smb: client: fix potential UAF in cifs_stats_proc_show()

commit 0865ffefea197b437ba78b5dd8d8e256253efd65 upstream.

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index 739525f976ce9bd5664faf0abfe8aee7fb0af406..aa95fa95ca1124bd9a470fc017a9914e964cff14 100644 (file)
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -739,6 +739,8 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v)
                        }
 #endif /* STATS2 */
                list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+                       if (cifs_ses_exiting(ses))
+                               continue;
                        list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
                                i++;
                                seq_printf(m, "\n%d) %s", i, tcon->tree_name);