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34 * @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
35 * $FreeBSD: src/sys/kern/kern_prot.c,v 1.53.2.9 2002/03/09 05:20:26 dd Exp $
39 * System calls related to processes and protection
42 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/sysmsg.h>
46 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/pioctl.h>
52 #include <sys/resourcevar.h>
54 #include <sys/lockf.h>
55 #include <sys/spinlock.h>
57 #include <sys/spinlock2.h>
59 static MALLOC_DEFINE(M_CRED, "cred", "credentials");
62 sys_getpid(struct sysmsg *sysmsg, const struct getpid_args *uap)
64 struct proc *p = curproc;
66 sysmsg->sysmsg_fds[0] = p->p_pid;
71 sys_getppid(struct sysmsg *sysmsg, const struct getppid_args *uap)
73 struct proc *p = curproc;
75 sysmsg->sysmsg_result = p->p_ppid;
81 sys_lwp_gettid(struct sysmsg *sysmsg, const struct lwp_gettid_args *uap)
83 struct lwp *lp = curthread->td_lwp;
84 sysmsg->sysmsg_result = lp->lwp_tid;
89 * Get process group ID; note that POSIX getpgrp takes no parameter
92 sys_getpgrp(struct sysmsg *sysmsg, const struct getpgrp_args *uap)
94 struct proc *p = curproc;
96 lwkt_gettoken_shared(&p->p_token);
97 sysmsg->sysmsg_result = p->p_pgrp->pg_id;
98 lwkt_reltoken(&p->p_token);
104 * Get an arbitrary pid's process group id
107 sys_getpgid(struct sysmsg *sysmsg, const struct getpgid_args *uap)
109 struct proc *p = curproc;
119 pt = pfind(uap->pid);
124 lwkt_gettoken_shared(&pt->p_token);
125 sysmsg->sysmsg_result = pt->p_pgrp->pg_id;
126 lwkt_reltoken(&pt->p_token);
134 * Get an arbitrary pid's session id.
137 sys_getsid(struct sysmsg *sysmsg, const struct getsid_args *uap)
139 struct proc *p = curproc;
149 pt = pfind(uap->pid);
154 sysmsg->sysmsg_result = pt->p_session->s_sid;
165 sys_getuid(struct sysmsg *sysmsg, const struct getuid_args *uap)
167 struct ucred *cred = curthread->td_ucred;
169 sysmsg->sysmsg_fds[0] = cred->cr_ruid;
177 sys_geteuid(struct sysmsg *sysmsg, const struct geteuid_args *uap)
179 struct ucred *cred = curthread->td_ucred;
181 sysmsg->sysmsg_result = cred->cr_uid;
189 sys_getgid(struct sysmsg *sysmsg, const struct getgid_args *uap)
191 struct ucred *cred = curthread->td_ucred;
193 sysmsg->sysmsg_fds[0] = cred->cr_rgid;
198 * Get effective group ID. The "egid" is groups[0], and could be obtained
199 * via getgroups. This syscall exists because it is somewhat painful to do
200 * correctly in a library function.
203 sys_getegid(struct sysmsg *sysmsg, const struct getegid_args *uap)
205 struct ucred *cred = curthread->td_ucred;
207 sysmsg->sysmsg_result = cred->cr_groups[0];
212 sys_getgroups(struct sysmsg *sysmsg, const struct getgroups_args *uap)
218 cr = curthread->td_ucred;
219 if ((ngrp = uap->gidsetsize) == 0) {
220 sysmsg->sysmsg_result = cr->cr_ngroups;
223 if (ngrp < cr->cr_ngroups)
225 ngrp = cr->cr_ngroups;
226 error = copyout((caddr_t)cr->cr_groups,
227 (caddr_t)uap->gidset, ngrp * sizeof(gid_t));
229 sysmsg->sysmsg_result = ngrp;
234 * Set the per-thread title for ps
237 sys_lwp_setname(struct sysmsg *sysmsg, const struct lwp_setname_args *uap)
239 struct proc *p = curproc;
241 char buf[LPMAP_MAXTHREADTITLE];
245 if (uap->name != NULL) {
246 error = copyinstr(uap->name, buf, sizeof(buf), &len);
248 if (error != ENAMETOOLONG)
250 buf[sizeof(buf)-1] = 0;
251 len = sizeof(buf) - 1;
258 lwkt_gettoken(&p->p_token);
260 lp = lwpfind(p, uap->tid);
262 lwkt_gettoken(&lp->lwp_token);
263 if (lp->lwp_lpmap == NULL)
266 bcopy(buf, lp->lwp_lpmap->thread_title, len);
267 lwkt_reltoken(&lp->lwp_token);
274 lwkt_reltoken(&p->p_token);
280 * Retrieve the per-thread title for ps
283 sys_lwp_getname(struct sysmsg *sysmsg, const struct lwp_getname_args *uap)
285 struct proc *p = curproc;
287 char buf[LPMAP_MAXTHREADTITLE];
293 lwkt_gettoken(&p->p_token);
295 lp = lwpfind(p, uap->tid);
297 lwkt_gettoken(&lp->lwp_token);
298 if (lp->lwp_lpmap == NULL)
301 for (len = 0; len < LPMAP_MAXTHREADTITLE - 1 &&
302 len < uap->len - 1; ++len) {
303 c = lp->lwp_lpmap->thread_title[len];
309 lwkt_reltoken(&lp->lwp_token);
317 lwkt_reltoken(&p->p_token);
320 error = copyout(buf, uap->name, len);
326 sys_setsid(struct sysmsg *sysmsg, const struct setsid_args *uap)
328 struct proc *p = curproc;
329 struct pgrp *pg = NULL;
332 lwkt_gettoken(&p->p_token);
333 if (p->p_pgid == p->p_pid || (pg = pgfind(p->p_pid)) != NULL) {
338 enterpgrp(p, p->p_pid, 1);
339 sysmsg->sysmsg_result = p->p_pid;
342 lwkt_reltoken(&p->p_token);
347 * set process group (setpgid/old setpgrp)
349 * caller does setpgid(targpid, targpgid)
351 * pid must be caller or child of caller (ESRCH)
353 * pid must be in same session (EPERM)
354 * pid can't have done an exec (EACCES)
356 * there must exist some pid in same session having pgid (EPERM)
357 * pid must not be session leader (EPERM)
360 sys_setpgid(struct sysmsg *sysmsg, const struct setpgid_args *uap)
362 struct proc *curp = curproc;
363 struct proc *targp; /* target process */
364 struct pgrp *pgrp = NULL; /* target pgrp */
366 int pgid = uap->pgid;
371 if (uap->pid != 0 && uap->pid != curp->p_pid) {
372 if ((targp = pfind(uap->pid)) == NULL || !inferior(targp)) {
379 lwkt_gettoken(&targp->p_token);
380 /* targp now referenced and its token is held */
382 if (targp->p_pgrp == NULL ||
383 targp->p_session != curp->p_session) {
387 if (targp->p_flags & P_EXEC) {
394 lwkt_gettoken(&targp->p_token);
396 if (SESS_LEADER(targp)) {
402 } else if (pgid != targp->p_pid) {
403 if ((pgrp = pgfind(pgid)) == NULL ||
404 pgrp->pg_session != curp->p_session) {
409 error = enterpgrp(targp, pgid, 0);
414 lwkt_reltoken(&targp->p_token);
421 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
422 * compatible. It says that setting the uid/gid to euid/egid is a special
423 * case of "appropriate privilege". Once the rules are expanded out, this
424 * basically means that setuid(nnn) sets all three id's, in all permitted
425 * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
426 * does not set the saved id - this is dangerous for traditional BSD
427 * programs. For this reason, we *really* do not want to set
428 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
430 #define POSIX_APPENDIX_B_4_2_2
433 sys_setuid(struct sysmsg *sysmsg, const struct setuid_args *uap)
435 struct proc *p = curproc;
440 lwkt_gettoken(&p->p_token);
444 * See if we have "permission" by POSIX 1003.1 rules.
446 * Note that setuid(geteuid()) is a special case of
447 * "appropriate privileges" in appendix B.4.2.2. We need
448 * to use this clause to be compatible with traditional BSD
449 * semantics. Basically, it means that "setuid(xx)" sets all
450 * three id's (assuming you have privs).
452 * Notes on the logic. We do things in three steps.
453 * 1: We determine if the euid is going to change, and do EPERM
454 * right away. We unconditionally change the euid later if this
455 * test is satisfied, simplifying that part of the logic.
456 * 2: We determine if the real and/or saved uid's are going to
457 * change. Determined by compile options.
458 * 3: Change euid last. (after tests in #2 for "appropriate privs")
461 if (uid != cr->cr_ruid && /* allow setuid(getuid()) */
462 #ifdef _POSIX_SAVED_IDS
463 uid != crc->cr_svuid && /* allow setuid(saved gid) */
465 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
466 uid != cr->cr_uid && /* allow setuid(geteuid()) */
468 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETUID)))
471 #ifdef _POSIX_SAVED_IDS
473 * Do we have "appropriate privileges" (are we root or uid == euid)
474 * If so, we are changing the real uid and/or saved uid.
477 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
480 caps_priv_check(cr, SYSCAP_NOCRED_SETUID, 0) == 0) /* using privs */
484 * Set the real uid and transfer proc count to new user.
486 if (uid != cr->cr_ruid) {
487 cr = change_ruid(uid);
493 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as
494 * the security of seteuid() depends on it. B.4.2.2 says it
495 * is important that we should do this.
497 if (cr->cr_svuid != uid) {
505 * In all permitted cases, we are changing the euid.
506 * Copy credentials so other references do not see our changes.
508 if (cr->cr_uid != uid) {
514 lwkt_reltoken(&p->p_token);
519 sys_seteuid(struct sysmsg *sysmsg, const struct seteuid_args *uap)
521 struct proc *p = curproc;
526 lwkt_gettoken(&p->p_token);
529 if (euid != cr->cr_ruid && /* allow seteuid(getuid()) */
530 euid != cr->cr_svuid && /* allow seteuid(saved uid) */
531 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETEUID)))
533 lwkt_reltoken(&p->p_token);
538 * Everything's okay, do it. Copy credentials so other references do
539 * not see our changes.
541 if (cr->cr_uid != euid) {
545 lwkt_reltoken(&p->p_token);
550 sys_setgid(struct sysmsg *sysmsg, const struct setgid_args *uap)
552 struct proc *p = curproc;
557 lwkt_gettoken(&p->p_token);
561 * See if we have "permission" by POSIX 1003.1 rules.
563 * Note that setgid(getegid()) is a special case of
564 * "appropriate privileges" in appendix B.4.2.2. We need
565 * to use this clause to be compatible with traditional BSD
566 * semantics. Basically, it means that "setgid(xx)" sets all
567 * three id's (assuming you have privs).
569 * For notes on the logic here, see setuid() above.
572 if (gid != cr->cr_rgid && /* allow setgid(getgid()) */
573 #ifdef _POSIX_SAVED_IDS
574 gid != cr->cr_svgid && /* allow setgid(saved gid) */
576 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
577 gid != cr->cr_groups[0] && /* allow setgid(getegid()) */
579 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETGID)))
584 #ifdef _POSIX_SAVED_IDS
586 * Do we have "appropriate privileges" (are we root or gid == egid)
587 * If so, we are changing the real uid and saved gid.
590 #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
591 gid == cr->cr_groups[0] ||
593 cpas_priv_check(cr, SYSCAP_NOCRED_SETGID) == 0) /* using privs */
599 if (cr->cr_rgid != gid) {
607 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as
608 * the security of setegid() depends on it. B.4.2.2 says it
609 * is important that we should do this.
611 if (cr->cr_svgid != gid) {
618 * In all cases permitted cases, we are changing the egid.
619 * Copy credentials so other references do not see our changes.
621 if (cr->cr_groups[0] != gid) {
623 cr->cr_groups[0] = gid;
628 lwkt_reltoken(&p->p_token);
633 sys_setegid(struct sysmsg *sysmsg, const struct setegid_args *uap)
635 struct proc *p = curproc;
640 lwkt_gettoken(&p->p_token);
643 if (egid != cr->cr_rgid && /* allow setegid(getgid()) */
644 egid != cr->cr_svgid && /* allow setegid(saved gid) */
645 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETEGID)))
649 if (cr->cr_groups[0] != egid) {
651 cr->cr_groups[0] = egid;
656 lwkt_reltoken(&p->p_token);
661 sys_setgroups(struct sysmsg *sysmsg, const struct setgroups_args *uap)
663 struct proc *p = curproc;
668 lwkt_gettoken(&p->p_token);
671 if ((error = caps_priv_check(cr, SYSCAP_NOCRED_SETGROUPS)))
673 ngrp = uap->gidsetsize;
674 if (ngrp > NGROUPS) {
679 * XXX A little bit lazy here. We could test if anything has
680 * changed before cratom() and setting P_SUGID.
685 * setgroups(0, NULL) is a legitimate way of clearing the
686 * groups vector on non-BSD systems (which generally do not
687 * have the egid in the groups[0]). We risk security holes
688 * when running non-BSD software if we do not do the same.
692 error = copyin(uap->gidset, cr->cr_groups,
693 ngrp * sizeof(gid_t));
696 cr->cr_ngroups = ngrp;
701 lwkt_reltoken(&p->p_token);
706 sys_setreuid(struct sysmsg *sysmsg, const struct setreuid_args *uap)
708 struct proc *p = curproc;
713 lwkt_gettoken(&p->p_token);
718 if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid &&
719 ruid != cr->cr_svuid) ||
720 (euid != (uid_t)-1 && euid != cr->cr_uid &&
721 euid != cr->cr_ruid && euid != cr->cr_svuid)) &&
722 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETREUID)) != 0)
727 if (euid != (uid_t)-1 && cr->cr_uid != euid) {
728 cr = change_euid(euid);
731 if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) {
732 cr = change_ruid(ruid);
735 if ((ruid != (uid_t)-1 || cr->cr_uid != cr->cr_ruid) &&
736 cr->cr_svuid != cr->cr_uid) {
738 cr->cr_svuid = cr->cr_uid;
743 lwkt_reltoken(&p->p_token);
748 sys_setregid(struct sysmsg *sysmsg, const struct setregid_args *uap)
750 struct proc *p = curproc;
755 lwkt_gettoken(&p->p_token);
760 if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid &&
761 rgid != cr->cr_svgid) ||
762 (egid != (gid_t)-1 && egid != cr->cr_groups[0] &&
763 egid != cr->cr_rgid && egid != cr->cr_svgid)) &&
764 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETREGID)) != 0)
769 if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) {
771 cr->cr_groups[0] = egid;
774 if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) {
779 if ((rgid != (gid_t)-1 || cr->cr_groups[0] != cr->cr_rgid) &&
780 cr->cr_svgid != cr->cr_groups[0]) {
782 cr->cr_svgid = cr->cr_groups[0];
787 lwkt_reltoken(&p->p_token);
792 * setresuid(ruid, euid, suid) is like setreuid except control over the
793 * saved uid is explicit.
796 sys_setresuid(struct sysmsg *sysmsg, const struct setresuid_args *uap)
798 struct proc *p = curproc;
800 uid_t ruid, euid, suid;
803 lwkt_gettoken(&p->p_token);
809 if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid &&
810 ruid != cr->cr_svuid && ruid != cr->cr_uid) ||
811 (euid != (uid_t)-1 && euid != cr->cr_ruid &&
812 euid != cr->cr_svuid && euid != cr->cr_uid) ||
813 (suid != (uid_t)-1 && suid != cr->cr_ruid &&
814 suid != cr->cr_svuid && suid != cr->cr_uid)) &&
815 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETRESUID)) != 0)
819 if (euid != (uid_t)-1 && cr->cr_uid != euid) {
820 cr = change_euid(euid);
823 if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) {
824 cr = change_ruid(ruid);
827 if (suid != (uid_t)-1 && cr->cr_svuid != suid) {
834 lwkt_reltoken(&p->p_token);
839 * setresgid(rgid, egid, sgid) is like setregid except control over the
840 * saved gid is explicit.
843 sys_setresgid(struct sysmsg *sysmsg, const struct setresgid_args *uap)
845 struct proc *p = curproc;
847 gid_t rgid, egid, sgid;
850 lwkt_gettoken(&p->p_token);
855 if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid &&
856 rgid != cr->cr_svgid && rgid != cr->cr_groups[0]) ||
857 (egid != (gid_t)-1 && egid != cr->cr_rgid &&
858 egid != cr->cr_svgid && egid != cr->cr_groups[0]) ||
859 (sgid != (gid_t)-1 && sgid != cr->cr_rgid &&
860 sgid != cr->cr_svgid && sgid != cr->cr_groups[0])) &&
861 (error = caps_priv_check(cr, SYSCAP_NOCRED_SETRESGID)) != 0)
866 if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) {
868 cr->cr_groups[0] = egid;
871 if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) {
876 if (sgid != (gid_t)-1 && cr->cr_svgid != sgid) {
883 lwkt_reltoken(&p->p_token);
888 sys_getresuid(struct sysmsg *sysmsg, const struct getresuid_args *uap)
891 int error1 = 0, error2 = 0, error3 = 0;
894 * copyout's can fault synchronously so we cannot use a shared
897 cr = curthread->td_ucred;
899 error1 = copyout((caddr_t)&cr->cr_ruid,
900 (caddr_t)uap->ruid, sizeof(cr->cr_ruid));
902 error2 = copyout((caddr_t)&cr->cr_uid,
903 (caddr_t)uap->euid, sizeof(cr->cr_uid));
905 error3 = copyout((caddr_t)&cr->cr_svuid,
906 (caddr_t)uap->suid, sizeof(cr->cr_svuid));
907 return error1 ? error1 : (error2 ? error2 : error3);
911 sys_getresgid(struct sysmsg *sysmsg, const struct getresgid_args *uap)
914 int error1 = 0, error2 = 0, error3 = 0;
916 cr = curthread->td_ucred;
918 error1 = copyout(&cr->cr_rgid, uap->rgid,
919 sizeof(cr->cr_rgid));
921 error2 = copyout(&cr->cr_groups[0], uap->egid,
922 sizeof(cr->cr_groups[0]));
924 error3 = copyout(&cr->cr_svgid, uap->sgid,
925 sizeof(cr->cr_svgid));
926 return error1 ? error1 : (error2 ? error2 : error3);
931 * NOTE: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
932 * we use P_SUGID because we consider changing the owners as
933 * "tainting" as well.
934 * This is significant for procs that start as root and "become"
935 * a user without an exec - programs cannot know *everything*
936 * that libc *might* have put in their data segment.
939 sys_issetugid(struct sysmsg *sysmsg, const struct issetugid_args *uap)
941 sysmsg->sysmsg_result = (curproc->p_flags & P_SUGID) ? 1 : 0;
946 * Check if gid is a member of the group set.
949 groupmember(gid_t gid, struct ucred *cred)
954 egp = &(cred->cr_groups[cred->cr_ngroups]);
955 for (gp = cred->cr_groups; gp < egp; gp++) {
964 * Test whether the specified credentials have the privilege
967 * A kernel thread without a process context is assumed to have
968 * the privilege in question. In situations where the caller always
969 * expect a cred to exist, the cred should be passed separately and
970 * priv_check_cred() should be used instead of priv_check().
972 * Returns 0 or error.
975 priv_check(struct thread *td, int priv)
977 if (td->td_lwp != NULL)
978 return priv_check_cred(td->td_ucred, priv, 0);
983 * Check a credential for privilege.
985 * A non-null credential is expected unless NULL_CRED_OKAY is set.
988 priv_check_cred(struct ucred *cred, int priv, int flags)
992 KASSERT(PRIV_VALID(priv), ("priv_check_cred: invalid privilege"));
994 KASSERT(cred != NULL || (flags & NULL_CRED_OKAY),
995 ("priv_check_cred: NULL cred!"));
998 if (flags & NULL_CRED_OKAY)
1003 if (cred->cr_uid != 0)
1006 error = prison_priv_check(cred, priv);
1009 error = caps_priv_check(cred, priv);
1013 /* NOTE: accounting for suser access (p_acflag/ASU) removed */
1020 * Return zero if p1 can signal p2, return errno (EPERM/ESRCH) otherwise.
1023 p_trespass(struct ucred *cr1, struct ucred *cr2)
1029 * Disallow signals crossing outside of a prison boundary
1031 if (!PRISON_CHECK(cr1, cr2))
1035 * Processes inside a restricted root cannot signal processes
1036 * outside of a restricted root. Unless it is also jailed, this will
1037 * still allow cross-signaling between unrelated restricted roots.
1039 if ((caps_get(cr1, SYSCAP_RESTRICTEDROOT) & __SYSCAP_SELF) &&
1040 (caps_get(cr2, SYSCAP_RESTRICTEDROOT) & __SYSCAP_SELF) == 0)
1045 if (cr1->cr_ruid == cr2->cr_ruid)
1047 if (cr1->cr_uid == cr2->cr_ruid)
1049 if (cr1->cr_ruid == cr2->cr_uid)
1051 if (cr1->cr_uid == cr2->cr_uid)
1053 if (caps_priv_check(cr1, SYSCAP_NOPROC_TRESPASS) == 0)
1055 if (cr1->cr_uid == 0)
1061 * Allocate a zeroed cred structure.
1068 cr = kmalloc(sizeof(*cr), M_CRED, M_WAITOK|M_ZERO);
1075 * Claim another reference to a ucred structure. Can be used with special
1078 * It must be possible to call this routine with spinlocks held, meaning
1079 * that this routine itself cannot obtain a spinlock.
1082 crhold(struct ucred *cr)
1084 if (cr != NOCRED && cr != FSCRED)
1085 atomic_add_long(&cr->cr_ref, 1);
1090 * Drop a reference from the cred structure, free it if the reference count
1093 * NOTE: because we used atomic_add_int() above, without a spinlock, we
1094 * must also use atomic_subtract_int() below. A spinlock is required
1095 * in crfree() to handle multiple callers racing the refcount to 0.
1098 crfree(struct ucred *cr)
1100 if (cr->cr_ref <= 0)
1101 panic("Freeing already free credential! %p", cr);
1102 if (atomic_fetchadd_long(&cr->cr_ref, -1) == 1) {
1104 * Some callers of crget(), such as nfs_statfs(),
1105 * allocate a temporary credential, but don't
1106 * allocate a uidinfo structure.
1108 if (cr->cr_uidinfo != NULL) {
1109 uidrop(cr->cr_uidinfo);
1110 cr->cr_uidinfo = NULL;
1112 if (cr->cr_ruidinfo != NULL) {
1113 uidrop(cr->cr_ruidinfo);
1114 cr->cr_ruidinfo = NULL;
1118 * Destroy empty prisons
1121 prison_free(cr->cr_prison);
1122 cr->cr_prison = NULL; /* safety */
1124 kfree((caddr_t)cr, M_CRED);
1129 * Atomize a cred structure so it can be modified without polluting
1130 * other references to it.
1132 * MPSAFE (however, *pcr must be stable)
1135 cratom(struct ucred **pcr)
1137 struct ucred *oldcr;
1138 struct ucred *newcr;
1141 if (oldcr->cr_ref == 1)
1143 newcr = crget(); /* this might block */
1144 oldcr = *pcr; /* re-cache after potentially blocking */
1146 uihold(newcr->cr_uidinfo);
1147 uihold(newcr->cr_ruidinfo);
1149 prison_hold(newcr->cr_prison);
1158 * Called with a modifying token held, but must still obtain p_spin to
1159 * actually replace p_ucred to handle races against syscall entry from
1160 * other threads which cache p_ucred->td_ucred.
1162 * (the threads will only get the spin-lock, and they only need to in
1163 * the case where td_ucred != p_ucred so this is optimal).
1166 cratom_proc(struct proc *p)
1168 struct ucred *oldcr;
1169 struct ucred *newcr;
1172 if (oldcr->cr_ref == 1)
1175 newcr = crget(); /* this might block */
1176 oldcr = p->p_ucred; /* so re-cache oldcr (do not re-test) */
1178 uihold(newcr->cr_uidinfo);
1179 uihold(newcr->cr_ruidinfo);
1181 prison_hold(newcr->cr_prison);
1184 spin_lock(&p->p_spin);
1186 spin_unlock(&p->p_spin);
1193 * Dup cred struct to a new held one.
1196 crdup(struct ucred *cr)
1198 struct ucred *newcr;
1202 uihold(newcr->cr_uidinfo);
1203 uihold(newcr->cr_ruidinfo);
1205 prison_hold(newcr->cr_prison);
1212 * Dup cred structure without caps or prison
1215 crdup_nocaps(struct ucred *cr)
1217 struct ucred *newcr;
1221 uihold(newcr->cr_uidinfo);
1222 uihold(newcr->cr_ruidinfo);
1223 newcr->cr_prison = NULL;
1224 bzero(&newcr->cr_caps, sizeof(newcr->cr_caps));
1231 * Fill in a struct xucred based on a struct ucred.
1234 cru2x(struct ucred *cr, struct xucred *xcr)
1237 bzero(xcr, sizeof(*xcr));
1238 xcr->cr_version = XUCRED_VERSION;
1239 xcr->cr_uid = cr->cr_uid;
1240 xcr->cr_ngroups = cr->cr_ngroups;
1241 bcopy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups));
1245 * Get login name, if available.
1248 sys_getlogin(struct sysmsg *sysmsg, const struct getlogin_args *uap)
1250 struct proc *p = curproc;
1251 char buf[MAXLOGNAME];
1255 namelen = uap->namelen;
1256 if (namelen > MAXLOGNAME) /* namelen is unsigned */
1257 namelen = MAXLOGNAME;
1258 bzero(buf, sizeof(buf));
1259 lwkt_gettoken_shared(&p->p_token);
1260 bcopy(p->p_pgrp->pg_session->s_login, buf, namelen);
1261 lwkt_reltoken(&p->p_token);
1263 error = copyout(buf, uap->namebuf, namelen);
1272 sys_setlogin(struct sysmsg *sysmsg, const struct setlogin_args *uap)
1274 struct thread *td = curthread;
1277 char buf[MAXLOGNAME];
1280 cred = td->td_ucred;
1283 if ((error = caps_priv_check(cred, SYSCAP_NOPROC_SETLOGIN)))
1285 bzero(buf, sizeof(buf));
1286 error = copyinstr(uap->namebuf, buf, sizeof(buf), NULL);
1287 if (error == ENAMETOOLONG)
1290 lwkt_gettoken_shared(&p->p_token);
1291 memcpy(p->p_pgrp->pg_session->s_login, buf, sizeof(buf));
1292 lwkt_reltoken(&p->p_token);
1300 struct proc *p = curproc;
1302 KKASSERT(p != NULL);
1303 lwkt_gettoken(&p->p_token);
1304 p->p_flags |= P_SUGID;
1305 if (!(p->p_pfsflags & PF_ISUGID))
1307 lwkt_reltoken(&p->p_token);
1311 * Helper function to change the effective uid of a process
1314 change_euid(uid_t euid)
1316 struct proc *p = curproc;
1319 KKASSERT(p != NULL);
1320 lf_count_adjust(p, 0);
1321 cr = cratom_proc(p);
1323 uireplace(&cr->cr_uidinfo, uifind(euid));
1324 lf_count_adjust(p, 1);
1329 * Helper function to change the real uid of a process
1331 * The per-uid process count for this process is transfered from
1332 * the old uid to the new uid.
1335 change_ruid(uid_t ruid)
1337 struct proc *p = curproc;
1340 KKASSERT(p != NULL);
1342 cr = cratom_proc(p);
1343 chgproccnt(cr->cr_ruidinfo, -1, 0);
1345 uireplace(&cr->cr_ruidinfo, uifind(ruid));
1346 chgproccnt(cr->cr_ruidinfo, 1, 0);