| /* |
| * 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> |
| |
| unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ |
| |
| 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; |
| } |