252 lines
6.6 KiB
C
252 lines
6.6 KiB
C
/*
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* linux/kernel/capability.c
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*
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* Copyright (C) 1997 Andrew Main <zefram@fysh.org>
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*
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* Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com>
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* 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
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*/
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#include <linux/capability.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <asm/uaccess.h>
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unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
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kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
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EXPORT_SYMBOL(securebits);
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EXPORT_SYMBOL(cap_bset);
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/*
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* This lock protects task->cap_* for all tasks including current.
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* Locking rule: acquire this prior to tasklist_lock.
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*/
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static DEFINE_SPINLOCK(task_capability_lock);
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/*
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* For sys_getproccap() and sys_setproccap(), any of the three
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* capability set pointers may be NULL -- indicating that that set is
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* uninteresting and/or not to be changed.
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*/
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/**
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* sys_capget - get the capabilities of a given process.
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* @header: pointer to struct that contains capability version and
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* target pid data
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* @dataptr: pointer to struct that contains the effective, permitted,
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* and inheritable capabilities that are returned
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*
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* Returns 0 on success and < 0 on error.
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*/
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asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
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{
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int ret = 0;
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pid_t pid;
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__u32 version;
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struct task_struct *target;
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struct __user_cap_data_struct data;
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if (get_user(version, &header->version))
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return -EFAULT;
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if (version != _LINUX_CAPABILITY_VERSION) {
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if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
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return -EFAULT;
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return -EINVAL;
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}
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if (get_user(pid, &header->pid))
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return -EFAULT;
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if (pid < 0)
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return -EINVAL;
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spin_lock(&task_capability_lock);
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read_lock(&tasklist_lock);
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if (pid && pid != current->pid) {
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target = find_task_by_pid(pid);
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if (!target) {
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ret = -ESRCH;
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goto out;
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}
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} else
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target = current;
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ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
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out:
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read_unlock(&tasklist_lock);
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spin_unlock(&task_capability_lock);
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if (!ret && copy_to_user(dataptr, &data, sizeof data))
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return -EFAULT;
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return ret;
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}
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/*
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* cap_set_pg - set capabilities for all processes in a given process
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* group. We call this holding task_capability_lock and tasklist_lock.
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*/
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static inline int cap_set_pg(int pgrp, kernel_cap_t *effective,
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kernel_cap_t *inheritable,
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kernel_cap_t *permitted)
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{
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struct task_struct *g, *target;
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int ret = -EPERM;
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int found = 0;
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do_each_task_pid(pgrp, PIDTYPE_PGID, g) {
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target = g;
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while_each_thread(g, target) {
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if (!security_capset_check(target, effective,
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inheritable,
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permitted)) {
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security_capset_set(target, effective,
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inheritable,
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permitted);
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ret = 0;
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}
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found = 1;
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}
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} while_each_task_pid(pgrp, PIDTYPE_PGID, g);
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if (!found)
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ret = 0;
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return ret;
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}
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/*
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* cap_set_all - set capabilities for all processes other than init
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* and self. We call this holding task_capability_lock and tasklist_lock.
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*/
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static inline int cap_set_all(kernel_cap_t *effective,
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kernel_cap_t *inheritable,
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kernel_cap_t *permitted)
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{
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struct task_struct *g, *target;
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int ret = -EPERM;
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int found = 0;
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do_each_thread(g, target) {
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if (target == current || target->pid == 1)
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continue;
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found = 1;
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if (security_capset_check(target, effective, inheritable,
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permitted))
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continue;
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ret = 0;
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security_capset_set(target, effective, inheritable, permitted);
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} while_each_thread(g, target);
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if (!found)
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ret = 0;
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return ret;
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}
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/**
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* sys_capset - set capabilities for a process or a group of processes
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* @header: pointer to struct that contains capability version and
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* target pid data
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* @data: pointer to struct that contains the effective, permitted,
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* and inheritable capabilities
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*
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* Set capabilities for a given process, all processes, or all
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* processes in a given process group.
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*
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* The restrictions on setting capabilities are specified as:
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*
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* [pid is for the 'target' task. 'current' is the calling task.]
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*
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* I: any raised capabilities must be a subset of the (old current) permitted
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* P: any raised capabilities must be a subset of the (old current) permitted
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* E: must be set to a subset of (new target) permitted
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*
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* Returns 0 on success and < 0 on error.
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*/
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asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
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{
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kernel_cap_t inheritable, permitted, effective;
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__u32 version;
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struct task_struct *target;
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int ret;
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pid_t pid;
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if (get_user(version, &header->version))
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return -EFAULT;
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if (version != _LINUX_CAPABILITY_VERSION) {
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if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
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return -EFAULT;
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return -EINVAL;
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}
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if (get_user(pid, &header->pid))
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return -EFAULT;
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if (pid && pid != current->pid && !capable(CAP_SETPCAP))
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return -EPERM;
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if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
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copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
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copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
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return -EFAULT;
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spin_lock(&task_capability_lock);
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read_lock(&tasklist_lock);
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if (pid > 0 && pid != current->pid) {
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target = find_task_by_pid(pid);
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if (!target) {
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ret = -ESRCH;
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goto out;
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}
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} else
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target = current;
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ret = 0;
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/* having verified that the proposed changes are legal,
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we now put them into effect. */
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if (pid < 0) {
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if (pid == -1) /* all procs other than current and init */
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ret = cap_set_all(&effective, &inheritable, &permitted);
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else /* all procs in process group */
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ret = cap_set_pg(-pid, &effective, &inheritable,
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&permitted);
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} else {
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ret = security_capset_check(target, &effective, &inheritable,
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&permitted);
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if (!ret)
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security_capset_set(target, &effective, &inheritable,
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&permitted);
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}
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out:
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read_unlock(&tasklist_lock);
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spin_unlock(&task_capability_lock);
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return ret;
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}
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int __capable(struct task_struct *t, int cap)
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{
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if (security_capable(t, cap) == 0) {
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t->flags |= PF_SUPERPRIV;
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return 1;
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}
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return 0;
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}
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EXPORT_SYMBOL(__capable);
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int capable(int cap)
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{
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return __capable(current, cap);
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}
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EXPORT_SYMBOL(capable);
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