usr/src/sys.386bsd/kern/kern_prot.c

/*
 * Copyright (c) 1982, 1986, 1989, 1990, 1991 Regents of the University
 * of California.  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 7.21 (Berkeley) 5/3/91
 */

/*
 * System calls related to processes and protection
 */

#include "param.h"
#include "acct.h"
#include "systm.h"
#include "ucred.h"
#include "proc.h"
#include "timeb.h"
#include "times.h"
#include "malloc.h"

/* ARGSUSED */
getpid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_pid;
#ifdef COMPAT_43
        retval[1] = p->p_pptr->p_pid;
#endif
        return (0);
}

/* ARGSUSED */
getppid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_pptr->p_pid;
        return (0);
}

/* Get process group ID; note that POSIX getpgrp takes no parameter */
getpgrp(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_pgrp->pg_id;
        return (0);
}

/* ARGSUSED */
getuid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_cred->p_ruid;
#ifdef COMPAT_43
        retval[1] = p->p_ucred->cr_uid;
#endif
        return (0);
}

/* ARGSUSED */
geteuid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_ucred->cr_uid;
        return (0);
}

/* ARGSUSED */
getgid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_cred->p_rgid;
#ifdef COMPAT_43
        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.
 */
/* ARGSUSED */
getegid(p, uap, retval)
        struct proc *p;
        void *uap;
        int *retval;
{

        *retval = p->p_ucred->cr_groups[0];
        return (0);
}

getgroups(p, uap, retval)
        struct proc *p;
        register struct arg {
                u_int   gidsetsize;
                int     *gidset;                /* XXX not yet POSIX */
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register gid_t *gp;
        register int *lp;
        register u_int ngrp;
        int groups[NGROUPS];
        int error;

        if ((ngrp = uap->gidsetsize) == 0) {
                *retval = pc->pc_ucred->cr_ngroups;
                return (0);
        }
        if (ngrp < pc->pc_ucred->cr_ngroups)
                return (EINVAL);
        ngrp = pc->pc_ucred->cr_ngroups;
        for (gp = pc->pc_ucred->cr_groups, lp = groups; lp < &groups[ngrp]; )
                *lp++ = *gp++;
        if (error = copyout((caddr_t)groups, (caddr_t)uap->gidset,
            ngrp * sizeof (groups[0])))
                return (error);
        *retval = ngrp;
        return (0);
}

/* ARGSUSED */
setsid(p, uap, retval)
        register struct proc *p;
        void *uap;
        int *retval;
{

        if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
                return (EPERM);
        } else {
                enterpgrp(p, p->p_pid, 1);
                *retval = 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)
 */
/* ARGSUSED */
setpgid(curp, uap, retval)
        struct proc *curp;
        register struct args {
                int     pid;    /* target process id */
                int     pgid;   /* target pgrp id */
        } *uap;
        int *retval;
{
        register struct proc *targp;            /* target process */
        register struct pgrp *pgrp;             /* target pgrp */

        if (uap->pid != 0 && uap->pid != curp->p_pid) {
                if ((targp = pfind(uap->pid)) == 0 || !inferior(targp))
                        return (ESRCH);
                if (targp->p_session != curp->p_session)
                        return (EPERM);
                if (targp->p_flag&SEXEC)
                        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);
        enterpgrp(targp, uap->pgid, 0);
        return (0);
}

/* ARGSUSED */
setuid(p, uap, retval)
        struct proc *p;
        struct args {
                int     uid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register uid_t uid;
        int error;

        uid = uap->uid;
        if (uid != pc->p_ruid &&
            (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        /*
         * Everything's okay, do it.  Copy credentials so other references do
         * not see our changes.
         */
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_uid = uid;
        pc->p_ruid = uid;
        pc->p_svuid = uid;
        return (0);
}

/* ARGSUSED */
seteuid(p, uap, retval)
        struct proc *p;
        struct args {
                int     euid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register uid_t euid;
        int error;

        euid = uap->euid;
        if (euid != pc->p_ruid && euid != pc->p_svuid &&
            (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        /*
         * Everything's okay, do it.  Copy credentials so other references do
         * not see our changes.
         */
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_uid = euid;
        return (0);
}

/* ARGSUSED */
setgid(p, uap, retval)
        struct proc *p;
        struct args {
                int     gid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register gid_t gid;
        int error;

        gid = uap->gid;
        if (gid != pc->p_rgid && (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_groups[0] = gid;
        pc->p_rgid = gid;
        pc->p_svgid = gid;              /* ??? */
        return (0);
}

/* ARGSUSED */
setegid(p, uap, retval)
        struct proc *p;
        struct args {
                int     egid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register gid_t egid;
        int error;

        egid = uap->egid;
        if (egid != pc->p_rgid && egid != pc->p_svgid &&
            (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_groups[0] = egid;
        return (0);
}

#ifdef COMPAT_43
/* ARGSUSED */
osetreuid(p, uap, retval)
        register struct proc *p;
        struct args {
                int     ruid;
                int     euid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register uid_t ruid, euid;
        int error;

        if (uap->ruid == -1)
                ruid = pc->p_ruid;
        else
                ruid = uap->ruid;
        /*
         * Allow setting real uid to previous effective, for swapping real and
         * effective.  This should be:
         *
         * if (ruid != pc->p_ruid &&
         *     (error = suser(pc->pc_ucred, &p->p_acflag)))
         */
        if (ruid != pc->p_ruid && ruid != pc->pc_ucred->cr_uid /* XXX */ &&
            (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        if (uap->euid == -1)
                euid = pc->pc_ucred->cr_uid;
        else
                euid = uap->euid;
        if (euid != pc->pc_ucred->cr_uid && euid != pc->p_ruid &&
            euid != pc->p_svuid && (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        /*
         * Everything's okay, do it.  Copy credentials so other references do
         * not see our changes.
         */
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_uid = euid;
        pc->p_ruid = ruid;
        return (0);
}

/* ARGSUSED */
osetregid(p, uap, retval)
        register struct proc *p;
        struct args {
                int     rgid;
                int     egid;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register gid_t rgid, egid;
        int error;

        if (uap->rgid == -1)
                rgid = pc->p_rgid;
        else
                rgid = uap->rgid;
        /*
         * Allow setting real gid to previous effective, for swapping real and
         * effective.  This didn't really work correctly in 4.[23], but is
         * preserved so old stuff doesn't fail.  This should be:
         *
         * if (rgid != pc->p_rgid &&
         *     (error = suser(pc->pc_ucred, &p->p_acflag)))
         */
        if (rgid != pc->p_rgid && rgid != pc->pc_ucred->cr_groups[0] /* XXX */ &&
            (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        if (uap->egid == -1)
                egid = pc->pc_ucred->cr_groups[0];
        else
                egid = uap->egid;
        if (egid != pc->pc_ucred->cr_groups[0] && egid != pc->p_rgid &&
            egid != pc->p_svgid && (error = suser(pc->pc_ucred, &p->p_acflag)))
                return (error);
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_groups[0] = egid;
        pc->p_rgid = rgid;
        return (0);
}
#endif

/* ARGSUSED */
setgroups(p, uap, retval)
        struct proc *p;
        struct args {
                u_int   gidsetsize;
                int     *gidset;
        } *uap;
        int *retval;
{
        register struct pcred *pc = p->p_cred;
        register gid_t *gp;
        register u_int ngrp;
        register int *lp;
        int error, groups[NGROUPS];

        if (error = suser(pc->pc_ucred, &p->p_acflag))
                return (error);
        if ((ngrp = uap->gidsetsize) > NGROUPS)
                return (EINVAL);
        if (error = copyin((caddr_t)uap->gidset, (caddr_t)groups,
            ngrp * sizeof (groups[0])))
                return (error);
        pc->pc_ucred = crcopy(pc->pc_ucred);
        pc->pc_ucred->cr_ngroups = ngrp;
        /* convert from int's to gid_t's */
        for (gp = pc->pc_ucred->cr_groups, lp = groups; ngrp--; )
                *gp++ = *lp++;
        return (0);
}

/*
 * Check if gid is a member of the group set.
 */
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);
}

/*
 * 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.
 */
suser(cred, acflag)
        struct ucred *cred;
        short *acflag;
{
        if (cred->cr_uid == 0) {
                if (acflag)
                        *acflag |= ASU;
                return (0);
        }
        return (EPERM);
}

/*
 * 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.
 */
crfree(cr)
        struct ucred *cr;
{
        int s = splimp();                       /* ??? */

        if (--cr->cr_ref != 0) {
                (void) splx(s);
                return;
        }
        FREE((caddr_t)cr, M_CRED);
        (void) splx(s);
}

/*
 * 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.
 */
/* ARGSUSED */
getlogin(p, uap, retval)
        struct proc *p;
        struct args {
                char    *namebuf;
                u_int   namelen;
        } *uap;
        int *retval;
{

        if (uap->namelen > sizeof (p->p_pgrp->pg_session->s_login))
                uap->namelen = sizeof (p->p_pgrp->pg_session->s_login);
        return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
            (caddr_t) uap->namebuf, uap->namelen));
}

/*
 * Set login name.
 */
/* ARGSUSED */
setlogin(p, uap, retval)
        struct proc *p;
        struct args {
                char    *namebuf;
        } *uap;
        int *retval;
{
        int error;

        if (error = suser(p->p_ucred, &p->p_acflag))
                return (error);
        error = copyinstr((caddr_t) uap->namebuf,
            (caddr_t) p->p_pgrp->pg_session->s_login,
            sizeof (p->p_pgrp->pg_session->s_login) - 1, (u_int *)0);
        if (error == ENAMETOOLONG)
                error = EINVAL;
        return (error);
}