/* $OpenBSD: kern_prot.c,v 1.26 2003/09/01 18:06:03 henning Exp $ */ /* $NetBSD: kern_prot.c,v 1.33 1996/02/09 18:59:42 christos 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 8.6 (Berkeley) 1/21/94 */ /* * 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> #include <sys/filedesc.h> #include <sys/pool.h> #include <sys/mount.h> #include <sys/syscallargs.h> /* ARGSUSED */ int sys_getpid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_pid; #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_IBCS2) || \ defined(COMPAT_FREEBSD) || defined(COMPAT_BSDOS) retval[1] = p->p_pptr->p_pid; #endif return (0); } /* ARGSUSED */ int sys_getppid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_pptr->p_pid; return (0); } /* Get process group ID; note that POSIX getpgrp takes no parameter */ int sys_getpgrp(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_pgrp->pg_id; return (0); } /* * SysVR.4 compatible getpgid() */ pid_t sys_getpgid(curp, v, retval) struct proc *curp; void *v; register_t *retval; { struct sys_getpgid_args /* { syscallarg(pid_t) pid; } */ *uap = v; struct proc *targp = curp; if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == curp->p_pid) goto found; if ((targp = pfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (targp->p_session != curp->p_session) return (EPERM); found: *retval = targp->p_pgid; return (0); } pid_t sys_getsid(curp, v, retval) struct proc *curp; void *v; register_t *retval; { struct sys_getsid_args /* { syscallarg(pid_t) pid; } */ *uap = v; struct proc *targp = curp; if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == curp->p_pid) goto found; if ((targp = pfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (targp->p_session != curp->p_session) return (EPERM); found: /* Skip exiting processes */ if (targp->p_pgrp->pg_session->s_leader == NULL) return (ESRCH); *retval = targp->p_pgrp->pg_session->s_leader->p_pid; return (0); } /* ARGSUSED */ int sys_getuid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_cred->p_ruid; #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_IBCS2) || \ defined(COMPAT_FREEBSD) || defined(COMPAT_BSDOS) retval[1] = p->p_ucred->cr_uid; #endif return (0); } /* ARGSUSED */ int sys_geteuid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_ucred->cr_uid; return (0); } /* ARGSUSED */ int sys_issetugid(p, v, retval) struct proc *p; void *v; register_t *retval; { if (p->p_flag & P_SUGIDEXEC) *retval = 1; else *retval = 0; return (0); } /* ARGSUSED */ int sys_getgid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_cred->p_rgid; #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_FREEBSD) || defined(COMPAT_BSDOS) retval[1] = p->p_ucred->cr_gid; #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 */ int sys_getegid(p, v, retval) struct proc *p; void *v; register_t *retval; { *retval = p->p_ucred->cr_gid; return (0); } int sys_getgroups(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_getgroups_args /* { syscallarg(int) gidsetsize; syscallarg(gid_t *) gidset; } */ *uap = v; struct pcred *pc = p->p_cred; u_int ngrp; int error; if ((ngrp = SCARG(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; error = copyout((caddr_t)pc->pc_ucred->cr_groups, (caddr_t)SCARG(uap, gidset), ngrp * sizeof(gid_t)); if (error) return (error); *retval = ngrp; return (0); } /* ARGSUSED */ int sys_setsid(p, v, retval) struct proc *p; void *v; register_t *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) */ /* ARGSUSED */ int sys_setpgid(curp, v, retval) struct proc *curp; void *v; register_t *retval; { struct sys_setpgid_args /* { syscallarg(pid_t) pid; syscallarg(int) pgid; } */ *uap = v; struct proc *targp; /* target process */ struct pgrp *pgrp; /* target pgrp */ pid_t pid; int pgid; pid = SCARG(uap, pid); pgid = SCARG(uap, pgid); if (pgid < 0) return (EINVAL); if (pid != 0 && pid != curp->p_pid) { if ((targp = pfind(pid)) == 0 || !inferior(targp)) return (ESRCH); if (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 (pgid == 0) pgid = targp->p_pid; else if (pgid != targp->p_pid) if ((pgrp = pgfind(pgid)) == 0 || pgrp->pg_session != curp->p_session) return (EPERM); return (enterpgrp(targp, pgid, 0)); } /* ARGSUSED */ int sys_getresuid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_getresuid_args /* { syscallarg(uid_t *) ruid; syscallarg(uid_t *) euid; syscallarg(uid_t *) suid; } */ *uap = v; struct pcred *pc = p->p_cred; uid_t *ruid, *euid, *suid; int error1 = 0, error2 = 0, error3 = 0; ruid = SCARG(uap, ruid); euid = SCARG(uap, euid); suid = SCARG(uap, suid); if (ruid != NULL) error1 = copyout(&pc->p_ruid, ruid, sizeof(*ruid)); if (euid != NULL) error2 = copyout(&pc->pc_ucred->cr_uid, euid, sizeof(*euid)); if (suid != NULL) error3 = copyout(&pc->p_svuid, suid, sizeof(*suid)); return (error1 ? error1 : error2 ? error2 : error3); } /* ARGSUSED */ int sys_setresuid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setresuid_args /* { syscallarg(uid_t) ruid; syscallarg(uid_t) euid; syscallarg(uid_t) suid; } */ *uap = v; struct pcred *pc = p->p_cred; uid_t ruid, euid, suid; int error; ruid = SCARG(uap, ruid); euid = SCARG(uap, euid); suid = SCARG(uap, suid); if ((ruid == -1 || ruid == pc->p_ruid) && (euid == -1 || euid == pc->pc_ucred->cr_uid) && (suid == -1 || suid == pc->p_svuid)) return (0); /* no change */ /* * Any of the real, effective, and saved uids may be changed * to the current value of one of the three (root is not limited). */ if (ruid != (uid_t)-1 && ruid != pc->p_ruid && ruid != pc->pc_ucred->cr_uid && ruid != pc->p_svuid && (error = suser(p, 0))) return (error); if (euid != (uid_t)-1 && euid != pc->p_ruid && euid != pc->pc_ucred->cr_uid && euid != pc->p_svuid && (error = suser(p, 0))) return (error); if (suid != (uid_t)-1 && suid != pc->p_ruid && suid != pc->pc_ucred->cr_uid && suid != pc->p_svuid && (error = suser(p, 0))) return (error); /* * Note that unlike the other set*uid() calls, each * uid type is set independently of the others. */ if (ruid != (uid_t)-1 && ruid != pc->p_ruid) { /* * Transfer proc count to new user. */ (void)chgproccnt(pc->p_ruid, -1); (void)chgproccnt(ruid, 1); pc->p_ruid = ruid; } if (euid != (uid_t)-1 && euid != pc->pc_ucred->cr_uid) { /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_uid = euid; } if (suid != (uid_t)-1 && suid != pc->p_svuid) pc->p_svuid = suid; p->p_flag |= P_SUGID; return (0); } /* ARGSUSED */ int sys_getresgid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_getresgid_args /* { syscallarg(gid_t *) rgid; syscallarg(gid_t *) egid; syscallarg(gid_t *) sgid; } */ *uap = v; struct pcred *pc = p->p_cred; gid_t *rgid, *egid, *sgid; int error1 = 0, error2 = 0, error3 = 0; rgid = SCARG(uap, rgid); egid = SCARG(uap, egid); sgid = SCARG(uap, sgid); if (rgid != NULL) error1 = copyout(&pc->p_rgid, rgid, sizeof(*rgid)); if (egid != NULL) error2 = copyout(&pc->pc_ucred->cr_gid, egid, sizeof(*egid)); if (sgid != NULL) error3 = copyout(&pc->p_svgid, sgid, sizeof(*sgid)); return (error1 ? error1 : error2 ? error2 : error3); } /* ARGSUSED */ int sys_setresgid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setresgid_args /* { syscallarg(gid_t) rgid; syscallarg(gid_t) egid; syscallarg(gid_t) sgid; } */ *uap = v; struct pcred *pc = p->p_cred; gid_t rgid, egid, sgid; int error; rgid = SCARG(uap, rgid); egid = SCARG(uap, egid); sgid = SCARG(uap, sgid); if ((rgid == -1 || rgid == pc->p_rgid) && (egid == -1 || egid == pc->pc_ucred->cr_gid) && (sgid == -1 || sgid == pc->p_svgid)) return (0); /* no change */ /* * Any of the real, effective, and saved gids may be changed * to the current value of one of the three (root is not limited). */ if (rgid != (gid_t)-1 && rgid != pc->p_rgid && rgid != pc->pc_ucred->cr_gid && rgid != pc->p_svgid && (error = suser(p, 0))) return (error); if (egid != (gid_t)-1 && egid != pc->p_rgid && egid != pc->pc_ucred->cr_gid && egid != pc->p_svgid && (error = suser(p, 0))) return (error); if (sgid != (gid_t)-1 && sgid != pc->p_rgid && sgid != pc->pc_ucred->cr_gid && sgid != pc->p_svgid && (error = suser(p, 0))) return (error); /* * Note that unlike the other set*gid() calls, each * gid type is set independently of the others. */ if (rgid != (gid_t)-1) pc->p_rgid = rgid; if (egid != (gid_t)-1) { /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_gid = egid; } if (sgid != (gid_t)-1) pc->p_svgid = sgid; p->p_flag |= P_SUGID; return (0); } /* ARGSUSED */ int sys_setregid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setregid_args /* { syscallarg(gid_t) rgid; syscallarg(gid_t) egid; } */ *uap = v; struct pcred *pc = p->p_cred; struct sys_setresgid_args sresgidargs; gid_t rgid, egid; rgid = SCARG(&sresgidargs, rgid) = SCARG(uap, rgid); egid = SCARG(&sresgidargs, egid) = SCARG(uap, egid); /* * The saved gid presents a bit of a dilemma, as it did not * exist when setregid(2) was conceived. We only set the saved * gid when the real gid is specified and either its value would * change, or where the saved and effective gids are different. */ if (rgid != (gid_t)-1 && (rgid != pc->p_rgid || pc->p_svgid != (egid != (gid_t)-1 ? egid : pc->pc_ucred->cr_gid))) SCARG(&sresgidargs, sgid) = rgid; else SCARG(&sresgidargs, sgid) = (gid_t)-1; return (sys_setresgid(p, &sresgidargs, retval)); } /* ARGSUSED */ int sys_setreuid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setreuid_args /* { syscallarg(uid_t) ruid; syscallarg(uid_t) euid; } */ *uap = v; struct pcred *pc = p->p_cred; struct sys_setresuid_args sresuidargs; uid_t ruid, euid; ruid = SCARG(&sresuidargs, ruid) = SCARG(uap, ruid); euid = SCARG(&sresuidargs, euid) = SCARG(uap, euid); /* * The saved uid presents a bit of a dilemma, as it did not * exist when setreuid(2) was conceived. We only set the saved * uid when the real uid is specified and either its value would * change, or where the saved and effective uids are different. */ if (ruid != (uid_t)-1 && (ruid != pc->p_ruid || pc->p_svuid != (euid != (uid_t)-1 ? euid : pc->pc_ucred->cr_uid))) SCARG(&sresuidargs, suid) = ruid; else SCARG(&sresuidargs, suid) = (uid_t)-1; return (sys_setresuid(p, &sresuidargs, retval)); } /* ARGSUSED */ int sys_setuid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setuid_args /* { syscallarg(uid_t) uid; } */ *uap = v; struct pcred *pc = p->p_cred; uid_t uid; int error; uid = SCARG(uap, uid); if (pc->pc_ucred->cr_uid == uid && pc->p_ruid == uid && pc->p_svuid == uid) return (0); if (uid != pc->p_ruid && uid != pc->p_svuid && uid != pc->pc_ucred->cr_uid && (error = suser(p, 0))) return (error); /* * Everything's okay, do it. */ if (uid == pc->pc_ucred->cr_uid || suser(p, 0) == 0) { /* * Transfer proc count to new user. */ if (uid != pc->p_ruid) { (void)chgproccnt(pc->p_ruid, -1); (void)chgproccnt(uid, 1); } pc->p_ruid = uid; pc->p_svuid = uid; } /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_uid = uid; p->p_flag |= P_SUGID; return (0); } /* ARGSUSED */ int sys_seteuid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_seteuid_args /* { syscallarg(uid_t) euid; } */ *uap = v; struct pcred *pc = p->p_cred; uid_t euid; int error; euid = SCARG(uap, euid); if (pc->pc_ucred->cr_uid == euid) return (0); if (euid != pc->p_ruid && euid != pc->p_svuid && (error = suser(p, 0))) return (error); /* * 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 |= P_SUGID; return (0); } /* ARGSUSED */ int sys_setgid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setgid_args /* { syscallarg(gid_t) gid; } */ *uap = v; struct pcred *pc = p->p_cred; gid_t gid; int error; gid = SCARG(uap, gid); if (pc->pc_ucred->cr_gid == gid && pc->p_rgid == gid && pc->p_svgid == gid) return (0); if (gid != pc->p_rgid && gid != pc->p_svgid && gid != pc->pc_ucred->cr_gid && (error = suser(p, 0))) return (error); if (gid == pc->pc_ucred->cr_gid || suser(p, 0) == 0) { pc->p_rgid = gid; pc->p_svgid = gid; } /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_gid = gid; p->p_flag |= P_SUGID; return (0); } /* ARGSUSED */ int sys_setegid(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setegid_args /* { syscallarg(gid_t) egid; } */ *uap = v; struct pcred *pc = p->p_cred; gid_t egid; int error; egid = SCARG(uap, egid); if (pc->pc_ucred->cr_gid == egid) return (0); if (egid != pc->p_rgid && egid != pc->p_svgid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. */ pc->pc_ucred = crcopy(pc->pc_ucred); pc->pc_ucred->cr_gid = egid; p->p_flag |= P_SUGID; return (0); } /* ARGSUSED */ int sys_setgroups(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setgroups_args /* { syscallarg(int) gidsetsize; syscallarg(const gid_t *) gidset; } */ *uap = v; struct pcred *pc = p->p_cred; u_int ngrp; int error; if ((error = suser(p, 0)) != 0) return (error); ngrp = SCARG(uap, gidsetsize); if (ngrp > NGROUPS) return (EINVAL); pc->pc_ucred = crcopy(pc->pc_ucred); error = copyin((caddr_t)SCARG(uap, gidset), (caddr_t)pc->pc_ucred->cr_groups, ngrp * sizeof(gid_t)); if (error) return (error); pc->pc_ucred->cr_ngroups = ngrp; p->p_flag |= P_SUGID; return (0); } /* * Check if gid is a member of the group set. */ int groupmember(gid, cred) gid_t gid; struct ucred *cred; { 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 this process has special user powers. * Returns 0 or error. */ int suser(struct proc *p, u_int flags) { struct ucred *cred = p->p_ucred; if (cred->cr_uid == 0) { if (!(flags & SUSER_NOACCT)) p->p_acflag |= ASU; return (0); } return (EPERM); } /* * replacement for old suser, for callers who don't have a process */ int suser_ucred(struct ucred *cred) { if (cred->cr_uid == 0) return (0); return (EPERM); } /* * Allocate a zeroed cred structure. */ struct ucred * crget() { struct ucred *cr; cr = pool_get(&ucred_pool, PR_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) pool_put(&ucred_pool, cr); } /* * 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 */ int sys_getlogin(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_getlogin_args /* { syscallarg(char *) namebuf; syscallarg(u_int) namelen; } */ *uap = v; 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(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_setlogin_args /* { syscallarg(const char *) namebuf; } */ *uap = v; int error; if ((error = suser(p, 0)) != 0) return (error); error = copyinstr((caddr_t) SCARG(uap, namebuf), (caddr_t) p->p_pgrp->pg_session->s_login, sizeof (p->p_pgrp->pg_session->s_login), (size_t *)0); if (error == ENAMETOOLONG) error = EINVAL; return (error); } /* * Check if a process is allowed to raise its privileges. */ int proc_cansugid(struct proc *p) { /* ptrace(2)d processes shouldn't. */ if ((p->p_flag & P_TRACED) != 0) return (0); /* proceses with shared filedescriptors shouldn't. */ if (p->p_fd->fd_refcnt > 1) return (0); /* Allow. */ return (1); }