/* * 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. * @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;     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 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;     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;}