From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB67513AEB for ; Mon, 12 Jun 2023 10:51:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52CC5C433D2; Mon, 12 Jun 2023 10:51:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686567103; bh=MMy9Buj9E2uz57uhjwsO0fEk35IQe12oumUjy85CqYw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JX8mhR9cAWLKahShGc8IJF53LhtCaRPSxH7V8esXV5z9xQtZxA9LhVCs8a9Dsl7rP M5EcEJNW4HWwbrDs0uniwykIRKxfYGvkHrJA6/VfRLAHFkT0gyZz/KpIXaJ7u40uxR CNcEVbhxhPxKi7SotTyD8dPDnpNe2v3vLGKQ46HQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chih-Yen Chang , Namjae Jeon , Steve French Subject: [PATCH 6.3 152/160] ksmbd: check the validation of pdu_size in ksmbd_conn_handler_loop Date: Mon, 12 Jun 2023 12:28:04 +0200 Message-ID: <20230612101722.027209670@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101715.129581706@linuxfoundation.org> References: <20230612101715.129581706@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Namjae Jeon commit 368ba06881c395f1c9a7ba22203cf8d78b4addc0 upstream. The length field of netbios header must be greater than the SMB header sizes(smb1 or smb2 header), otherwise the packet is an invalid SMB packet. If `pdu_size` is 0, ksmbd allocates a 4 bytes chunk to `conn->request_buf`. In the function `get_smb2_cmd_val` ksmbd will read cmd from `rcv_hdr->Command`, which is `conn->request_buf + 12`, causing the KASAN detector to print the following error message: [ 7.205018] BUG: KASAN: slab-out-of-bounds in get_smb2_cmd_val+0x45/0x60 [ 7.205423] Read of size 2 at addr ffff8880062d8b50 by task ksmbd:42632/248 ... [ 7.207125] [ 7.209191] get_smb2_cmd_val+0x45/0x60 [ 7.209426] ksmbd_conn_enqueue_request+0x3a/0x100 [ 7.209712] ksmbd_server_process_request+0x72/0x160 [ 7.210295] ksmbd_conn_handler_loop+0x30c/0x550 [ 7.212280] kthread+0x160/0x190 [ 7.212762] ret_from_fork+0x1f/0x30 [ 7.212981] Cc: stable@vger.kernel.org Reported-by: Chih-Yen Chang Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/ksmbd/connection.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/fs/ksmbd/connection.c +++ b/fs/ksmbd/connection.c @@ -294,6 +294,9 @@ bool ksmbd_conn_alive(struct ksmbd_conn return true; } +#define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr)) +#define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4) + /** * ksmbd_conn_handler_loop() - session thread to listen on new smb requests * @p: connection instance @@ -350,6 +353,9 @@ int ksmbd_conn_handler_loop(void *p) if (pdu_size > MAX_STREAM_PROT_LEN) break; + if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE) + break; + /* 4 for rfc1002 length field */ /* 1 for implied bcc[0] */ size = pdu_size + 4 + 1; @@ -377,6 +383,12 @@ int ksmbd_conn_handler_loop(void *p) continue; } + if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId == + SMB2_PROTO_NUMBER) { + if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE) + break; + } + if (!default_conn_ops.process_fn) { pr_err("No connection request callback\n"); break;