mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
f44d9e24fb
pointer instead of a proc pointer and require the process pointed to by the second argument to be locked. We now use the thread ucred reference for the credential checks in p_can*() as a result. p_canfoo() should now no longer need Giant.
1955 lines
44 KiB
C
1955 lines
44 KiB
C
/*
|
|
* 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.
|
|
* Copyright (c) 2000-2001 Robert N. M. Watson. All rights reserved.
|
|
*
|
|
* 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 <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/acct.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/sx.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/sysproto.h>
|
|
#include <sys/jail.h>
|
|
#include <sys/pioctl.h>
|
|
#include <sys/resourcevar.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/socketvar.h>
|
|
#include <sys/sysctl.h>
|
|
|
|
static MALLOC_DEFINE(M_CRED, "cred", "credentials");
|
|
|
|
SYSCTL_DECL(_security);
|
|
SYSCTL_NODE(_security, OID_AUTO, bsd, CTLFLAG_RW, 0,
|
|
"BSD security policy");
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getpid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getpid(struct thread *td, struct getpid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int s;
|
|
|
|
s = mtx_lock_giant(kern_giant_proc);
|
|
td->td_retval[0] = p->p_pid;
|
|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
|
|
PROC_LOCK(p);
|
|
td->td_retval[1] = p->p_pptr->p_pid;
|
|
PROC_UNLOCK(p);
|
|
#endif
|
|
mtx_unlock_giant(s);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getppid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getppid(struct thread *td, struct getppid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int s;
|
|
|
|
s = mtx_lock_giant(kern_giant_proc);
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = p->p_pptr->p_pid;
|
|
PROC_UNLOCK(p);
|
|
mtx_unlock_giant(s);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Get process group ID; note that POSIX getpgrp takes no parameter.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getpgrp_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getpgrp(struct thread *td, struct getpgrp_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int s;
|
|
|
|
s = mtx_lock_giant(kern_giant_proc);
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = p->p_pgrp->pg_id;
|
|
PROC_UNLOCK(p);
|
|
mtx_unlock_giant(s);
|
|
return (0);
|
|
}
|
|
|
|
/* Get an arbitary pid's process group id */
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getpgid_args {
|
|
pid_t pid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getpgid(struct thread *td, struct getpgid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct proc *pt;
|
|
int error;
|
|
|
|
mtx_lock(&Giant);
|
|
error = 0;
|
|
if (uap->pid == 0) {
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = p->p_pgrp->pg_id;
|
|
PROC_UNLOCK(p);
|
|
} else if ((pt = pfind(uap->pid)) == NULL)
|
|
error = ESRCH;
|
|
else {
|
|
error = p_cansee(td, pt);
|
|
if (error == 0)
|
|
td->td_retval[0] = pt->p_pgrp->pg_id;
|
|
PROC_UNLOCK(pt);
|
|
}
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Get an arbitary pid's session id.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getsid_args {
|
|
pid_t pid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getsid(struct thread *td, struct getsid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct proc *pt;
|
|
int error;
|
|
|
|
mtx_lock(&Giant);
|
|
error = 0;
|
|
if (uap->pid == 0) {
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = p->p_session->s_sid;
|
|
PROC_UNLOCK(p);
|
|
} else if ((pt = pfind(uap->pid)) == NULL)
|
|
error = ESRCH;
|
|
else {
|
|
error = p_cansee(td, pt);
|
|
if (error == 0)
|
|
td->td_retval[0] = pt->p_session->s_sid;
|
|
PROC_UNLOCK(pt);
|
|
}
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getuid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getuid(struct thread *td, struct getuid_args *uap)
|
|
{
|
|
|
|
td->td_retval[0] = td->td_ucred->cr_ruid;
|
|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
|
|
td->td_retval[1] = td->td_ucred->cr_uid;
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct geteuid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
geteuid(struct thread *td, struct geteuid_args *uap)
|
|
{
|
|
|
|
td->td_retval[0] = td->td_ucred->cr_uid;
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getgid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getgid(struct thread *td, struct getgid_args *uap)
|
|
{
|
|
|
|
td->td_retval[0] = td->td_ucred->cr_rgid;
|
|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
|
|
td->td_retval[1] = td->td_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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getegid(struct thread *td, struct getegid_args *uap)
|
|
{
|
|
|
|
td->td_retval[0] = td->td_ucred->cr_groups[0];
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getgroups_args {
|
|
u_int gidsetsize;
|
|
gid_t *gidset;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getgroups(struct thread *td, register struct getgroups_args *uap)
|
|
{
|
|
struct ucred *cred;
|
|
u_int ngrp;
|
|
int error;
|
|
|
|
cred = td->td_ucred;
|
|
if ((ngrp = uap->gidsetsize) == 0) {
|
|
td->td_retval[0] = cred->cr_ngroups;
|
|
return (0);
|
|
}
|
|
if (ngrp < cred->cr_ngroups)
|
|
return (EINVAL);
|
|
ngrp = cred->cr_ngroups;
|
|
error = copyout((caddr_t)cred->cr_groups, (caddr_t)uap->gidset,
|
|
ngrp * sizeof(gid_t));
|
|
if (error == 0)
|
|
td->td_retval[0] = ngrp;
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setsid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setsid(register struct thread *td, struct setsid_args *uap)
|
|
{
|
|
struct pgrp *pgrp;
|
|
int error;
|
|
struct proc *p = td->td_proc;
|
|
struct pgrp *newpgrp;
|
|
struct session *newsess;
|
|
|
|
error = 0;
|
|
pgrp = NULL;
|
|
|
|
MALLOC(newpgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
|
|
MALLOC(newsess, struct session *, sizeof(struct session), M_SESSION, M_WAITOK | M_ZERO);
|
|
|
|
sx_xlock(&proctree_lock);
|
|
|
|
if (p->p_pgid == p->p_pid || (pgrp = pgfind(p->p_pid)) != NULL) {
|
|
if (pgrp != NULL)
|
|
PGRP_UNLOCK(pgrp);
|
|
error = EPERM;
|
|
} else {
|
|
(void)enterpgrp(p, p->p_pid, newpgrp, newsess);
|
|
td->td_retval[0] = p->p_pid;
|
|
newpgrp = NULL;
|
|
newsess = NULL;
|
|
}
|
|
|
|
sx_xunlock(&proctree_lock);
|
|
|
|
if (newpgrp != NULL)
|
|
FREE(newpgrp, M_PGRP);
|
|
if (newsess != NULL)
|
|
FREE(newsess, M_SESSION);
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setpgid(struct thread *td, register struct setpgid_args *uap)
|
|
{
|
|
struct proc *curp = td->td_proc;
|
|
register struct proc *targp; /* target process */
|
|
register struct pgrp *pgrp; /* target pgrp */
|
|
int error;
|
|
struct pgrp *newpgrp;
|
|
|
|
if (uap->pgid < 0)
|
|
return (EINVAL);
|
|
|
|
error = 0;
|
|
|
|
MALLOC(newpgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
|
|
|
|
sx_xlock(&proctree_lock);
|
|
if (uap->pid != 0 && uap->pid != curp->p_pid) {
|
|
if ((targp = pfind(uap->pid)) == NULL) {
|
|
if (targp)
|
|
PROC_UNLOCK(targp);
|
|
error = ESRCH;
|
|
goto done;
|
|
}
|
|
if (!inferior(targp)) {
|
|
PROC_UNLOCK(targp);
|
|
error = ESRCH;
|
|
goto done;
|
|
}
|
|
if ((error = p_cansee(curthread, targp))) {
|
|
PROC_UNLOCK(targp);
|
|
goto done;
|
|
}
|
|
if (targp->p_pgrp == NULL ||
|
|
targp->p_session != curp->p_session) {
|
|
PROC_UNLOCK(targp);
|
|
error = EPERM;
|
|
goto done;
|
|
}
|
|
if (targp->p_flag & P_EXEC) {
|
|
PROC_UNLOCK(targp);
|
|
error = EACCES;
|
|
goto done;
|
|
}
|
|
PROC_UNLOCK(targp);
|
|
} else
|
|
targp = curp;
|
|
if (SESS_LEADER(targp)) {
|
|
error = EPERM;
|
|
goto done;
|
|
}
|
|
if (uap->pgid == 0)
|
|
uap->pgid = targp->p_pid;
|
|
if (uap->pgid == targp->p_pid) {
|
|
if (targp->p_pgid == uap->pgid)
|
|
goto done;
|
|
error = enterpgrp(targp, uap->pgid, newpgrp, NULL);
|
|
if (error == 0)
|
|
newpgrp = NULL;
|
|
} else {
|
|
if ((pgrp = pgfind(uap->pgid)) == NULL ||
|
|
pgrp->pg_session != curp->p_session) {
|
|
if (pgrp != NULL)
|
|
PGRP_UNLOCK(pgrp);
|
|
error = EPERM;
|
|
goto done;
|
|
}
|
|
if (pgrp == targp->p_pgrp) {
|
|
PGRP_UNLOCK(pgrp);
|
|
goto done;
|
|
}
|
|
PGRP_UNLOCK(pgrp);
|
|
error = enterthispgrp(targp, pgrp);
|
|
}
|
|
done:
|
|
sx_xunlock(&proctree_lock);
|
|
KASSERT((error == 0) || (newpgrp != NULL),
|
|
("setpgid failed and newpgrp is NULL"));
|
|
if (newpgrp != NULL)
|
|
FREE(newpgrp, M_PGRP);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setuid(struct thread *td, struct setuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t uid;
|
|
int error;
|
|
|
|
mtx_lock(&Giant);
|
|
uid = uap->uid;
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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 uids 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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, 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_cred(oldcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct seteuid_args {
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
seteuid(struct thread *td, struct seteuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
|
|
euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
/*
|
|
* Everything's okay, do it. Copy credentials so other references do
|
|
* not see our changes.
|
|
*/
|
|
crcopy(newcred, oldcred);
|
|
if (oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgid_args {
|
|
gid_t gid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgid(struct thread *td, struct setgid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t gid;
|
|
int error;
|
|
|
|
gid = uap->gid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, 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_cred(oldcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setegid_args {
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setegid(struct thread *td, struct setegid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
|
|
egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
crcopy(newcred, oldcred);
|
|
if (oldcred->cr_groups[0] != egid) {
|
|
change_egid(newcred, egid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgroups_args {
|
|
u_int gidsetsize;
|
|
gid_t *gidset;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgroups(struct thread *td, struct setgroups_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *tempcred, *oldcred;
|
|
u_int ngrp;
|
|
int error;
|
|
|
|
ngrp = uap->gidsetsize;
|
|
if (ngrp > NGROUPS)
|
|
return (EINVAL);
|
|
mtx_lock(&Giant);
|
|
tempcred = crget();
|
|
error = copyin((caddr_t)uap->gidset, (caddr_t)tempcred->cr_groups,
|
|
ngrp * sizeof(gid_t));
|
|
if (error != 0) {
|
|
crfree(tempcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
error = suser_cred(oldcred, PRISON_ROOT);
|
|
if (error) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
crfree(tempcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* XXX A little bit lazy here. We could test if anything has
|
|
* changed before crcopy() and setting P_SUGID.
|
|
*/
|
|
crcopy(newcred, 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 {
|
|
bcopy(tempcred->cr_groups, newcred->cr_groups,
|
|
ngrp * sizeof(gid_t));
|
|
newcred->cr_ngroups = ngrp;
|
|
}
|
|
setsugid(p);
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(tempcred);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setreuid_args {
|
|
uid_t ruid;
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setreuid(register struct thread *td, struct setreuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid, ruid;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
ruid = uap->ruid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
crcopy(newcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setregid_args {
|
|
gid_t rgid;
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setregid(register struct thread *td, struct setregid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid, rgid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
rgid = uap->rgid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setresuid(register struct thread *td, struct setresuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid, ruid, suid;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
ruid = uap->ruid;
|
|
suid = uap->suid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setresgid(register struct thread *td, struct setresgid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid, rgid, sgid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
rgid = uap->rgid;
|
|
sgid = uap->sgid;
|
|
mtx_lock(&Giant);
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
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_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, 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;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getresuid_args {
|
|
uid_t *ruid;
|
|
uid_t *euid;
|
|
uid_t *suid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getresuid(register struct thread *td, struct getresuid_args *uap)
|
|
{
|
|
struct ucred *cred;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
cred = td->td_ucred;
|
|
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
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getresgid(register struct thread *td, struct getresgid_args *uap)
|
|
{
|
|
struct ucred *cred;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
cred = td->td_ucred;
|
|
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
|
|
/*
|
|
* NOT MPSAFE?
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
issetugid(register struct thread *td, struct issetugid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
|
|
PROC_UNLOCK(p);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
__setugid(struct thread *td, struct __setugid_args *uap)
|
|
{
|
|
#ifdef REGRESSION
|
|
struct proc *p;
|
|
|
|
p = td->td_proc;
|
|
switch (uap->flag) {
|
|
case 0:
|
|
mtx_lock(&Giant);
|
|
PROC_LOCK(p);
|
|
p->p_flag &= ~P_SUGID;
|
|
PROC_UNLOCK(p);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
case 1:
|
|
mtx_lock(&Giant);
|
|
PROC_LOCK(p);
|
|
p->p_flag |= P_SUGID;
|
|
PROC_UNLOCK(p);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
default:
|
|
return (EINVAL);
|
|
}
|
|
#else /* !REGRESSION */
|
|
|
|
return (ENOSYS);
|
|
#endif /* REGRESSION */
|
|
}
|
|
|
|
/*
|
|
* Check if gid is a member of the group set.
|
|
*
|
|
* MPSAFE (cred must be held)
|
|
*/
|
|
int
|
|
groupmember(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);
|
|
}
|
|
|
|
/*
|
|
* `suser_enabled' (which can be set by the security.suser_enabled
|
|
* sysctl) determines whether the system 'super-user' policy is in effect.
|
|
* If it is nonzero, an effective uid of 0 connotes special privilege,
|
|
* overriding many mandatory and discretionary protections. If it is zero,
|
|
* uid 0 is offered no special privilege in the kernel security policy.
|
|
* Setting it to zero may seriously impact the functionality of many
|
|
* existing userland programs, and should not be done without careful
|
|
* consideration of the consequences.
|
|
*/
|
|
int suser_enabled = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, suser_enabled, CTLFLAG_RW,
|
|
&suser_enabled, 0, "processes with uid 0 have privilege");
|
|
TUNABLE_INT("security.bsd.suser_enabled", &suser_enabled);
|
|
|
|
/*
|
|
* Test whether the specified credentials imply "super-user" privilege.
|
|
* Return 0 or EPERM. The flag argument is currently used only to
|
|
* specify jail interaction.
|
|
*/
|
|
int
|
|
suser_cred(struct ucred *cred, int flag)
|
|
{
|
|
|
|
if (!suser_enabled)
|
|
return (EPERM);
|
|
if (cred->cr_uid != 0)
|
|
return (EPERM);
|
|
if (jailed(cred) && !(flag & PRISON_ROOT))
|
|
return (EPERM);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Shortcut to hide contents of struct td and struct proc from the
|
|
* caller, promoting binary compatibility.
|
|
*/
|
|
int
|
|
suser(struct thread *td)
|
|
{
|
|
|
|
return (suser_cred(td->td_ucred, 0));
|
|
}
|
|
|
|
/*
|
|
* Test the active securelevel against a given level. securelevel_gt()
|
|
* implements (securelevel > level). securelevel_ge() implements
|
|
* (securelevel >= level). Note that the logic is inverted -- these
|
|
* functions return EPERM on "success" and 0 on "failure".
|
|
*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
securelevel_gt(struct ucred *cr, int level)
|
|
{
|
|
int active_securelevel;
|
|
|
|
active_securelevel = securelevel;
|
|
KASSERT(cr != NULL, ("securelevel_gt: null cr"));
|
|
if (cr->cr_prison != NULL) {
|
|
mtx_lock(&cr->cr_prison->pr_mtx);
|
|
active_securelevel = imax(cr->cr_prison->pr_securelevel,
|
|
active_securelevel);
|
|
mtx_unlock(&cr->cr_prison->pr_mtx);
|
|
}
|
|
return (active_securelevel > level ? EPERM : 0);
|
|
}
|
|
|
|
int
|
|
securelevel_ge(struct ucred *cr, int level)
|
|
{
|
|
int active_securelevel;
|
|
|
|
active_securelevel = securelevel;
|
|
KASSERT(cr != NULL, ("securelevel_ge: null cr"));
|
|
if (cr->cr_prison != NULL) {
|
|
mtx_lock(&cr->cr_prison->pr_mtx);
|
|
active_securelevel = imax(cr->cr_prison->pr_securelevel,
|
|
active_securelevel);
|
|
mtx_unlock(&cr->cr_prison->pr_mtx);
|
|
}
|
|
return (active_securelevel >= level ? EPERM : 0);
|
|
}
|
|
|
|
/*
|
|
* 'see_other_uids' determines whether or not visibility of processes
|
|
* and sockets with credentials holding different real uids is possible
|
|
* using a variety of system MIBs.
|
|
* XXX: data declarations should be together near the beginning of the file.
|
|
*/
|
|
static int see_other_uids = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, see_other_uids, CTLFLAG_RW,
|
|
&see_other_uids, 0,
|
|
"Unprivileged processes may see subjects/objects with different real uid");
|
|
|
|
/*-
|
|
* Determine if u1 "can see" the subject specified by u2, according to the
|
|
* 'see_other_uids' policy.
|
|
* Returns: 0 for permitted, ESRCH otherwise
|
|
* Locks: none
|
|
* References: *u1 and *u2 must not change during the call
|
|
* u1 may equal u2, in which case only one reference is required
|
|
*/
|
|
static int
|
|
cr_seeotheruids(struct ucred *u1, struct ucred *u2)
|
|
{
|
|
|
|
if (!see_other_uids && u1->cr_ruid != u2->cr_ruid) {
|
|
if (suser_cred(u1, PRISON_ROOT) != 0)
|
|
return (ESRCH);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine if u1 "can see" the subject specified by u2.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: none
|
|
* References: *u1 and *u2 must not change during the call
|
|
* u1 may equal u2, in which case only one reference is required
|
|
*/
|
|
int
|
|
cr_cansee(struct ucred *u1, struct ucred *u2)
|
|
{
|
|
int error;
|
|
|
|
if ((error = prison_check(u1, u2)))
|
|
return (error);
|
|
if ((error = cr_seeotheruids(u1, u2)))
|
|
return (error);
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine if td "can see" the subject specified by p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect p->p_ucred must be held. td really
|
|
* should be curthread.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansee(struct thread *td, struct proc *p)
|
|
{
|
|
|
|
/* Wrap cr_cansee() for all functionality. */
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
return (cr_cansee(td->td_ucred, p->p_ucred));
|
|
}
|
|
|
|
/*-
|
|
* Determine whether cred may deliver the specified signal to proc.
|
|
* Returns: 0 for permitted, an errno value otherwise.
|
|
* Locks: A lock must be held for proc.
|
|
* References: cred and proc must be valid for the lifetime of the call.
|
|
*/
|
|
int
|
|
cr_cansignal(struct ucred *cred, struct proc *proc, int signum)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(proc, MA_OWNED);
|
|
/*
|
|
* Jail semantics limit the scope of signalling to proc in the
|
|
* same jail as cred, if cred is in jail.
|
|
*/
|
|
error = prison_check(cred, proc->p_ucred);
|
|
if (error)
|
|
return (error);
|
|
error = cr_seeotheruids(cred, proc->p_ucred);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* UNIX signal semantics depend on the status of the P_SUGID
|
|
* bit on the target process. If the bit is set, then additional
|
|
* restrictions are placed on the set of available signals.
|
|
*/
|
|
if (proc->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:
|
|
/*
|
|
* Generally, permit job and terminal control
|
|
* signals.
|
|
*/
|
|
break;
|
|
default:
|
|
/* Not permitted without privilege. */
|
|
error = suser_cred(cred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generally, the target credential's ruid or svuid must match the
|
|
* subject credential's ruid or euid.
|
|
*/
|
|
if (cred->cr_ruid != proc->p_ucred->cr_ruid &&
|
|
cred->cr_ruid != proc->p_ucred->cr_svuid &&
|
|
cred->cr_uid != proc->p_ucred->cr_ruid &&
|
|
cred->cr_uid != proc->p_ucred->cr_svuid) {
|
|
/* Not permitted without privilege. */
|
|
error = suser_cred(cred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
|
|
/*-
|
|
* Determine whether td may deliver the specified signal to p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must be
|
|
* held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansignal(struct thread *td, struct proc *p, int signum)
|
|
{
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
|
|
/*
|
|
* UNIX signalling semantics require that processes in the same
|
|
* session always be able to deliver SIGCONT to one another,
|
|
* overriding the remaining protections.
|
|
*/
|
|
/* XXX: This will require an additional lock of some sort. */
|
|
if (signum == SIGCONT && td->td_proc->p_session == p->p_session)
|
|
return (0);
|
|
|
|
return (cr_cansignal(td->td_ucred, p, signum));
|
|
}
|
|
|
|
/*-
|
|
* Determine whether td may reschedule p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must
|
|
* be held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansched(struct thread *td, struct proc *p)
|
|
{
|
|
int error;
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
if ((error = prison_check(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if (td->td_ucred->cr_ruid == p->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (td->td_ucred->cr_uid == p->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (suser_cred(td->td_ucred, PRISON_ROOT) == 0)
|
|
return (0);
|
|
|
|
#ifdef CAPABILITIES
|
|
if (!cap_check(NULL, td, CAP_SYS_NICE, PRISON_ROOT))
|
|
return (0);
|
|
#endif
|
|
|
|
return (EPERM);
|
|
}
|
|
|
|
/*
|
|
* The 'unprivileged_proc_debug' flag may be used to disable a variety of
|
|
* unprivileged inter-process debugging services, including some procfs
|
|
* functionality, ptrace(), and ktrace(). In the past, inter-process
|
|
* debugging has been involved in a variety of security problems, and sites
|
|
* not requiring the service might choose to disable it when hardening
|
|
* systems.
|
|
*
|
|
* XXX: Should modifying and reading this variable require locking?
|
|
* XXX: data declarations should be together near the beginning of the file.
|
|
*/
|
|
static int unprivileged_proc_debug = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_proc_debug, CTLFLAG_RW,
|
|
&unprivileged_proc_debug, 0,
|
|
"Unprivileged processes may use process debugging facilities");
|
|
|
|
/*-
|
|
* Determine whether td may debug p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must
|
|
* be held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_candebug(struct thread *td, struct proc *p)
|
|
{
|
|
int credentialchanged, error, grpsubset, i, uidsubset;
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (!unprivileged_proc_debug) {
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
if ((error = prison_check(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
|
|
/*
|
|
* Is p's group set a subset of td's effective group set? This
|
|
* includes p's egid, group access list, rgid, and svgid.
|
|
*/
|
|
grpsubset = 1;
|
|
for (i = 0; i < p->p_ucred->cr_ngroups; i++) {
|
|
if (!groupmember(p->p_ucred->cr_groups[i], td->td_ucred)) {
|
|
grpsubset = 0;
|
|
break;
|
|
}
|
|
}
|
|
grpsubset = grpsubset &&
|
|
groupmember(p->p_ucred->cr_rgid, td->td_ucred) &&
|
|
groupmember(p->p_ucred->cr_svgid, td->td_ucred);
|
|
|
|
/*
|
|
* Are the uids present in p's credential equal to td's
|
|
* effective uid? This includes p's euid, svuid, and ruid.
|
|
*/
|
|
uidsubset = (td->td_ucred->cr_uid == p->p_ucred->cr_uid &&
|
|
td->td_ucred->cr_uid == p->p_ucred->cr_svuid &&
|
|
td->td_ucred->cr_uid == p->p_ucred->cr_ruid);
|
|
|
|
/*
|
|
* Has the credential of the process changed since the last exec()?
|
|
*/
|
|
credentialchanged = (p->p_flag & P_SUGID);
|
|
|
|
/*
|
|
* If p's gids aren't a subset, or the uids aren't a subset,
|
|
* or the credential has changed, require appropriate privilege
|
|
* for td to debug p. For POSIX.1e capabilities, this will
|
|
* require CAP_SYS_PTRACE.
|
|
*/
|
|
if (!grpsubset || !uidsubset || credentialchanged) {
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/* Can't trace init when securelevel > 0. */
|
|
if (p == initproc) {
|
|
error = securelevel_gt(td->td_ucred, 0);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Can't trace a process that's currently exec'ing.
|
|
* XXX: Note, this is not a security policy decision, it's a
|
|
* basic correctness/functionality decision. Therefore, this check
|
|
* should be moved to the caller's of p_candebug().
|
|
*/
|
|
if ((p->p_flag & P_INEXEC) != 0)
|
|
return (EAGAIN);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine whether the subject represented by cred can "see" a socket.
|
|
* Returns: 0 for permitted, ENOENT otherwise.
|
|
*/
|
|
int
|
|
cr_canseesocket(struct ucred *cred, struct socket *so)
|
|
{
|
|
int error;
|
|
|
|
error = prison_check(cred, so->so_cred);
|
|
if (error)
|
|
return (ENOENT);
|
|
if (cr_seeotheruids(cred, so->so_cred))
|
|
return (ENOENT);
|
|
#ifdef MAC
|
|
/* XXX: error = mac_cred_check_seesocket() here. */
|
|
#endif
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Allocate a zeroed cred structure.
|
|
*/
|
|
struct ucred *
|
|
crget(void)
|
|
{
|
|
register struct ucred *cr;
|
|
|
|
MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
|
|
cr->cr_ref = 1;
|
|
cr->cr_mtxp = mtx_pool_find(cr);
|
|
return (cr);
|
|
}
|
|
|
|
/*
|
|
* Claim another reference to a ucred structure.
|
|
*/
|
|
struct ucred *
|
|
crhold(struct ucred *cr)
|
|
{
|
|
|
|
mtx_lock(cr->cr_mtxp);
|
|
cr->cr_ref++;
|
|
mtx_unlock(cr->cr_mtxp);
|
|
return (cr);
|
|
}
|
|
|
|
/*
|
|
* Free a cred structure.
|
|
* Throws away space when ref count gets to 0.
|
|
*/
|
|
void
|
|
crfree(struct ucred *cr)
|
|
{
|
|
struct mtx *mtxp = cr->cr_mtxp;
|
|
|
|
mtx_lock(mtxp);
|
|
KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
|
|
if (--cr->cr_ref == 0) {
|
|
/*
|
|
* Some callers of crget(), such as nfs_statfs(),
|
|
* allocate a temporary credential, but don't
|
|
* allocate a uidinfo structure.
|
|
*/
|
|
mtx_unlock(mtxp);
|
|
mtx_lock(&Giant);
|
|
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);
|
|
mtx_unlock(&Giant);
|
|
} else {
|
|
mtx_unlock(mtxp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check to see if this ucred is shared.
|
|
*/
|
|
int
|
|
crshared(struct ucred *cr)
|
|
{
|
|
int shared;
|
|
|
|
mtx_lock(cr->cr_mtxp);
|
|
shared = (cr->cr_ref > 1);
|
|
mtx_unlock(cr->cr_mtxp);
|
|
return (shared);
|
|
}
|
|
|
|
/*
|
|
* Copy a ucred's contents from a template. Does not block.
|
|
*/
|
|
void
|
|
crcopy(struct ucred *dest, struct ucred *src)
|
|
{
|
|
|
|
KASSERT(crshared(dest) == 0, ("crcopy of shared ucred"));
|
|
bcopy(&src->cr_startcopy, &dest->cr_startcopy,
|
|
(unsigned)((caddr_t)&src->cr_endcopy -
|
|
(caddr_t)&src->cr_startcopy));
|
|
uihold(dest->cr_uidinfo);
|
|
uihold(dest->cr_ruidinfo);
|
|
if (jailed(dest))
|
|
prison_hold(dest->cr_prison);
|
|
}
|
|
|
|
/*
|
|
* Dup cred struct to a new held one.
|
|
*/
|
|
struct ucred *
|
|
crdup(struct ucred *cr)
|
|
{
|
|
struct ucred *newcr;
|
|
|
|
newcr = crget();
|
|
crcopy(newcr, cr);
|
|
return (newcr);
|
|
}
|
|
|
|
#ifdef DIAGNOSTIC
|
|
void
|
|
cred_free_thread(struct thread *td)
|
|
{
|
|
struct ucred *cred;
|
|
|
|
cred = td->td_ucred;
|
|
td->td_ucred = NULL;
|
|
if (cred != NULL)
|
|
crfree(cred);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Fill in a struct xucred based on a struct ucred.
|
|
*/
|
|
void
|
|
cru2x(struct ucred *cr, struct xucred *xcr)
|
|
{
|
|
|
|
bzero(xcr, sizeof(*xcr));
|
|
xcr->cr_version = XUCRED_VERSION;
|
|
xcr->cr_uid = cr->cr_uid;
|
|
xcr->cr_ngroups = cr->cr_ngroups;
|
|
bcopy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups));
|
|
}
|
|
|
|
/*
|
|
* small routine to swap a thread's current ucred for the correct one
|
|
* taken from the process.
|
|
*/
|
|
void
|
|
cred_update_thread(struct thread *td)
|
|
{
|
|
struct proc *p;
|
|
struct ucred *cred;
|
|
|
|
p = td->td_proc;
|
|
cred = td->td_ucred;
|
|
mtx_lock(&Giant);
|
|
PROC_LOCK(p);
|
|
td->td_ucred = crhold(p->p_ucred);
|
|
PROC_UNLOCK(p);
|
|
if (cred != NULL)
|
|
crfree(cred);
|
|
mtx_unlock(&Giant);
|
|
}
|
|
|
|
/*
|
|
* Get login name, if available.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getlogin_args {
|
|
char *namebuf;
|
|
u_int namelen;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getlogin(struct thread *td, struct getlogin_args *uap)
|
|
{
|
|
int error;
|
|
char login[MAXLOGNAME];
|
|
struct proc *p = td->td_proc;
|
|
|
|
if (uap->namelen > MAXLOGNAME)
|
|
uap->namelen = MAXLOGNAME;
|
|
PROC_LOCK(p);
|
|
SESS_LOCK(p->p_session);
|
|
bcopy(p->p_session->s_login, login, uap->namelen);
|
|
SESS_UNLOCK(p->p_session);
|
|
PROC_UNLOCK(p);
|
|
error = copyout((caddr_t) login, (caddr_t) uap->namebuf, uap->namelen);
|
|
return(error);
|
|
}
|
|
|
|
/*
|
|
* Set login name.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setlogin_args {
|
|
char *namebuf;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setlogin(struct thread *td, struct setlogin_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int error;
|
|
char logintmp[MAXLOGNAME];
|
|
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp,
|
|
sizeof(logintmp), (size_t *)0);
|
|
if (error == ENAMETOOLONG)
|
|
error = EINVAL;
|
|
else if (!error) {
|
|
PROC_LOCK(p);
|
|
SESS_LOCK(p->p_session);
|
|
(void) memcpy(p->p_session->s_login, logintmp,
|
|
sizeof(logintmp));
|
|
SESS_UNLOCK(p->p_session);
|
|
PROC_UNLOCK(p);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
void
|
|
setsugid(struct proc *p)
|
|
{
|
|
p->p_flag |= P_SUGID;
|
|
if (!(p->p_pfsflags & PF_ISUGID))
|
|
p->p_stops = 0;
|
|
}
|
|
|
|
/*-
|
|
* 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(struct ucred *newcred, uid_t euid)
|
|
{
|
|
|
|
newcred->cr_uid = euid;
|
|
uifree(newcred->cr_uidinfo);
|
|
newcred->cr_uidinfo = uifind(euid);
|
|
}
|
|
|
|
/*-
|
|
* 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(struct ucred *newcred, gid_t egid)
|
|
{
|
|
|
|
newcred->cr_groups[0] = egid;
|
|
}
|
|
|
|
/*-
|
|
* 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(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 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(struct ucred *newcred, gid_t rgid)
|
|
{
|
|
|
|
newcred->cr_rgid = rgid;
|
|
}
|
|
|
|
/*-
|
|
* 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(struct ucred *newcred, uid_t svuid)
|
|
{
|
|
|
|
newcred->cr_svuid = svuid;
|
|
}
|
|
|
|
/*-
|
|
* 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(struct ucred *newcred, gid_t svgid)
|
|
{
|
|
|
|
newcred->cr_svgid = svgid;
|
|
}
|