NetBSD/sys/kern/kern_prot.c

714 lines
18 KiB
C

/* $NetBSD: kern_prot.c,v 1.96 2006/11/01 10:17:58 yamt Exp $ */
/*
* 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. 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 8.9 (Berkeley) 2/14/95
*/
/*
* System calls related to processes and protection
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_prot.c,v 1.96 2006/11/01 10:17:58 yamt Exp $");
#include "opt_compat_43.h"
#include <sys/param.h>
#include <sys/acct.h>
#include <sys/systm.h>
#include <sys/ucred.h>
#include <sys/proc.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/pool.h>
#include <sys/syslog.h>
#include <sys/resourcevar.h>
#include <sys/kauth.h>
#include <sys/mount.h>
#include <sys/sa.h>
#include <sys/syscallargs.h>
#include <sys/malloc.h>
int sys_getpid(struct lwp *, void *, register_t *);
int sys_getpid_with_ppid(struct lwp *, void *, register_t *);
int sys_getuid(struct lwp *, void *, register_t *);
int sys_getuid_with_euid(struct lwp *, void *, register_t *);
int sys_getgid(struct lwp *, void *, register_t *);
int sys_getgid_with_egid(struct lwp *, void *, register_t *);
static int grsortu(gid_t *, int);
/* ARGSUSED */
int
sys_getpid(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_proc;
*retval = p->p_pid;
return (0);
}
/* ARGSUSED */
int
sys_getpid_with_ppid(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_proc;
retval[0] = p->p_pid;
retval[1] = p->p_pptr->p_pid;
return (0);
}
/* ARGSUSED */
int
sys_getppid(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_proc;
*retval = p->p_pptr->p_pid;
return (0);
}
/* Get process group ID; note that POSIX getpgrp takes no parameter */
int
sys_getpgrp(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_proc;
*retval = p->p_pgrp->pg_id;
return (0);
}
/*
* Return the process group ID of the session leader (session ID)
* for the specified process.
*/
int
sys_getsid(struct lwp *l, void *v, register_t *retval)
{
struct sys_getsid_args /* {
syscalldarg(pid_t) pid;
} */ *uap = v;
struct proc *p = l->l_proc;
if (SCARG(uap, pid) == 0)
goto found;
if ((p = pfind(SCARG(uap, pid))) == 0)
return (ESRCH);
found:
*retval = p->p_session->s_sid;
return (0);
}
int
sys_getpgid(struct lwp *l, void *v, register_t *retval)
{
struct sys_getpgid_args /* {
syscallarg(pid_t) pid;
} */ *uap = v;
struct proc *p = l->l_proc;
if (SCARG(uap, pid) == 0)
goto found;
if ((p = pfind(SCARG(uap, pid))) == 0)
return (ESRCH);
found:
*retval = p->p_pgid;
return (0);
}
/* ARGSUSED */
int
sys_getuid(struct lwp *l, void *v, register_t *retval)
{
*retval = kauth_cred_getuid(l->l_cred);
return (0);
}
/* ARGSUSED */
int
sys_getuid_with_euid(struct lwp *l, void *v, register_t *retval)
{
retval[0] = kauth_cred_getuid(l->l_cred);
retval[1] = kauth_cred_geteuid(l->l_cred);
return (0);
}
/* ARGSUSED */
int
sys_geteuid(struct lwp *l, void *v, register_t *retval)
{
*retval = kauth_cred_geteuid(l->l_cred);
return (0);
}
/* ARGSUSED */
int
sys_getgid(struct lwp *l, void *v, register_t *retval)
{
*retval = kauth_cred_getgid(l->l_cred);
return (0);
}
/* ARGSUSED */
int
sys_getgid_with_egid(struct lwp *l, void *v, register_t *retval)
{
retval[0] = kauth_cred_getgid(l->l_cred);
retval[1] = kauth_cred_getegid(l->l_cred);
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.
*/
/* ARGSUSED */
int
sys_getegid(struct lwp *l, void *v, register_t *retval)
{
*retval = kauth_cred_getegid(l->l_cred);
return (0);
}
int
sys_getgroups(struct lwp *l, void *v, register_t *retval)
{
struct sys_getgroups_args /* {
syscallarg(int) gidsetsize;
syscallarg(gid_t *) gidset;
} */ *uap = v;
kauth_cred_t cred = l->l_cred;
u_int ngrp;
int error;
gid_t *grbuf;
if (SCARG(uap, gidsetsize) == 0) {
*retval = kauth_cred_ngroups(cred);
return (0);
} else if (SCARG(uap, gidsetsize) < 0)
return (EINVAL);
ngrp = SCARG(uap, gidsetsize);
if (ngrp < kauth_cred_ngroups(cred))
return (EINVAL);
ngrp = kauth_cred_ngroups(cred);
grbuf = malloc(ngrp * sizeof(*grbuf), M_TEMP, M_WAITOK);
kauth_cred_getgroups(cred, grbuf, ngrp);
error = copyout(grbuf, (caddr_t)SCARG(uap, gidset),
ngrp * sizeof(gid_t));
free(grbuf, M_TEMP);
if (error)
return (error);
*retval = ngrp;
return (0);
}
/* ARGSUSED */
int
sys_setsid(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_proc;
if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
return (EPERM);
} else {
(void)enterpgrp(p, p->p_pid, 1);
*retval = p->p_pid;
return (0);
}
}
/*
* set process group (setpgid/old setpgrp)
*
* caller does setpgid(targpid, targpgid)
*
* pgid must be in valid range (EINVAL)
* 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)
*
* Permission checks now in enterpgrp()
*/
/* ARGSUSED */
int
sys_setpgid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setpgid_args /* {
syscallarg(int) pid;
syscallarg(int) pgid;
} */ *uap = v;
struct proc *curp = l->l_proc;
struct proc *targp; /* target process */
if (SCARG(uap, pgid) < 0)
return EINVAL;
/* XXX MP - there is a horrid race here with targp exiting! */
if (SCARG(uap, pid) != 0 && SCARG(uap, pid) != curp->p_pid) {
targp = pfind(SCARG(uap, pid));
if (targp == NULL)
return ESRCH;
} else
targp = curp;
if (SCARG(uap, pgid) == 0)
SCARG(uap, pgid) = targp->p_pid;
return enterpgrp(targp, SCARG(uap, pgid), 0);
}
/*
* Set real, effective and saved uids to the requested values.
* non-root callers can only ever change uids to values that match
* one of the processes current uid values.
* This is further restricted by the flags argument.
*/
int
do_setresuid(struct lwp *l, uid_t r, uid_t e, uid_t sv, u_int flags)
{
struct proc *p = l->l_proc;
kauth_cred_t cred;
/* Get a write lock on the process credential. */
proc_crmod_enter(p);
cred = p->p_cred;
/*
* Check that the new value is one of the allowed existing values,
* or that we have root privilege.
*/
if ((r != -1
&& !((flags & ID_R_EQ_R) && r == kauth_cred_getuid(cred))
&& !((flags & ID_R_EQ_E) && r == kauth_cred_geteuid(cred))
&& !((flags & ID_R_EQ_S) && r == kauth_cred_getsvuid(cred))) ||
(e != -1
&& !((flags & ID_E_EQ_R) && e == kauth_cred_getuid(cred))
&& !((flags & ID_E_EQ_E) && e == kauth_cred_geteuid(cred))
&& !((flags & ID_E_EQ_S) && e == kauth_cred_getsvuid(cred))) ||
(sv != -1
&& !((flags & ID_S_EQ_R) && sv == kauth_cred_getuid(cred))
&& !((flags & ID_S_EQ_E) && sv == kauth_cred_geteuid(cred))
&& !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvuid(cred)))) {
int error;
error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
p, NULL, NULL, NULL);
if (error != 0) {
proc_crmod_leave(p, cred, NULL);
return error;
}
}
/* If nothing has changed, short circuit the request */
if ((r == -1 || r == kauth_cred_getuid(cred))
&& (e == -1 || e == kauth_cred_geteuid(cred))
&& (sv == -1 || sv == kauth_cred_getsvuid(cred))) {
proc_crmod_leave(p, cred, NULL);
return 0;
}
cred = kauth_cred_dup(cred);
if (r != -1 && r != kauth_cred_getuid(cred)) {
/* Update count of processes for this user */
(void)chgproccnt(kauth_cred_getuid(cred), -1);
(void)chgproccnt(r, 1);
kauth_cred_setuid(cred, r);
}
if (sv != -1)
kauth_cred_setsvuid(cred, sv);
if (e != -1)
kauth_cred_seteuid(cred, e);
/* Mark process as having changed credentials, stops tracing etc. */
p_sugid(p);
/* Broadcast our credentials to the process and other LWPs. */
proc_crmod_leave(p, cred, p->p_cred);
/* Update our copy of the credentials. */
lwp_update_creds(l);
return 0;
}
/*
* Set real, effective and saved gids to the requested values.
* non-root callers can only ever change gids to values that match
* one of the processes current gid values.
* This is further restricted by the flags argument.
*/
int
do_setresgid(struct lwp *l, gid_t r, gid_t e, gid_t sv, u_int flags)
{
struct proc *p = l->l_proc;
kauth_cred_t cred;
/* Get a write lock on the process credential. */
proc_crmod_enter(p);
cred = p->p_cred;
/*
* check new value is one of the allowed existing values.
* otherwise, check if we have root privilege.
*/
if ((r != -1
&& !((flags & ID_R_EQ_R) && r == kauth_cred_getgid(cred))
&& !((flags & ID_R_EQ_E) && r == kauth_cred_getegid(cred))
&& !((flags & ID_R_EQ_S) && r == kauth_cred_getsvgid(cred))) ||
(e != -1
&& !((flags & ID_E_EQ_R) && e == kauth_cred_getgid(cred))
&& !((flags & ID_E_EQ_E) && e == kauth_cred_getegid(cred))
&& !((flags & ID_E_EQ_S) && e == kauth_cred_getsvgid(cred))) ||
(sv != -1
&& !((flags & ID_S_EQ_R) && sv == kauth_cred_getgid(cred))
&& !((flags & ID_S_EQ_E) && sv == kauth_cred_getegid(cred))
&& !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvgid(cred)))) {
int error;
error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
p, NULL, NULL, NULL);
if (error != 0) {
proc_crmod_leave(p, cred, NULL);
return error;
}
}
/* If nothing has changed, short circuit the request */
if ((r == -1 || r == kauth_cred_getgid(cred))
&& (e == -1 || e == kauth_cred_getegid(cred))
&& (sv == -1 || sv == kauth_cred_getsvgid(cred))) {
proc_crmod_leave(p, cred, NULL);
return 0;
}
cred = kauth_cred_dup(cred);
if (r != -1)
kauth_cred_setgid(cred, r);
if (sv != -1)
kauth_cred_setsvgid(cred, sv);
if (e != -1)
kauth_cred_setegid(cred, e);
/* Mark process as having changed credentials, stops tracing etc. */
p_sugid(p);
/* Broadcast our credentials to the process and other LWPs. */
proc_crmod_leave(p, cred, p->p_cred);
/* Update our copy of the credentials. */
lwp_update_creds(l);
return 0;
}
/* ARGSUSED */
int
sys_setuid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setuid_args /* {
syscallarg(uid_t) uid;
} */ *uap = v;
uid_t uid = SCARG(uap, uid);
return do_setresuid(l, uid, uid, uid,
ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
}
/* ARGSUSED */
int
sys_seteuid(struct lwp *l, void *v, register_t *retval)
{
struct sys_seteuid_args /* {
syscallarg(uid_t) euid;
} */ *uap = v;
return do_setresuid(l, -1, SCARG(uap, euid), -1, ID_E_EQ_R | ID_E_EQ_S);
}
int
sys_setreuid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setreuid_args /* {
syscallarg(uid_t) ruid;
syscallarg(uid_t) euid;
} */ *uap = v;
kauth_cred_t cred = l->l_cred;
uid_t ruid, euid, svuid;
ruid = SCARG(uap, ruid);
euid = SCARG(uap, euid);
if (ruid == -1)
ruid = kauth_cred_getuid(cred);
if (euid == -1)
euid = kauth_cred_geteuid(cred);
/* Saved uid is set to the new euid if the ruid changed */
svuid = (ruid == kauth_cred_getuid(cred)) ? -1 : euid;
return do_setresuid(l, ruid, euid, svuid,
ID_R_EQ_R | ID_R_EQ_E |
ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
}
/* ARGSUSED */
int
sys_setgid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setgid_args /* {
syscallarg(gid_t) gid;
} */ *uap = v;
gid_t gid = SCARG(uap, gid);
return do_setresgid(l, gid, gid, gid,
ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
}
/* ARGSUSED */
int
sys_setegid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setegid_args /* {
syscallarg(gid_t) egid;
} */ *uap = v;
return do_setresgid(l, -1, SCARG(uap, egid), -1, ID_E_EQ_R | ID_E_EQ_S);
}
int
sys_setregid(struct lwp *l, void *v, register_t *retval)
{
struct sys_setregid_args /* {
syscallarg(gid_t) rgid;
syscallarg(gid_t) egid;
} */ *uap = v;
kauth_cred_t cred = l->l_cred;
gid_t rgid, egid, svgid;
rgid = SCARG(uap, rgid);
egid = SCARG(uap, egid);
if (rgid == -1)
rgid = kauth_cred_getgid(cred);
if (egid == -1)
egid = kauth_cred_getegid(cred);
/* Saved gid is set to the new egid if the rgid changed */
svgid = rgid == kauth_cred_getgid(cred) ? -1 : egid;
return do_setresgid(l, rgid, egid, svgid,
ID_R_EQ_R | ID_R_EQ_E |
ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
}
int
sys_issetugid(struct lwp *l, void *v, register_t *retval)
{
struct proc *p = l->l_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.
*/
*retval = (p->p_flag & P_SUGID) != 0;
return (0);
}
/*
* sort -u for groups.
*/
static int
grsortu(gid_t *grp, int ngrp)
{
const gid_t *src, *end;
gid_t *dst;
gid_t group;
int i, j;
/* bubble sort */
for (i = 0; i < ngrp; i++)
for (j = i + 1; j < ngrp; j++)
if (grp[i] > grp[j]) {
gid_t tmp = grp[i];
grp[i] = grp[j];
grp[j] = tmp;
}
/* uniq */
end = grp + ngrp;
src = grp;
dst = grp;
while (src < end) {
group = *src++;
while (src < end && *src == group)
src++;
*dst++ = group;
}
#ifdef DIAGNOSTIC
/* zero out the rest of the array */
(void)memset(dst, 0, sizeof(*grp) * (end - dst));
#endif
return dst - grp;
}
/* ARGSUSED */
int
sys_setgroups(struct lwp *l, void *v, register_t *retval)
{
struct sys_setgroups_args /* {
syscallarg(int) gidsetsize;
syscallarg(const gid_t *) gidset;
} */ *uap = v;
kauth_cred_t cred;
struct proc *p = l->l_proc;
int ngrp;
int error;
gid_t grp[NGROUPS];
size_t grsize;
proc_crmod_enter(p);
cred = p->p_cred;
if ((error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
p, NULL, NULL, NULL)) != 0)
goto bad;
ngrp = SCARG(uap, gidsetsize);
if ((u_int)ngrp > NGROUPS) {
error = EINVAL;
goto bad;
}
grsize = ngrp * sizeof(gid_t);
error = copyin(SCARG(uap, gidset), grp, grsize);
if (error)
goto bad;
ngrp = grsortu(grp, ngrp);
cred = kauth_cred_dup(cred);
kauth_cred_setgroups(cred, grp, ngrp, -1);
/* Mark process as having changed credentials, stops tracing etc. */
p_sugid(p);
/* Broadcast our credentials to the process and other LWPs. */
proc_crmod_leave(p, cred, p->p_cred);
/* Update our copy of the credentials. */
lwp_update_creds(l);
return (0);
bad:
proc_crmod_leave(p, cred, NULL);
return (error);
}
/*
* Get login name, if available.
*/
/* ARGSUSED */
int
sys___getlogin(struct lwp *l, void *v, register_t *retval)
{
struct sys___getlogin_args /* {
syscallarg(char *) namebuf;
syscallarg(size_t) namelen;
} */ *uap = v;
struct proc *p = l->l_proc;
if (SCARG(uap, namelen) > sizeof(p->p_pgrp->pg_session->s_login))
SCARG(uap, namelen) = sizeof(p->p_pgrp->pg_session->s_login);
return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
(caddr_t) SCARG(uap, namebuf), SCARG(uap, namelen)));
}
/*
* Set login name.
*/
/* ARGSUSED */
int
sys___setlogin(struct lwp *l, void *v, register_t *retval)
{
struct sys___setlogin_args /* {
syscallarg(const char *) namebuf;
} */ *uap = v;
struct proc *p = l->l_proc;
struct session *s = p->p_pgrp->pg_session;
char newname[sizeof s->s_login + 1];
int error;
if ((error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SETID,
p, NULL, NULL, NULL)) != 0)
return (error);
error = copyinstr(SCARG(uap, namebuf), &newname, sizeof newname, NULL);
if (error != 0)
return (error == ENAMETOOLONG ? EINVAL : error);
if (s->s_flags & S_LOGIN_SET && p->p_pid != s->s_sid &&
strncmp(newname, s->s_login, sizeof s->s_login) != 0)
log(LOG_WARNING, "%s (pid %d) changing logname from "
"%.*s to %s\n", p->p_comm, p->p_pid,
(int)sizeof s->s_login, s->s_login, newname);
s->s_flags |= S_LOGIN_SET;
strncpy(s->s_login, newname, sizeof s->s_login);
return (0);
}