1 files changed, 24 insertions, 54 deletions

diff --git a/kernel/capability.c b/kernel/capability.c
index a404b980b1bd..36b4b4daebec 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -15,12 +15,7 @@
 #include <linux/syscalls.h>
 #include <linux/pid_namespace.h>
 #include <asm/uaccess.h>
-
-/*
- * This lock protects task->cap_* for all tasks including current.
- * Locking rule: acquire this prior to tasklist_lock.
- */
-static DEFINE_SPINLOCK(task_capability_lock);
+#include "cred-internals.h"
 
 /*
  * Leveraged for setting/resetting capabilities
@@ -128,12 +123,11 @@ static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
 }
 
 /*
- * If we have configured with filesystem capability support, then the
- * only thing that can change the capabilities of the current process
- * is the current process. As such, we can't be in this code at the
- * same time as we are in the process of setting capabilities in this
- * process. The net result is that we can limit our use of locks to
- * when we are reading the caps of another process.
+ * The only thing that can change the capabilities of the current
+ * process is the current process. As such, we can't be in this code
+ * at the same time as we are in the process of setting capabilities
+ * in this process. The net result is that we can limit our use of
+ * locks to when we are reading the caps of another process.
  */
 static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
                                      kernel_cap_t *pIp, kernel_cap_t *pPp)
@@ -143,7 +137,6 @@ static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
         if (pid && (pid != task_pid_vnr(current))) {
                 struct task_struct *target;
 
-                spin_lock(&task_capability_lock);
                 read_lock(&tasklist_lock);
 
                 target = find_task_by_vpid(pid);
@@ -153,34 +146,12 @@ static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
                         ret = security_capget(target, pEp, pIp, pPp);
 
                 read_unlock(&tasklist_lock);
-                spin_unlock(&task_capability_lock);
         } else
                 ret = security_capget(current, pEp, pIp, pPp);
 
         return ret;
 }
 
-/*
- * Atomically modify the effective capabilities returning the original
- * value. No permission check is performed here - it is assumed that the
- * caller is permitted to set the desired effective capabilities.
- */
-kernel_cap_t cap_set_effective(const kernel_cap_t pE_new)
-{
-        kernel_cap_t pE_old;
-
-        spin_lock(&task_capability_lock);
-
-        pE_old = current->cred->cap_effective;
-        current->cred->cap_effective = pE_new;
-
-        spin_unlock(&task_capability_lock);
-
-        return pE_old;
-}
-
-EXPORT_SYMBOL(cap_set_effective);
-
 /**
  * sys_capget - get the capabilities of a given process.
  * @header: pointer to struct that contains capability version and
@@ -208,7 +179,6 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
                 return -EINVAL;
 
         ret = cap_get_target_pid(pid, &pE, &pI, &pP);
-
         if (!ret) {
                 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
                 unsigned i;
@@ -270,6 +240,7 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
         struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
         unsigned i, tocopy;
         kernel_cap_t inheritable, permitted, effective;
+        struct cred *new;
         int ret;
         pid_t pid;
 
@@ -284,8 +255,8 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
         if (pid != 0 && pid != task_pid_vnr(current))
                 return -EPERM;
 
-        if (copy_from_user(&kdata, data, tocopy
-                           * sizeof(struct __user_cap_data_struct)))
+        if (copy_from_user(&kdata, data,
+                           tocopy * sizeof(struct __user_cap_data_struct)))
                 return -EFAULT;
 
         for (i = 0; i < tocopy; i++) {
@@ -300,24 +271,23 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
                 i++;
         }
 
-        ret = audit_log_capset(pid, &effective, &inheritable, &permitted);
-        if (ret)
+        new = prepare_creds();
+        if (!new)
+                return -ENOMEM;
+
+        ret = security_capset(new, current_cred(),
+                              &effective, &inheritable, &permitted);
+        if (ret < 0)
+                goto error;
+
+        ret = audit_log_capset(pid, new, current_cred());
+        if (ret < 0)
                 return ret;
 
-        /* This lock is required even when filesystem capability support is
-         * configured - it protects the sys_capget() call from returning
-         * incorrect data in the case that the targeted process is not the
-         * current one.
-         */
-        spin_lock(&task_capability_lock);
-
-        ret = security_capset_check(&effective, &inheritable, &permitted);
-        /* Having verified that the proposed changes are legal, we now put them
-         * into effect.
-         */
-        if (!ret)
-                security_capset_set(&effective, &inheritable, &permitted);
-        spin_unlock(&task_capability_lock);
+        return commit_creds(new);
+
+error:
+        abort_creds(new);
         return ret;
 }