[PATCH] refactor capable() to one implementation, add __capable() helper

Move capable() to kernel/capability.c and eliminate duplicate
implementations.  Add __capable() function which can be used to check for
capabiilty of any process.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 34 insertions, 42 deletions

diff --git a/include/linux/capability.h b/include/linux/capability.h
index 5a23ce752629..6548b35ab9f6 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -357,7 +357,8 @@ static inline kernel_cap_t cap_invert(kernel_cap_t c)
 
 #define cap_is_fs_cap(c)     (CAP_TO_MASK(c) & CAP_FS_MASK)
 
-extern int capable(int cap);
+int capable(int cap);
+int __capable(struct task_struct *t, int cap);
 
 #endif /* __KERNEL__ */
 
diff --git a/include/linux/security.h b/include/linux/security.h
index b18eb8cfa639..3c19be35124b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1040,6 +1040,11 @@ struct swap_info_struct;
  *      @effective contains the effective capability set.
  *      @inheritable contains the inheritable capability set.
  *      @permitted contains the permitted capability set.
+ * @capable:
+ *      Check whether the @tsk process has the @cap capability.
+ *      @tsk contains the task_struct for the process.
+ *      @cap contains the capability <include/linux/capability.h>.
+ *      Return 0 if the capability is granted for @tsk.
  * @acct:
  *      Check permission before enabling or disabling process accounting.  If
  *      accounting is being enabled, then @file refers to the open file used to
@@ -1053,11 +1058,6 @@ struct swap_info_struct;
  *      @table contains the ctl_table structure for the sysctl variable.
  *      @op contains the operation (001 = search, 002 = write, 004 = read).
  *      Return 0 if permission is granted.
- * @capable:
- *      Check whether the @tsk process has the @cap capability.
- *      @tsk contains the task_struct for the process.
- *      @cap contains the capability <include/linux/capability.h>.
- *      Return 0 if the capability is granted for @tsk.
  * @syslog:
  *      Check permission before accessing the kernel message ring or changing
  *      logging to the console.
@@ -1099,9 +1099,9 @@ struct security_operations {
                             kernel_cap_t * effective,
                             kernel_cap_t * inheritable,
                             kernel_cap_t * permitted);
+        int (*capable) (struct task_struct * tsk, int cap);
         int (*acct) (struct file * file);
         int (*sysctl) (struct ctl_table * table, int op);
-        int (*capable) (struct task_struct * tsk, int cap);
         int (*quotactl) (int cmds, int type, int id, struct super_block * sb);
         int (*quota_on) (struct dentry * dentry);
         int (*syslog) (int type);
@@ -1347,6 +1347,11 @@ static inline void security_capset_set (struct task_struct *target,
         security_ops->capset_set (target, effective, inheritable, permitted);
 }
 
+static inline int security_capable(struct task_struct *tsk, int cap)
+{
+        return security_ops->capable(tsk, cap);
+}
+
 static inline int security_acct (struct file *file)
 {
         return security_ops->acct (file);
@@ -2050,6 +2055,11 @@ static inline void security_capset_set (struct task_struct *target,
         cap_capset_set (target, effective, inheritable, permitted);
 }
 
+static inline int security_capable(struct task_struct *tsk, int cap)
+{
+        return cap_capable(tsk, cap);
+}
+
 static inline int security_acct (struct file *file)
 {
         return 0;
diff --git a/kernel/capability.c b/kernel/capability.c
index bfa3c92e16f2..1a4d8a40d3f9 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -233,3 +233,19 @@ out:
 
      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);
diff --git a/kernel/sys.c b/kernel/sys.c
index 19d058be49d4..421009cedb51 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -224,18 +224,6 @@ int unregister_reboot_notifier(struct notifier_block * nb)
 
 EXPORT_SYMBOL(unregister_reboot_notifier);
 
-#ifndef CONFIG_SECURITY
-int capable(int cap)
-{
-        if (cap_raised(current->cap_effective, cap)) {
-               current->flags |= PF_SUPERPRIV;
-               return 1;
-        }
-        return 0;
-}
-EXPORT_SYMBOL(capable);
-#endif
-
 static int set_one_prio(struct task_struct *p, int niceval, int error)
 {
         int no_nice;
diff --git a/security/security.c b/security/security.c
index f693e1f66b98..51ef509710b9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -174,31 +174,8 @@ int mod_unreg_security(const char *name, struct security_operations *ops)
         return security_ops->unregister_security(name, ops);
 }
 
-/**
- * capable - calls the currently loaded security module's capable() function with the specified capability
- * @cap: the requested capability level.
- *
- * This function calls the currently loaded security module's capable()
- * function with a pointer to the current task and the specified @cap value.
- *
- * This allows the security module to implement the capable function call
- * however it chooses to.
- */
-int capable(int cap)
-{
-        if (security_ops->capable(current, cap)) {
-                /* capability denied */
-                return 0;
-        }
-
-        /* capability granted */
-        current->flags |= PF_SUPERPRIV;
-        return 1;
-}
-
 EXPORT_SYMBOL_GPL(register_security);
 EXPORT_SYMBOL_GPL(unregister_security);
 EXPORT_SYMBOL_GPL(mod_reg_security);
 EXPORT_SYMBOL_GPL(mod_unreg_security);
-EXPORT_SYMBOL(capable);
 EXPORT_SYMBOL(security_ops);