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/asan.h> 41 #include <sys/capsicum.h> 42 #include <sys/compressor.h> 43 #include <sys/eventhandler.h> 44 #include <sys/exec.h> 45 #include <sys/fcntl.h> 46 #include <sys/filedesc.h> 47 #include <sys/imgact.h> 48 #include <sys/imgact_elf.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/malloc.h> 52 #include <sys/mman.h> 53 #include <sys/mount.h> 54 #include <sys/mutex.h> 55 #include <sys/namei.h> 56 #include <sys/priv.h> 57 #include <sys/proc.h> 58 #include <sys/ptrace.h> 59 #include <sys/reg.h> 60 #include <sys/resourcevar.h> 61 #include <sys/rwlock.h> 62 #include <sys/sched.h> 63 #include <sys/sdt.h> 64 #include <sys/sf_buf.h> 65 #include <sys/shm.h> 66 #include <sys/signalvar.h> 67 #include <sys/smp.h> 68 #include <sys/stat.h> 69 #include <sys/syscallsubr.h> 70 #include <sys/sysctl.h> 71 #include <sys/sysent.h> 72 #include <sys/sysproto.h> 73 #include <sys/timers.h> 74 #include <sys/umtxvar.h> 75 #include <sys/vnode.h> 76 #include <sys/wait.h> 77 #ifdef KTRACE 78 #include <sys/ktrace.h> 79 #endif 80 81 #include <vm/vm.h> 82 #include <vm/vm_param.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_page.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_kern.h> 87 #include <vm/vm_extern.h> 88 #include <vm/vm_object.h> 89 #include <vm/vm_pager.h> 90 91 #ifdef HWPMC_HOOKS 92 #include <sys/pmckern.h> 93 #endif 94 95 #include <security/audit/audit.h> 96 #include <security/mac/mac_framework.h> 97 98 #ifdef KDTRACE_HOOKS 99 #include <sys/dtrace_bsd.h> 100 dtrace_execexit_func_t dtrace_fasttrap_exec; 101 #endif 102 103 SDT_PROVIDER_DECLARE(proc); 104 SDT_PROBE_DEFINE1(proc, , , exec, "char *"); 105 SDT_PROBE_DEFINE1(proc, , , exec__failure, "int"); 106 SDT_PROBE_DEFINE1(proc, , , exec__success, "char *"); 107 108 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 109 110 int coredump_pack_fileinfo = 1; 111 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_fileinfo, CTLFLAG_RWTUN, 112 &coredump_pack_fileinfo, 0, 113 "Enable file path packing in 'procstat -f' coredump notes"); 114 115 int coredump_pack_vmmapinfo = 1; 116 SYSCTL_INT(_kern, OID_AUTO, coredump_pack_vmmapinfo, CTLFLAG_RWTUN, 117 &coredump_pack_vmmapinfo, 0, 118 "Enable file path packing in 'procstat -v' coredump notes"); 119 120 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS); 121 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS); 122 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS); 123 static int do_execve(struct thread *td, struct image_args *args, 124 struct mac *mac_p, struct vmspace *oldvmspace); 125 126 /* XXX This should be vm_size_t. */ 127 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD| 128 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_ps_strings, "LU", 129 "Location of process' ps_strings structure"); 130 131 /* XXX This should be vm_size_t. */ 132 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD| 133 CTLFLAG_CAPRD|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_usrstack, "LU", 134 "Top of process stack"); 135 136 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD|CTLFLAG_MPSAFE, 137 NULL, 0, sysctl_kern_stackprot, "I", 138 "Stack memory permissions"); 139 140 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 141 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 142 &ps_arg_cache_limit, 0, 143 "Process' command line characters cache limit"); 144 145 static int disallow_high_osrel; 146 SYSCTL_INT(_kern, OID_AUTO, disallow_high_osrel, CTLFLAG_RW, 147 &disallow_high_osrel, 0, 148 "Disallow execution of binaries built for higher version of the world"); 149 150 static int map_at_zero = 0; 151 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RWTUN, &map_at_zero, 0, 152 "Permit processes to map an object at virtual address 0."); 153 154 static int 155 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS) 156 { 157 struct proc *p; 158 int error; 159 160 p = curproc; 161 #ifdef SCTL_MASK32 162 if (req->flags & SCTL_MASK32) { 163 unsigned int val; 164 val = (unsigned int)p->p_sysent->sv_psstrings; 165 error = SYSCTL_OUT(req, &val, sizeof(val)); 166 } else 167 #endif 168 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings, 169 sizeof(p->p_sysent->sv_psstrings)); 170 return error; 171 } 172 173 static int 174 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS) 175 { 176 struct proc *p; 177 int error; 178 179 p = curproc; 180 #ifdef SCTL_MASK32 181 if (req->flags & SCTL_MASK32) { 182 unsigned int val; 183 val = (unsigned int)p->p_sysent->sv_usrstack; 184 error = SYSCTL_OUT(req, &val, sizeof(val)); 185 } else 186 #endif 187 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack, 188 sizeof(p->p_sysent->sv_usrstack)); 189 return error; 190 } 191 192 static int 193 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS) 194 { 195 struct proc *p; 196 197 p = curproc; 198 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot, 199 sizeof(p->p_sysent->sv_stackprot))); 200 } 201 202 /* 203 * Each of the items is a pointer to a `const struct execsw', hence the 204 * double pointer here. 205 */ 206 static const struct execsw **execsw; 207 208 #ifndef _SYS_SYSPROTO_H_ 209 struct execve_args { 210 char *fname; 211 char **argv; 212 char **envv; 213 }; 214 #endif 215 216 int 217 sys_execve(struct thread *td, struct execve_args *uap) 218 { 219 struct image_args args; 220 struct vmspace *oldvmspace; 221 int error; 222 223 error = pre_execve(td, &oldvmspace); 224 if (error != 0) 225 return (error); 226 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 227 uap->argv, uap->envv); 228 if (error == 0) 229 error = kern_execve(td, &args, NULL, oldvmspace); 230 post_execve(td, error, oldvmspace); 231 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 232 return (error); 233 } 234 235 #ifndef _SYS_SYSPROTO_H_ 236 struct fexecve_args { 237 int fd; 238 char **argv; 239 char **envv; 240 }; 241 #endif 242 int 243 sys_fexecve(struct thread *td, struct fexecve_args *uap) 244 { 245 struct image_args args; 246 struct vmspace *oldvmspace; 247 int error; 248 249 error = pre_execve(td, &oldvmspace); 250 if (error != 0) 251 return (error); 252 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE, 253 uap->argv, uap->envv); 254 if (error == 0) { 255 args.fd = uap->fd; 256 error = kern_execve(td, &args, NULL, oldvmspace); 257 } 258 post_execve(td, error, oldvmspace); 259 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 260 return (error); 261 } 262 263 #ifndef _SYS_SYSPROTO_H_ 264 struct __mac_execve_args { 265 char *fname; 266 char **argv; 267 char **envv; 268 struct mac *mac_p; 269 }; 270 #endif 271 272 int 273 sys___mac_execve(struct thread *td, struct __mac_execve_args *uap) 274 { 275 #ifdef MAC 276 struct image_args args; 277 struct vmspace *oldvmspace; 278 int error; 279 280 error = pre_execve(td, &oldvmspace); 281 if (error != 0) 282 return (error); 283 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE, 284 uap->argv, uap->envv); 285 if (error == 0) 286 error = kern_execve(td, &args, uap->mac_p, oldvmspace); 287 post_execve(td, error, oldvmspace); 288 AUDIT_SYSCALL_EXIT(error == EJUSTRETURN ? 0 : error, td); 289 return (error); 290 #else 291 return (ENOSYS); 292 #endif 293 } 294 295 int 296 pre_execve(struct thread *td, struct vmspace **oldvmspace) 297 { 298 struct proc *p; 299 int error; 300 301 KASSERT(td == curthread, ("non-current thread %p", td)); 302 error = 0; 303 p = td->td_proc; 304 if ((p->p_flag & P_HADTHREADS) != 0) { 305 PROC_LOCK(p); 306 if (thread_single(p, SINGLE_BOUNDARY) != 0) 307 error = ERESTART; 308 PROC_UNLOCK(p); 309 } 310 KASSERT(error != 0 || (td->td_pflags & TDP_EXECVMSPC) == 0, 311 ("nested execve")); 312 *oldvmspace = p->p_vmspace; 313 return (error); 314 } 315 316 void 317 post_execve(struct thread *td, int error, struct vmspace *oldvmspace) 318 { 319 struct proc *p; 320 321 KASSERT(td == curthread, ("non-current thread %p", td)); 322 p = td->td_proc; 323 if ((p->p_flag & P_HADTHREADS) != 0) { 324 PROC_LOCK(p); 325 /* 326 * If success, we upgrade to SINGLE_EXIT state to 327 * force other threads to suicide. 328 */ 329 if (error == EJUSTRETURN) 330 thread_single(p, SINGLE_EXIT); 331 else 332 thread_single_end(p, SINGLE_BOUNDARY); 333 PROC_UNLOCK(p); 334 } 335 exec_cleanup(td, oldvmspace); 336 } 337 338 /* 339 * kern_execve() has the astonishing property of not always returning to 340 * the caller. If sufficiently bad things happen during the call to 341 * do_execve(), it can end up calling exit1(); as a result, callers must 342 * avoid doing anything which they might need to undo (e.g., allocating 343 * memory). 344 */ 345 int 346 kern_execve(struct thread *td, struct image_args *args, struct mac *mac_p, 347 struct vmspace *oldvmspace) 348 { 349 350 AUDIT_ARG_ARGV(args->begin_argv, args->argc, 351 exec_args_get_begin_envv(args) - args->begin_argv); 352 AUDIT_ARG_ENVV(exec_args_get_begin_envv(args), args->envc, 353 args->endp - exec_args_get_begin_envv(args)); 354 return (do_execve(td, args, mac_p, oldvmspace)); 355 } 356 357 static void 358 execve_nosetid(struct image_params *imgp) 359 { 360 imgp->credential_setid = false; 361 if (imgp->newcred != NULL) { 362 crfree(imgp->newcred); 363 imgp->newcred = NULL; 364 } 365 } 366 367 /* 368 * In-kernel implementation of execve(). All arguments are assumed to be 369 * userspace pointers from the passed thread. 370 */ 371 static int 372 do_execve(struct thread *td, struct image_args *args, struct mac *mac_p, 373 struct vmspace *oldvmspace) 374 { 375 struct proc *p = td->td_proc; 376 struct nameidata nd; 377 struct ucred *oldcred; 378 struct uidinfo *euip = NULL; 379 uintptr_t stack_base; 380 struct image_params image_params, *imgp; 381 struct vattr attr; 382 int (*img_first)(struct image_params *); 383 struct pargs *oldargs = NULL, *newargs = NULL; 384 struct sigacts *oldsigacts = NULL, *newsigacts = NULL; 385 #ifdef KTRACE 386 struct ktr_io_params *kiop; 387 #endif 388 struct vnode *oldtextvp = NULL, *newtextvp; 389 int credential_changing; 390 #ifdef MAC 391 struct label *interpvplabel = NULL; 392 int will_transition; 393 #endif 394 #ifdef HWPMC_HOOKS 395 struct pmckern_procexec pe; 396 #endif 397 int error, i, orig_osrel; 398 uint32_t orig_fctl0; 399 Elf_Brandinfo *orig_brandinfo; 400 static const char fexecv_proc_title[] = "(fexecv)"; 401 402 imgp = &image_params; 403 #ifdef KTRACE 404 kiop = NULL; 405 #endif 406 407 /* 408 * Lock the process and set the P_INEXEC flag to indicate that 409 * it should be left alone until we're done here. This is 410 * necessary to avoid race conditions - e.g. in ptrace() - 411 * that might allow a local user to illicitly obtain elevated 412 * privileges. 413 */ 414 PROC_LOCK(p); 415 KASSERT((p->p_flag & P_INEXEC) == 0, 416 ("%s(): process already has P_INEXEC flag", __func__)); 417 p->p_flag |= P_INEXEC; 418 PROC_UNLOCK(p); 419 420 /* 421 * Initialize part of the common data 422 */ 423 bzero(imgp, sizeof(*imgp)); 424 imgp->proc = p; 425 imgp->attr = &attr; 426 imgp->args = args; 427 oldcred = p->p_ucred; 428 orig_osrel = p->p_osrel; 429 orig_fctl0 = p->p_fctl0; 430 orig_brandinfo = p->p_elf_brandinfo; 431 432 #ifdef MAC 433 error = mac_execve_enter(imgp, mac_p); 434 if (error) 435 goto exec_fail; 436 #endif 437 438 /* 439 * Translate the file name. namei() returns a vnode pointer 440 * in ni_vp among other things. 441 * 442 * XXXAUDIT: It would be desirable to also audit the name of the 443 * interpreter if this is an interpreted binary. 444 */ 445 if (args->fname != NULL) { 446 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 447 SAVENAME | AUDITVNODE1, UIO_SYSSPACE, args->fname, td); 448 } 449 450 SDT_PROBE1(proc, , , exec, args->fname); 451 452 interpret: 453 if (args->fname != NULL) { 454 #ifdef CAPABILITY_MODE 455 /* 456 * While capability mode can't reach this point via direct 457 * path arguments to execve(), we also don't allow 458 * interpreters to be used in capability mode (for now). 459 * Catch indirect lookups and return a permissions error. 460 */ 461 if (IN_CAPABILITY_MODE(td)) { 462 error = ECAPMODE; 463 goto exec_fail; 464 } 465 #endif 466 error = namei(&nd); 467 if (error) 468 goto exec_fail; 469 470 newtextvp = nd.ni_vp; 471 imgp->vp = newtextvp; 472 } else { 473 AUDIT_ARG_FD(args->fd); 474 /* 475 * Descriptors opened only with O_EXEC or O_RDONLY are allowed. 476 */ 477 error = fgetvp_exec(td, args->fd, &cap_fexecve_rights, &newtextvp); 478 if (error) 479 goto exec_fail; 480 vn_lock(newtextvp, LK_SHARED | LK_RETRY); 481 AUDIT_ARG_VNODE1(newtextvp); 482 imgp->vp = newtextvp; 483 } 484 485 /* 486 * Check file permissions. Also 'opens' file and sets its vnode to 487 * text mode. 488 */ 489 error = exec_check_permissions(imgp); 490 if (error) 491 goto exec_fail_dealloc; 492 493 imgp->object = imgp->vp->v_object; 494 if (imgp->object != NULL) 495 vm_object_reference(imgp->object); 496 497 error = exec_map_first_page(imgp); 498 if (error) 499 goto exec_fail_dealloc; 500 501 imgp->proc->p_osrel = 0; 502 imgp->proc->p_fctl0 = 0; 503 imgp->proc->p_elf_brandinfo = NULL; 504 505 /* 506 * Implement image setuid/setgid. 507 * 508 * Determine new credentials before attempting image activators 509 * so that it can be used by process_exec handlers to determine 510 * credential/setid changes. 511 * 512 * Don't honor setuid/setgid if the filesystem prohibits it or if 513 * the process is being traced. 514 * 515 * We disable setuid/setgid/etc in capability mode on the basis 516 * that most setugid applications are not written with that 517 * environment in mind, and will therefore almost certainly operate 518 * incorrectly. In principle there's no reason that setugid 519 * applications might not be useful in capability mode, so we may want 520 * to reconsider this conservative design choice in the future. 521 * 522 * XXXMAC: For the time being, use NOSUID to also prohibit 523 * transitions on the file system. 524 */ 525 credential_changing = 0; 526 credential_changing |= (attr.va_mode & S_ISUID) && 527 oldcred->cr_uid != attr.va_uid; 528 credential_changing |= (attr.va_mode & S_ISGID) && 529 oldcred->cr_gid != attr.va_gid; 530 #ifdef MAC 531 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp, 532 interpvplabel, imgp); 533 credential_changing |= will_transition; 534 #endif 535 536 /* Don't inherit PROC_PDEATHSIG_CTL value if setuid/setgid. */ 537 if (credential_changing) 538 imgp->proc->p_pdeathsig = 0; 539 540 if (credential_changing && 541 #ifdef CAPABILITY_MODE 542 ((oldcred->cr_flags & CRED_FLAG_CAPMODE) == 0) && 543 #endif 544 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 545 (p->p_flag & P_TRACED) == 0) { 546 imgp->credential_setid = true; 547 VOP_UNLOCK(imgp->vp); 548 imgp->newcred = crdup(oldcred); 549 if (attr.va_mode & S_ISUID) { 550 euip = uifind(attr.va_uid); 551 change_euid(imgp->newcred, euip); 552 } 553 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 554 if (attr.va_mode & S_ISGID) 555 change_egid(imgp->newcred, attr.va_gid); 556 /* 557 * Implement correct POSIX saved-id behavior. 558 * 559 * XXXMAC: Note that the current logic will save the 560 * uid and gid if a MAC domain transition occurs, even 561 * though maybe it shouldn't. 562 */ 563 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 564 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 565 } else { 566 /* 567 * Implement correct POSIX saved-id behavior. 568 * 569 * XXX: It's not clear that the existing behavior is 570 * POSIX-compliant. A number of sources indicate that the 571 * saved uid/gid should only be updated if the new ruid is 572 * not equal to the old ruid, or the new euid is not equal 573 * to the old euid and the new euid is not equal to the old 574 * ruid. The FreeBSD code always updates the saved uid/gid. 575 * Also, this code uses the new (replaced) euid and egid as 576 * the source, which may or may not be the right ones to use. 577 */ 578 if (oldcred->cr_svuid != oldcred->cr_uid || 579 oldcred->cr_svgid != oldcred->cr_gid) { 580 VOP_UNLOCK(imgp->vp); 581 imgp->newcred = crdup(oldcred); 582 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 583 change_svuid(imgp->newcred, imgp->newcred->cr_uid); 584 change_svgid(imgp->newcred, imgp->newcred->cr_gid); 585 } 586 } 587 /* The new credentials are installed into the process later. */ 588 589 /* 590 * Do the best to calculate the full path to the image file. 591 */ 592 if (args->fname != NULL && args->fname[0] == '/') 593 imgp->execpath = args->fname; 594 else { 595 VOP_UNLOCK(imgp->vp); 596 if (vn_fullpath(imgp->vp, &imgp->execpath, &imgp->freepath) != 0) 597 imgp->execpath = args->fname; 598 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 599 } 600 601 /* 602 * If the current process has a special image activator it 603 * wants to try first, call it. For example, emulating shell 604 * scripts differently. 605 */ 606 error = -1; 607 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 608 error = img_first(imgp); 609 610 /* 611 * Loop through the list of image activators, calling each one. 612 * An activator returns -1 if there is no match, 0 on success, 613 * and an error otherwise. 614 */ 615 for (i = 0; error == -1 && execsw[i]; ++i) { 616 if (execsw[i]->ex_imgact == NULL || 617 execsw[i]->ex_imgact == img_first) { 618 continue; 619 } 620 error = (*execsw[i]->ex_imgact)(imgp); 621 } 622 623 if (error) { 624 if (error == -1) 625 error = ENOEXEC; 626 goto exec_fail_dealloc; 627 } 628 629 /* 630 * Special interpreter operation, cleanup and loop up to try to 631 * activate the interpreter. 632 */ 633 if (imgp->interpreted) { 634 exec_unmap_first_page(imgp); 635 /* 636 * The text reference needs to be removed for scripts. 637 * There is a short period before we determine that 638 * something is a script where text reference is active. 639 * The vnode lock is held over this entire period 640 * so nothing should illegitimately be blocked. 641 */ 642 MPASS(imgp->textset); 643 VOP_UNSET_TEXT_CHECKED(newtextvp); 644 imgp->textset = false; 645 /* free name buffer and old vnode */ 646 if (args->fname != NULL) 647 NDFREE(&nd, NDF_ONLY_PNBUF); 648 #ifdef MAC 649 mac_execve_interpreter_enter(newtextvp, &interpvplabel); 650 #endif 651 if (imgp->opened) { 652 VOP_CLOSE(newtextvp, FREAD, td->td_ucred, td); 653 imgp->opened = 0; 654 } 655 vput(newtextvp); 656 vm_object_deallocate(imgp->object); 657 imgp->object = NULL; 658 execve_nosetid(imgp); 659 imgp->execpath = NULL; 660 free(imgp->freepath, M_TEMP); 661 imgp->freepath = NULL; 662 /* set new name to that of the interpreter */ 663 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | LOCKSHARED | FOLLOW | 664 SAVENAME, UIO_SYSSPACE, imgp->interpreter_name, td); 665 args->fname = imgp->interpreter_name; 666 goto interpret; 667 } 668 669 /* 670 * NB: We unlock the vnode here because it is believed that none 671 * of the sv_copyout_strings/sv_fixup operations require the vnode. 672 */ 673 VOP_UNLOCK(imgp->vp); 674 675 if (disallow_high_osrel && 676 P_OSREL_MAJOR(p->p_osrel) > P_OSREL_MAJOR(__FreeBSD_version)) { 677 error = ENOEXEC; 678 uprintf("Osrel %d for image %s too high\n", p->p_osrel, 679 imgp->execpath != NULL ? imgp->execpath : "<unresolved>"); 680 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 681 goto exec_fail_dealloc; 682 } 683 684 /* ABI enforces the use of Capsicum. Switch into capabilities mode. */ 685 if (SV_PROC_FLAG(p, SV_CAPSICUM)) 686 sys_cap_enter(td, NULL); 687 688 /* 689 * Copy out strings (args and env) and initialize stack base. 690 */ 691 error = (*p->p_sysent->sv_copyout_strings)(imgp, &stack_base); 692 if (error != 0) { 693 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 694 goto exec_fail_dealloc; 695 } 696 697 /* 698 * Stack setup. 699 */ 700 error = (*p->p_sysent->sv_fixup)(&stack_base, imgp); 701 if (error != 0) { 702 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 703 goto exec_fail_dealloc; 704 } 705 706 if (args->fdp != NULL) { 707 /* Install a brand new file descriptor table. */ 708 fdinstall_remapped(td, args->fdp); 709 args->fdp = NULL; 710 } else { 711 /* 712 * Keep on using the existing file descriptor table. For 713 * security and other reasons, the file descriptor table 714 * cannot be shared after an exec. 715 */ 716 fdunshare(td); 717 pdunshare(td); 718 /* close files on exec */ 719 fdcloseexec(td); 720 } 721 722 /* 723 * Malloc things before we need locks. 724 */ 725 i = exec_args_get_begin_envv(imgp->args) - imgp->args->begin_argv; 726 /* Cache arguments if they fit inside our allowance */ 727 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 728 newargs = pargs_alloc(i); 729 bcopy(imgp->args->begin_argv, newargs->ar_args, i); 730 } 731 732 /* 733 * For security and other reasons, signal handlers cannot 734 * be shared after an exec. The new process gets a copy of the old 735 * handlers. In execsigs(), the new process will have its signals 736 * reset. 737 */ 738 if (sigacts_shared(p->p_sigacts)) { 739 oldsigacts = p->p_sigacts; 740 newsigacts = sigacts_alloc(); 741 sigacts_copy(newsigacts, oldsigacts); 742 } 743 744 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 745 746 PROC_LOCK(p); 747 if (oldsigacts) 748 p->p_sigacts = newsigacts; 749 /* Stop profiling */ 750 stopprofclock(p); 751 752 /* reset caught signals */ 753 execsigs(p); 754 755 /* name this process - nameiexec(p, ndp) */ 756 bzero(p->p_comm, sizeof(p->p_comm)); 757 if (args->fname) 758 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, 759 min(nd.ni_cnd.cn_namelen, MAXCOMLEN)); 760 else if (vn_commname(newtextvp, p->p_comm, sizeof(p->p_comm)) != 0) 761 bcopy(fexecv_proc_title, p->p_comm, sizeof(fexecv_proc_title)); 762 bcopy(p->p_comm, td->td_name, sizeof(td->td_name)); 763 #ifdef KTR 764 sched_clear_tdname(td); 765 #endif 766 767 /* 768 * mark as execed, wakeup the process that vforked (if any) and tell 769 * it that it now has its own resources back 770 */ 771 p->p_flag |= P_EXEC; 772 if ((p->p_flag2 & P2_NOTRACE_EXEC) == 0) 773 p->p_flag2 &= ~P2_NOTRACE; 774 if ((p->p_flag2 & P2_STKGAP_DISABLE_EXEC) == 0) 775 p->p_flag2 &= ~P2_STKGAP_DISABLE; 776 if (p->p_flag & P_PPWAIT) { 777 p->p_flag &= ~(P_PPWAIT | P_PPTRACE); 778 cv_broadcast(&p->p_pwait); 779 /* STOPs are no longer ignored, arrange for AST */ 780 signotify(td); 781 } 782 783 if ((imgp->sysent->sv_setid_allowed != NULL && 784 !(*imgp->sysent->sv_setid_allowed)(td, imgp)) || 785 (p->p_flag2 & P2_NO_NEW_PRIVS) != 0) 786 execve_nosetid(imgp); 787 788 /* 789 * Implement image setuid/setgid installation. 790 */ 791 if (imgp->credential_setid) { 792 /* 793 * Turn off syscall tracing for set-id programs, except for 794 * root. Record any set-id flags first to make sure that 795 * we do not regain any tracing during a possible block. 796 */ 797 setsugid(p); 798 #ifdef KTRACE 799 kiop = ktrprocexec(p); 800 #endif 801 /* 802 * Close any file descriptors 0..2 that reference procfs, 803 * then make sure file descriptors 0..2 are in use. 804 * 805 * Both fdsetugidsafety() and fdcheckstd() may call functions 806 * taking sleepable locks, so temporarily drop our locks. 807 */ 808 PROC_UNLOCK(p); 809 VOP_UNLOCK(imgp->vp); 810 fdsetugidsafety(td); 811 error = fdcheckstd(td); 812 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 813 if (error != 0) 814 goto exec_fail_dealloc; 815 PROC_LOCK(p); 816 #ifdef MAC 817 if (will_transition) { 818 mac_vnode_execve_transition(oldcred, imgp->newcred, 819 imgp->vp, interpvplabel, imgp); 820 } 821 #endif 822 } else { 823 if (oldcred->cr_uid == oldcred->cr_ruid && 824 oldcred->cr_gid == oldcred->cr_rgid) 825 p->p_flag &= ~P_SUGID; 826 } 827 /* 828 * Set the new credentials. 829 */ 830 if (imgp->newcred != NULL) { 831 proc_set_cred(p, imgp->newcred); 832 crfree(oldcred); 833 oldcred = NULL; 834 } 835 836 /* 837 * Store the vp for use in procfs. This vnode was referenced by namei 838 * or fgetvp_exec. 839 */ 840 oldtextvp = p->p_textvp; 841 p->p_textvp = newtextvp; 842 843 #ifdef KDTRACE_HOOKS 844 /* 845 * Tell the DTrace fasttrap provider about the exec if it 846 * has declared an interest. 847 */ 848 if (dtrace_fasttrap_exec) 849 dtrace_fasttrap_exec(p); 850 #endif 851 852 /* 853 * Notify others that we exec'd, and clear the P_INEXEC flag 854 * as we're now a bona fide freshly-execed process. 855 */ 856 KNOTE_LOCKED(p->p_klist, NOTE_EXEC); 857 p->p_flag &= ~P_INEXEC; 858 859 /* clear "fork but no exec" flag, as we _are_ execing */ 860 p->p_acflag &= ~AFORK; 861 862 /* 863 * Free any previous argument cache and replace it with 864 * the new argument cache, if any. 865 */ 866 oldargs = p->p_args; 867 p->p_args = newargs; 868 newargs = NULL; 869 870 PROC_UNLOCK(p); 871 872 #ifdef HWPMC_HOOKS 873 /* 874 * Check if system-wide sampling is in effect or if the 875 * current process is using PMCs. If so, do exec() time 876 * processing. This processing needs to happen AFTER the 877 * P_INEXEC flag is cleared. 878 */ 879 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { 880 VOP_UNLOCK(imgp->vp); 881 pe.pm_credentialschanged = credential_changing; 882 pe.pm_entryaddr = imgp->entry_addr; 883 884 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe); 885 vn_lock(imgp->vp, LK_SHARED | LK_RETRY); 886 } 887 #endif 888 889 /* Set values passed into the program in registers. */ 890 (*p->p_sysent->sv_setregs)(td, imgp, stack_base); 891 892 VOP_MMAPPED(imgp->vp); 893 894 SDT_PROBE1(proc, , , exec__success, args->fname); 895 896 exec_fail_dealloc: 897 if (error != 0) { 898 p->p_osrel = orig_osrel; 899 p->p_fctl0 = orig_fctl0; 900 p->p_elf_brandinfo = orig_brandinfo; 901 } 902 903 if (imgp->firstpage != NULL) 904 exec_unmap_first_page(imgp); 905 906 if (imgp->vp != NULL) { 907 if (args->fname) 908 NDFREE(&nd, NDF_ONLY_PNBUF); 909 if (imgp->opened) 910 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td); 911 if (imgp->textset) 912 VOP_UNSET_TEXT_CHECKED(imgp->vp); 913 if (error != 0) 914 vput(imgp->vp); 915 else 916 VOP_UNLOCK(imgp->vp); 917 } 918 919 if (imgp->object != NULL) 920 vm_object_deallocate(imgp->object); 921 922 free(imgp->freepath, M_TEMP); 923 924 if (error == 0) { 925 if (p->p_ptevents & PTRACE_EXEC) { 926 PROC_LOCK(p); 927 if (p->p_ptevents & PTRACE_EXEC) 928 td->td_dbgflags |= TDB_EXEC; 929 PROC_UNLOCK(p); 930 } 931 } else { 932 exec_fail: 933 /* we're done here, clear P_INEXEC */ 934 PROC_LOCK(p); 935 p->p_flag &= ~P_INEXEC; 936 PROC_UNLOCK(p); 937 938 SDT_PROBE1(proc, , , exec__failure, error); 939 } 940 941 if (imgp->newcred != NULL && oldcred != NULL) 942 crfree(imgp->newcred); 943 944 #ifdef MAC 945 mac_execve_exit(imgp); 946 mac_execve_interpreter_exit(interpvplabel); 947 #endif 948 exec_free_args(args); 949 950 /* 951 * Handle deferred decrement of ref counts. 952 */ 953 if (oldtextvp != NULL) 954 vrele(oldtextvp); 955 #ifdef KTRACE 956 ktr_io_params_free(kiop); 957 #endif 958 pargs_drop(oldargs); 959 pargs_drop(newargs); 960 if (oldsigacts != NULL) 961 sigacts_free(oldsigacts); 962 if (euip != NULL) 963 uifree(euip); 964 965 if (error && imgp->vmspace_destroyed) { 966 /* sorry, no more process anymore. exit gracefully */ 967 exec_cleanup(td, oldvmspace); 968 exit1(td, 0, SIGABRT); 969 /* NOT REACHED */ 970 } 971 972 #ifdef KTRACE 973 if (error == 0) 974 ktrprocctor(p); 975 #endif 976 977 /* 978 * We don't want cpu_set_syscall_retval() to overwrite any of 979 * the register values put in place by exec_setregs(). 980 * Implementations of cpu_set_syscall_retval() will leave 981 * registers unmodified when returning EJUSTRETURN. 982 */ 983 return (error == 0 ? EJUSTRETURN : error); 984 } 985 986 void 987 exec_cleanup(struct thread *td, struct vmspace *oldvmspace) 988 { 989 if ((td->td_pflags & TDP_EXECVMSPC) != 0) { 990 KASSERT(td->td_proc->p_vmspace != oldvmspace, 991 ("oldvmspace still used")); 992 vmspace_free(oldvmspace); 993 td->td_pflags &= ~TDP_EXECVMSPC; 994 } 995 } 996 997 int 998 exec_map_first_page(struct image_params *imgp) 999 { 1000 vm_object_t object; 1001 vm_page_t m; 1002 int error; 1003 1004 if (imgp->firstpage != NULL) 1005 exec_unmap_first_page(imgp); 1006 1007 object = imgp->vp->v_object; 1008 if (object == NULL) 1009 return (EACCES); 1010 #if VM_NRESERVLEVEL > 0 1011 if ((object->flags & OBJ_COLORED) == 0) { 1012 VM_OBJECT_WLOCK(object); 1013 vm_object_color(object, 0); 1014 VM_OBJECT_WUNLOCK(object); 1015 } 1016 #endif 1017 error = vm_page_grab_valid_unlocked(&m, object, 0, 1018 VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) | 1019 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED); 1020 1021 if (error != VM_PAGER_OK) 1022 return (EIO); 1023 imgp->firstpage = sf_buf_alloc(m, 0); 1024 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage); 1025 1026 return (0); 1027 } 1028 1029 void 1030 exec_unmap_first_page(struct image_params *imgp) 1031 { 1032 vm_page_t m; 1033 1034 if (imgp->firstpage != NULL) { 1035 m = sf_buf_page(imgp->firstpage); 1036 sf_buf_free(imgp->firstpage); 1037 imgp->firstpage = NULL; 1038 vm_page_unwire(m, PQ_ACTIVE); 1039 } 1040 } 1041 1042 void 1043 exec_onexec_old(struct thread *td) 1044 { 1045 sigfastblock_clear(td); 1046 umtx_exec(td->td_proc); 1047 } 1048 1049 /* 1050 * Destroy old address space, and allocate a new stack. 1051 * The new stack is only sgrowsiz large because it is grown 1052 * automatically on a page fault. 1053 */ 1054 int 1055 exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) 1056 { 1057 int error; 1058 struct proc *p = imgp->proc; 1059 struct vmspace *vmspace = p->p_vmspace; 1060 struct thread *td = curthread; 1061 vm_object_t obj; 1062 struct rlimit rlim_stack; 1063 vm_offset_t sv_minuser, stack_addr; 1064 vm_map_t map; 1065 vm_prot_t stack_prot; 1066 u_long ssiz; 1067 1068 imgp->vmspace_destroyed = 1; 1069 imgp->sysent = sv; 1070 1071 if (p->p_sysent->sv_onexec_old != NULL) 1072 p->p_sysent->sv_onexec_old(td); 1073 itimers_exec(p); 1074 1075 EVENTHANDLER_DIRECT_INVOKE(process_exec, p, imgp); 1076 1077 /* 1078 * Blow away entire process VM, if address space not shared, 1079 * otherwise, create a new VM space so that other threads are 1080 * not disrupted 1081 */ 1082 map = &vmspace->vm_map; 1083 if (map_at_zero) 1084 sv_minuser = sv->sv_minuser; 1085 else 1086 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE); 1087 if (refcount_load(&vmspace->vm_refcnt) == 1 && 1088 vm_map_min(map) == sv_minuser && 1089 vm_map_max(map) == sv->sv_maxuser && 1090 cpu_exec_vmspace_reuse(p, map)) { 1091 shmexit(vmspace); 1092 pmap_remove_pages(vmspace_pmap(vmspace)); 1093 vm_map_remove(map, vm_map_min(map), vm_map_max(map)); 1094 /* 1095 * An exec terminates mlockall(MCL_FUTURE). 1096 * ASLR and W^X states must be re-evaluated. 1097 */ 1098 vm_map_lock(map); 1099 vm_map_modflags(map, 0, MAP_WIREFUTURE | MAP_ASLR | 1100 MAP_ASLR_IGNSTART | MAP_WXORX); 1101 vm_map_unlock(map); 1102 } else { 1103 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); 1104 if (error) 1105 return (error); 1106 vmspace = p->p_vmspace; 1107 map = &vmspace->vm_map; 1108 } 1109 map->flags |= imgp->map_flags; 1110 1111 /* Map a shared page */ 1112 obj = sv->sv_shared_page_obj; 1113 if (obj != NULL) { 1114 vm_object_reference(obj); 1115 error = vm_map_fixed(map, obj, 0, 1116 sv->sv_shared_page_base, sv->sv_shared_page_len, 1117 VM_PROT_READ | VM_PROT_EXECUTE, 1118 VM_PROT_READ | VM_PROT_EXECUTE, 1119 MAP_INHERIT_SHARE | MAP_ACC_NO_CHARGE); 1120 if (error != KERN_SUCCESS) { 1121 vm_object_deallocate(obj); 1122 return (vm_mmap_to_errno(error)); 1123 } 1124 } 1125 1126 /* Allocate a new stack */ 1127 if (imgp->stack_sz != 0) { 1128 ssiz = trunc_page(imgp->stack_sz); 1129 PROC_LOCK(p); 1130 lim_rlimit_proc(p, RLIMIT_STACK, &rlim_stack); 1131 PROC_UNLOCK(p); 1132 if (ssiz > rlim_stack.rlim_max) 1133 ssiz = rlim_stack.rlim_max; 1134 if (ssiz > rlim_stack.rlim_cur) { 1135 rlim_stack.rlim_cur = ssiz; 1136 kern_setrlimit(curthread, RLIMIT_STACK, &rlim_stack); 1137 } 1138 } else if (sv->sv_maxssiz != NULL) { 1139 ssiz = *sv->sv_maxssiz; 1140 } else { 1141 ssiz = maxssiz; 1142 } 1143 imgp->eff_stack_sz = lim_cur(curthread, RLIMIT_STACK); 1144 if (ssiz < imgp->eff_stack_sz) 1145 imgp->eff_stack_sz = ssiz; 1146 stack_addr = sv->sv_usrstack - ssiz; 1147 stack_prot = obj != NULL && imgp->stack_prot != 0 ? 1148 imgp->stack_prot : sv->sv_stackprot; 1149 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz, stack_prot, 1150 VM_PROT_ALL, MAP_STACK_GROWS_DOWN); 1151 if (error != KERN_SUCCESS) { 1152 uprintf("exec_new_vmspace: mapping stack size %#jx prot %#x " 1153 "failed mach error %d errno %d\n", (uintmax_t)ssiz, 1154 stack_prot, error, vm_mmap_to_errno(error)); 1155 return (vm_mmap_to_errno(error)); 1156 } 1157 1158 /* 1159 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they 1160 * are still used to enforce the stack rlimit on the process stack. 1161 */ 1162 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 1163 vmspace->vm_maxsaddr = (char *)stack_addr; 1164 1165 return (sv->sv_onexec != NULL ? sv->sv_onexec(p, imgp) : 0); 1166 } 1167 1168 /* 1169 * Copy out argument and environment strings from the old process address 1170 * space into the temporary string buffer. 1171 */ 1172 int 1173 exec_copyin_args(struct image_args *args, const char *fname, 1174 enum uio_seg segflg, char **argv, char **envv) 1175 { 1176 u_long arg, env; 1177 int error; 1178 1179 bzero(args, sizeof(*args)); 1180 if (argv == NULL) 1181 return (EFAULT); 1182 1183 /* 1184 * Allocate demand-paged memory for the file name, argument, and 1185 * environment strings. 1186 */ 1187 error = exec_alloc_args(args); 1188 if (error != 0) 1189 return (error); 1190 1191 /* 1192 * Copy the file name. 1193 */ 1194 error = exec_args_add_fname(args, fname, segflg); 1195 if (error != 0) 1196 goto err_exit; 1197 1198 /* 1199 * extract arguments first 1200 */ 1201 for (;;) { 1202 error = fueword(argv++, &arg); 1203 if (error == -1) { 1204 error = EFAULT; 1205 goto err_exit; 1206 } 1207 if (arg == 0) 1208 break; 1209 error = exec_args_add_arg(args, (char *)(uintptr_t)arg, 1210 UIO_USERSPACE); 1211 if (error != 0) 1212 goto err_exit; 1213 } 1214 1215 /* 1216 * extract environment strings 1217 */ 1218 if (envv) { 1219 for (;;) { 1220 error = fueword(envv++, &env); 1221 if (error == -1) { 1222 error = EFAULT; 1223 goto err_exit; 1224 } 1225 if (env == 0) 1226 break; 1227 error = exec_args_add_env(args, 1228 (char *)(uintptr_t)env, UIO_USERSPACE); 1229 if (error != 0) 1230 goto err_exit; 1231 } 1232 } 1233 1234 return (0); 1235 1236 err_exit: 1237 exec_free_args(args); 1238 return (error); 1239 } 1240 1241 int 1242 exec_copyin_data_fds(struct thread *td, struct image_args *args, 1243 const void *data, size_t datalen, const int *fds, size_t fdslen) 1244 { 1245 struct filedesc *ofdp; 1246 const char *p; 1247 int *kfds; 1248 int error; 1249 1250 memset(args, '\0', sizeof(*args)); 1251 ofdp = td->td_proc->p_fd; 1252 if (datalen >= ARG_MAX || fdslen >= ofdp->fd_nfiles) 1253 return (E2BIG); 1254 error = exec_alloc_args(args); 1255 if (error != 0) 1256 return (error); 1257 1258 args->begin_argv = args->buf; 1259 args->stringspace = ARG_MAX; 1260 1261 if (datalen > 0) { 1262 /* 1263 * Argument buffer has been provided. Copy it into the 1264 * kernel as a single string and add a terminating null 1265 * byte. 1266 */ 1267 error = copyin(data, args->begin_argv, datalen); 1268 if (error != 0) 1269 goto err_exit; 1270 args->begin_argv[datalen] = '\0'; 1271 args->endp = args->begin_argv + datalen + 1; 1272 args->stringspace -= datalen + 1; 1273 1274 /* 1275 * Traditional argument counting. Count the number of 1276 * null bytes. 1277 */ 1278 for (p = args->begin_argv; p < args->endp; ++p) 1279 if (*p == '\0') 1280 ++args->argc; 1281 } else { 1282 /* No argument buffer provided. */ 1283 args->endp = args->begin_argv; 1284 } 1285 1286 /* Create new file descriptor table. */ 1287 kfds = malloc(fdslen * sizeof(int), M_TEMP, M_WAITOK); 1288 error = copyin(fds, kfds, fdslen * sizeof(int)); 1289 if (error != 0) { 1290 free(kfds, M_TEMP); 1291 goto err_exit; 1292 } 1293 error = fdcopy_remapped(ofdp, kfds, fdslen, &args->fdp); 1294 free(kfds, M_TEMP); 1295 if (error != 0) 1296 goto err_exit; 1297 1298 return (0); 1299 err_exit: 1300 exec_free_args(args); 1301 return (error); 1302 } 1303 1304 struct exec_args_kva { 1305 vm_offset_t addr; 1306 u_int gen; 1307 SLIST_ENTRY(exec_args_kva) next; 1308 }; 1309 1310 DPCPU_DEFINE_STATIC(struct exec_args_kva *, exec_args_kva); 1311 1312 static SLIST_HEAD(, exec_args_kva) exec_args_kva_freelist; 1313 static struct mtx exec_args_kva_mtx; 1314 static u_int exec_args_gen; 1315 1316 static void 1317 exec_prealloc_args_kva(void *arg __unused) 1318 { 1319 struct exec_args_kva *argkva; 1320 u_int i; 1321 1322 SLIST_INIT(&exec_args_kva_freelist); 1323 mtx_init(&exec_args_kva_mtx, "exec args kva", NULL, MTX_DEF); 1324 for (i = 0; i < exec_map_entries; i++) { 1325 argkva = malloc(sizeof(*argkva), M_PARGS, M_WAITOK); 1326 argkva->addr = kmap_alloc_wait(exec_map, exec_map_entry_size); 1327 argkva->gen = exec_args_gen; 1328 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1329 } 1330 } 1331 SYSINIT(exec_args_kva, SI_SUB_EXEC, SI_ORDER_ANY, exec_prealloc_args_kva, NULL); 1332 1333 static vm_offset_t 1334 exec_alloc_args_kva(void **cookie) 1335 { 1336 struct exec_args_kva *argkva; 1337 1338 argkva = (void *)atomic_readandclear_ptr( 1339 (uintptr_t *)DPCPU_PTR(exec_args_kva)); 1340 if (argkva == NULL) { 1341 mtx_lock(&exec_args_kva_mtx); 1342 while ((argkva = SLIST_FIRST(&exec_args_kva_freelist)) == NULL) 1343 (void)mtx_sleep(&exec_args_kva_freelist, 1344 &exec_args_kva_mtx, 0, "execkva", 0); 1345 SLIST_REMOVE_HEAD(&exec_args_kva_freelist, next); 1346 mtx_unlock(&exec_args_kva_mtx); 1347 } 1348 kasan_mark((void *)argkva->addr, exec_map_entry_size, 1349 exec_map_entry_size, 0); 1350 *(struct exec_args_kva **)cookie = argkva; 1351 return (argkva->addr); 1352 } 1353 1354 static void 1355 exec_release_args_kva(struct exec_args_kva *argkva, u_int gen) 1356 { 1357 vm_offset_t base; 1358 1359 base = argkva->addr; 1360 kasan_mark((void *)argkva->addr, 0, exec_map_entry_size, 1361 KASAN_EXEC_ARGS_FREED); 1362 if (argkva->gen != gen) { 1363 (void)vm_map_madvise(exec_map, base, base + exec_map_entry_size, 1364 MADV_FREE); 1365 argkva->gen = gen; 1366 } 1367 if (!atomic_cmpset_ptr((uintptr_t *)DPCPU_PTR(exec_args_kva), 1368 (uintptr_t)NULL, (uintptr_t)argkva)) { 1369 mtx_lock(&exec_args_kva_mtx); 1370 SLIST_INSERT_HEAD(&exec_args_kva_freelist, argkva, next); 1371 wakeup_one(&exec_args_kva_freelist); 1372 mtx_unlock(&exec_args_kva_mtx); 1373 } 1374 } 1375 1376 static void 1377 exec_free_args_kva(void *cookie) 1378 { 1379 1380 exec_release_args_kva(cookie, exec_args_gen); 1381 } 1382 1383 static void 1384 exec_args_kva_lowmem(void *arg __unused) 1385 { 1386 SLIST_HEAD(, exec_args_kva) head; 1387 struct exec_args_kva *argkva; 1388 u_int gen; 1389 int i; 1390 1391 gen = atomic_fetchadd_int(&exec_args_gen, 1) + 1; 1392 1393 /* 1394 * Force an madvise of each KVA range. Any currently allocated ranges 1395 * will have MADV_FREE applied once they are freed. 1396 */ 1397 SLIST_INIT(&head); 1398 mtx_lock(&exec_args_kva_mtx); 1399 SLIST_SWAP(&head, &exec_args_kva_freelist, exec_args_kva); 1400 mtx_unlock(&exec_args_kva_mtx); 1401 while ((argkva = SLIST_FIRST(&head)) != NULL) { 1402 SLIST_REMOVE_HEAD(&head, next); 1403 exec_release_args_kva(argkva, gen); 1404 } 1405 1406 CPU_FOREACH(i) { 1407 argkva = (void *)atomic_readandclear_ptr( 1408 (uintptr_t *)DPCPU_ID_PTR(i, exec_args_kva)); 1409 if (argkva != NULL) 1410 exec_release_args_kva(argkva, gen); 1411 } 1412 } 1413 EVENTHANDLER_DEFINE(vm_lowmem, exec_args_kva_lowmem, NULL, 1414 EVENTHANDLER_PRI_ANY); 1415 1416 /* 1417 * Allocate temporary demand-paged, zero-filled memory for the file name, 1418 * argument, and environment strings. 1419 */ 1420 int 1421 exec_alloc_args(struct image_args *args) 1422 { 1423 1424 args->buf = (char *)exec_alloc_args_kva(&args->bufkva); 1425 return (0); 1426 } 1427 1428 void 1429 exec_free_args(struct image_args *args) 1430 { 1431 1432 if (args->buf != NULL) { 1433 exec_free_args_kva(args->bufkva); 1434 args->buf = NULL; 1435 } 1436 if (args->fname_buf != NULL) { 1437 free(args->fname_buf, M_TEMP); 1438 args->fname_buf = NULL; 1439 } 1440 if (args->fdp != NULL) 1441 fdescfree_remapped(args->fdp); 1442 } 1443 1444 /* 1445 * A set to functions to fill struct image args. 1446 * 1447 * NOTE: exec_args_add_fname() must be called (possibly with a NULL 1448 * fname) before the other functions. All exec_args_add_arg() calls must 1449 * be made before any exec_args_add_env() calls. exec_args_adjust_args() 1450 * may be called any time after exec_args_add_fname(). 1451 * 1452 * exec_args_add_fname() - install path to be executed 1453 * exec_args_add_arg() - append an argument string 1454 * exec_args_add_env() - append an env string 1455 * exec_args_adjust_args() - adjust location of the argument list to 1456 * allow new arguments to be prepended 1457 */ 1458 int 1459 exec_args_add_fname(struct image_args *args, const char *fname, 1460 enum uio_seg segflg) 1461 { 1462 int error; 1463 size_t length; 1464 1465 KASSERT(args->fname == NULL, ("fname already appended")); 1466 KASSERT(args->endp == NULL, ("already appending to args")); 1467 1468 if (fname != NULL) { 1469 args->fname = args->buf; 1470 error = segflg == UIO_SYSSPACE ? 1471 copystr(fname, args->fname, PATH_MAX, &length) : 1472 copyinstr(fname, args->fname, PATH_MAX, &length); 1473 if (error != 0) 1474 return (error == ENAMETOOLONG ? E2BIG : error); 1475 } else 1476 length = 0; 1477 1478 /* Set up for _arg_*()/_env_*() */ 1479 args->endp = args->buf + length; 1480 /* begin_argv must be set and kept updated */ 1481 args->begin_argv = args->endp; 1482 KASSERT(exec_map_entry_size - length >= ARG_MAX, 1483 ("too little space remaining for arguments %zu < %zu", 1484 exec_map_entry_size - length, (size_t)ARG_MAX)); 1485 args->stringspace = ARG_MAX; 1486 1487 return (0); 1488 } 1489 1490 static int 1491 exec_args_add_str(struct image_args *args, const char *str, 1492 enum uio_seg segflg, int *countp) 1493 { 1494 int error; 1495 size_t length; 1496 1497 KASSERT(args->endp != NULL, ("endp not initialized")); 1498 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1499 1500 error = (segflg == UIO_SYSSPACE) ? 1501 copystr(str, args->endp, args->stringspace, &length) : 1502 copyinstr(str, args->endp, args->stringspace, &length); 1503 if (error != 0) 1504 return (error == ENAMETOOLONG ? E2BIG : error); 1505 args->stringspace -= length; 1506 args->endp += length; 1507 (*countp)++; 1508 1509 return (0); 1510 } 1511 1512 int 1513 exec_args_add_arg(struct image_args *args, const char *argp, 1514 enum uio_seg segflg) 1515 { 1516 1517 KASSERT(args->envc == 0, ("appending args after env")); 1518 1519 return (exec_args_add_str(args, argp, segflg, &args->argc)); 1520 } 1521 1522 int 1523 exec_args_add_env(struct image_args *args, const char *envp, 1524 enum uio_seg segflg) 1525 { 1526 1527 if (args->envc == 0) 1528 args->begin_envv = args->endp; 1529 1530 return (exec_args_add_str(args, envp, segflg, &args->envc)); 1531 } 1532 1533 int 1534 exec_args_adjust_args(struct image_args *args, size_t consume, ssize_t extend) 1535 { 1536 ssize_t offset; 1537 1538 KASSERT(args->endp != NULL, ("endp not initialized")); 1539 KASSERT(args->begin_argv != NULL, ("begin_argp not initialized")); 1540 1541 offset = extend - consume; 1542 if (args->stringspace < offset) 1543 return (E2BIG); 1544 memmove(args->begin_argv + extend, args->begin_argv + consume, 1545 args->endp - args->begin_argv + consume); 1546 if (args->envc > 0) 1547 args->begin_envv += offset; 1548 args->endp += offset; 1549 args->stringspace -= offset; 1550 return (0); 1551 } 1552 1553 char * 1554 exec_args_get_begin_envv(struct image_args *args) 1555 { 1556 1557 KASSERT(args->endp != NULL, ("endp not initialized")); 1558 1559 if (args->envc > 0) 1560 return (args->begin_envv); 1561 return (args->endp); 1562 } 1563 1564 void 1565 exec_stackgap(struct image_params *imgp, uintptr_t *dp) 1566 { 1567 if (imgp->sysent->sv_stackgap == NULL || 1568 (imgp->proc->p_fctl0 & (NT_FREEBSD_FCTL_ASLR_DISABLE | 1569 NT_FREEBSD_FCTL_ASG_DISABLE)) != 0 || 1570 (imgp->map_flags & MAP_ASLR) == 0) 1571 return; 1572 imgp->sysent->sv_stackgap(imgp, dp); 1573 } 1574 1575 /* 1576 * Copy strings out to the new process address space, constructing new arg 1577 * and env vector tables. Return a pointer to the base so that it can be used 1578 * as the initial stack pointer. 1579 */ 1580 int 1581 exec_copyout_strings(struct image_params *imgp, uintptr_t *stack_base) 1582 { 1583 int argc, envc; 1584 char **vectp; 1585 char *stringp; 1586 uintptr_t destp, ustringp; 1587 struct ps_strings *arginfo; 1588 struct proc *p; 1589 size_t execpath_len; 1590 int error, szsigcode, szps; 1591 char canary[sizeof(long) * 8]; 1592 1593 szps = sizeof(pagesizes[0]) * MAXPAGESIZES; 1594 /* 1595 * Calculate string base and vector table pointers. 1596 * Also deal with signal trampoline code for this exec type. 1597 */ 1598 if (imgp->execpath != NULL && imgp->auxargs != NULL) 1599 execpath_len = strlen(imgp->execpath) + 1; 1600 else 1601 execpath_len = 0; 1602 p = imgp->proc; 1603 szsigcode = 0; 1604 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 1605 imgp->ps_strings = arginfo; 1606 if (p->p_sysent->sv_sigcode_base == 0) { 1607 if (p->p_sysent->sv_szsigcode != NULL) 1608 szsigcode = *(p->p_sysent->sv_szsigcode); 1609 } 1610 destp = (uintptr_t)arginfo; 1611 1612 /* 1613 * install sigcode 1614 */ 1615 if (szsigcode != 0) { 1616 destp -= szsigcode; 1617 destp = rounddown2(destp, sizeof(void *)); 1618 error = copyout(p->p_sysent->sv_sigcode, (void *)destp, 1619 szsigcode); 1620 if (error != 0) 1621 return (error); 1622 } 1623 1624 /* 1625 * Copy the image path for the rtld. 1626 */ 1627 if (execpath_len != 0) { 1628 destp -= execpath_len; 1629 destp = rounddown2(destp, sizeof(void *)); 1630 imgp->execpathp = (void *)destp; 1631 error = copyout(imgp->execpath, imgp->execpathp, execpath_len); 1632 if (error != 0) 1633 return (error); 1634 } 1635 1636 /* 1637 * Prepare the canary for SSP. 1638 */ 1639 arc4rand(canary, sizeof(canary), 0); 1640 destp -= sizeof(canary); 1641 imgp->canary = (void *)destp; 1642 error = copyout(canary, imgp->canary, sizeof(canary)); 1643 if (error != 0) 1644 return (error); 1645 imgp->canarylen = sizeof(canary); 1646 1647 /* 1648 * Prepare the pagesizes array. 1649 */ 1650 destp -= szps; 1651 destp = rounddown2(destp, sizeof(void *)); 1652 imgp->pagesizes = (void *)destp; 1653 error = copyout(pagesizes, imgp->pagesizes, szps); 1654 if (error != 0) 1655 return (error); 1656 imgp->pagesizeslen = szps; 1657 1658 /* 1659 * Allocate room for the argument and environment strings. 1660 */ 1661 destp -= ARG_MAX - imgp->args->stringspace; 1662 destp = rounddown2(destp, sizeof(void *)); 1663 ustringp = destp; 1664 1665 exec_stackgap(imgp, &destp); 1666 1667 if (imgp->auxargs) { 1668 /* 1669 * Allocate room on the stack for the ELF auxargs 1670 * array. It has up to AT_COUNT entries. 1671 */ 1672 destp -= AT_COUNT * sizeof(Elf_Auxinfo); 1673 destp = rounddown2(destp, sizeof(void *)); 1674 } 1675 1676 vectp = (char **)destp; 1677 1678 /* 1679 * Allocate room for the argv[] and env vectors including the 1680 * terminating NULL pointers. 1681 */ 1682 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 1683 1684 /* 1685 * vectp also becomes our initial stack base 1686 */ 1687 *stack_base = (uintptr_t)vectp; 1688 1689 stringp = imgp->args->begin_argv; 1690 argc = imgp->args->argc; 1691 envc = imgp->args->envc; 1692 1693 /* 1694 * Copy out strings - arguments and environment. 1695 */ 1696 error = copyout(stringp, (void *)ustringp, 1697 ARG_MAX - imgp->args->stringspace); 1698 if (error != 0) 1699 return (error); 1700 1701 /* 1702 * Fill in "ps_strings" struct for ps, w, etc. 1703 */ 1704 imgp->argv = vectp; 1705 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 || 1706 suword32(&arginfo->ps_nargvstr, argc) != 0) 1707 return (EFAULT); 1708 1709 /* 1710 * Fill in argument portion of vector table. 1711 */ 1712 for (; argc > 0; --argc) { 1713 if (suword(vectp++, ustringp) != 0) 1714 return (EFAULT); 1715 while (*stringp++ != 0) 1716 ustringp++; 1717 ustringp++; 1718 } 1719 1720 /* a null vector table pointer separates the argp's from the envp's */ 1721 if (suword(vectp++, 0) != 0) 1722 return (EFAULT); 1723 1724 imgp->envv = vectp; 1725 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 || 1726 suword32(&arginfo->ps_nenvstr, envc) != 0) 1727 return (EFAULT); 1728 1729 /* 1730 * Fill in environment portion of vector table. 1731 */ 1732 for (; envc > 0; --envc) { 1733 if (suword(vectp++, ustringp) != 0) 1734 return (EFAULT); 1735 while (*stringp++ != 0) 1736 ustringp++; 1737 ustringp++; 1738 } 1739 1740 /* end of vector table is a null pointer */ 1741 if (suword(vectp, 0) != 0) 1742 return (EFAULT); 1743 1744 if (imgp->auxargs) { 1745 vectp++; 1746 error = imgp->sysent->sv_copyout_auxargs(imgp, 1747 (uintptr_t)vectp); 1748 if (error != 0) 1749 return (error); 1750 } 1751 1752 return (0); 1753 } 1754 1755 /* 1756 * Check permissions of file to execute. 1757 * Called with imgp->vp locked. 1758 * Return 0 for success or error code on failure. 1759 */ 1760 int 1761 exec_check_permissions(struct image_params *imgp) 1762 { 1763 struct vnode *vp = imgp->vp; 1764 struct vattr *attr = imgp->attr; 1765 struct thread *td; 1766 int error; 1767 1768 td = curthread; 1769 1770 /* Get file attributes */ 1771 error = VOP_GETATTR(vp, attr, td->td_ucred); 1772 if (error) 1773 return (error); 1774 1775 #ifdef MAC 1776 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp); 1777 if (error) 1778 return (error); 1779 #endif 1780 1781 /* 1782 * 1) Check if file execution is disabled for the filesystem that 1783 * this file resides on. 1784 * 2) Ensure that at least one execute bit is on. Otherwise, a 1785 * privileged user will always succeed, and we don't want this 1786 * to happen unless the file really is executable. 1787 * 3) Ensure that the file is a regular file. 1788 */ 1789 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 1790 (attr->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0 || 1791 (attr->va_type != VREG)) 1792 return (EACCES); 1793 1794 /* 1795 * Zero length files can't be exec'd 1796 */ 1797 if (attr->va_size == 0) 1798 return (ENOEXEC); 1799 1800 /* 1801 * Check for execute permission to file based on current credentials. 1802 */ 1803 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td); 1804 if (error) 1805 return (error); 1806 1807 /* 1808 * Check number of open-for-writes on the file and deny execution 1809 * if there are any. 1810 * 1811 * Add a text reference now so no one can write to the 1812 * executable while we're activating it. 1813 * 1814 * Remember if this was set before and unset it in case this is not 1815 * actually an executable image. 1816 */ 1817 error = VOP_SET_TEXT(vp); 1818 if (error != 0) 1819 return (error); 1820 imgp->textset = true; 1821 1822 /* 1823 * Call filesystem specific open routine (which does nothing in the 1824 * general case). 1825 */ 1826 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL); 1827 if (error == 0) 1828 imgp->opened = 1; 1829 return (error); 1830 } 1831 1832 /* 1833 * Exec handler registration 1834 */ 1835 int 1836 exec_register(const struct execsw *execsw_arg) 1837 { 1838 const struct execsw **es, **xs, **newexecsw; 1839 u_int count = 2; /* New slot and trailing NULL */ 1840 1841 if (execsw) 1842 for (es = execsw; *es; es++) 1843 count++; 1844 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1845 xs = newexecsw; 1846 if (execsw) 1847 for (es = execsw; *es; es++) 1848 *xs++ = *es; 1849 *xs++ = execsw_arg; 1850 *xs = NULL; 1851 if (execsw) 1852 free(execsw, M_TEMP); 1853 execsw = newexecsw; 1854 return (0); 1855 } 1856 1857 int 1858 exec_unregister(const struct execsw *execsw_arg) 1859 { 1860 const struct execsw **es, **xs, **newexecsw; 1861 int count = 1; 1862 1863 if (execsw == NULL) 1864 panic("unregister with no handlers left?\n"); 1865 1866 for (es = execsw; *es; es++) { 1867 if (*es == execsw_arg) 1868 break; 1869 } 1870 if (*es == NULL) 1871 return (ENOENT); 1872 for (es = execsw; *es; es++) 1873 if (*es != execsw_arg) 1874 count++; 1875 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 1876 xs = newexecsw; 1877 for (es = execsw; *es; es++) 1878 if (*es != execsw_arg) 1879 *xs++ = *es; 1880 *xs = NULL; 1881 if (execsw) 1882 free(execsw, M_TEMP); 1883 execsw = newexecsw; 1884 return (0); 1885 } 1886 1887 /* 1888 * Write out a core segment to the compression stream. 1889 */ 1890 static int 1891 compress_chunk(struct coredump_params *cp, char *base, char *buf, u_int len) 1892 { 1893 u_int chunk_len; 1894 int error; 1895 1896 while (len > 0) { 1897 chunk_len = MIN(len, CORE_BUF_SIZE); 1898 1899 /* 1900 * We can get EFAULT error here. 1901 * In that case zero out the current chunk of the segment. 1902 */ 1903 error = copyin(base, buf, chunk_len); 1904 if (error != 0) 1905 bzero(buf, chunk_len); 1906 error = compressor_write(cp->comp, buf, chunk_len); 1907 if (error != 0) 1908 break; 1909 base += chunk_len; 1910 len -= chunk_len; 1911 } 1912 return (error); 1913 } 1914 1915 int 1916 core_write(struct coredump_params *cp, const void *base, size_t len, 1917 off_t offset, enum uio_seg seg, size_t *resid) 1918 { 1919 1920 return (vn_rdwr_inchunks(UIO_WRITE, cp->vp, __DECONST(void *, base), 1921 len, offset, seg, IO_UNIT | IO_DIRECT | IO_RANGELOCKED, 1922 cp->active_cred, cp->file_cred, resid, cp->td)); 1923 } 1924 1925 int 1926 core_output(char *base, size_t len, off_t offset, struct coredump_params *cp, 1927 void *tmpbuf) 1928 { 1929 vm_map_t map; 1930 struct mount *mp; 1931 size_t resid, runlen; 1932 int error; 1933 bool success; 1934 1935 KASSERT((uintptr_t)base % PAGE_SIZE == 0, 1936 ("%s: user address %p is not page-aligned", __func__, base)); 1937 1938 if (cp->comp != NULL) 1939 return (compress_chunk(cp, base, tmpbuf, len)); 1940 1941 map = &cp->td->td_proc->p_vmspace->vm_map; 1942 for (; len > 0; base += runlen, offset += runlen, len -= runlen) { 1943 /* 1944 * Attempt to page in all virtual pages in the range. If a 1945 * virtual page is not backed by the pager, it is represented as 1946 * a hole in the file. This can occur with zero-filled 1947 * anonymous memory or truncated files, for example. 1948 */ 1949 for (runlen = 0; runlen < len; runlen += PAGE_SIZE) { 1950 error = vm_fault(map, (uintptr_t)base + runlen, 1951 VM_PROT_READ, VM_FAULT_NOFILL, NULL); 1952 if (runlen == 0) 1953 success = error == KERN_SUCCESS; 1954 else if ((error == KERN_SUCCESS) != success) 1955 break; 1956 } 1957 1958 if (success) { 1959 error = core_write(cp, base, runlen, offset, 1960 UIO_USERSPACE, &resid); 1961 if (error != 0) { 1962 if (error != EFAULT) 1963 break; 1964 1965 /* 1966 * EFAULT may be returned if the user mapping 1967 * could not be accessed, e.g., because a mapped 1968 * file has been truncated. Skip the page if no 1969 * progress was made, to protect against a 1970 * hypothetical scenario where vm_fault() was 1971 * successful but core_write() returns EFAULT 1972 * anyway. 1973 */ 1974 runlen -= resid; 1975 if (runlen == 0) { 1976 success = false; 1977 runlen = PAGE_SIZE; 1978 } 1979 } 1980 } 1981 if (!success) { 1982 error = vn_start_write(cp->vp, &mp, V_WAIT); 1983 if (error != 0) 1984 break; 1985 vn_lock(cp->vp, LK_EXCLUSIVE | LK_RETRY); 1986 error = vn_truncate_locked(cp->vp, offset + runlen, 1987 false, cp->td->td_ucred); 1988 VOP_UNLOCK(cp->vp); 1989 vn_finished_write(mp); 1990 if (error != 0) 1991 break; 1992 } 1993 } 1994 return (error); 1995 } 1996 1997 /* 1998 * Drain into a core file. 1999 */ 2000 int 2001 sbuf_drain_core_output(void *arg, const char *data, int len) 2002 { 2003 struct coredump_params *cp; 2004 struct proc *p; 2005 int error, locked; 2006 2007 cp = arg; 2008 p = cp->td->td_proc; 2009 2010 /* 2011 * Some kern_proc out routines that print to this sbuf may 2012 * call us with the process lock held. Draining with the 2013 * non-sleepable lock held is unsafe. The lock is needed for 2014 * those routines when dumping a live process. In our case we 2015 * can safely release the lock before draining and acquire 2016 * again after. 2017 */ 2018 locked = PROC_LOCKED(p); 2019 if (locked) 2020 PROC_UNLOCK(p); 2021 if (cp->comp != NULL) 2022 error = compressor_write(cp->comp, __DECONST(char *, data), len); 2023 else 2024 error = core_write(cp, __DECONST(void *, data), len, cp->offset, 2025 UIO_SYSSPACE, NULL); 2026 if (locked) 2027 PROC_LOCK(p); 2028 if (error != 0) 2029 return (-error); 2030 cp->offset += len; 2031 return (len); 2032 } 2033