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