/* $OpenBSD: kern_prot.c,v 1.60 2014/04/18 11:51:17 guenther 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 #include #include #include #include #include #include #include #include #ifdef __HAVE_MD_TCB # include #endif inline void crset(struct ucred *newcr, const struct ucred *cr) { KASSERT(cr->cr_ref > 0); memcpy( (char *)newcr + offsetof(struct ucred, cr_startcopy), (const char *)cr + offsetof(struct ucred, cr_startcopy), sizeof(*cr) - offsetof(struct ucred, cr_startcopy)); } int sys_getpid(struct proc *p, void *v, register_t *retval) { *retval = p->p_p->ps_pid; return (0); } int sys_getthrid(struct proc *p, void *v, register_t *retval) { *retval = p->p_pid + THREAD_PID_OFFSET; return (0); } int sys_getppid(struct proc *p, void *v, register_t *retval) { *retval = p->p_p->ps_pptr->ps_pid; return (0); } /* Get process group ID; note that POSIX getpgrp takes no parameter */ int sys_getpgrp(struct proc *p, void *v, register_t *retval) { *retval = p->p_p->ps_pgrp->pg_id; return (0); } /* * SysVR.4 compatible getpgid() */ int sys_getpgid(struct proc *curp, void *v, register_t *retval) { struct sys_getpgid_args /* { syscallarg(pid_t) pid; } */ *uap = v; struct process *targpr = curp->p_p; if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid) goto found; if ((targpr = prfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (targpr->ps_session != curp->p_p->ps_session) return (EPERM); found: *retval = targpr->ps_pgid; return (0); } int sys_getsid(struct proc *curp, void *v, register_t *retval) { struct sys_getsid_args /* { syscallarg(pid_t) pid; } */ *uap = v; struct process *targpr = curp->p_p; if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid) goto found; if ((targpr = prfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (targpr->ps_session != curp->p_p->ps_session) return (EPERM); found: /* Skip exiting processes */ if (targpr->ps_pgrp->pg_session->s_leader == NULL) return (ESRCH); *retval = targpr->ps_pgrp->pg_session->s_leader->ps_pid; return (0); } int sys_getuid(struct proc *p, void *v, register_t *retval) { *retval = p->p_ucred->cr_ruid; return (0); } int sys_geteuid(struct proc *p, void *v, register_t *retval) { *retval = p->p_ucred->cr_uid; return (0); } int sys_issetugid(struct proc *p, void *v, register_t *retval) { if (p->p_p->ps_flags & PS_SUGIDEXEC) *retval = 1; else *retval = 0; return (0); } int sys_getgid(struct proc *p, void *v, register_t *retval) { *retval = p->p_ucred->cr_rgid; 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. */ int sys_getegid(struct proc *p, void *v, register_t *retval) { *retval = p->p_ucred->cr_gid; return (0); } int sys_getgroups(struct proc *p, void *v, register_t *retval) { struct sys_getgroups_args /* { syscallarg(int) gidsetsize; syscallarg(gid_t *) gidset; } */ *uap = v; struct ucred *uc = p->p_ucred; u_int ngrp; int error; if ((ngrp = SCARG(uap, gidsetsize)) == 0) { *retval = uc->cr_ngroups; return (0); } if (ngrp < uc->cr_ngroups) return (EINVAL); ngrp = uc->cr_ngroups; error = copyout(uc->cr_groups, SCARG(uap, gidset), ngrp * sizeof(gid_t)); if (error) return (error); *retval = ngrp; return (0); } int sys_setsid(struct proc *p, void *v, register_t *retval) { struct session *newsess; struct pgrp *newpgrp; struct process *pr = p->p_p; pid_t pid = pr->ps_pid; newsess = pool_get(&session_pool, PR_WAITOK); newpgrp = pool_get(&pgrp_pool, PR_WAITOK); if (pr->ps_pgid == pid || pgfind(pid)) { pool_put(&pgrp_pool, newpgrp); pool_put(&session_pool, newsess); return (EPERM); } else { (void) enterpgrp(pr, pid, newpgrp, newsess); *retval = 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) */ int sys_setpgid(struct proc *curp, void *v, register_t *retval) { struct sys_setpgid_args /* { syscallarg(pid_t) pid; syscallarg(int) pgid; } */ *uap = v; struct process *curpr = curp->p_p; struct process *targpr; /* target process */ struct pgrp *pgrp, *newpgrp; /* target pgrp */ pid_t pid; int pgid, error; pid = SCARG(uap, pid); pgid = SCARG(uap, pgid); if (pgid < 0) return (EINVAL); newpgrp = pool_get(&pgrp_pool, PR_WAITOK); if (pid != 0 && pid != curpr->ps_pid) { if ((targpr = prfind(pid)) == 0 || !inferior(targpr, curpr)) { error = ESRCH; goto out; } if (targpr->ps_session != curpr->ps_session) { error = EPERM; goto out; } if (targpr->ps_flags & PS_EXEC) { error = EACCES; goto out; } } else targpr = curpr; if (SESS_LEADER(targpr)) { error = EPERM; goto out; } if (pgid == 0) pgid = targpr->ps_pid; else if (pgid != targpr->ps_pid) if ((pgrp = pgfind(pgid)) == 0 || pgrp->pg_session != curpr->ps_session) { error = EPERM; goto out; } return (enterpgrp(targpr, pgid, newpgrp, NULL)); out: pool_put(&pgrp_pool, newpgrp); return (error); } int sys_getresuid(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 ucred *uc = p->p_ucred; 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(&uc->cr_ruid, ruid, sizeof(*ruid)); if (euid != NULL) error2 = copyout(&uc->cr_uid, euid, sizeof(*euid)); if (suid != NULL) error3 = copyout(&uc->cr_svuid, suid, sizeof(*suid)); return (error1 ? error1 : error2 ? error2 : error3); } int sys_setresuid(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 process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; uid_t ruid, euid, suid; int error; ruid = SCARG(uap, ruid); euid = SCARG(uap, euid); suid = SCARG(uap, suid); /* * make permission checks against the thread's ucred, * but the actual changes will be to the process's ucred */ pruc = pr->ps_ucred; if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) && (euid == (uid_t)-1 || euid == pruc->cr_uid) && (suid == (uid_t)-1 || suid == pruc->cr_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 != uc->cr_ruid && ruid != uc->cr_uid && ruid != uc->cr_svuid && (error = suser(p, 0))) return (error); if (euid != (uid_t)-1 && euid != uc->cr_ruid && euid != uc->cr_uid && euid != uc->cr_svuid && (error = suser(p, 0))) return (error); if (suid != (uid_t)-1 && suid != uc->cr_ruid && suid != uc->cr_uid && suid != uc->cr_svuid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); /* * Note that unlike the other set*uid() calls, each * uid type is set independently of the others. */ if (ruid != (uid_t)-1) newcred->cr_ruid = ruid; if (euid != (uid_t)-1) newcred->cr_uid = euid; if (suid != (uid_t)-1) newcred->cr_svuid = suid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); /* now that we can sleep, transfer proc count to new user */ if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) { chgproccnt(pruc->cr_ruid, -1); chgproccnt(ruid, 1); } crfree(pruc); return (0); } int sys_getresgid(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 ucred *uc = p->p_ucred; 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(&uc->cr_rgid, rgid, sizeof(*rgid)); if (egid != NULL) error2 = copyout(&uc->cr_gid, egid, sizeof(*egid)); if (sgid != NULL) error3 = copyout(&uc->cr_svgid, sgid, sizeof(*sgid)); return (error1 ? error1 : error2 ? error2 : error3); } int sys_setresgid(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 process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; gid_t rgid, egid, sgid; int error; rgid = SCARG(uap, rgid); egid = SCARG(uap, egid); sgid = SCARG(uap, sgid); /* * make permission checks against the thread's ucred, * but the actual changes will be to the process's ucred */ pruc = pr->ps_ucred; if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) && (egid == (gid_t)-1 || egid == pruc->cr_gid) && (sgid == (gid_t)-1 || sgid == pruc->cr_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 != uc->cr_rgid && rgid != uc->cr_gid && rgid != uc->cr_svgid && (error = suser(p, 0))) return (error); if (egid != (gid_t)-1 && egid != uc->cr_rgid && egid != uc->cr_gid && egid != uc->cr_svgid && (error = suser(p, 0))) return (error); if (sgid != (gid_t)-1 && sgid != uc->cr_rgid && sgid != uc->cr_gid && sgid != uc->cr_svgid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); /* * Note that unlike the other set*gid() calls, each * gid type is set independently of the others. */ if (rgid != (gid_t)-1) newcred->cr_rgid = rgid; if (egid != (gid_t)-1) newcred->cr_gid = egid; if (sgid != (gid_t)-1) newcred->cr_svgid = sgid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); return (0); } int sys_setregid(struct proc *p, void *v, register_t *retval) { struct sys_setregid_args /* { syscallarg(gid_t) rgid; syscallarg(gid_t) egid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; gid_t rgid, egid; int error; rgid = SCARG(uap, rgid); egid = SCARG(uap, egid); /* * make permission checks against the thread's ucred, * but the actual changes will be to the process's ucred * * The saved gid check here is complicated: we reset the * saved gid to the real gid if the real gid is specified * *and* either it's changing _or_ the saved gid won't equal * the effective gid. So, the svgid *won't* change when * the rgid isn't specified or when the rgid isn't changing * and the svgid equals the requested egid. */ pruc = pr->ps_ucred; if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) && (egid == (gid_t)-1 || egid == pruc->cr_gid) && (rgid == (gid_t)-1 || (rgid == pruc->cr_rgid && pruc->cr_svgid == (egid != (gid_t)-1 ? egid : pruc->cr_gid)))) 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 != uc->cr_rgid && rgid != uc->cr_gid && rgid != uc->cr_svgid && (error = suser(p, 0))) return (error); if (egid != (gid_t)-1 && egid != uc->cr_rgid && egid != uc->cr_gid && egid != uc->cr_svgid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); if (rgid != (gid_t)-1) newcred->cr_rgid = rgid; if (egid != (gid_t)-1) newcred->cr_gid = 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 != pruc->cr_rgid || pruc->cr_svgid != (egid != (gid_t)-1 ? egid : pruc->cr_gid))) newcred->cr_svgid = rgid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); return (0); } int sys_setreuid(struct proc *p, void *v, register_t *retval) { struct sys_setreuid_args /* { syscallarg(uid_t) ruid; syscallarg(uid_t) euid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; uid_t ruid, euid; int error; ruid = SCARG(uap, ruid); euid = SCARG(uap, euid); /* * make permission checks against the thread's ucred, * but the actual changes will be to the process's ucred * * The saved uid check here is complicated: we reset the * saved uid to the real uid if the real uid is specified * *and* either it's changing _or_ the saved uid won't equal * the effective uid. So, the svuid *won't* change when * the ruid isn't specified or when the ruid isn't changing * and the svuid equals the requested euid. */ pruc = pr->ps_ucred; if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) && (euid == (uid_t)-1 || euid == pruc->cr_uid) && (ruid == (uid_t)-1 || (ruid == pruc->cr_ruid && pruc->cr_svuid == (euid != (uid_t)-1 ? euid : pruc->cr_uid)))) 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 != uc->cr_ruid && ruid != uc->cr_uid && ruid != uc->cr_svuid && (error = suser(p, 0))) return (error); if (euid != (uid_t)-1 && euid != uc->cr_ruid && euid != uc->cr_uid && euid != uc->cr_svuid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); if (ruid != (uid_t)-1) newcred->cr_ruid = ruid; if (euid != (uid_t)-1) newcred->cr_uid = 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 != pruc->cr_ruid || pruc->cr_svuid != (euid != (uid_t)-1 ? euid : pruc->cr_uid))) newcred->cr_svuid = ruid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); /* now that we can sleep, transfer proc count to new user */ if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) { chgproccnt(pruc->cr_ruid, -1); chgproccnt(ruid, 1); } crfree(pruc); return (0); } int sys_setuid(struct proc *p, void *v, register_t *retval) { struct sys_setuid_args /* { syscallarg(uid_t) uid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; uid_t uid; int did_real, error; uid = SCARG(uap, uid); pruc = pr->ps_ucred; if (pruc->cr_uid == uid && pruc->cr_ruid == uid && pruc->cr_svuid == uid) return (0); if (uid != uc->cr_ruid && uid != uc->cr_svuid && uid != uc->cr_uid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); /* * Everything's okay, do it. */ if (uid == pruc->cr_uid || suser(p, 0) == 0) { did_real = 1; newcred->cr_ruid = uid; newcred->cr_svuid = uid; } else did_real = 0; newcred->cr_uid = uid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); /* * Transfer proc count to new user. */ if (did_real && uid != pruc->cr_ruid) { chgproccnt(pruc->cr_ruid, -1); chgproccnt(uid, 1); } crfree(pruc); return (0); } int sys_seteuid(struct proc *p, void *v, register_t *retval) { struct sys_seteuid_args /* { syscallarg(uid_t) euid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; uid_t euid; int error; euid = SCARG(uap, euid); if (pr->ps_ucred->cr_uid == euid) return (0); if (euid != uc->cr_ruid && euid != uc->cr_svuid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); newcred->cr_uid = euid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); return (0); } int sys_setgid(struct proc *p, void *v, register_t *retval) { struct sys_setgid_args /* { syscallarg(gid_t) gid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; gid_t gid; int error; gid = SCARG(uap, gid); pruc = pr->ps_ucred; if (pruc->cr_gid == gid && pruc->cr_rgid == gid && pruc->cr_svgid == gid) return (0); if (gid != uc->cr_rgid && gid != uc->cr_svgid && gid != uc->cr_gid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); if (gid == pruc->cr_gid || suser(p, 0) == 0) { newcred->cr_rgid = gid; newcred->cr_svgid = gid; } newcred->cr_gid = gid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); return (0); } int sys_setegid(struct proc *p, void *v, register_t *retval) { struct sys_setegid_args /* { syscallarg(gid_t) egid; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred, *uc = p->p_ucred; gid_t egid; int error; egid = SCARG(uap, egid); if (pr->ps_ucred->cr_gid == egid) return (0); if (egid != uc->cr_rgid && egid != uc->cr_svgid && (error = suser(p, 0))) return (error); /* * Copy credentials so other references do not see our changes. * ps_ucred may change during the crget(). */ newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); newcred->cr_gid = egid; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); return (0); } int sys_setgroups(struct proc *p, void *v, register_t *retval) { struct sys_setgroups_args /* { syscallarg(int) gidsetsize; syscallarg(const gid_t *) gidset; } */ *uap = v; struct process *pr = p->p_p; struct ucred *pruc, *newcred; gid_t groups[NGROUPS]; u_int ngrp; int error; if ((error = suser(p, 0)) != 0) return (error); ngrp = SCARG(uap, gidsetsize); if (ngrp > NGROUPS) return (EINVAL); error = copyin(SCARG(uap, gidset), groups, ngrp * sizeof(gid_t)); if (error == 0) { newcred = crget(); pruc = pr->ps_ucred; crset(newcred, pruc); memcpy(newcred->cr_groups, groups, ngrp * sizeof(gid_t)); newcred->cr_ngroups = ngrp; pr->ps_ucred = newcred; atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); crfree(pruc); } return (error); } /* * Check if gid is a member of the group set. */ int groupmember(gid_t gid, struct ucred *cred) { gid_t *gp; gid_t *egp; if (cred->cr_gid == gid) return (1); 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_p->ps_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(void) { struct ucred *cr; cr = pool_get(&ucred_pool, PR_WAITOK|PR_ZERO); cr->cr_ref = 1; return (cr); } /* * Free a cred structure. * Throws away space when ref count gets to 0. */ void crfree(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(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(struct ucred *cr) { struct ucred *newcr; newcr = crget(); *newcr = *cr; newcr->cr_ref = 1; return (newcr); } /* * Convert the userspace xucred to a kernel ucred */ void crfromxucred(struct ucred *cr, const struct xucred *xcr) { cr->cr_ref = 1; cr->cr_uid = xcr->cr_uid; cr->cr_gid = xcr->cr_gid; cr->cr_ngroups = xcr->cr_ngroups; memcpy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups[0]) * xcr->cr_ngroups); } /* * Get login name, if available. */ int sys_getlogin(struct proc *p, void *v, register_t *retval) { struct sys_getlogin_args /* { syscallarg(char *) namebuf; syscallarg(u_int) namelen; } */ *uap = v; struct session *s = p->p_p->ps_pgrp->pg_session; if (SCARG(uap, namelen) > sizeof(s->s_login)) SCARG(uap, namelen) = sizeof(s->s_login); return (copyout((caddr_t)s->s_login, (caddr_t)SCARG(uap, namebuf), SCARG(uap, namelen))); } /* * Set login name. */ int sys_setlogin(struct proc *p, void *v, register_t *retval) { struct sys_setlogin_args /* { syscallarg(const char *) namebuf; } */ *uap = v; struct session *s = p->p_p->ps_pgrp->pg_session; int error; if ((error = suser(p, 0)) != 0) return (error); error = copyinstr((caddr_t)SCARG(uap, namebuf), (caddr_t)s->s_login, sizeof(s->s_login), NULL); 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_p->ps_flags & PS_TRACED) != 0) return (0); /* processes with shared filedescriptors shouldn't. */ if (p->p_fd->fd_refcnt > 1) return (0); /* Allow. */ return (1); } /* * Set address of the proc's thread-control-block */ int sys___set_tcb(struct proc *p, void *v, register_t *retval) { struct sys___set_tcb_args /* { syscallarg(void *) tcb; } */ *uap = v; TCB_SET(p, SCARG(uap, tcb)); return (0); } /* * Get address of the proc's thread-control-block */ int sys___get_tcb(struct proc *p, void *v, register_t *retval) { *retval = (register_t)TCB_GET(p); return (0); } /* * Refresh the thread's reference to the process's credentials */ void dorefreshcreds(struct process *pr, struct proc *p) { struct ucred *uc = p->p_ucred; KERNEL_LOCK(); /* XXX should be PROCESS_RLOCK(pr) */ if (uc != pr->ps_ucred) { p->p_ucred = pr->ps_ucred; crhold(p->p_ucred); crfree(uc); } KERNEL_UNLOCK(); }