pid namespaces: changes to show virtual ids to user
[safe/jmp/linux-2.6] / kernel / capability.c
index 64db1ee..d4377c5 100644 (file)
@@ -3,22 +3,18 @@
  *
  * Copyright (C) 1997  Andrew Main <zefram@fysh.org>
  *
- * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@transmeta.com>
+ * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@kernel.org>
  * 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 <linux/pid_namespace.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.
@@ -31,69 +27,78 @@ static DEFINE_SPINLOCK(task_capability_lock);
  * 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;
+       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 != task_pid_vnr(current)) {
+               target = find_task_by_pid_ns(pid,
+                               current->nsproxy->pid_ns);
+               if (!target) {
+                       ret = -ESRCH;
+                       goto out;
+               }
+       } else
+               target = current;
 
-     ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
+       ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
 
 out:
-     read_unlock(&tasklist_lock); 
-     spin_unlock(&task_capability_lock);
+       read_unlock(&tasklist_lock);
+       spin_unlock(&task_capability_lock);
 
-     if (!ret && copy_to_user(dataptr, &data, sizeof data))
-          return -EFAULT; 
+       if (!ret && copy_to_user(dataptr, &data, sizeof data))
+               return -EFAULT;
 
-     return ret;
+       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,
+static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
                              kernel_cap_t *inheritable,
                              kernel_cap_t *permitted)
 {
-       task_t *g, *target;
+       struct task_struct *g, *target;
        int ret = -EPERM;
        int found = 0;
+       struct pid *pgrp;
 
-       do_each_task_pid(pgrp, PIDTYPE_PGID, g) {
+       pgrp = find_pid_ns(pgrp_nr, current->nsproxy->pid_ns);
+       do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
                target = g;
                while_each_thread(g, target) {
                        if (!security_capset_check(target, effective,
@@ -106,10 +111,10 @@ static inline int cap_set_pg(int pgrp, kernel_cap_t *effective,
                        }
                        found = 1;
                }
-       } while_each_task_pid(pgrp, PIDTYPE_PGID, g);
+       } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
 
        if (!found)
-            ret = 0;
+               ret = 0;
        return ret;
 }
 
@@ -121,12 +126,12 @@ static inline int cap_set_all(kernel_cap_t *effective,
                               kernel_cap_t *inheritable,
                               kernel_cap_t *permitted)
 {
-     task_t *g, *target;
+     struct task_struct *g, *target;
      int ret = -EPERM;
      int found = 0;
 
      do_each_thread(g, target) {
-             if (target == current || target->pid == 1)
+             if (target == current || is_container_init(target->group_leader))
                      continue;
              found = 1;
             if (security_capset_check(target, effective, inheritable,
@@ -141,8 +146,14 @@ static inline int cap_set_all(kernel_cap_t *effective,
      return ret;
 }
 
-/*
- * sys_capset - set capabilities for a given process, all processes, or all
+/**
+ * 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:
@@ -152,69 +163,87 @@ static inline int cap_set_all(kernel_cap_t *effective,
  * 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);
-     }
+       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 != task_pid_vnr(current) && !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 != task_pid_vnr(current)) {
+               target = find_task_by_pid_ns(pid,
+                               current->nsproxy->pid_ns);
+               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);
+       read_unlock(&tasklist_lock);
+       spin_unlock(&task_capability_lock);
 
-     return ret;
+       return ret;
+}
+
+int __capable(struct task_struct *t, int cap)
+{
+       if (security_capable(t, cap) == 0) {
+               t->flags |= PF_SUPERPRIV;
+               return 1;
+       }
+       return 0;
+}
+
+int capable(int cap)
+{
+       return __capable(current, cap);
 }
+EXPORT_SYMBOL(capable);