/* * 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;}