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161 lines
3.3 KiB
161 lines
3.3 KiB
/*
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* Copyright (c) 2018 Samsung Electronics Co., Ltd. All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*/
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#include <linux/cred.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/kobject.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/sysfs.h>
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#include "include/defex_debug.h"
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#include "include/defex_internal.h"
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static int last_cmd;
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static int set_user(struct cred *new_cred)
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{
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struct user_struct *new_user;
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new_user = alloc_uid(new_cred->uid);
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if (!new_user)
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return -EAGAIN;
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free_uid(new_cred->user);
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new_cred->user = new_user;
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return 0;
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}
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/*
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* target_id = (0 - set all uids, 1 - set fsuid, 2 - set all gids)
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*/
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static int set_cred(int target_id, int new_val)
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{
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struct user_namespace *ns = current_user_ns();
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const struct cred *old_cred;
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struct cred *new_cred;
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kuid_t kuid;
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kgid_t kgid;
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uid_t new_uid;
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gid_t new_gid;
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new_cred = prepare_creds();
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if (!new_cred)
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return -ENOMEM;
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old_cred = current_cred();
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switch (target_id) {
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case 0:
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new_uid = new_val;
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kuid = make_kuid(ns, new_uid);
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if (!uid_valid(kuid))
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goto do_abort;
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new_cred->uid = new_cred->euid = new_cred->suid = new_cred->fsuid = kuid;
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if (!uid_eq(new_cred->uid, old_cred->uid)) {
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if (set_user(new_cred) < 0)
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goto do_abort;
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}
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break;
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case 1:
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new_uid = new_val;
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kuid = make_kuid(ns, new_uid);
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if (!uid_valid(kuid))
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goto do_abort;
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new_cred->fsuid = kuid;
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break;
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case 2:
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new_gid = new_val;
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kgid = make_kgid(ns, new_gid);
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if (!gid_valid(kgid))
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goto do_abort;
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new_cred->gid = new_cred->egid = new_cred->sgid = new_cred->fsgid = kgid;
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break;
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}
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return commit_creds(new_cred);
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do_abort:
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abort_creds(new_cred);
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return -EPERM;
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}
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static ssize_t debug_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count)
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{
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struct task_struct *p = current;
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int i, l, new_val = -1;
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int ret = 0;
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static const char *prefix[] = {
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"uid=",
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"fsuid=",
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"gid="
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};
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if (!buf || !p)
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return -EINVAL;
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for (i = 0; i < sizeof(prefix) / sizeof(prefix[0]); i++) {
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l = strlen(prefix[i]);
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if (!strncmp(buf, prefix[i], l))
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break;
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}
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if (i == (sizeof(prefix) / sizeof(prefix[0])))
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return -EINVAL;
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switch (i) {
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case DBG_SETUID ... DBG_SETGID:
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ret = kstrtoint(buf + l, 10, &new_val);
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if (ret != 0)
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return -EINVAL;
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ret = set_cred(i, new_val);
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break;
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default:
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break;
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}
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last_cmd = i;
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return (!ret)?count:ret;
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}
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static ssize_t debug_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
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{
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struct task_struct *p = current;
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int res = 0;
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if (!p)
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return 0;
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switch (last_cmd) {
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case DBG_SETUID ... DBG_SETGID:
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res = snprintf(buf, MAX_LEN + 1, "pid=%d\nuid=%d\ngid=%d\neuid=%d\negid=%d\n",
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p->pid,
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uid_get_value(p->cred->uid),
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uid_get_value(p->cred->gid),
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uid_get_value(p->cred->euid),
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uid_get_value(p->cred->egid));
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break;
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}
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return res;
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}
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static struct kobj_attribute debug_attribute = __ATTR(debug, 0660, debug_show, debug_store);
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int defex_create_debug(struct kset *defex_kset)
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{
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int retval;
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retval = sysfs_create_file(&defex_kset->kobj, &debug_attribute.attr);
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if (retval)
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return DEFEX_NOK;
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kobject_uevent(&defex_kset->kobj, KOBJ_ADD);
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return DEFEX_OK;
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}
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