 error = copyin(data, args->begin_argv, datalen); 1257 if (error != 0) 1258 goto err_exit; 1259 args->begin_argv[datalen] = '\0'; 1260 args->endp = args->begin_argv + datalen + 1; 1261 args->stringspace -= datalen + 1; 1262 1263 /* 1264 * Traditional argument counting. Count the number of 1265 * null bytes. 1266 */ 1267 for (p = args->begin_argv; p < args->endp; ++p) 1268 if (*p == '\0') 1269 ++args->argc; 1270 } else { 1271 /* No argument buffer provided. */ 1272 args->endp = args->begin_argv; 1273 } 1274 1275 /* Create new file descriptor table. */ 1276 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1277 error = copyin(fds, kfds, fdslen * sizeof(int)); 1278 if (error != 0) { 1279 free(kfds, M_TEMP); 1280 goto err_exit; 1281 } 1282 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1283 free(kfds, M_TEMP); 1284 if (error != 0) 1285 goto err_exit; 1286 1287 return (0); 1288err_exit: 1289 exec_free_args(args); 1290 return (error); 1291} 1292 1293struct exec_args_kva { 1294 vm_offset_t addr; 1295 u_int gen; 1296 SLIST_ENTRY(exec_args_kva) next; 1297}; 1298 1299DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva); 1300 1301static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1302static struct mtx exec_args_kva_mtx; 1303static u_int exec_args_gen; 1304 1305static void 1306exec_prealloc_args_kva(void *arg __unused) 1307{ 1308 struct exec_args_kva *argkva; 1309 u_int i; 1310 1311 SLIST_INIT(&exec_args_kva_freelist); 1312 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1313 for (i = 0; i < exec_map_entries; i++) { 1314 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1315 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1316 argkva->gen = exec_args_gen; 1317 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1318 } 1319} 1320SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1321 1322static vm_offset_t 1323exec_alloc_args_kva(void **cookie) 1324{ 1325 struct exec_args_kva *argkva; 1326 1327 argkva = (void *)atomic_readandclear_ptr( 1328 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1329 if (argkva == NULL) { 1330 mtx_lock(&exec_args_kva_mtx); 1331 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1332 (void)mtx_sleep(&exec_args_kva_freelist, 1333 &exec_args_kva_mtx, 0, "execkva", 0); 1334 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1335 mtx_unlock(&exec_args_kva_mtx); 1336 } 1337 *(struct exec_args_kva **)cookie = argkva; 1338 return (argkva->addr); 1339} 1340 1341static void 1342exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1343{ 1344 vm_offset_t base; 1345 1346 base = argkva->addr; 1347 if (argkva->gen != gen) { 1348 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1349 MADV_FREE); 1350 argkva->gen = gen; 1351 } 1352 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1353 (uintptr_t)NULL, (uintptr_t)argkva)) { 1354 mtx_lock(&exec_args_kva_mtx); 1355 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1356 wakeup_one(&exec_args_kva_freelist); 1357 mtx_unlock(&exec_args_kva_mtx); 1358 } 1359} 1360 1361static void 1362exec_free_args_kva(void *cookie) 1363{ 1364 1365 exec_release_args_kva(cookie, exec_args_gen); 1366} 1367 1368static void 1369exec_args_kva_lowmem(void *arg __unused) 1370{ 1371 SLIST_HEAD(, exec_args_kva) head; 1372 struct exec_args_kva *argkva; 1373 u_int gen; 1374 int i; 1375 1376 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1377 1378 /* 1379 * Force an madvise of each KVA range. Any currently allocated ranges 1380 * will have MADV_FREE applied once they are freed. 1381 */ 1382 SLIST_INIT(&head); 1383 mtx_lock(&exec_args_kva_mtx); 1384 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1385 mtx_unlock(&exec_args_kva_mtx); 1386 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1387 SLIST_REMOVE_HEAD(&head, next); 1388 exec_release_args_kva(argkva, gen); 1389 } 1390 1391 CPU_FOREACH(i) { 1392 argkva = (void *)atomic_readandclear_ptr( 1393 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1394 if (argkva != NULL) 1395 exec_release_args_kva(argkva, gen); 1396 } 1397} 1398EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1399 EVENTHANDLER_PRI_ANY); 1400 1401/* 1402 * Allocate temporary demand-paged, zero-filled memory for the file name, 1403 * argument, and environment strings. 1404 */ 1405int 1406exec_alloc_args(struct image_args *args) 1407{ 1408 1409 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1410 return (0); 1411} 1412 1413void 1414exec_free_args(struct image_args *args) 1415{ 1416 1417 if (args->buf != NULL) { 1418 exec_free_args_kva(args->bufkva); 1419 args->buf = NULL; 1420 } 1421 if (args->fname_buf != NULL) { 1422 free(args->fname_buf, M_TEMP); 1423 args->fname_buf = NULL; 1424 } 1425 if (args->fdp != NULL) 1426 fdescfree_remapped(args->fdp); 1427} 1428 1429/* 1430 * A set to functions to fill struct image args. 1431 * 1432 * NOTE: exec_args_add_fname() must be called (possibly with a NULL 1433 * fname) before the other functions. All exec_args_add_arg() calls must 1434 * be made before any exec_args_add_env() calls. exec_args_adjust_args() 1435 * may be called any time after exec_args_add_fname(). 1436 * 1437 * exec_args_add_fname() - install path to be executed 1438 * exec_args_add_arg() - append an argument string 1439 * exec_args_add_env() - append an env string 1440 * exec_args_adjust_args() - adjust location of the argument list to 1441 * allow new arguments to be prepended 1442 */ 1443int 1444exec_args_add_fname(struct image_args *args, const char *fname, 1445 enum uio_seg segflg) 1446{ 1447 int error; 1448 size_t length; 1449 1450 KASSERT(args->fname == NULL, ("fname already appended")); 1451 KASSERT(args->endp == NULL, ("already appending to args")); 1452 1453 if (fname != NULL) { 1454 args->fname = args->buf; 1455 error = segflg == UIO_SYSSPACE ? 1456 copystr(fname, args->fname, PATH_MAX, &length) : 1457 copyinstr(fname, args->fname, PATH_MAX, &length); 1458 if (error != 0) 1459 return (error == ENAMETOOLONG ? E2BIG : error); 1460 } else 1461 length = 0; 1462 1463 /* Set up for _arg_*()/_env_*() */ 1464 args->endp = args->buf + length; 1465 /* begin_argv must be set and kept updated */ 1466 args->begin_argv = args->endp; 1467 KASSERT(exec_map_entry_size - length >= ARG_MAX, 1468 ("too little space remaining for arguments %zu < %zu", 1469 exec_map_entry_size - length, (size_t)ARG_MAX)); 1470 args->stringspace = ARG_MAX; 1471 1472 return (0); 1473} 1474 1475static int 1476exec_args_add_str(struct image_args *args, const char *str, 1477 enum uio_seg segflg, int *countp) 1478{ 1479 int error; 1480 size_t length; 1481 1482 KASSERT(args->endp != NULL, ("endp not initialized")); 1483 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1484 1485 error = (segflg == UIO_SYSSPACE) ? 1486 copystr(str, args->endp, args->stringspace, &length) : 1487 copyinstr(str, args->endp, args->stringspace, &length); 1488 if (error != 0) 1489 return (error == ENAMETOOLONG ? E2BIG : error); 1490 args->stringspace -= length; 1491 args->endp += length; 1492 (*countp)++; 1493 1494 return (0); 1495} 1496 1497int 1498exec_args_add_arg(struct image_args *args, const char *argp, 1499 enum uio_seg segflg) 1500{ 1501 1502 KASSERT(args->envc == 0, ("appending args after env")); 1503 1504 return (exec_args_add_str(args, argp, segflg, &args->argc)); 1505} 1506 1507int 1508exec_args_add_env(struct image_args *args, const char *envp, 1509 enum uio_seg segflg) 1510{ 1511 1512 if (args->envc == 0) 1513 args->begin_envv = args->endp; 1514 1515 return (exec_args_add_str(args, envp, segflg, &args->envc)); 1516} 1517 1518int 1519exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend) 1520{ 1521 ssize_t offset; 1522 1523 KASSERT(args->endp != NULL, ("endp not initialized")); 1524 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1525 1526 offset = extend - consume; 1527 if (args->stringspace < offset) 1528 return (E2BIG); 1529 memmove(args->begin_argv + extend, args->begin_argv + consume, 1530 args->endp - args->begin_argv + consume); 1531 if (args->envc > 0) 1532 args->begin_envv += offset; 1533 args->endp += offset; 1534 args->stringspace -= offset; 1535 return (0); 1536} 1537 1538char * 1539exec_args_get_begin_envv(struct image_args *args) 1540{ 1541 1542 KASSERT(args->endp != NULL, ("endp not initialized")); 1543 1544 if (args->envc > 0) 1545 return (args->begin_envv); 1546 return (args->endp); 1547} 1548 1549void 1550exec_stackgap(struct image_params *imgp, uintptr_t *dp) 1551{ 1552 if (imgp->sysent->sv_stackgap == NULL || 1553 (imgp->proc->p_fctl0 & (NT_FREEBSD_FCTL_ASLR_DISABLE | 1554 NT_FREEBSD_FCTL_ASG_DISABLE)) != 0 || 1555 (imgp->map_flags & MAP_ASLR) == 0) 1556 return; 1557 imgp->sysent->sv_stackgap(imgp, dp); 1558} 1559 1560/* 1561 * Copy strings out to the new process address space, constructing new arg 1562 * and env vector tables. Return a pointer to the base so that it can be used 1563 * as the initial stack pointer. 1564 */ 1565int 1566exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base) 1567{ 1568 int argc, envc; 1569 char **vectp; 1570 char *stringp; 1571 uintptr_t destp, ustringp; 1572 struct ps_strings *arginfo; 1573 struct proc *p; 1574 size_t execpath_len; 1575 int error, szsigcode, szps; 1576 char canary[sizeof(long) * 8]; 1577 1578 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1579 /* 1580 * Calculate string base and vector table pointers. 1581 * Also deal with signal trampoline code for this exec type. 1582 */ 1583 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1584 execpath_len = strlen(imgp->execpath) + 1; 1585 else 1586 execpath_len = 0; 1587 p = imgp->proc; 1588 szsigcode = 0; 1589 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1590 imgp->ps_strings = arginfo; 1591 if (p->p_sysent->sv_sigcode_base == 0) { 1592 if (p->p_sysent->sv_szsigcode != NULL) 1593 szsigcode = *(p->p_sysent->sv_szsigcode); 1594 } 1595 destp = (uintptr_t)arginfo; 1596 1597 /* 1598 * install sigcode 1599 */ 1600 if (szsigcode != 0) { 1601 destp -= szsigcode; 1602 destp = rounddown2(destp, sizeof(void *)); 1603 error = copyout(p->p_sysent->sv_sigcode, (void *)destp, 1604 szsigcode); 1605 if (error != 0) 1606 return (error); 1607 } 1608 1609 /* 1610 * Copy the image path for the rtld. 1611 */ 1612 if (execpath_len != 0) { 1613 destp -= execpath_len; 1614 destp = rounddown2(destp, sizeof(void *)); 1615 imgp->execpathp = (void *)destp; 1616 error = copyout(imgp->execpath, imgp->execpathp, execpath_len); 1617 if (error != 0) 1618 return (error); 1619 } 1620 1621 /* 1622 * Prepare the canary for SSP. 1623 */ 1624 arc4rand(canary, sizeof(canary), 0); 1625 destp -= sizeof(canary); 1626 imgp->canary = (void *)destp; 1627 error = copyout(canary, imgp->canary, sizeof(canary)); 1628 if (error != 0) 1629 return (error); 1630 imgp->canarylen = sizeof(canary); 1631 1632 /* 1633 * Prepare the pagesizes array. 1634 */ 1635 destp -= szps; 1636 destp = rounddown2(destp, sizeof(void *)); 1637 imgp->pagesizes = (void *)destp; 1638 error = copyout(pagesizes, imgp->pagesizes, szps); 1639 if (error != 0) 1640 return (error); 1641 imgp->pagesizeslen = szps; 1642 1643 /* 1644 * Allocate room for the argument and environment strings. 1645 */ 1646 destp -= ARG_MAX - imgp->args->stringspace; 1647 destp = rounddown2(destp, sizeof(void *)); 1648 ustringp = destp; 1649 1650 exec_stackgap(imgp, &destp); 1651 1652 if (imgp->auxargs) { 1653 /* 1654 * Allocate room on the stack for the ELF auxargs 1655 * array. It has up to AT_COUNT entries. 1656 */ 1657 destp -= AT_COUNT * sizeof(Elf_Auxinfo); 1658 destp = rounddown2(destp, sizeof(void *)); 1659 } 1660 1661 vectp = (char **)destp; 1662 1663 /* 1664 * Allocate room for the argv[] and env vectors including the 1665 * terminating NULL pointers. 1666 */ 1667 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 1668 1669 /* 1670 * vectp also becomes our initial stack base 1671 */ 1672 *stack_base = (uintptr_t)vectp; 1673 1674 stringp = imgp->args->begin_argv; 1675 argc = imgp->args->argc; 1676 envc = imgp->args->envc; 1677 1678 /* 1679 * Copy out strings - arguments and environment. 1680 */ 1681 error = copyout(stringp, (void *)ustringp, 1682 ARG_MAX - imgp->args->stringspace); 1683 if (error != 0) 1684 return (error); 1685 1686 /* 1687 * Fill in "ps_strings" struct for ps, w, etc. 1688 */ 1689 imgp->argv = vectp; 1690 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 || 1691 suword32(&arginfo->ps_nargvstr, argc) != 0) 1692 return (EFAULT); 1693 1694 /* 1695 * Fill in argument portion of vector table. 1696 */ 1697 for (; argc > 0; --argc) { 1698 if (suword(vectp++, ustringp) != 0) 1699 return (EFAULT); 1700 while (*stringp++ != 0) 1701 ustringp++; 1702 ustringp++; 1703 } 1704 1705 /* a null vector table pointer separates the argp's from the envp's */ 1706 if (suword(vectp++, 0) != 0) 1707 return (EFAULT); 1708 1709 imgp->envv = vectp; 1710 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 || 1711 suword32(&arginfo->ps_nenvstr, envc) != 0) 1712 return (EFAULT); 1713 1714 /* 1715 * Fill in environment portion of vector table. 1716 */ 1717 for (; envc > 0; --envc) { 1718 if (suword(vectp++, ustringp) != 0) 1719 return (EFAULT); 1720 while (*stringp++ != 0) 1721 ustringp++; 1722 ustringp++; 1723 } 1724 1725 /* end of vector table is a null pointer */ 1726 if (suword(vectp, 0) != 0) 1727 return (EFAULT); 1728 1729 if (imgp->auxargs) { 1730 vectp++; 1731 error = imgp->sysent->sv_copyout_auxargs(imgp, 1732 (uintptr_t)vectp); 1733 if (error != 0) 1734 return (error); 1735 } 1736 1737 return (0); 1738} 1739 1740/* 1741 * Check permissions of file to execute. 1742 * Called with imgp->vp locked. 1743 * Return 0 for success or error code on failure. 1744 */ 1745int 1746exec_check_permissions(struct image_params *imgp) 1747{ 1748 struct vnode *vp = imgp->vp; 1749 struct vattr *attr = imgp->attr; 1750 struct thread *td; 1751 int error; 1752 1753 td = curthread; 1754 1755 /* Get file attributes */ 1756 error = VOP_GETATTR(vp, attr, td->td_ucred); 1757 if (error) 1758 return (error); 1759 1760#ifdef MAC 1761 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1762 if (error) 1763 return (error); 1764#endif 1765 1766 /* 1767 * 1) Check if file execution is disabled for the filesystem that 1768 * this file resides on. 1769 * 2) Ensure that at least one execute bit is on. Otherwise, a 1770 * privileged user will always succeed, and we don't want this 1771 * to happen unless the file really is executable. 1772 * 3) Ensure that the file is a regular file. 1773 */ 1774 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1775 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1776 (attr->va_type != VREG)) 1777 return (EACCES); 1778 1779 /* 1780 * Zero length files can't be exec'd 1781 */ 1782 if (attr->va_size == 0) 1783 return (ENOEXEC); 1784 1785 /* 1786 * Check for execute permission to file based on current credentials. 1787 */ 1788 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1789 if (error) 1790 return (error); 1791 1792 /* 1793 * Check number of open-for-writes on the file and deny execution 1794 * if there are any. 1795 * 1796 * Add a text reference now so no one can write to the 1797 * executable while we're activating it. 1798 * 1799 * Remember if this was set before and unset it in case this is not 1800 * actually an executable image. 1801 */ 1802 error = VOP_SET_TEXT(vp); 1803 if (error != 0) 1804 return (error); 1805 imgp->textset = true; 1806 1807 /* 1808 * Call filesystem specific open routine (which does nothing in the 1809 * general case). 1810 */ 1811 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1812 if (error == 0) 1813 imgp->opened = 1; 1814 return (error); 1815} 1816 1817/* 1818 * Exec handler registration 1819 */ 1820int 1821exec_register(const struct execsw *execsw_arg) 1822{ 1823 const struct execsw **es, **xs, **newexecsw; 1824 u_int count = 2; /* New slot and trailing NULL */ 1825 1826 if (execsw) 1827 for (es = execsw; *es; es++) 1828 count++; 1829 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1830 xs = newexecsw; 1831 if (execsw) 1832 for (es = execsw; *es; es++) 1833 *xs++ = *es; 1834 *xs++ = execsw_arg; 1835 *xs = NULL; 1836 if (execsw) 1837 free(execsw, M_TEMP); 1838 execsw = newexecsw; 1839 return (0); 1840} 1841 1842int 1843exec_unregister(const struct execsw *execsw_arg) 1844{ 1845 const struct execsw **es, **xs, **newexecsw; 1846 int count = 1; 1847 1848 if (execsw == NULL) 1849 panic("unregister with no handlers left?\n"); 1850 1851 for (es = execsw; *es; es++) { 1852 if (*es == execsw_arg) 1853 break; 1854 } 1855 if (*es == NULL) 1856 return (ENOENT); 1857 for (es = execsw; *es; es++) 1858 if (*es != execsw_arg) 1859 count++; 1860 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1861 xs = newexecsw; 1862 for (es = execsw; *es; es++) 1863 if (*es != execsw_arg) 1864 *xs++ = *es; 1865 *xs = NULL; 1866 if (execsw) 1867 free(execsw, M_TEMP); 1868 execsw = newexecsw; 1869 return (0); 1870} 1871