CRED: Use RCU to access another task's creds and to release a task's own creds

[net-next-2.6.git] / fs / fcntl.c

diff --git a/fs/fcntl.c b/fs/fcntl.c
index c594cc0e40fbcb2af3a6cb928e0bca2392d04156..87c39f1f0817c1d9b6c05f3da6f17730b2453941 100644 (file)
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -401,10 +401,17 @@ static const long band_table[NSIGPOLL] = {
 static inline int sigio_perm(struct task_struct *p,
                              struct fown_struct *fown, int sig)
 {
-       return (((fown->euid == 0) ||
-                (fown->euid == p->cred->suid) || (fown->euid == p->cred->uid) ||
-                (fown->uid == p->cred->suid) || (fown->uid == p->cred->uid)) &&
-               !security_file_send_sigiotask(p, fown, sig));
+       const struct cred *cred;
+       int ret;
+
+       rcu_read_lock();
+       cred = __task_cred(p);
+       ret = ((fown->euid == 0 ||
+               fown->euid == cred->suid || fown->euid == cred->uid ||
+               fown->uid  == cred->suid || fown->uid  == cred->uid) &&
+              !security_file_send_sigiotask(p, fown, sig));
+       rcu_read_unlock();
+       return ret;
 }
 
 static void send_sigio_to_task(struct task_struct *p,