In the Linux kernel, the following vulnerability has been resolved: cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and cifs_close_deferred_fi…

Overview

In the Linux kernel, the following vulnerability has been resolved:

cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths

In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and cifs_close_deferred_file_under_dentry(), when a pending deferred close is cancelled via cancel_delayed_work(), the subsequent kmalloc_obj() to add the file to the local processing list may fail under memory pressure. The loop breaks immediately, but the cancelled work is no longer pending (it would have called _cifsFileInfo_put()), and the cfile is never added to file_head for processing. The cifsFileInfo reference and the open server handle both leak.

Fix by saving the cfile that failed allocation in a local variable, breaking as before, and calling _cifsFileInfo_put() on it after releasing the lock. Any files later in the iteration are unaffected since their deferred work is still pending and will fire normally.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.