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linux/debian/patches/patchset-pf/smb/0009-ksmbd-fix-null-pointer-dereference-in-destroy_previo.patch
2025-06-19 18:06:35 +03:00

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From 9d330e139e9993f2489fcfe3048c8e737085646d Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Fri, 13 Jun 2025 10:12:43 +0900
Subject: ksmbd: fix null pointer dereference in destroy_previous_session
If client set ->PreviousSessionId on kerberos session setup stage,
NULL pointer dereference error will happen. Since sess->user is not
set yet, It can pass the user argument as NULL to destroy_previous_session.
sess->user will be set in ksmbd_krb5_authenticate(). So this patch move
calling destroy_previous_session() after ksmbd_krb5_authenticate().
Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-27391
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
fs/smb/server/smb2pdu.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -1607,17 +1607,18 @@ static int krb5_authenticate(struct ksmb
out_len = work->response_sz -
(le16_to_cpu(rsp->SecurityBufferOffset) + 4);
- /* Check previous session */
- prev_sess_id = le64_to_cpu(req->PreviousSessionId);
- if (prev_sess_id && prev_sess_id != sess->id)
- destroy_previous_session(conn, sess->user, prev_sess_id);
-
retval = ksmbd_krb5_authenticate(sess, in_blob, in_len,
out_blob, &out_len);
if (retval) {
ksmbd_debug(SMB, "krb5 authentication failed\n");
return -EINVAL;
}
+
+ /* Check previous session */
+ prev_sess_id = le64_to_cpu(req->PreviousSessionId);
+ if (prev_sess_id && prev_sess_id != sess->id)
+ destroy_previous_session(conn, sess->user, prev_sess_id);
+
rsp->SecurityBufferLength = cpu_to_le16(out_len);
if ((conn->sign || server_conf.enforced_signing) ||