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freebsd/sys/kern/kern_prot.c
Robert Watson e7f65fdcf9 o Modify p_candebug() such that there is no longer automatic acceptance 
of debugging the current process when that is in conflict with other
  restrictions (such as jail, unprivileged_procdebug_permitted, etc).
o This corrects anomolies in the behavior of
  kern.security.unprivileged_procdebug_permitted when using truss and
  ktrace.  The theory goes that this is now safe to use.

Obtained from:	TrustedBSD Project
2001-07-31 17:25:12 +00:00

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/*
* Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
* $FreeBSD$
*/
/*
* System calls related to processes and protection
*/
#include "opt_compat.h"
#include "opt_global.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/acct.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sysproto.h>
#include <sys/malloc.h>
#include <sys/pioctl.h>
#include <sys/resourcevar.h>
#include <sys/sysctl.h>
#include <sys/jail.h>
static MALLOC_DEFINE(M_CRED, "cred", "credentials");
SYSCTL_NODE(_kern, OID_AUTO, security, CTLFLAG_RW, 0,
"Kernel security policy");
#ifndef _SYS_SYSPROTO_H_
struct getpid_args {
int dummy;
};
#endif
/*
* getpid - MP SAFE
*/
/* ARGSUSED */
int
getpid(p, uap)
struct proc *p;
struct getpid_args *uap;
{
p->p_retval[0] = p->p_pid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
PROC_LOCK(p);
p->p_retval[1] = p->p_pptr->p_pid;
PROC_UNLOCK(p);
#endif
return (0);
}
/*
* getppid - MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct getppid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getppid(p, uap)
struct proc *p;
struct getppid_args *uap;
{
PROC_LOCK(p);
p->p_retval[0] = p->p_pptr->p_pid;
PROC_UNLOCK(p);
return (0);
}
/*
* Get process group ID; note that POSIX getpgrp takes no parameter
*
* MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct getpgrp_args {
int dummy;
};
#endif
int
getpgrp(p, uap)
struct proc *p;
struct getpgrp_args *uap;
{
p->p_retval[0] = p->p_pgrp->pg_id;
return (0);
}
/* Get an arbitary pid's process group id */
#ifndef _SYS_SYSPROTO_H_
struct getpgid_args {
pid_t pid;
};
#endif
int
getpgid(p, uap)
struct proc *p;
struct getpgid_args *uap;
{
struct proc *pt;
int error;
if (uap->pid == 0)
p->p_retval[0] = p->p_pgrp->pg_id;
else {
if ((pt = pfind(uap->pid)) == NULL)
return ESRCH;
if ((error = p_cansee(p, pt))) {
PROC_UNLOCK(pt);
return (error);
}
p->p_retval[0] = pt->p_pgrp->pg_id;
PROC_UNLOCK(pt);
}
return 0;
}
/*
* Get an arbitary pid's session id.
*/
#ifndef _SYS_SYSPROTO_H_
struct getsid_args {
pid_t pid;
};
#endif
int
getsid(p, uap)
struct proc *p;
struct getsid_args *uap;
{
struct proc *pt;
int error;
if (uap->pid == 0)
p->p_retval[0] = p->p_session->s_sid;
else {
if ((pt = pfind(uap->pid)) == NULL)
return ESRCH;
if ((error = p_cansee(p, pt))) {
PROC_UNLOCK(pt);
return (error);
}
p->p_retval[0] = pt->p_session->s_sid;
PROC_UNLOCK(pt);
}
return 0;
}
/*
* getuid() - MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct getuid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getuid(p, uap)
struct proc *p;
struct getuid_args *uap;
{
p->p_retval[0] = p->p_ucred->cr_ruid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
p->p_retval[1] = p->p_ucred->cr_uid;
#endif
return (0);
}
/*
* geteuid() - MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct geteuid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
geteuid(p, uap)
struct proc *p;
struct geteuid_args *uap;
{
p->p_retval[0] = p->p_ucred->cr_uid;
return (0);
}
/*
* getgid() - MP SAFE
*/
#ifndef _SYS_SYSPROTO_H_
struct getgid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getgid(p, uap)
struct proc *p;
struct getgid_args *uap;
{
p->p_retval[0] = p->p_ucred->cr_rgid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
p->p_retval[1] = p->p_ucred->cr_groups[0];
#endif
return (0);
}
/*
* Get effective group ID. The "egid" is groups[0], and could be obtained
* via getgroups. This syscall exists because it is somewhat painful to do
* correctly in a library function.
*/
#ifndef _SYS_SYSPROTO_H_
struct getegid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getegid(p, uap)
struct proc *p;
struct getegid_args *uap;
{
p->p_retval[0] = p->p_ucred->cr_groups[0];
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct getgroups_args {
u_int gidsetsize;
gid_t *gidset;
};
#endif
int
getgroups(p, uap)
struct proc *p;
register struct getgroups_args *uap;
{
struct ucred *cred = p->p_ucred;
u_int ngrp;
int error;
if ((ngrp = uap->gidsetsize) == 0) {
p->p_retval[0] = cred->cr_ngroups;
return (0);
}
if (ngrp < cred->cr_ngroups)
return (EINVAL);
ngrp = cred->cr_ngroups;
if ((error = copyout((caddr_t)cred->cr_groups,
(caddr_t)uap->gidset, ngrp * sizeof(gid_t))))
return (error);
p->p_retval[0] = ngrp;
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setsid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
setsid(p, uap)
register struct proc *p;
struct setsid_args *uap;
{
if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
return (EPERM);
} else {
(void)enterpgrp(p, p->p_pid, 1);
p->p_retval[0] = p->p_pid;
return (0);
}
}
/*
* set process group (setpgid/old setpgrp)
*
* caller does setpgid(targpid, targpgid)
*
* pid must be caller or child of caller (ESRCH)
* if a child
* pid must be in same session (EPERM)
* pid can't have done an exec (EACCES)
* if pgid != pid
* there must exist some pid in same session having pgid (EPERM)
* pid must not be session leader (EPERM)
*/
#ifndef _SYS_SYSPROTO_H_
struct setpgid_args {
int pid; /* target process id */
int pgid; /* target pgrp id */
};
#endif
/* ARGSUSED */
int
setpgid(curp, uap)
struct proc *curp;
register struct setpgid_args *uap;
{
register struct proc *targp; /* target process */
register struct pgrp *pgrp; /* target pgrp */
int error;
if (uap->pgid < 0)
return (EINVAL);
if (uap->pid != 0 && uap->pid != curp->p_pid) {
if ((targp = pfind(uap->pid)) == NULL || !inferior(targp)) {
if (targp)
PROC_UNLOCK(targp);
return (ESRCH);
}
if ((error = p_cansee(curproc, targp))) {
PROC_UNLOCK(targp);
return (error);
}
if (targp->p_pgrp == NULL ||
targp->p_session != curp->p_session) {
PROC_UNLOCK(targp);
return (EPERM);
}
if (targp->p_flag & P_EXEC) {
PROC_UNLOCK(targp);
return (EACCES);
}
} else {
targp = curp;
PROC_LOCK(curp); /* XXX: not needed */
}
if (SESS_LEADER(targp)) {
PROC_UNLOCK(targp);
return (EPERM);
}
if (uap->pgid == 0)
uap->pgid = targp->p_pid;
else if (uap->pgid != targp->p_pid)
if ((pgrp = pgfind(uap->pgid)) == 0 ||
pgrp->pg_session != curp->p_session) {
PROC_UNLOCK(targp);
return (EPERM);
}
/* XXX: We should probably hold the lock across enterpgrp. */
PROC_UNLOCK(targp);
return (enterpgrp(targp, uap->pgid, 0));
}
/*
* Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
* compatible. It says that setting the uid/gid to euid/egid is a special
* case of "appropriate privilege". Once the rules are expanded out, this
* basically means that setuid(nnn) sets all three id's, in all permitted
* cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
* does not set the saved id - this is dangerous for traditional BSD
* programs. For this reason, we *really* do not want to set
* _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
*/
#define POSIX_APPENDIX_B_4_2_2
#ifndef _SYS_SYSPROTO_H_
struct setuid_args {
uid_t uid;
};
#endif
/* ARGSUSED */
int
setuid(p, uap)
struct proc *p;
struct setuid_args *uap;
{
struct ucred *newcred, *oldcred;
uid_t uid;
int error;
uid = uap->uid;
oldcred = p->p_ucred;
/*
* See if we have "permission" by POSIX 1003.1 rules.
*
* Note that setuid(geteuid()) is a special case of
* "appropriate privileges" in appendix B.4.2.2. We need
* to use this clause to be compatible with traditional BSD
* semantics. Basically, it means that "setuid(xx)" sets all
* three id's (assuming you have privs).
*
* Notes on the logic. We do things in three steps.
* 1: We determine if the euid is going to change, and do EPERM
* right away. We unconditionally change the euid later if this
* test is satisfied, simplifying that part of the logic.
* 2: We determine if the real and/or saved uid's are going to
* change. Determined by compile options.
* 3: Change euid last. (after tests in #2 for "appropriate privs")
*/
if (uid != oldcred->cr_ruid && /* allow setuid(getuid()) */
#ifdef _POSIX_SAVED_IDS
uid != oldcred->cr_svuid && /* allow setuid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
uid != oldcred->cr_uid && /* allow setuid(geteuid()) */
#endif
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
return (error);
newcred = crdup(oldcred);
#ifdef _POSIX_SAVED_IDS
/*
* Do we have "appropriate privileges" (are we root or uid == euid)
* If so, we are changing the real uid and/or saved uid.
*/
if (
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
uid == oldcred->cr_uid ||
#endif
suser_xxx(oldcred, NULL, PRISON_ROOT) == 0) /* we are using privs */
#endif
{
/*
* Set the real uid and transfer proc count to new user.
*/
if (uid != oldcred->cr_ruid) {
change_ruid(newcred, uid);
setsugid(p);
}
/*
* Set saved uid
*
* XXX always set saved uid even if not _POSIX_SAVED_IDS, as
* the security of seteuid() depends on it. B.4.2.2 says it
* is important that we should do this.
*/
if (uid != oldcred->cr_svuid) {
change_svuid(newcred, uid);
setsugid(p);
}
}
/*
* In all permitted cases, we are changing the euid.
* Copy credentials so other references do not see our changes.
*/
if (uid != oldcred->cr_uid) {
change_euid(newcred, uid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct seteuid_args {
uid_t euid;
};
#endif
/* ARGSUSED */
int
seteuid(p, uap)
struct proc *p;
struct seteuid_args *uap;
{
struct ucred *newcred, *oldcred;
uid_t euid;
int error;
euid = uap->euid;
oldcred = p->p_ucred;
if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
return (error);
/*
* Everything's okay, do it. Copy credentials so other references do
* not see our changes.
*/
newcred = crdup(oldcred);
if (oldcred->cr_uid != euid) {
change_euid(newcred, euid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setgid_args {
gid_t gid;
};
#endif
/* ARGSUSED */
int
setgid(p, uap)
struct proc *p;
struct setgid_args *uap;
{
struct ucred *newcred, *oldcred;
gid_t gid;
int error;
gid = uap->gid;
oldcred = p->p_ucred;
/*
* See if we have "permission" by POSIX 1003.1 rules.
*
* Note that setgid(getegid()) is a special case of
* "appropriate privileges" in appendix B.4.2.2. We need
* to use this clause to be compatible with traditional BSD
* semantics. Basically, it means that "setgid(xx)" sets all
* three id's (assuming you have privs).
*
* For notes on the logic here, see setuid() above.
*/
if (gid != oldcred->cr_rgid && /* allow setgid(getgid()) */
#ifdef _POSIX_SAVED_IDS
gid != oldcred->cr_svgid && /* allow setgid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
gid != oldcred->cr_groups[0] && /* allow setgid(getegid()) */
#endif
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
return (error);
newcred = crdup(oldcred);
#ifdef _POSIX_SAVED_IDS
/*
* Do we have "appropriate privileges" (are we root or gid == egid)
* If so, we are changing the real uid and saved gid.
*/
if (
#ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
gid == oldcred->cr_groups[0] ||
#endif
suser_xxx(oldcred, NULL, PRISON_ROOT) == 0) /* we are using privs */
#endif
{
/*
* Set real gid
*/
if (oldcred->cr_rgid != gid) {
change_rgid(newcred, gid);
setsugid(p);
}
/*
* Set saved gid
*
* XXX always set saved gid even if not _POSIX_SAVED_IDS, as
* the security of setegid() depends on it. B.4.2.2 says it
* is important that we should do this.
*/
if (oldcred->cr_svgid != gid) {
change_svgid(newcred, gid);
setsugid(p);
}
}
/*
* In all cases permitted cases, we are changing the egid.
* Copy credentials so other references do not see our changes.
*/
if (oldcred->cr_groups[0] != gid) {
change_egid(newcred, gid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setegid_args {
gid_t egid;
};
#endif
/* ARGSUSED */
int
setegid(p, uap)
struct proc *p;
struct setegid_args *uap;
{
struct ucred *newcred, *oldcred;
gid_t egid;
int error;
egid = uap->egid;
oldcred = p->p_ucred;
if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
return (error);
newcred = crdup(oldcred);
if (oldcred->cr_groups[0] != egid) {
change_egid(newcred, egid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setgroups_args {
u_int gidsetsize;
gid_t *gidset;
};
#endif
/* ARGSUSED */
int
setgroups(p, uap)
struct proc *p;
struct setgroups_args *uap;
{
struct ucred *newcred, *oldcred;
u_int ngrp;
int error;
ngrp = uap->gidsetsize;
oldcred = p->p_ucred;
if ((error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
return (error);
if (ngrp > NGROUPS)
return (EINVAL);
/*
* XXX A little bit lazy here. We could test if anything has
* changed before crcopy() and setting P_SUGID.
*/
newcred = crdup(oldcred);
if (ngrp < 1) {
/*
* setgroups(0, NULL) is a legitimate way of clearing the
* groups vector on non-BSD systems (which generally do not
* have the egid in the groups[0]). We risk security holes
* when running non-BSD software if we do not do the same.
*/
newcred->cr_ngroups = 1;
} else {
if ((error = copyin((caddr_t)uap->gidset,
(caddr_t)newcred->cr_groups, ngrp * sizeof(gid_t)))) {
crfree(newcred);
return (error);
}
newcred->cr_ngroups = ngrp;
}
setsugid(p);
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setreuid_args {
uid_t ruid;
uid_t euid;
};
#endif
/* ARGSUSED */
int
setreuid(p, uap)
register struct proc *p;
struct setreuid_args *uap;
{
struct ucred *newcred, *oldcred;
uid_t ruid, euid;
int error;
ruid = uap->ruid;
euid = uap->euid;
oldcred = p->p_ucred;
if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
ruid != oldcred->cr_svuid) ||
(euid != (uid_t)-1 && euid != oldcred->cr_uid &&
euid != oldcred->cr_ruid && euid != oldcred->cr_svuid)) &&
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)) != 0)
return (error);
newcred = crdup(oldcred);
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
change_euid(newcred, euid);
setsugid(p);
}
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
change_ruid(newcred, ruid);
setsugid(p);
}
if ((ruid != (uid_t)-1 || newcred->cr_uid != newcred->cr_ruid) &&
newcred->cr_svuid != newcred->cr_uid) {
change_svuid(newcred, newcred->cr_uid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct setregid_args {
gid_t rgid;
gid_t egid;
};
#endif
/* ARGSUSED */
int
setregid(p, uap)
register struct proc *p;
struct setregid_args *uap;
{
struct ucred *newcred, *oldcred;
gid_t rgid, egid;
int error;
rgid = uap->rgid;
egid = uap->egid;
oldcred = p->p_ucred;
if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
rgid != oldcred->cr_svgid) ||
(egid != (gid_t)-1 && egid != oldcred->cr_groups[0] &&
egid != oldcred->cr_rgid && egid != oldcred->cr_svgid)) &&
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)) != 0)
return (error);
newcred = crdup(oldcred);
if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
change_egid(newcred, egid);
setsugid(p);
}
if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
change_rgid(newcred, rgid);
setsugid(p);
}
if ((rgid != (gid_t)-1 || newcred->cr_groups[0] != newcred->cr_rgid) &&
newcred->cr_svgid != newcred->cr_groups[0]) {
change_svgid(newcred, newcred->cr_groups[0]);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
/*
* setresuid(ruid, euid, suid) is like setreuid except control over the
* saved uid is explicit.
*/
#ifndef _SYS_SYSPROTO_H_
struct setresuid_args {
uid_t ruid;
uid_t euid;
uid_t suid;
};
#endif
/* ARGSUSED */
int
setresuid(p, uap)
register struct proc *p;
struct setresuid_args *uap;
{
struct ucred *newcred, *oldcred;
uid_t ruid, euid, suid;
int error;
ruid = uap->ruid;
euid = uap->euid;
suid = uap->suid;
oldcred = p->p_ucred;
if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
ruid != oldcred->cr_svuid &&
ruid != oldcred->cr_uid) ||
(euid != (uid_t)-1 && euid != oldcred->cr_ruid &&
euid != oldcred->cr_svuid &&
euid != oldcred->cr_uid) ||
(suid != (uid_t)-1 && suid != oldcred->cr_ruid &&
suid != oldcred->cr_svuid &&
suid != oldcred->cr_uid)) &&
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)) != 0)
return (error);
newcred = crdup(oldcred);
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
change_euid(newcred, euid);
setsugid(p);
}
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
change_ruid(newcred, ruid);
setsugid(p);
}
if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
change_svuid(newcred, suid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
/*
* setresgid(rgid, egid, sgid) is like setregid except control over the
* saved gid is explicit.
*/
#ifndef _SYS_SYSPROTO_H_
struct setresgid_args {
gid_t rgid;
gid_t egid;
gid_t sgid;
};
#endif
/* ARGSUSED */
int
setresgid(p, uap)
register struct proc *p;
struct setresgid_args *uap;
{
struct ucred *newcred, *oldcred;
gid_t rgid, egid, sgid;
int error;
rgid = uap->rgid;
egid = uap->egid;
sgid = uap->sgid;
oldcred = p->p_ucred;
if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
rgid != oldcred->cr_svgid &&
rgid != oldcred->cr_groups[0]) ||
(egid != (gid_t)-1 && egid != oldcred->cr_rgid &&
egid != oldcred->cr_svgid &&
egid != oldcred->cr_groups[0]) ||
(sgid != (gid_t)-1 && sgid != oldcred->cr_rgid &&
sgid != oldcred->cr_svgid &&
sgid != oldcred->cr_groups[0])) &&
(error = suser_xxx(oldcred, NULL, PRISON_ROOT)) != 0)
return (error);
newcred = crdup(oldcred);
if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
change_egid(newcred, egid);
setsugid(p);
}
if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
change_rgid(newcred, rgid);
setsugid(p);
}
if (sgid != (gid_t)-1 && oldcred->cr_svgid != sgid) {
change_svgid(newcred, sgid);
setsugid(p);
}
p->p_ucred = newcred;
crfree(oldcred);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct getresuid_args {
uid_t *ruid;
uid_t *euid;
uid_t *suid;
};
#endif
/* ARGSUSED */
int
getresuid(p, uap)
register struct proc *p;
struct getresuid_args *uap;
{
struct ucred *cred = p->p_ucred;
int error1 = 0, error2 = 0, error3 = 0;
if (uap->ruid)
error1 = copyout((caddr_t)&cred->cr_ruid,
(caddr_t)uap->ruid, sizeof(cred->cr_ruid));
if (uap->euid)
error2 = copyout((caddr_t)&cred->cr_uid,
(caddr_t)uap->euid, sizeof(cred->cr_uid));
if (uap->suid)
error3 = copyout((caddr_t)&cred->cr_svuid,
(caddr_t)uap->suid, sizeof(cred->cr_svuid));
return error1 ? error1 : (error2 ? error2 : error3);
}
#ifndef _SYS_SYSPROTO_H_
struct getresgid_args {
gid_t *rgid;
gid_t *egid;
gid_t *sgid;
};
#endif
/* ARGSUSED */
int
getresgid(p, uap)
register struct proc *p;
struct getresgid_args *uap;
{
struct ucred *cred = p->p_ucred;
int error1 = 0, error2 = 0, error3 = 0;
if (uap->rgid)
error1 = copyout((caddr_t)&cred->cr_rgid,
(caddr_t)uap->rgid, sizeof(cred->cr_rgid));
if (uap->egid)
error2 = copyout((caddr_t)&cred->cr_groups[0],
(caddr_t)uap->egid, sizeof(cred->cr_groups[0]));
if (uap->sgid)
error3 = copyout((caddr_t)&cred->cr_svgid,
(caddr_t)uap->sgid, sizeof(cred->cr_svgid));
return error1 ? error1 : (error2 ? error2 : error3);
}
#ifndef _SYS_SYSPROTO_H_
struct issetugid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
issetugid(p, uap)
register struct proc *p;
struct issetugid_args *uap;
{
/*
* Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
* we use P_SUGID because we consider changing the owners as
* "tainting" as well.
* This is significant for procs that start as root and "become"
* a user without an exec - programs cannot know *everything*
* that libc *might* have put in their data segment.
*/
p->p_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
return (0);
}
int
__setugid(p, uap)
struct proc *p;
struct __setugid_args *uap;
{
#ifdef REGRESSION
switch (uap->flag) {
case 0:
p->p_flag &= ~P_SUGID;
return (0);
case 1:
p->p_flag |= P_SUGID;
return (0);
default:
return (EINVAL);
}
#else /* !REGRESSION */
return (ENOSYS);
#endif /* !REGRESSION */
}
/*
* Check if gid is a member of the group set.
*/
int
groupmember(gid, cred)
gid_t gid;
struct ucred *cred;
{
register gid_t *gp;
gid_t *egp;
egp = &(cred->cr_groups[cred->cr_ngroups]);
for (gp = cred->cr_groups; gp < egp; gp++)
if (*gp == gid)
return (1);
return (0);
}
static int suser_permitted = 1;
SYSCTL_INT(_kern_security, OID_AUTO, suser_permitted, CTLFLAG_RW,
&suser_permitted, 0, "processes with uid 0 have privilege");
/*
* Test whether the specified credentials imply "super-user"
* privilege; if so, and we have accounting info, set the flag
* indicating use of super-powers.
* Returns 0 or error.
*/
int
suser(p)
struct proc *p;
{
return suser_xxx(0, p, 0);
}
int
suser_xxx(cred, proc, flag)
struct ucred *cred;
struct proc *proc;
int flag;
{
if (!suser_permitted)
return (EPERM);
if (!cred && !proc) {
printf("suser_xxx(): THINK!\n");
return (EPERM);
}
if (!cred)
cred = proc->p_ucred;
if (cred->cr_uid != 0)
return (EPERM);
if (jailed(cred) && !(flag & PRISON_ROOT))
return (EPERM);
return (0);
}
/*
* u_cansee(u1, u2): determine if u1 "can see" the subject specified by u2
* Arguments: imutable credentials u1, u2
* Returns: 0 for permitted, an errno value otherwise
* Locks: none
* References: u1 and u2 must be valid for the lifetime of the call
* u1 may equal u2, in which case only one reference is required
*/
int
u_cansee(struct ucred *u1, struct ucred *u2)
{
int error;
if ((error = prison_check(u1, u2)))
return (error);
if (!ps_showallprocs && u1->cr_ruid != u2->cr_ruid) {
if (suser_xxx(u1, NULL, PRISON_ROOT) != 0)
return (ESRCH);
}
return (0);
}
int
p_cansee(struct proc *p1, struct proc *p2)
{
/* Wrap u_cansee() for all functionality. */
return (u_cansee(p1->p_ucred, p2->p_ucred));
}
/*
* Can process p1 send the signal signum to process p2?
*/
int
p_cansignal(struct proc *p1, struct proc *p2, int signum)
{
int error;
if (p1 == p2)
return (0);
/*
* Jail semantics limit the scope of signalling to p2 in the same
* jail as p1, if p1 is in jail.
*/
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
return (error);
/*
* UNIX signalling semantics require that processes in the same
* session always be able to deliver SIGCONT to one another,
* overriding the remaining protections.
*/
if (signum == SIGCONT && p1->p_session == p2->p_session)
return (0);
/*
* UNIX uid semantics depend on the status of the P_SUGID
* bit on the target process. If the bit is set, then more
* restricted signal sets are permitted.
*/
if (p2->p_flag & P_SUGID) {
switch (signum) {
case 0:
case SIGKILL:
case SIGINT:
case SIGTERM:
case SIGSTOP:
case SIGTTIN:
case SIGTTOU:
case SIGTSTP:
case SIGHUP:
case SIGUSR1:
case SIGUSR2:
break;
default:
/* Not permitted, try privilege. */
error = suser_xxx(NULL, p1, PRISON_ROOT);
if (error)
return (error);
}
}
/*
* Generally, the object credential's ruid or svuid must match the
* subject credential's ruid or euid.
*/
if (p1->p_ucred->cr_ruid != p2->p_ucred->cr_ruid &&
p1->p_ucred->cr_ruid != p2->p_ucred->cr_svuid &&
p1->p_ucred->cr_uid != p2->p_ucred->cr_ruid &&
p1->p_ucred->cr_uid != p2->p_ucred->cr_svuid) {
/* Not permitted, try privilege. */
error = suser_xxx(NULL, p1, PRISON_ROOT);
if (error)
return (error);
}
return (0);
}
int
p_cansched(struct proc *p1, struct proc *p2)
{
int error;
if (p1 == p2)
return (0);
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
return (error);
if (p1->p_ucred->cr_ruid == p2->p_ucred->cr_ruid)
return (0);
if (p1->p_ucred->cr_uid == p2->p_ucred->cr_ruid)
return (0);
if (!suser_xxx(0, p1, PRISON_ROOT))
return (0);
#ifdef CAPABILITIES
if (!cap_check_xxx(0, p1, CAP_SYS_NICE, PRISON_ROOT))
return (0);
#endif
return (EPERM);
}
static int kern_unprivileged_procdebug_permitted = 1;
SYSCTL_INT(_kern_security, OID_AUTO, unprivileged_procdebug_permitted,
CTLFLAG_RW, &kern_unprivileged_procdebug_permitted, 0,
"Unprivileged processes may use process debugging facilities");
int
p_candebug(struct proc *p1, struct proc *p2)
{
int error;
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
return (error);
/* not owned by you, has done setuid (unless you're root) */
/* add a CAP_SYS_PTRACE here? */
if (p1->p_ucred->cr_uid != p2->p_ucred->cr_uid ||
p1->p_ucred->cr_uid != p2->p_ucred->cr_svuid ||
p1->p_ucred->cr_uid != p2->p_ucred->cr_ruid ||
p2->p_flag & P_SUGID || !kern_unprivileged_procdebug_permitted)
if ((error = suser_xxx(0, p1, PRISON_ROOT)))
return (error);
/* can't trace init when securelevel > 0 */
if (securelevel > 0 && p2->p_pid == 1)
return (EPERM);
return (0);
}
/*
* Allocate a zeroed cred structure.
*/
struct ucred *
crget()
{
register struct ucred *cr;
MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK|M_ZERO);
cr->cr_ref = 1;
mtx_init(&cr->cr_mtx, "ucred", MTX_DEF);
return (cr);
}
/*
* Claim another reference to a ucred structure
*/
void
crhold(cr)
struct ucred *cr;
{
mtx_lock(&cr->cr_mtx);
cr->cr_ref++;
mtx_unlock(&(cr)->cr_mtx);
}
/*
* Free a cred structure.
* Throws away space when ref count gets to 0.
*/
void
crfree(cr)
struct ucred *cr;
{
mtx_lock(&cr->cr_mtx);
KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
if (--cr->cr_ref == 0) {
mtx_destroy(&cr->cr_mtx);
/*
* Some callers of crget(), such as nfs_statfs(),
* allocate a temporary credential, but don't
* allocate a uidinfo structure.
*/
if (cr->cr_uidinfo != NULL)
uifree(cr->cr_uidinfo);
if (cr->cr_ruidinfo != NULL)
uifree(cr->cr_ruidinfo);
/*
* Free a prison, if any.
*/
if (jailed(cr))
prison_free(cr->cr_prison);
FREE((caddr_t)cr, M_CRED);
} else {
mtx_unlock(&cr->cr_mtx);
}
}
/*
* Copy cred structure to a new one and free the old one.
*/
struct ucred *
crcopy(cr)
struct ucred *cr;
{
struct ucred *newcr;
mtx_lock(&cr->cr_mtx);
if (cr->cr_ref == 1) {
mtx_unlock(&cr->cr_mtx);
return (cr);
}
mtx_unlock(&cr->cr_mtx);
newcr = crdup(cr);
crfree(cr);
return (newcr);
}
/*
* Dup cred struct to a new held one.
*/
struct ucred *
crdup(cr)
struct ucred *cr;
{
struct ucred *newcr;
MALLOC(newcr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK);
*newcr = *cr;
mtx_init(&newcr->cr_mtx, "ucred", MTX_DEF);
uihold(newcr->cr_uidinfo);
uihold(newcr->cr_ruidinfo);
if (jailed(newcr))
prison_hold(newcr->cr_prison);
newcr->cr_ref = 1;
return (newcr);
}
/*
* Get login name, if available.
*/
#ifndef _SYS_SYSPROTO_H_
struct getlogin_args {
char *namebuf;
u_int namelen;
};
#endif
/* ARGSUSED */
int
getlogin(p, uap)
struct proc *p;
struct getlogin_args *uap;
{
if (uap->namelen > MAXLOGNAME)
uap->namelen = MAXLOGNAME;
return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
(caddr_t) uap->namebuf, uap->namelen));
}
/*
* Set login name.
*/
#ifndef _SYS_SYSPROTO_H_
struct setlogin_args {
char *namebuf;
};
#endif
/* ARGSUSED */
int
setlogin(p, uap)
struct proc *p;
struct setlogin_args *uap;
{
int error;
char logintmp[MAXLOGNAME];
if ((error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp,
sizeof(logintmp), (size_t *)0);
if (error == ENAMETOOLONG)
error = EINVAL;
else if (!error)
(void) memcpy(p->p_pgrp->pg_session->s_login, logintmp,
sizeof(logintmp));
return (error);
}
void
setsugid(p)
struct proc *p;
{
p->p_flag |= P_SUGID;
if (!(p->p_pfsflags & PF_ISUGID))
p->p_stops = 0;
}
/*
* change_euid(): Change a process's effective uid.
* Side effects: newcred->cr_uid and newcred->cr_uidinfo will be modified.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_euid(newcred, euid)
struct ucred *newcred;
uid_t euid;
{
newcred->cr_uid = euid;
uifree(newcred->cr_uidinfo);
newcred->cr_uidinfo = uifind(euid);
}
/*
* change_egid(): Change a process's effective gid.
* Side effects: newcred->cr_gid will be modified.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_egid(newcred, egid)
struct ucred *newcred;
gid_t egid;
{
newcred->cr_groups[0] = egid;
}
/*
* change_ruid(): Change a process's real uid.
* Side effects: newcred->cr_ruid will be updated, newcred->cr_ruidinfo
* will be updated, and the old and new cr_ruidinfo proc
* counts will be updated.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_ruid(newcred, ruid)
struct ucred *newcred;
uid_t ruid;
{
(void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
newcred->cr_ruid = ruid;
uifree(newcred->cr_ruidinfo);
newcred->cr_ruidinfo = uifind(ruid);
(void)chgproccnt(newcred->cr_ruidinfo, 1, 0);
}
/*
* change_rgid(): Change a process's real gid.
* Side effects: newcred->cr_rgid will be updated.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_rgid(newcred, rgid)
struct ucred *newcred;
gid_t rgid;
{
newcred->cr_rgid = rgid;
}
/*
* change_svuid(): Change a process's saved uid.
* Side effects: newcred->cr_svuid will be updated.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_svuid(newcred, svuid)
struct ucred *newcred;
uid_t svuid;
{
newcred->cr_svuid = svuid;
}
/*
* change_svgid(): Change a process's saved gid.
* Side effects: newcred->cr_svgid will be updated.
* References: newcred must be an exclusive credential reference for the
* duration of the call.
*/
void
change_svgid(newcred, svgid)
struct ucred *newcred;
gid_t svgid;
{
newcred->cr_svgid = svgid;
}
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