ksmbd: Fix dangling pointer in krb_authenticate

krb_authenticate frees sess->user and does not set the pointer
to NULL. It calls ksmbd_krb5_authenticate to reinitialise
sess->user but that function may return without doing so. If
that happens then smb2_sess_setup, which calls krb_authenticate,
will be accessing free'd memory when it later uses sess->user.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Heelan <seanheelan@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Sean Heelan 2025-04-07 11:26:50 +00:00 committed by Steve French
parent 8ffd015db8
commit 1e440d5b25

View File

@ -1602,8 +1602,10 @@ static int krb5_authenticate(struct ksmbd_work *work,
if (prev_sess_id && prev_sess_id != sess->id)
destroy_previous_session(conn, sess->user, prev_sess_id);
if (sess->state == SMB2_SESSION_VALID)
if (sess->state == SMB2_SESSION_VALID) {
ksmbd_free_user(sess->user);
sess->user = NULL;
}
retval = ksmbd_krb5_authenticate(sess, in_blob, in_len,
out_blob, &out_len);