FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exec.c
1 /* $OpenBSD: kern_exec.c,v 1.243 2023/01/13 23:02:43 kettenis Exp $ */
2 /* $NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $ */
3
4 /*-
5 * Copyright (C) 1993, 1994 Christopher G. Demetriou
6 * Copyright (C) 1992 Wolfgang Solfrank.
7 * Copyright (C) 1992 TooLs GmbH.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by TooLs GmbH.
21 * 4. The name of TooLs GmbH may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/filedesc.h>
39 #include <sys/proc.h>
40 #include <sys/mount.h>
41 #include <sys/malloc.h>
42 #include <sys/pool.h>
43 #include <sys/namei.h>
44 #include <sys/vnode.h>
45 #include <sys/fcntl.h>
46 #include <sys/file.h>
47 #include <sys/acct.h>
48 #include <sys/exec.h>
49 #include <sys/exec_elf.h>
50 #include <sys/ktrace.h>
51 #include <sys/resourcevar.h>
52 #include <sys/mman.h>
53 #include <sys/signalvar.h>
54 #include <sys/stat.h>
55 #include <sys/conf.h>
56 #include <sys/pledge.h>
57 #ifdef SYSVSHM
58 #include <sys/shm.h>
59 #endif
60
61 #include <sys/syscallargs.h>
62
63 #include <uvm/uvm_extern.h>
64 #include <machine/tcb.h>
65
66 #include <sys/timetc.h>
67
68 struct uvm_object *sigobject; /* shared sigcode object */
69 vaddr_t sigcode_va;
70 vsize_t sigcode_sz;
71 struct uvm_object *timekeep_object;
72 struct timekeep *timekeep;
73
74 void unveil_destroy(struct process *ps);
75
76 const struct kmem_va_mode kv_exec = {
77 .kv_wait = 1,
78 .kv_map = &exec_map
79 };
80
81 /*
82 * Map the shared signal code.
83 */
84 int exec_sigcode_map(struct process *);
85
86 /*
87 * Map the shared timekeep page.
88 */
89 int exec_timekeep_map(struct process *);
90
91 /*
92 * If non-zero, stackgap_random specifies the upper limit of the random gap size
93 * added to the fixed stack position. Must be n^2.
94 */
95 int stackgap_random = STACKGAP_RANDOM;
96
97 /*
98 * check exec:
99 * given an "executable" described in the exec package's namei info,
100 * see what we can do with it.
101 *
102 * ON ENTRY:
103 * exec package with appropriate namei info
104 * proc pointer of exec'ing proc
105 * NO SELF-LOCKED VNODES
106 *
107 * ON EXIT:
108 * error: nothing held, etc. exec header still allocated.
109 * ok: filled exec package, one locked vnode.
110 *
111 * EXEC SWITCH ENTRY:
112 * Locked vnode to check, exec package, proc.
113 *
114 * EXEC SWITCH EXIT:
115 * ok: return 0, filled exec package, one locked vnode.
116 * error: destructive:
117 * everything deallocated except exec header.
118 * non-destructive:
119 * error code, locked vnode, exec header unmodified
120 */
121 int
122 check_exec(struct proc *p, struct exec_package *epp)
123 {
124 int error, i;
125 struct vnode *vp;
126 struct nameidata *ndp;
127 size_t resid;
128
129 ndp = epp->ep_ndp;
130 ndp->ni_cnd.cn_nameiop = LOOKUP;
131 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME;
132 if (epp->ep_flags & EXEC_INDIR)
133 ndp->ni_cnd.cn_flags |= BYPASSUNVEIL;
134 /* first get the vnode */
135 if ((error = namei(ndp)) != 0)
136 return (error);
137 epp->ep_vp = vp = ndp->ni_vp;
138
139 /* check for regular file */
140 if (vp->v_type != VREG) {
141 error = EACCES;
142 goto bad1;
143 }
144
145 /* get attributes */
146 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0)
147 goto bad1;
148
149 /* Check mount point */
150 if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
151 error = EACCES;
152 goto bad1;
153 }
154
155 /* SUID programs may not be started with execpromises */
156 if ((epp->ep_vap->va_mode & (VSUID | VSGID)) &&
157 (p->p_p->ps_flags & PS_EXECPLEDGE)) {
158 error = EACCES;
159 goto bad1;
160 }
161
162 if ((vp->v_mount->mnt_flag & MNT_NOSUID))
163 epp->ep_vap->va_mode &= ~(VSUID | VSGID);
164
165 /* check access. for root we have to see if any exec bit on */
166 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
167 goto bad1;
168 if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) {
169 error = EACCES;
170 goto bad1;
171 }
172
173 /* try to open it */
174 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0)
175 goto bad1;
176
177 /* unlock vp, we need it unlocked from here */
178 VOP_UNLOCK(vp);
179
180 /* now we have the file, get the exec header */
181 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0,
182 UIO_SYSSPACE, 0, p->p_ucred, &resid, p);
183 if (error)
184 goto bad2;
185 epp->ep_hdrvalid = epp->ep_hdrlen - resid;
186
187 /*
188 * set up the vmcmds for creation of the process
189 * address space
190 */
191 error = ENOEXEC;
192 for (i = 0; i < nexecs && error != 0; i++) {
193 int newerror;
194
195 if (execsw[i].es_check == NULL)
196 continue;
197 newerror = (*execsw[i].es_check)(p, epp);
198 /* make sure the first "interesting" error code is saved. */
199 if (!newerror || error == ENOEXEC)
200 error = newerror;
201 if (epp->ep_flags & EXEC_DESTR && error != 0)
202 return (error);
203 }
204 if (!error) {
205 /* check that entry point is sane */
206 if (epp->ep_entry > VM_MAXUSER_ADDRESS) {
207 error = ENOEXEC;
208 }
209
210 /* check limits */
211 if ((epp->ep_tsize > MAXTSIZ) ||
212 (epp->ep_dsize > lim_cur(RLIMIT_DATA)))
213 error = ENOMEM;
214
215 if (!error)
216 return (0);
217 }
218
219 /*
220 * free any vmspace-creation commands,
221 * and release their references
222 */
223 kill_vmcmds(&epp->ep_vmcmds);
224
225 bad2:
226 /*
227 * close the vnode, free the pathname buf, and punt.
228 */
229 vn_close(vp, FREAD, p->p_ucred, p);
230 pool_put(&namei_pool, ndp->ni_cnd.cn_pnbuf);
231 return (error);
232
233 bad1:
234 /*
235 * free the namei pathname buffer, and put the vnode
236 * (which we don't yet have open).
237 */
238 pool_put(&namei_pool, ndp->ni_cnd.cn_pnbuf);
239 vput(vp);
240 return (error);
241 }
242
243 /*
244 * exec system call
245 */
246 int
247 sys_execve(struct proc *p, void *v, register_t *retval)
248 {
249 struct sys_execve_args /* {
250 syscallarg(const char *) path;
251 syscallarg(char *const *) argp;
252 syscallarg(char *const *) envp;
253 } */ *uap = v;
254 int error;
255 struct exec_package pack;
256 struct nameidata nid;
257 struct vattr attr;
258 struct ucred *cred = p->p_ucred;
259 char *argp;
260 char * const *cpp, *dp, *sp;
261 #ifdef KTRACE
262 char *env_start;
263 #endif
264 struct process *pr = p->p_p;
265 long argc, envc;
266 size_t len, sgap, dstsize;
267 #ifdef MACHINE_STACK_GROWS_UP
268 size_t slen;
269 #endif
270 char *stack;
271 struct ps_strings arginfo;
272 struct vmspace *vm;
273 struct vnode *otvp;
274
275 /* get other threads to stop */
276 if ((error = single_thread_set(p, SINGLE_UNWIND, 1)))
277 return (error);
278
279 /*
280 * Cheap solution to complicated problems.
281 * Mark this process as "leave me alone, I'm execing".
282 */
283 atomic_setbits_int(&pr->ps_flags, PS_INEXEC);
284
285 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
286 nid.ni_pledge = PLEDGE_EXEC;
287 nid.ni_unveil = UNVEIL_EXEC;
288
289 /*
290 * initialize the fields of the exec package.
291 */
292 pack.ep_name = (char *)SCARG(uap, path);
293 pack.ep_hdr = malloc(exec_maxhdrsz, M_EXEC, M_WAITOK);
294 pack.ep_hdrlen = exec_maxhdrsz;
295 pack.ep_hdrvalid = 0;
296 pack.ep_ndp = &nid;
297 pack.ep_interp = NULL;
298 pack.ep_args = NULL;
299 pack.ep_auxinfo = NULL;
300 VMCMDSET_INIT(&pack.ep_vmcmds);
301 pack.ep_vap = &attr;
302 pack.ep_flags = 0;
303
304 /* see if we can run it. */
305 if ((error = check_exec(p, &pack)) != 0) {
306 goto freehdr;
307 }
308
309 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */
310
311 /* allocate an argument buffer */
312 argp = km_alloc(NCARGS, &kv_exec, &kp_pageable, &kd_waitok);
313 #ifdef DIAGNOSTIC
314 if (argp == NULL)
315 panic("execve: argp == NULL");
316 #endif
317 dp = argp;
318 argc = 0;
319
320 /*
321 * Copy the fake args list, if there's one, freeing it as we go.
322 * exec_script_makecmds() allocates either 2 or 3 fake args bounded
323 * by MAXINTERP + MAXPATHLEN < NCARGS so no overflow can happen.
324 */
325 if (pack.ep_flags & EXEC_HASARGL) {
326 dstsize = NCARGS;
327 for(; pack.ep_fa[argc] != NULL; argc++) {
328 len = strlcpy(dp, pack.ep_fa[argc], dstsize);
329 len++;
330 dp += len; dstsize -= len;
331 if (pack.ep_fa[argc+1] != NULL)
332 free(pack.ep_fa[argc], M_EXEC, len);
333 else
334 free(pack.ep_fa[argc], M_EXEC, MAXPATHLEN);
335 }
336 free(pack.ep_fa, M_EXEC, 4 * sizeof(char *));
337 pack.ep_flags &= ~EXEC_HASARGL;
338 }
339
340 /* Now get argv & environment */
341 if (!(cpp = SCARG(uap, argp))) {
342 error = EFAULT;
343 goto bad;
344 }
345
346 if (pack.ep_flags & EXEC_SKIPARG)
347 cpp++;
348
349 while (1) {
350 len = argp + ARG_MAX - dp;
351 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
352 goto bad;
353 if (!sp)
354 break;
355 if ((error = copyinstr(sp, dp, len, &len)) != 0) {
356 if (error == ENAMETOOLONG)
357 error = E2BIG;
358 goto bad;
359 }
360 dp += len;
361 cpp++;
362 argc++;
363 }
364
365 /* must have at least one argument */
366 if (argc == 0) {
367 error = EINVAL;
368 goto bad;
369 }
370
371 #ifdef KTRACE
372 if (KTRPOINT(p, KTR_EXECARGS))
373 ktrexec(p, KTR_EXECARGS, argp, dp - argp);
374 #endif
375
376 envc = 0;
377 /* environment does not need to be there */
378 if ((cpp = SCARG(uap, envp)) != NULL ) {
379 #ifdef KTRACE
380 env_start = dp;
381 #endif
382 while (1) {
383 len = argp + ARG_MAX - dp;
384 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
385 goto bad;
386 if (!sp)
387 break;
388 if ((error = copyinstr(sp, dp, len, &len)) != 0) {
389 if (error == ENAMETOOLONG)
390 error = E2BIG;
391 goto bad;
392 }
393 dp += len;
394 cpp++;
395 envc++;
396 }
397
398 #ifdef KTRACE
399 if (KTRPOINT(p, KTR_EXECENV))
400 ktrexec(p, KTR_EXECENV, env_start, dp - env_start);
401 #endif
402 }
403
404 dp = (char *)(((long)dp + _STACKALIGNBYTES) & ~_STACKALIGNBYTES);
405
406 /*
407 * If we have enabled random stackgap, the stack itself has already
408 * been moved from a random location, but is still aligned to a page
409 * boundary. Provide the lower bits of random placement now.
410 */
411 if (stackgap_random == 0) {
412 sgap = 0;
413 } else {
414 sgap = arc4random() & PAGE_MASK;
415 sgap = (sgap + _STACKALIGNBYTES) & ~_STACKALIGNBYTES;
416 }
417
418 /* Now check if args & environ fit into new stack */
419 len = ((argc + envc + 2 + ELF_AUX_WORDS) * sizeof(char *) +
420 sizeof(long) + dp + sgap + sizeof(struct ps_strings)) - argp;
421
422 len = (len + _STACKALIGNBYTES) &~ _STACKALIGNBYTES;
423
424 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */
425 error = ENOMEM;
426 goto bad;
427 }
428
429 /* adjust "active stack depth" for process VSZ */
430 pack.ep_ssize = len; /* maybe should go elsewhere, but... */
431
432 /*
433 * we're committed: any further errors will kill the process, so
434 * kill the other threads now.
435 */
436 single_thread_set(p, SINGLE_EXIT, 1);
437
438 /*
439 * Prepare vmspace for remapping. Note that uvmspace_exec can replace
440 * ps_vmspace!
441 */
442 uvmspace_exec(p, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
443
444 vm = pr->ps_vmspace;
445 /* Now map address space */
446 vm->vm_taddr = (char *)trunc_page(pack.ep_taddr);
447 vm->vm_tsize = atop(round_page(pack.ep_taddr + pack.ep_tsize) -
448 trunc_page(pack.ep_taddr));
449 vm->vm_daddr = (char *)trunc_page(pack.ep_daddr);
450 vm->vm_dsize = atop(round_page(pack.ep_daddr + pack.ep_dsize) -
451 trunc_page(pack.ep_daddr));
452 vm->vm_dused = 0;
453 vm->vm_ssize = atop(round_page(pack.ep_ssize));
454 vm->vm_maxsaddr = (char *)pack.ep_maxsaddr;
455 vm->vm_minsaddr = (char *)pack.ep_minsaddr;
456
457 /* create the new process's VM space by running the vmcmds */
458 #ifdef DIAGNOSTIC
459 if (pack.ep_vmcmds.evs_used == 0)
460 panic("execve: no vmcmds");
461 #endif
462 error = exec_process_vmcmds(p, &pack);
463
464 /* if an error happened, deallocate and punt */
465 if (error)
466 goto exec_abort;
467
468 #ifdef MACHINE_STACK_GROWS_UP
469 pr->ps_strings = (vaddr_t)vm->vm_maxsaddr + sgap;
470 if (uvm_map_protect(&vm->vm_map, (vaddr_t)vm->vm_maxsaddr,
471 trunc_page(pr->ps_strings), PROT_NONE, 0, TRUE, FALSE))
472 goto exec_abort;
473 #else
474 pr->ps_strings = (vaddr_t)vm->vm_minsaddr - sizeof(arginfo) - sgap;
475 if (uvm_map_protect(&vm->vm_map,
476 round_page(pr->ps_strings + sizeof(arginfo)),
477 (vaddr_t)vm->vm_minsaddr, PROT_NONE, 0, TRUE, FALSE))
478 goto exec_abort;
479 #endif
480
481 memset(&arginfo, 0, sizeof(arginfo));
482
483 /* remember information about the process */
484 arginfo.ps_nargvstr = argc;
485 arginfo.ps_nenvstr = envc;
486
487 #ifdef MACHINE_STACK_GROWS_UP
488 stack = (char *)vm->vm_maxsaddr + sizeof(arginfo) + sgap;
489 slen = len - sizeof(arginfo) - sgap;
490 #else
491 stack = (char *)(vm->vm_minsaddr - len);
492 #endif
493 /* Now copy argc, args & environ to new stack */
494 if (!copyargs(&pack, &arginfo, stack, argp))
495 goto exec_abort;
496
497 pr->ps_auxinfo = (vaddr_t)pack.ep_auxinfo;
498
499 /* copy out the process's ps_strings structure */
500 if (copyout(&arginfo, (char *)pr->ps_strings, sizeof(arginfo)))
501 goto exec_abort;
502
503 stopprofclock(pr); /* stop profiling */
504 fdcloseexec(p); /* handle close on exec */
505 execsigs(p); /* reset caught signals */
506 TCB_SET(p, NULL); /* reset the TCB address */
507 pr->ps_kbind_addr = 0; /* reset the kbind bits */
508 pr->ps_kbind_cookie = 0;
509 arc4random_buf(&pr->ps_sigcookie, sizeof pr->ps_sigcookie);
510
511 /* set command name & other accounting info */
512 memset(pr->ps_comm, 0, sizeof(pr->ps_comm));
513 strlcpy(pr->ps_comm, nid.ni_cnd.cn_nameptr, sizeof(pr->ps_comm));
514 pr->ps_acflag &= ~AFORK;
515
516 /* record proc's vnode, for use by sysctl */
517 otvp = pr->ps_textvp;
518 vref(pack.ep_vp);
519 pr->ps_textvp = pack.ep_vp;
520 if (otvp)
521 vrele(otvp);
522
523 atomic_setbits_int(&pr->ps_flags, PS_EXEC);
524 if (pr->ps_flags & PS_PPWAIT) {
525 atomic_clearbits_int(&pr->ps_flags, PS_PPWAIT);
526 atomic_clearbits_int(&pr->ps_pptr->ps_flags, PS_ISPWAIT);
527 wakeup(pr->ps_pptr);
528 }
529
530 /*
531 * If process does execve() while it has a mismatched real,
532 * effective, or saved uid/gid, we set PS_SUGIDEXEC.
533 */
534 if (cred->cr_uid != cred->cr_ruid ||
535 cred->cr_uid != cred->cr_svuid ||
536 cred->cr_gid != cred->cr_rgid ||
537 cred->cr_gid != cred->cr_svgid)
538 atomic_setbits_int(&pr->ps_flags, PS_SUGIDEXEC);
539 else
540 atomic_clearbits_int(&pr->ps_flags, PS_SUGIDEXEC);
541
542 if (pr->ps_flags & PS_EXECPLEDGE) {
543 pr->ps_pledge = pr->ps_execpledge;
544 atomic_setbits_int(&pr->ps_flags, PS_PLEDGE);
545 } else {
546 atomic_clearbits_int(&pr->ps_flags, PS_PLEDGE);
547 pr->ps_pledge = 0;
548 /* XXX XXX XXX XXX */
549 /* Clear our unveil paths out so the child
550 * starts afresh
551 */
552 unveil_destroy(pr);
553 pr->ps_uvdone = 0;
554 }
555
556 /*
557 * deal with set[ug]id.
558 * MNT_NOEXEC has already been used to disable s[ug]id.
559 */
560 if ((attr.va_mode & (VSUID | VSGID)) && proc_cansugid(p)) {
561 int i;
562
563 atomic_setbits_int(&pr->ps_flags, PS_SUGID|PS_SUGIDEXEC);
564
565 #ifdef KTRACE
566 /*
567 * If process is being ktraced, turn off - unless
568 * root set it.
569 */
570 if (pr->ps_tracevp && !(pr->ps_traceflag & KTRFAC_ROOT))
571 ktrcleartrace(pr);
572 #endif
573 p->p_ucred = cred = crcopy(cred);
574 if (attr.va_mode & VSUID)
575 cred->cr_uid = attr.va_uid;
576 if (attr.va_mode & VSGID)
577 cred->cr_gid = attr.va_gid;
578
579 /*
580 * For set[ug]id processes, a few caveats apply to
581 * stdin, stdout, and stderr.
582 */
583 error = 0;
584 fdplock(p->p_fd);
585 for (i = 0; i < 3; i++) {
586 struct file *fp = NULL;
587
588 /*
589 * NOTE - This will never return NULL because of
590 * immature fds. The file descriptor table is not
591 * shared because we're suid.
592 */
593 fp = fd_getfile(p->p_fd, i);
594
595 /*
596 * Ensure that stdin, stdout, and stderr are already
597 * allocated. We do not want userland to accidentally
598 * allocate descriptors in this range which has implied
599 * meaning to libc.
600 */
601 if (fp == NULL) {
602 short flags = FREAD | (i == 0 ? 0 : FWRITE);
603 struct vnode *vp;
604 int indx;
605
606 if ((error = falloc(p, &fp, &indx)) != 0)
607 break;
608 #ifdef DIAGNOSTIC
609 if (indx != i)
610 panic("sys_execve: falloc indx != i");
611 #endif
612 if ((error = cdevvp(getnulldev(), &vp)) != 0) {
613 fdremove(p->p_fd, indx);
614 closef(fp, p);
615 break;
616 }
617 if ((error = VOP_OPEN(vp, flags, cred, p)) != 0) {
618 fdremove(p->p_fd, indx);
619 closef(fp, p);
620 vrele(vp);
621 break;
622 }
623 if (flags & FWRITE)
624 vp->v_writecount++;
625 fp->f_flag = flags;
626 fp->f_type = DTYPE_VNODE;
627 fp->f_ops = &vnops;
628 fp->f_data = (caddr_t)vp;
629 fdinsert(p->p_fd, indx, 0, fp);
630 }
631 FRELE(fp, p);
632 }
633 fdpunlock(p->p_fd);
634 if (error)
635 goto exec_abort;
636 } else
637 atomic_clearbits_int(&pr->ps_flags, PS_SUGID);
638
639 /*
640 * Reset the saved ugids and update the process's copy of the
641 * creds if the creds have been changed
642 */
643 if (cred->cr_uid != cred->cr_svuid ||
644 cred->cr_gid != cred->cr_svgid) {
645 /* make sure we have unshared ucreds */
646 p->p_ucred = cred = crcopy(cred);
647 cred->cr_svuid = cred->cr_uid;
648 cred->cr_svgid = cred->cr_gid;
649 }
650
651 if (pr->ps_ucred != cred) {
652 struct ucred *ocred;
653
654 ocred = pr->ps_ucred;
655 crhold(cred);
656 pr->ps_ucred = cred;
657 crfree(ocred);
658 }
659
660 if (pr->ps_flags & PS_SUGIDEXEC) {
661 cancel_all_itimers();
662 }
663
664 /* reset CPU time usage for the thread, but not the process */
665 timespecclear(&p->p_tu.tu_runtime);
666 p->p_tu.tu_uticks = p->p_tu.tu_sticks = p->p_tu.tu_iticks = 0;
667
668 memset(p->p_name, 0, sizeof p->p_name);
669
670 km_free(argp, NCARGS, &kv_exec, &kp_pageable);
671
672 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf);
673 vn_close(pack.ep_vp, FREAD, cred, p);
674
675 /*
676 * notify others that we exec'd
677 */
678 KNOTE(&pr->ps_klist, NOTE_EXEC);
679
680 /* map the process's timekeep page, needs to be before exec_elf_fixup */
681 if (exec_timekeep_map(pr))
682 goto free_pack_abort;
683
684 /* setup new registers and do misc. setup. */
685 if (exec_elf_fixup(p, &pack) != 0)
686 goto free_pack_abort;
687 #ifdef MACHINE_STACK_GROWS_UP
688 setregs(p, &pack, (u_long)stack + slen, &arginfo);
689 #else
690 setregs(p, &pack, (u_long)stack, &arginfo);
691 #endif
692
693 /* map the process's signal trampoline code */
694 if (exec_sigcode_map(pr))
695 goto free_pack_abort;
696
697 #ifdef __HAVE_EXEC_MD_MAP
698 /* perform md specific mappings that process might need */
699 if (exec_md_map(p, &pack))
700 goto free_pack_abort;
701 #endif
702
703 if (pr->ps_flags & PS_TRACED)
704 psignal(p, SIGTRAP);
705
706 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen);
707
708 p->p_descfd = 255;
709 if ((pack.ep_flags & EXEC_HASFD) && pack.ep_fd < 255)
710 p->p_descfd = pack.ep_fd;
711
712 if (pack.ep_flags & EXEC_WXNEEDED)
713 atomic_setbits_int(&p->p_p->ps_flags, PS_WXNEEDED);
714 else
715 atomic_clearbits_int(&p->p_p->ps_flags, PS_WXNEEDED);
716
717 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC);
718 single_thread_clear(p, P_SUSPSIG);
719
720 /* setregs() sets up all the registers, so just 'return' */
721 return EJUSTRETURN;
722
723 bad:
724 /* free the vmspace-creation commands, and release their references */
725 kill_vmcmds(&pack.ep_vmcmds);
726 /* kill any opened file descriptor, if necessary */
727 if (pack.ep_flags & EXEC_HASFD) {
728 pack.ep_flags &= ~EXEC_HASFD;
729 fdplock(p->p_fd);
730 /* fdrelease unlocks p->p_fd. */
731 (void) fdrelease(p, pack.ep_fd);
732 }
733 if (pack.ep_interp != NULL)
734 pool_put(&namei_pool, pack.ep_interp);
735 free(pack.ep_args, M_TEMP, sizeof *pack.ep_args);
736 /* close and put the exec'd file */
737 vn_close(pack.ep_vp, FREAD, cred, p);
738 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf);
739 km_free(argp, NCARGS, &kv_exec, &kp_pageable);
740
741 freehdr:
742 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen);
743 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC);
744 single_thread_clear(p, P_SUSPSIG);
745
746 return (error);
747
748 exec_abort:
749 /*
750 * the old process doesn't exist anymore. exit gracefully.
751 * get rid of the (new) address space we have created, if any, get rid
752 * of our namei data and vnode, and exit noting failure
753 */
754 uvm_unmap(&vm->vm_map, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
755 if (pack.ep_interp != NULL)
756 pool_put(&namei_pool, pack.ep_interp);
757 free(pack.ep_args, M_TEMP, sizeof *pack.ep_args);
758 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf);
759 vn_close(pack.ep_vp, FREAD, cred, p);
760 km_free(argp, NCARGS, &kv_exec, &kp_pageable);
761
762 free_pack_abort:
763 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen);
764 exit1(p, 0, SIGABRT, EXIT_NORMAL);
765
766 /* NOTREACHED */
767 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC);
768
769 return (0);
770 }
771
772
773 int
774 copyargs(struct exec_package *pack, struct ps_strings *arginfo, void *stack,
775 void *argp)
776 {
777 char **cpp = stack;
778 char *dp, *sp;
779 size_t len;
780 void *nullp = NULL;
781 long argc = arginfo->ps_nargvstr;
782 int envc = arginfo->ps_nenvstr;
783
784 if (copyout(&argc, cpp++, sizeof(argc)))
785 return (0);
786
787 dp = (char *) (cpp + argc + envc + 2 + ELF_AUX_WORDS);
788 sp = argp;
789
790 /* XXX don't copy them out, remap them! */
791 arginfo->ps_argvstr = cpp; /* remember location of argv for later */
792
793 for (; --argc >= 0; sp += len, dp += len)
794 if (copyout(&dp, cpp++, sizeof(dp)) ||
795 copyoutstr(sp, dp, ARG_MAX, &len))
796 return (0);
797
798 if (copyout(&nullp, cpp++, sizeof(nullp)))
799 return (0);
800
801 arginfo->ps_envstr = cpp; /* remember location of envp for later */
802
803 for (; --envc >= 0; sp += len, dp += len)
804 if (copyout(&dp, cpp++, sizeof(dp)) ||
805 copyoutstr(sp, dp, ARG_MAX, &len))
806 return (0);
807
808 if (copyout(&nullp, cpp++, sizeof(nullp)))
809 return (0);
810
811 /* if this process needs auxinfo, note where to place it */
812 if (pack->ep_args != NULL)
813 pack->ep_auxinfo = cpp;
814
815 return (1);
816 }
817
818 int
819 exec_sigcode_map(struct process *pr)
820 {
821 extern char sigcode[], esigcode[], sigcoderet[];
822 vsize_t sz;
823
824 sz = (vaddr_t)esigcode - (vaddr_t)sigcode;
825
826 /*
827 * If we don't have a sigobject yet, create one.
828 *
829 * sigobject is an anonymous memory object (just like SYSV shared
830 * memory) that we keep a permanent reference to and that we map
831 * in all processes that need this sigcode. The creation is simple,
832 * we create an object, add a permanent reference to it, map it in
833 * kernel space, copy out the sigcode to it and unmap it. Then we map
834 * it with PROT_EXEC into the process just the way sys_mmap would map it.
835 */
836 if (sigobject == NULL) {
837 extern int sigfillsiz;
838 extern u_char sigfill[];
839 size_t off, left;
840 vaddr_t va;
841 int r;
842
843 sigobject = uao_create(sz, 0);
844 uao_reference(sigobject); /* permanent reference */
845
846 if ((r = uvm_map(kernel_map, &va, round_page(sz), sigobject,
847 0, 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE,
848 MAP_INHERIT_SHARE, MADV_RANDOM, 0)))) {
849 uao_detach(sigobject);
850 return (ENOMEM);
851 }
852
853 for (off = 0, left = round_page(sz); left != 0;
854 off += sigfillsiz) {
855 size_t chunk = ulmin(left, sigfillsiz);
856 memcpy((caddr_t)va + off, sigfill, chunk);
857 left -= chunk;
858 }
859 memcpy((caddr_t)va, sigcode, sz);
860
861 (void) uvm_map_protect(kernel_map, va, round_page(sz),
862 PROT_READ, 0, FALSE, FALSE);
863 sigcode_va = va;
864 sigcode_sz = round_page(sz);
865 }
866
867 pr->ps_sigcode = 0; /* no hint */
868 uao_reference(sigobject);
869 if (uvm_map(&pr->ps_vmspace->vm_map, &pr->ps_sigcode, round_page(sz),
870 sigobject, 0, 0, UVM_MAPFLAG(PROT_EXEC,
871 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_INHERIT_COPY,
872 MADV_RANDOM, UVM_FLAG_COPYONW | UVM_FLAG_SYSCALL))) {
873 uao_detach(sigobject);
874 return (ENOMEM);
875 }
876 uvm_map_immutable(&pr->ps_vmspace->vm_map, pr->ps_sigcode,
877 pr->ps_sigcode + round_page(sz), 1);
878
879 /* Calculate PC at point of sigreturn entry */
880 pr->ps_sigcoderet = pr->ps_sigcode + (sigcoderet - sigcode);
881
882 return (0);
883 }
884
885 int
886 exec_timekeep_map(struct process *pr)
887 {
888 size_t timekeep_sz = round_page(sizeof(struct timekeep));
889
890 /*
891 * Similar to the sigcode object
892 */
893 if (timekeep_object == NULL) {
894 vaddr_t va = 0;
895
896 timekeep_object = uao_create(timekeep_sz, 0);
897 uao_reference(timekeep_object);
898
899 if (uvm_map(kernel_map, &va, timekeep_sz, timekeep_object,
900 0, 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE,
901 MAP_INHERIT_SHARE, MADV_RANDOM, 0))) {
902 uao_detach(timekeep_object);
903 timekeep_object = NULL;
904 return (ENOMEM);
905 }
906 if (uvm_fault_wire(kernel_map, va, va + timekeep_sz,
907 PROT_READ | PROT_WRITE)) {
908 uvm_unmap(kernel_map, va, va + timekeep_sz);
909 uao_detach(timekeep_object);
910 timekeep_object = NULL;
911 return (ENOMEM);
912 }
913
914 timekeep = (struct timekeep *)va;
915 timekeep->tk_version = TK_VERSION;
916 }
917
918 pr->ps_timekeep = 0; /* no hint */
919 uao_reference(timekeep_object);
920 if (uvm_map(&pr->ps_vmspace->vm_map, &pr->ps_timekeep, timekeep_sz,
921 timekeep_object, 0, 0, UVM_MAPFLAG(PROT_READ, PROT_READ,
922 MAP_INHERIT_COPY, MADV_RANDOM, 0))) {
923 uao_detach(timekeep_object);
924 return (ENOMEM);
925 }
926 uvm_map_immutable(&pr->ps_vmspace->vm_map, pr->ps_timekeep,
927 pr->ps_timekeep + timekeep_sz, 1);
928
929 return (0);
930 }
Cache object: dd9b5dcf85d34d2d6f7b35f23761fea2
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