Commit 516b3eb8 authored by Li Nan's avatar Li Nan Committed by Steve French
Browse files

ksmbd: validate the zero field of packet header 

The SMB2 Protocol requires that "The first byte of the Direct TCP
transport packet header MUST be zero (0x00)"[1]. Commit 1c1bcf2d
("ksmbd: validate smb request protocol id") removed the validation of
this 1-byte zero. Add the validation back now.

[1]: [MS-SMB2] - v20230227, page 30.
https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-SMB2/%5bMS-SMB2%5d-230227.pdf



Fixes: 1c1bcf2d ("ksmbd: validate smb request protocol id")
Signed-off-by: default avatarLi Nan <linan122@huawei.com>
Acked-by: default avatarTom Talpey <tom@talpey.com>
Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 0dd3ee31

fs/smb/server/smb_common.c

+5 −1
Original line number Diff line number Diff line
@@ -158,8 +158,12 @@ int ksmbd_verify_smb_message(struct ksmbd_work *work) 
 */

bool ksmbd_smb_request(struct ksmbd_conn *conn)

{

	__le32 *proto = (__le32 *)smb2_get_msg(conn->request_buf);

	__le32 *proto;



	if (conn->request_buf[0] != 0)

		return false;



	proto = (__le32 *)smb2_get_msg(conn->request_buf);

	if (*proto == SMB2_COMPRESSION_TRANSFORM_ID) {

		pr_err_ratelimited("smb2 compression not support yet");

		return false;