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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>
* 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
EXPORT_SYMBOL(securebits);
EXPORT_SYMBOL(cap_bset);
/*
* This lock protects task->cap_* for all tasks including current.
* Locking rule: acquire this prior to tasklist_lock.
*/
static DEFINE_SPINLOCK(task_capability_lock);
/*
* 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.
*/
/*
* sys_capget - get the capabilities of a given process.
*/
asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
int ret = 0;
pid_t pid;
__u32 version;
task_t *target;
struct __user_cap_data_struct data;
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid < 0)
return -EINVAL;
spin_lock(&task_capability_lock);
read_lock(&tasklist_lock);
if (pid && pid != current->pid) {
target = find_task_by_pid(pid);
if (!target) {
ret = -ESRCH;
goto out;
}
} else
target = current;
ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
out:
read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
if (!ret && copy_to_user(dataptr, &data, sizeof data))
return -EFAULT;
return ret;
}
/*
* cap_set_pg - set capabilities for all processes in a given process
* group. We call this holding task_capability_lock and tasklist_lock.
*/
static inline int cap_set_pg(int pgrp, kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
task_t *g, *target;
int ret = -EPERM;
int found = 0;
do_each_task_pid(pgrp, PIDTYPE_PGID, g) {
target = g;
while_each_thread(g, target) {
if (!security_capset_check(target, effective,
inheritable,
permitted)) {
security_capset_set(target, effective,
inheritable,
permitted);
ret = 0;
}
found = 1;
}
} while_each_task_pid(pgrp, PIDTYPE_PGID, g);
if (!found)
ret = 0;
return ret;
}
/*
* cap_set_all - set capabilities for all processes other than init
* and self. We call this holding task_capability_lock and tasklist_lock.
*/
static inline int cap_set_all(kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
task_t *g, *target;
int ret = -EPERM;
int found = 0;
do_each_thread(g, target) {
if (target == current || target->pid == 1)
continue;
found = 1;
if (security_capset_check(target, effective, inheritable,
permitted))
continue;
ret = 0;
security_capset_set(target, effective, inheritable, permitted);
} while_each_thread(g, target);
if (!found)
ret = 0;
return ret;
}
/*
* sys_capset - set capabilities for a given process, all processes, or all
* processes in a given process group.
*
* 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;
task_t *target;
int ret;
pid_t pid;
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
}
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid && pid != current->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;
spin_lock(&task_capability_lock);
read_lock(&tasklist_lock);
if (pid > 0 && pid != current->pid) {
target = find_task_by_pid(pid);
if (!target) {
ret = -ESRCH;
goto out;
}
} else
target = current;
ret = 0;
/* having verified that the proposed changes are legal,
we now put them into effect. */
if (pid < 0) {
if (pid == -1) /* all procs other than current and init */
ret = cap_set_all(&effective, &inheritable, &permitted);
else /* all procs in process group */
ret = cap_set_pg(-pid, &effective, &inheritable,
&permitted);
} else {
ret = security_capset_check(target, &effective, &inheritable,
&permitted);
if (!ret)
security_capset_set(target, &effective, &inheritable,
&permitted);
}
out:
read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
return ret;
}
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