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From: Steve French <smfrench@gmail.com>
To: "Aurélien Aptel" <aaptel@suse.com>
Cc: CIFS <linux-cifs@vger.kernel.org>,
	"Stefan (metze) Metzmacher" <metze@samba.org>
Subject: Re: [PATCH v1 1/2] cifs: set server->cipher_type to AES-128-CCM for SMB3.0
Date: Thu, 27 May 2021 15:23:55 -0500	[thread overview]
Message-ID: <CAH2r5mv3CfzEdWFrGzA2JYuW4dgHcXU7CDuZ6X=sqcjx6fH3mA@mail.gmail.com> (raw)
In-Reply-To: <20210521151928.17730-2-aaptel@suse.com>

Added cc:stable

On Fri, May 21, 2021 at 10:19 AM Aurélien Aptel <aaptel@suse.com> wrote:
>
> From: Aurelien Aptel <aaptel@suse.com>
>
> SMB3.0 doesn't have encryption negotiate context but simply uses
> the SMB2_GLOBAL_CAP_ENCRYPTION flag.
>
> When that flag is present in the neg response cifs.ko uses AES-128-CCM
> which is the only cipher available in this context.
>
> cipher_type was set to the server cipher only when parsing encryption
> negotiate context (SMB3.1.1).
>
> For SMB3.0 it was set to 0. This means cipher_type value can be 0 or 1
> for AES-128-CCM.
>
> Fix this by checking for SMB3.0 and encryption capability and setting
> cipher_type appropriately.
>
> Signed-off-by: Aurelien Aptel <aaptel@suse.com>
> ---
>  fs/cifs/smb2pdu.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 9f24eb88297a..c205f93e0a10 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -958,6 +958,13 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>         /* Internal types */
>         server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;
>
> +       /*
> +        * SMB3.0 supports only 1 cipher and doesn't have a encryption neg context
> +        * Set the cipher type manually.
> +        */
> +       if (server->dialect == SMB30_PROT_ID && (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
> +               server->cipher_type = SMB2_ENCRYPTION_AES128_CCM;
> +
>         security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
>                                                (struct smb2_sync_hdr *)rsp);
>         /*
> --
> 2.31.1
>


-- 
Thanks,

Steve

  parent reply	other threads:[~2021-05-27 20:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21 15:19 [PATCH v1 0/2] Change CIFS_FULL_KEY_DUMP ioctl to return variable size keys Aurélien Aptel
2021-05-21 15:19 ` [PATCH v1 1/2] cifs: set server->cipher_type to AES-128-CCM for SMB3.0 Aurélien Aptel
2021-05-21 18:39   ` Steve French
2021-05-28  8:37     ` Aurélien Aptel
2021-05-27 20:23   ` Steve French [this message]
2021-05-21 15:19 ` [PATCH v1 2/2] cifs: change format of CIFS_FULL_KEY_DUMP ioctl Aurélien Aptel
2021-05-21 19:47   ` Steve French
2021-05-21 15:42 ` [PATCH v1 0/2] Change CIFS_FULL_KEY_DUMP ioctl to return variable size keys Paulo Alcantara

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