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/*
* linux/kernel/capability.c
*
* Copyright (C) 1997 Andrew Main <zefram@fysh.org>
* Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com>
*/
#include <linux/mm.h>
#include <asm/uaccess.h>
kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
/* Note: never hold tasklist_lock while spinning for this one */
spinlock_t task_capability_lock = SPIN_LOCK_UNLOCKED;
/*
* For sys_getproccap() and sys_setproccap(), any of the three
* capability set pointers may be NULL -- indicating that that set is
* uninteresting and/or not to be changed.
*/
asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
int error, pid;
__u32 version;
struct task_struct *target;
struct __user_cap_data_struct data;
if (get_user(version, &header->version))
return -EFAULT;
error = -EINVAL;
if (version != _LINUX_CAPABILITY_VERSION) {
version = _LINUX_CAPABILITY_VERSION;
if (put_user(version, &header->version))
error = -EFAULT;
return error;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid < 0)
return -EINVAL;
error = 0;
spin_lock(&task_capability_lock);
if (pid && pid != current->pid) {
read_lock(&tasklist_lock);
target = find_task_by_pid(pid); /* identify target of query */
if (!target)
error = -ESRCH;
} else {
target = current;
}
if (!error) {
data.permitted = cap_t(target->cap_permitted);
data.inheritable = cap_t(target->cap_inheritable);
data.effective = cap_t(target->cap_effective);
}
if (target != current)
read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
if (!error) {
if (copy_to_user(dataptr, &data, sizeof data))
return -EFAULT;
}
return error;
}
/* set capabilities for all processes in a given process group */
static void cap_set_pg(int pgrp,
kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
struct task_struct *target;
/* FIXME: do we need to have a write lock here..? */
read_lock(&tasklist_lock);
for_each_task(target) {
if (target->pgrp != pgrp)
continue;
target->cap_effective = *effective;
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
read_unlock(&tasklist_lock);
}
/* set capabilities for all processes other than 1 and self */
static void cap_set_all(kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
struct task_struct *target;
/* FIXME: do we need to have a write lock here..? */
read_lock(&tasklist_lock);
/* ALL means everyone other than self or 'init' */
for_each_task(target) {
if (target == current || target->pid == 1)
continue;
target->cap_effective = *effective;
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
read_unlock(&tasklist_lock);
}
/*
* The restrictions on setting capabilities are specified as:
*
* [pid is for the 'target' task. 'current' is the calling task.]
*
* I: any raised capabilities must be a subset of the (old current) Permitted
* P: any raised capabilities must be a subset of the (old current) permitted
* E: must be set to a subset of (new target) Permitted
*/
asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
{
kernel_cap_t inheritable, permitted, effective;
__u32 version;
struct task_struct *target;
int error, pid;
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
version = _LINUX_CAPABILITY_VERSION;
if (put_user(version, &header->version))
return -EFAULT;
return -EINVAL;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid && !capable(CAP_SETPCAP))
return -EPERM;
if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
return -EFAULT;
error = -EPERM;
spin_lock(&task_capability_lock);
if (pid > 0 && pid != current->pid) {
read_lock(&tasklist_lock);
target = find_task_by_pid(pid); /* identify target of query */
if (!target) {
error = -ESRCH;
goto out;
}
} else {
target = current;
}
/* verify restrictions on target's new Inheritable set */
if (!cap_issubset(inheritable,
cap_combine(target->cap_inheritable,
current->cap_permitted))) {
goto out;
}
/* verify restrictions on target's new Permitted set */
if (!cap_issubset(permitted,
cap_combine(target->cap_permitted,
current->cap_permitted))) {
goto out;
}
/* verify the _new_Effective_ is a subset of the _new_Permitted_ */
if (!cap_issubset(effective, permitted)) {
goto out;
}
/* having verified that the proposed changes are legal,
we now put them into effect. */
error = 0;
if (pid < 0) {
if (pid == -1) /* all procs other than current and init */
cap_set_all(&effective, &inheritable, &permitted);
else /* all procs in process group */
cap_set_pg(-pid, &effective, &inheritable, &permitted);
goto spin_out;
} else {
/* FIXME: do we need to have a write lock here..? */
target->cap_effective = effective;
target->cap_inheritable = inheritable;
target->cap_permitted = permitted;
}
out:
if (target != current) {
read_unlock(&tasklist_lock);
}
spin_out:
spin_unlock(&task_capability_lock);
return error;
}
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