/* * 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/capability.h> #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. * @header: pointer to struct that contains capability version and * target pid data * @dataptr: pointer to struct that contains the effective, permitted, * and inheritable capabilities that are returned * * Returns 0 on success and < 0 on error. */ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) { int ret = 0; pid_t pid; __u32 version; struct task_struct *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) { struct task_struct *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) { struct task_struct *g, *target; int ret = -EPERM; int found = 0; do_each_thread(g, target) { if (target == current || is_init(target)) 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 process or a group of processes * @header: pointer to struct that contains capability version and * target pid data * @data: pointer to struct that contains the effective, permitted, * and inheritable capabilities * * 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 * * Returns 0 on success and < 0 on error. */ 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 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; } int __capable(struct task_struct *t, int cap) { if (security_capable(t, cap) == 0) { t->flags |= PF_SUPERPRIV; return 1; } return 0; } EXPORT_SYMBOL(__capable); int capable(int cap) { return __capable(current, cap); } EXPORT_SYMBOL(capable);