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3dc6d2b9ea
freebsd-skq/sys/kern/kern_prot.c
rwatson 3dc6d2b9ea o Centralize inter-process access control, introducing: 
int p_can(p1, p2, operation, privused)

  which allows specification of subject process, object process,
  inter-process operation, and an optional call-by-reference privused
  flag, allowing the caller to determine if privilege was required
  for the call to succeed.  This allows jail, kern.ps_showallprocs and
  regular credential-based interaction checks to occur in one block of
  code.  Possible operations are P_CAN_SEE, P_CAN_SCHED, P_CAN_KILL,
  and P_CAN_DEBUG.  p_can currently breaks out as a wrapper to a
  series of static function checks in kern_prot, which should not
  be invoked directly.

o Commented out capabilities entries are included for some checks.

o Update most inter-process authorization to make use of p_can() instead
  of manual checks, PRISON_CHECK(), P_TRESPASS(), and
  kern.ps_showallprocs.

o Modify suser{,_xxx} to use const arguments, as it no longer modifies
  process flags due to the disabling of ASU.

o Modify some checks/errors in procfs so that ENOENT is returned instead
  of ESRCH, further improving concealment of processes that should not
  be visible to other processes.  Also introduce new access checks to
  improve hiding of processes for procfs_lookup(), procfs_getattr(),
  procfs_readdir().  Correct a bug reported by bp concerning not
  handling the CREATE case in procfs_lookup().  Remove volatile flag in
  procfs that caused apparently spurious qualifier warnigns (approved by
  bde).

o Add comment noting that ktrace() has not been updated, as its access
  control checks are different from ptrace(), whereas they should
  probably be the same.  Further discussion should happen on this topic.

Reviewed by:	bde, green, phk, freebsd-security, others
Approved by:	bde
Obtained from:	TrustedBSD Project
2000-08-30 04:49:09 +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 <sys/param.h>
#include <sys/acct.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/pioctl.h>
#include <sys/sysctl.h>
static MALLOC_DEFINE(M_CRED, "cred", "credentials");
#ifndef _SYS_SYSPROTO_H_
struct getpid_args {
int dummy;
};
#endif
/*
* NOT MP SAFE due to p_pptr access
*/
/* 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)
p->p_retval[1] = p->p_pptr->p_pid;
#endif
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct getppid_args {
int dummy;
};
#endif
/* ARGSUSED */
int
getppid(p, uap)
struct proc *p;
struct getppid_args *uap;
{
p->p_retval[0] = p->p_pptr->p_pid;
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;
pt = p;
if (uap->pid == 0)
goto found;
if ((pt = pfind(uap->pid)) == 0)
return ESRCH;
found:
p->p_retval[0] = pt->p_pgrp->pg_id;
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;
pt = p;
if (uap->pid == 0)
goto found;
if ((pt == pfind(uap->pid)) == 0)
return ESRCH;
found:
p->p_retval[0] = pt->p_session->s_sid;
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_cred->p_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_cred->p_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;
{
register struct pcred *pc = p->p_cred;
register u_int ngrp;
int error;
if ((ngrp = uap->gidsetsize) == 0) {
p->p_retval[0] = pc->pc_ucred->cr_ngroups;
return (0);
}
if (ngrp < pc->pc_ucred->cr_ngroups)
return (EINVAL);
ngrp = pc->pc_ucred->cr_ngroups;
if ((error = copyout((caddr_t)pc->pc_ucred->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 */
if (uap->pgid < 0)
return (EINVAL);
if (uap->pid != 0 && uap->pid != curp->p_pid) {
if ((targp = pfind(uap->pid)) == 0 || !inferior(targp))
return (ESRCH);
if (targp->p_pgrp == NULL || targp->p_session != curp->p_session)
return (EPERM);
if (targp->p_flag & P_EXEC)
return (EACCES);
} else
targp = curp;
if (SESS_LEADER(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)
return (EPERM);
return (enterpgrp(targp, uap->pgid, 0));
}
/*
* Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
* compatable. 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;
{
register struct pcred *pc = p->p_cred;
register uid_t uid;
int error;
/*
* 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 compatable 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")
*/
uid = uap->uid;
if (uid != pc->p_ruid && /* allow setuid(getuid()) */
#ifdef _POSIX_SAVED_IDS
uid != pc->p_svuid && /* allow setuid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
uid != pc->pc_ucred->cr_uid && /* allow setuid(geteuid()) */
#endif
(error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
#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 == pc->pc_ucred->cr_uid ||
#endif
suser_xxx(0, p, PRISON_ROOT) == 0) /* we are using privs */
#endif
{
/*
* Transfer proc count to new user.
*/
if (uid != pc->p_ruid) {
(void)chgproccnt(pc->p_ruid, -1, 0);
(void)chgproccnt(uid, 1, 0);
}
/*
* Set real uid
*/
if (uid != pc->p_ruid) {
pc->p_ruid = 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 (pc->p_svuid != uid) {
pc->p_svuid = uid;
setsugid(p);
}
}
/*
* In all permitted cases, we are changing the euid.
* Copy credentials so other references do not see our changes.
*/
if (pc->pc_ucred->cr_uid != uid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_uid = uid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register uid_t euid;
int error;
euid = uap->euid;
if (euid != pc->p_ruid && /* allow seteuid(getuid()) */
euid != pc->p_svuid && /* allow seteuid(saved uid) */
(error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
/*
* Everything's okay, do it. Copy credentials so other references do
* not see our changes.
*/
if (pc->pc_ucred->cr_uid != euid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_uid = euid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register gid_t gid;
int error;
/*
* 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 compatable 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.
*/
gid = uap->gid;
if (gid != pc->p_rgid && /* allow setgid(getgid()) */
#ifdef _POSIX_SAVED_IDS
gid != pc->p_svgid && /* allow setgid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
gid != pc->pc_ucred->cr_groups[0] && /* allow setgid(getegid()) */
#endif
(error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
#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 == pc->pc_ucred->cr_groups[0] ||
#endif
suser_xxx(0, p, PRISON_ROOT) == 0) /* we are using privs */
#endif
{
/*
* Set real gid
*/
if (pc->p_rgid != gid) {
pc->p_rgid = 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 (pc->p_svgid != gid) {
pc->p_svgid = gid;
setsugid(p);
}
}
/*
* In all cases permitted cases, we are changing the egid.
* Copy credentials so other references do not see our changes.
*/
if (pc->pc_ucred->cr_groups[0] != gid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_groups[0] = gid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register gid_t egid;
int error;
egid = uap->egid;
if (egid != pc->p_rgid && /* allow setegid(getgid()) */
egid != pc->p_svgid && /* allow setegid(saved gid) */
(error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
if (pc->pc_ucred->cr_groups[0] != egid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_groups[0] = egid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register u_int ngrp;
int error;
if ((error = suser_xxx(0, p, PRISON_ROOT)))
return (error);
ngrp = uap->gidsetsize;
if (ngrp > NGROUPS)
return (EINVAL);
/*
* XXX A little bit lazy here. We could test if anything has
* changed before crcopy() and setting P_SUGID.
*/
pc->pc_ucred = crcopy(pc->pc_ucred);
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.
*/
pc->pc_ucred->cr_ngroups = 1;
} else {
if ((error = copyin((caddr_t)uap->gidset,
(caddr_t)pc->pc_ucred->cr_groups, ngrp * sizeof(gid_t))))
return (error);
pc->pc_ucred->cr_ngroups = ngrp;
}
setsugid(p);
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;
{
register struct pcred *pc = p->p_cred;
register uid_t ruid, euid;
int error;
ruid = uap->ruid;
euid = uap->euid;
if (((ruid != (uid_t)-1 && ruid != pc->p_ruid && ruid != pc->p_svuid) ||
(euid != (uid_t)-1 && euid != pc->pc_ucred->cr_uid &&
euid != pc->p_ruid && euid != pc->p_svuid)) &&
(error = suser_xxx(0, p, PRISON_ROOT)) != 0)
return (error);
if (euid != (uid_t)-1 && pc->pc_ucred->cr_uid != euid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_uid = euid;
setsugid(p);
}
if (ruid != (uid_t)-1 && pc->p_ruid != ruid) {
(void)chgproccnt(pc->p_ruid, -1, 0);
(void)chgproccnt(ruid, 1, 0);
pc->p_ruid = ruid;
setsugid(p);
}
if ((ruid != (uid_t)-1 || pc->pc_ucred->cr_uid != pc->p_ruid) &&
pc->p_svuid != pc->pc_ucred->cr_uid) {
pc->p_svuid = pc->pc_ucred->cr_uid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register gid_t rgid, egid;
int error;
rgid = uap->rgid;
egid = uap->egid;
if (((rgid != (gid_t)-1 && rgid != pc->p_rgid && rgid != pc->p_svgid) ||
(egid != (gid_t)-1 && egid != pc->pc_ucred->cr_groups[0] &&
egid != pc->p_rgid && egid != pc->p_svgid)) &&
(error = suser_xxx(0, p, PRISON_ROOT)) != 0)
return (error);
if (egid != (gid_t)-1 && pc->pc_ucred->cr_groups[0] != egid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_groups[0] = egid;
setsugid(p);
}
if (rgid != (gid_t)-1 && pc->p_rgid != rgid) {
pc->p_rgid = rgid;
setsugid(p);
}
if ((rgid != (gid_t)-1 || pc->pc_ucred->cr_groups[0] != pc->p_rgid) &&
pc->p_svgid != pc->pc_ucred->cr_groups[0]) {
pc->p_svgid = pc->pc_ucred->cr_groups[0];
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register uid_t ruid, euid, suid;
int error;
ruid = uap->ruid;
euid = uap->euid;
suid = uap->suid;
if (((ruid != (uid_t)-1 && ruid != pc->p_ruid && ruid != pc->p_svuid &&
ruid != pc->pc_ucred->cr_uid) ||
(euid != (uid_t)-1 && euid != pc->p_ruid && euid != pc->p_svuid &&
euid != pc->pc_ucred->cr_uid) ||
(suid != (uid_t)-1 && suid != pc->p_ruid && suid != pc->p_svuid &&
suid != pc->pc_ucred->cr_uid)) &&
(error = suser_xxx(0, p, PRISON_ROOT)) != 0)
return (error);
if (euid != (uid_t)-1 && pc->pc_ucred->cr_uid != euid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_uid = euid;
setsugid(p);
}
if (ruid != (uid_t)-1 && pc->p_ruid != ruid) {
(void)chgproccnt(pc->p_ruid, -1, 0);
(void)chgproccnt(ruid, 1, 0);
pc->p_ruid = ruid;
setsugid(p);
}
if (suid != (uid_t)-1 && pc->p_svuid != suid) {
pc->p_svuid = suid;
setsugid(p);
}
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;
{
register struct pcred *pc = p->p_cred;
register gid_t rgid, egid, sgid;
int error;
rgid = uap->rgid;
egid = uap->egid;
sgid = uap->sgid;
if (((rgid != (gid_t)-1 && rgid != pc->p_rgid && rgid != pc->p_svgid &&
rgid != pc->pc_ucred->cr_groups[0]) ||
(egid != (gid_t)-1 && egid != pc->p_rgid && egid != pc->p_svgid &&
egid != pc->pc_ucred->cr_groups[0]) ||
(sgid != (gid_t)-1 && sgid != pc->p_rgid && sgid != pc->p_svgid &&
sgid != pc->pc_ucred->cr_groups[0])) &&
(error = suser_xxx(0, p, PRISON_ROOT)) != 0)
return (error);
if (egid != (gid_t)-1 && pc->pc_ucred->cr_groups[0] != egid) {
pc->pc_ucred = crcopy(pc->pc_ucred);
pc->pc_ucred->cr_groups[0] = egid;
setsugid(p);
}
if (rgid != (gid_t)-1 && pc->p_rgid != rgid) {
pc->p_rgid = rgid;
setsugid(p);
}
if (sgid != (gid_t)-1 && pc->p_svgid != sgid) {
pc->p_svgid = sgid;
setsugid(p);
}
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 pcred *pc = p->p_cred;
int error1 = 0, error2 = 0, error3 = 0;
if (uap->ruid)
error1 = copyout((caddr_t)&pc->p_ruid,
(caddr_t)uap->ruid, sizeof(pc->p_ruid));
if (uap->euid)
error2 = copyout((caddr_t)&pc->pc_ucred->cr_uid,
(caddr_t)uap->euid, sizeof(pc->pc_ucred->cr_uid));
if (uap->suid)
error3 = copyout((caddr_t)&pc->p_svuid,
(caddr_t)uap->suid, sizeof(pc->p_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 pcred *pc = p->p_cred;
int error1 = 0, error2 = 0, error3 = 0;
if (uap->rgid)
error1 = copyout((caddr_t)&pc->p_rgid,
(caddr_t)uap->rgid, sizeof(pc->p_rgid));
if (uap->egid)
error2 = copyout((caddr_t)&pc->pc_ucred->cr_groups[0],
(caddr_t)uap->egid, sizeof(pc->pc_ucred->cr_groups[0]));
if (uap->sgid)
error3 = copyout((caddr_t)&pc->p_svgid,
(caddr_t)uap->sgid, sizeof(pc->p_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);
}
/*
* Check if gid is a member of the group set.
*/
int
groupmember(gid, cred)
gid_t gid;
register 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, 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)
const struct proc *p;
{
return suser_xxx(0, p, 0);
}
int
suser_xxx(cred, proc, flag)
const struct ucred *cred;
const 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 (proc && proc->p_prison && !(flag & PRISON_ROOT))
return (EPERM);
return (0);
}
static int
p_cansee(const struct proc *p1, const struct proc *p2, int *privused)
{
if (privused != NULL)
*privused = 0;
if (!PRISON_CHECK(p1, p2))
return (ESRCH);
if (!ps_showallprocs && (p1->p_ucred->cr_uid != p2->p_ucred->cr_uid) &&
suser_xxx(NULL, p1, PRISON_ROOT))
return (ESRCH);
return (0);
}
static int
p_cankill(const struct proc *p1, const struct proc *p2, int *privused)
{
if (privused != NULL)
*privused = 0;
if (p1 == p2)
return (0);
if (!PRISON_CHECK(p1, p2))
return (ESRCH);
if (p1->p_cred->p_ruid == p2->p_cred->p_ruid)
return (0);
if (p1->p_ucred->cr_uid == p2->p_cred->p_ruid)
return (0);
/*
* XXX should a process be able to affect another process
* acting as the same uid (i.e., a userland nfsd or the like?)
*/
if (p1->p_cred->p_ruid == p2->p_ucred->cr_uid)
return (0);
if (p1->p_ucred->cr_uid == p2->p_ucred->cr_uid)
return (0);
if (!suser_xxx(0, p1, PRISON_ROOT)) {
if (privused != NULL)
*privused = 1;
return (0);
}
#ifdef CAPABILITIES
if (!cap_check_xxx(0, p1, CAP_KILL, PRISON_ROOT)) {
if (privused != NULL)
*privused = 1;
return (0);
}
#endif
return (EPERM);
}
static int
p_cansched(const struct proc *p1, const struct proc *p2, int *privused)
{
if (privused != NULL)
*privused = 0;
if (p1 == p2)
return (0);
if (!PRISON_CHECK(p1, p2))
return (ESRCH);
if (p1->p_cred->p_ruid == p2->p_cred->p_ruid)
return (0);
if (p1->p_ucred->cr_uid == p2->p_cred->p_ruid)
return (0);
/*
* XXX should a process be able to affect another process
* acting as the same uid (i.e., a userland nfsd or the like?)
*/
if (p1->p_cred->p_ruid == p2->p_ucred->cr_uid)
return (0);
if (p1->p_ucred->cr_uid == p2->p_ucred->cr_uid)
return (0);
if (!suser_xxx(0, p1, PRISON_ROOT)) {
if (privused != NULL)
*privused = 1;
return (0);
}
#ifdef CAPABILITIES
if (!cap_check_xxx(0, p1, CAP_SYS_NICE, PRISON_ROOT)) {
if (privused != NULL)
*privused = 1;
return (0);
}
#endif
return (EPERM);
}
static int
p_candebug(const struct proc *p1, const struct proc *p2, int *privused)
{
int error;
if (privused != NULL)
*privused = 0;
/* XXX it is authorized, but semantics don't permit it */
if (p1 == p2)
return (0);
if (!PRISON_CHECK(p1, p2))
return (ESRCH);
/* not owned by you, has done setuid (unless you're root) */
/* add a CAP_SYS_PTRACE here? */
if ((p1->p_cred->p_ruid != p2->p_cred->p_ruid) ||
(p2->p_flag & P_SUGID)) {
if ((error = suser_xxx(0, p1, PRISON_ROOT)))
return (error);
if (privused != NULL)
*privused = 1;
}
/* can't trace init when securelevel > 0 */
if (securelevel > 0 && p2->p_pid == 1)
return (EPERM);
return (0);
}
int
p_can(const struct proc *p1, const struct proc *p2, int operation,
int *privused)
{
switch(operation) {
case P_CAN_SEE:
return (p_cansee(p1, p2, privused));
case P_CAN_KILL:
return (p_cankill(p1, p2, privused));
case P_CAN_SCHED:
return (p_cansched(p1, p2, privused));
case P_CAN_DEBUG:
return (p_candebug(p1, p2, privused));
default:
panic("p_can: invalid operation");
}
}
/*
* Allocate a zeroed cred structure.
*/
struct ucred *
crget()
{
register struct ucred *cr;
MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK);
bzero((caddr_t)cr, sizeof(*cr));
cr->cr_ref = 1;
return (cr);
}
/*
* Free a cred structure.
* Throws away space when ref count gets to 0.
*/
void
crfree(cr)
struct ucred *cr;
{
if (--cr->cr_ref == 0)
FREE((caddr_t)cr, M_CRED);
}
/*
* Copy cred structure to a new one and free the old one.
*/
struct ucred *
crcopy(cr)
struct ucred *cr;
{
struct ucred *newcr;
if (cr->cr_ref == 1)
return (cr);
newcr = crget();
*newcr = *cr;
crfree(cr);
newcr->cr_ref = 1;
return (newcr);
}
/*
* Dup cred struct to a new held one.
*/
struct ucred *
crdup(cr)
struct ucred *cr;
{
struct ucred *newcr;
newcr = crget();
*newcr = *cr;
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;
}
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