nitro_enclaves: Fix race when accessing has_event flag

The `has_event` flag is set while holding the `enclave_info_mutex` mutex. Let's also hold the mutex while reading the flag to avoid races. Signed-off-by: Costin Lupu <[email protected]>
aws · Jan 29, 2024 · c6d4cb7 · c6d4cb7
1 parent 001ec4f
commit c6d4cb7
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -1645,9 +1645,13 @@ static __poll_t ne_enclave_poll(struct file *file, poll_table *wait)
 
 	poll_wait(file, &ne_enclave->eventq, wait);
 
+	mutex_lock(&ne_enclave->enclave_info_mutex);
+
 	if (ne_enclave->has_event)
 		mask |= EPOLLHUP;
 
+	mutex_unlock(&ne_enclave->enclave_info_mutex);
+
 	return mask;
 }