linux-kernel - Re: [PATCH 4.13 28/43] SMB3: Validate negotiate request must always be signed

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Date:   Tue, 31 Oct 2017 15:02:11 +0200
From:   Thomas Backlund <tmb@...eia.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-kernel@...r.kernel.org>
CC:     <stable@...r.kernel.org>, Steve French <smfrench@...il.com>
Subject: Re: [PATCH 4.13 28/43] SMB3: Validate negotiate request must always
 be signed

Den 31.10.2017 kl. 11:55, skrev Greg Kroah-Hartman:
> 4.13-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Steve French <smfrench@...il.com>
> 
> commit 4587eee04e2ac7ac3ac9fa2bc164fb6e548f99cd upstream.
> 
> According to MS-SMB2 3.2.55 validate_negotiate request must
> always be signed. Some Windows can fail the request if you send it unsigned
> 
> See kernel bugzilla bug 197311
> 
> Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
> Signed-off-by: Steve French <smfrench@...il.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
> ---
>   fs/cifs/smb2pdu.c |    3 +++
>   1 file changed, 3 insertions(+)
> 
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -1963,6 +1963,9 @@ SMB2_ioctl(const unsigned int xid, struc
>   	} else
>   		iov[0].iov_len = get_rfc1002_length(req) + 4;
>   
> +	/* validate negotiate request must be signed - see MS-SMB2 3.2.5.5 */
> +	if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO)
> +		req->hdr.sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
>   
>   	rc = SendReceive2(xid, ses, iov, n_iov, &resp_buftype, flags, &rsp_iov);
>   	cifs_small_buf_release(req);
> 
> 
> 

This one needs to be backported to all stable kernels as the commit that 
introduced the regression:
'
0603c96f3af50e2f9299fa410c224ab1d465e0f9
SMB: Validate negotiate (to protect against downgrade) even if signing off

is backported in stable trees as of: 4.9.53, 4.4.90, 3.18.73


--
Thomas