[PATCH 5.10.y 2/2] smb: client: fix potential UAF in cifs_stats_proc_show()

[jianqi.ren.cn]

From: Paulo Alcantara <pc@xxxxxxxxxxxxx>

commit 0865ffefea197b437ba78b5dd8d8e256253efd65 upstream.

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

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paulo Alcantara (Red Hat) <pc@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
[ cifs_debug.c was moved from fs/cifs to fs/smb/client since
38c8a9a52082 ("smb: move client and server files to common directory fs/smb").
The cifs_ses_exiting() was introduced to cifs_debug.c since
ca545b7f0823 ("smb: client: fix potential UAF in cifs_debug_files_proc_show()")
 which has been sent to upstream already.]
Signed-off-by: Jianqi Ren <jianqi.ren.cn@xxxxxxxxxxxxx>
Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
---
Verified the build test
---
 fs/cifs/cifs_debug.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 8b88b0705481..257eae4673d2 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -593,6 +593,8 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v)
 		list_for_each(tmp2, &server->smb_ses_list) {
 			ses = list_entry(tmp2, struct cifs_ses,
 					 smb_ses_list);
+			if (cifs_ses_exiting(ses))
+				continue;
 			list_for_each(tmp3, &ses->tcon_list) {
 				tcon = list_entry(tmp3,
 						  struct cifs_tcon,
-- 
2.34.1