BSD 4_4 release

[unix-history] / usr / src / sys / kern / kern_prot.c

/*
* Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
*      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 8.1 (Berkeley) 6/10/93
*/

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

#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/malloc.h>

struct args {
       int     dummy;
};

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

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

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

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

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

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

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

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

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

       *retval = p->p_cred->p_rgid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
       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;
       struct args *uap;
       int *retval;
{

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

struct getgroups_args {
       u_int   gidsetsize;
       gid_t   *gidset;
};
getgroups(p, uap, retval)
       struct proc *p;
       register struct getgroups_args *uap;
       int *retval;
{
       register struct pcred *pc = p->p_cred;
       register u_int ngrp;
       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;
       if (error = copyout((caddr_t)pc->pc_ucred->cr_groups,
           (caddr_t)uap->gidset, ngrp * sizeof(gid_t)))
               return (error);
       *retval = ngrp;
       return (0);
}

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

       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)
*
* 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)
*/
struct setpgid_args {
       int     pid;    /* target process id */
       int     pgid;   /* target pgrp id */
};
/* ARGSUSED */
setpgid(curp, uap, retval)
       struct proc *curp;
       register struct setpgid_args *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);
       return (enterpgrp(targp, uap->pgid, 0));
}

struct setuid_args {
       uid_t   uid;
};
/* ARGSUSED */
setuid(p, uap, retval)
       struct proc *p;
       struct setuid_args *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.
        * Transfer proc count to new user.
        * Copy credentials so other references do not see our changes.
        */
       (void)chgproccnt(pc->p_ruid, -1);
       (void)chgproccnt(uid, 1);
       pc->pc_ucred = crcopy(pc->pc_ucred);
       pc->pc_ucred->cr_uid = uid;
       pc->p_ruid = uid;
       pc->p_svuid = uid;
       p->p_flag |= SUGID;
       return (0);
}

struct seteuid_args {
       uid_t   euid;
};
/* ARGSUSED */
seteuid(p, uap, retval)
       struct proc *p;
       struct seteuid_args *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;
       p->p_flag |= SUGID;
       return (0);
}

struct setgid_args {
       gid_t   gid;
};
/* ARGSUSED */
setgid(p, uap, retval)
       struct proc *p;
       struct setgid_args *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;              /* ??? */
       p->p_flag |= SUGID;
       return (0);
}

struct setegid_args {
       gid_t   egid;
};
/* ARGSUSED */
setegid(p, uap, retval)
       struct proc *p;
       struct setegid_args *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;
       p->p_flag |= SUGID;
       return (0);
}

struct setgroups_args {
       u_int   gidsetsize;
       gid_t   *gidset;
};
/* ARGSUSED */
setgroups(p, uap, retval)
       struct proc *p;
       struct setgroups_args *uap;
       int *retval;
{
       register struct pcred *pc = p->p_cred;
       register u_int ngrp;
       int error;

       if (error = suser(pc->pc_ucred, &p->p_acflag))
               return (error);
       if ((ngrp = uap->gidsetsize) > NGROUPS)
               return (EINVAL);
       pc->pc_ucred = crcopy(pc->pc_ucred);
       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;
       p->p_flag |= SUGID;
       return (0);
}

#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
struct setreuid_args {
       int     ruid;
       int     euid;
};
/* ARGSUSED */
osetreuid(p, uap, retval)
       register struct proc *p;
       struct setreuid_args *uap;
       int *retval;
{
       register struct pcred *pc = p->p_cred;
       struct seteuid_args args;

       /*
        * we assume that the intent of setting ruid is to be able to get
        * back ruid priviledge. So we make sure that we will be able to
        * do so, but do not actually set the ruid.
        */
       if (uap->ruid != -1 && uap->ruid != pc->p_ruid &&
           uap->ruid != pc->p_svuid)
               return (EPERM);
       if (uap->euid == -1)
               return (0);
       args.euid = uap->euid;
       return (seteuid(p, &args, retval));
}

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

       /*
        * we assume that the intent of setting rgid is to be able to get
        * back rgid priviledge. So we make sure that we will be able to
        * do so, but do not actually set the rgid.
        */
       if (uap->rgid != -1 && uap->rgid != pc->p_rgid &&
           uap->rgid != pc->p_svgid)
               return (EPERM);
       if (uap->egid == -1)
               return (0);
       args.egid = uap->egid;
       return (setegid(p, &args, retval));
}
#endif /* defined(COMPAT_43) || defined(COMPAT_SUNOS) */

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