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Thu, 27 Nov 2025 07:05:17 -0800 (PST) Received: from cherrypc.astracloud.ru ([81.9.21.4]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-596bf8b0ea7sm463504e87.42.2025.11.27.07.05.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Nov 2025 07:05:17 -0800 (PST) From: Nazar Kalashnikov X-Google-Original-From: Nazar Kalashnikov To: stable@vger.kernel.org, Greg Kroah-Hartman Cc: Nazar Kalashnikov , Namjae Jeon , Steve French , Sergey Senozhatsky , Tom Talpey , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org, Sean Heelan , Steve French Subject: [PATCH 6.1] ksmbd: fix use-after-free in session logoff Date: Thu, 27 Nov 2025 18:05:10 +0300 Message-ID: <20251127150512.106552-1-nkalashnikov@astralinux.ru> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Nazar Kalashnikov From: Sean Heelan commit 2fc9feff45d92a92cd5f96487655d5be23fb7e2b upstream. The sess->user object can currently be in use by another thread, for example if another connection has sent a session setup request to bind to the session being free'd. The handler for that connection could be in the smb2_sess_setup function which makes use of sess->user. Signed-off-by: Sean Heelan Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Nazar Kalashnikov --- Backport fix for CVE-2025-37899 fs/smb/server/smb2pdu.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index d2dca5d2f17c..f72ef3fe4968 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -2252,10 +2252,6 @@ int smb2_session_logoff(struct ksmbd_work *work) sess->state =3D SMB2_SESSION_EXPIRED; up_write(&conn->session_lock); =20 - if (sess->user) { - ksmbd_free_user(sess->user); - sess->user =3D NULL; - } ksmbd_all_conn_set_status(sess_id, KSMBD_SESS_NEED_NEGOTIATE); =20 rsp->StructureSize =3D cpu_to_le16(4); --=20 2.39.2