This is a note to let you know that I've just added the patch titled ksmbd: validate the zero field of packet header to the 6.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ksmbd-validate-the-zero-field-of-packet-header.patch and it can be found in the queue-6.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit fec258a3fb75ba808c7ddb3889556e171f0c1a72 Author: Li Nan <linan122@xxxxxxxxxx> Date: Fri Dec 8 14:56:47 2023 +0800 ksmbd: validate the zero field of packet header [ Upstream commit 516b3eb8c8065f7465f87608d37a7ed08298c7a5 ] The SMB2 Protocol requires that "The first byte of the Direct TCP transport packet header MUST be zero (0x00)"[1]. Commit 1c1bcf2d3ea0 ("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: 1c1bcf2d3ea0 ("ksmbd: validate smb request protocol id") Signed-off-by: Li Nan <linan122@xxxxxxxxxx> Acked-by: Tom Talpey <tom@xxxxxxxxxx> Acked-by: Namjae Jeon <linkinjeon@xxxxxxxxxx> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c index 6691ae68af0c..7c98bf699772 100644 --- a/fs/smb/server/smb_common.c +++ b/fs/smb/server/smb_common.c @@ -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;