[PATCH] smb3: add smb3.1.1 to default dialect list

[Steve French]

Minor updates to the structure (to make it one dialect longer) used in
validate_negotiate


On Thu, Jan 3, 2019 at 2:43 AM Steve French <smfrench at gmail.com> wrote:
>
> SMB3.1.1 dialect has additional security (among other) features
> and should be requested when mounting to modern servers so it
> can be used if the server supports it.
>
> Add SMB3.1.1 to the default list of dialects requested.
>
> Signed-off-by: Steve French <stfrench at microsoft.com>
> ---
>  fs/cifs/smb2pdu.c | 38 ++++++++++++++++++++++++++------------
>  1 file changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index e283590955cd..9bc1dec84b35 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -451,10 +451,6 @@ smb2_plain_req_init(__le16 smb2_command, struct
> cifs_tcon *tcon,
>  }
>
>
> -/* offset is sizeof smb2_negotiate_req but rounded up to 8 bytes */
> -#define OFFSET_OF_NEG_CONTEXT 0x68  /* sizeof(struct smb2_negotiate_req) */
> -
> -
>  #define SMB2_PREAUTH_INTEGRITY_CAPABILITIES    cpu_to_le16(1)
>  #define SMB2_ENCRYPTION_CAPABILITIES        cpu_to_le16(2)
>  #define SMB2_POSIX_EXTENSIONS_AVAILABLE        cpu_to_le16(0x100)
> @@ -491,10 +487,24 @@ static void
>  assemble_neg_contexts(struct smb2_negotiate_req *req,
>                unsigned int *total_len)
>  {
> -    char *pneg_ctxt = (char *)req + OFFSET_OF_NEG_CONTEXT;
> +    char *pneg_ctxt = (char *)req;
>      unsigned int ctxt_len;
>
> -    *total_len += 2; /* Add 2 due to round to 8 byte boundary for 1st ctxt */
> +    if (*total_len > 200) {
> +        /* In case length corrupted don't want to overrun smb buffer */
> +        cifs_dbg(VFS, "Bad frame length assembling neg contexts\n");
> +        return;
> +    }
> +
> +    /*
> +     * round up total_len of fixed part of SMB3 negotiate request to 8
> +     * byte boundary before adding negotiate contexts
> +     */
> +    *total_len = roundup(*total_len, 8);
> +
> +    pneg_ctxt = (*total_len) + (char *)req;
> +    req->NegotiateContextOffset = cpu_to_le32(*total_len);
> +
>      build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
>      ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_preauth_neg_context), 8) * 8;
>      *total_len += ctxt_len;
> @@ -508,7 +518,6 @@ assemble_neg_contexts(struct smb2_negotiate_req *req,
>      build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);
>      *total_len += sizeof(struct smb2_posix_neg_context);
>
> -    req->NegotiateContextOffset = cpu_to_le32(OFFSET_OF_NEG_CONTEXT);
>      req->NegotiateContextCount = cpu_to_le16(3);
>  }
>
> @@ -724,8 +733,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>          req->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
>          req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
>          req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> -        req->DialectCount = cpu_to_le16(3);
> -        total_len += 6;
> +        req->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
> +        req->DialectCount = cpu_to_le16(4);
> +        total_len += 8;
>      } else {
>          /* otherwise send specific dialect */
>          req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);
> @@ -749,7 +759,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>      else {
>          memcpy(req->ClientGUID, server->client_guid,
>              SMB2_CLIENT_GUID_SIZE);
> -        if (ses->server->vals->protocol_id == SMB311_PROT_ID)
> +        if ((ses->server->vals->protocol_id == SMB311_PROT_ID) ||
> +            (strcmp(ses->server->vals->version_string,
> +             SMBDEFAULT_VERSION_STRING) == 0))
>              assemble_neg_contexts(req, &total_len);
>      }
>      iov[0].iov_base = (char *)req;
> @@ -794,7 +806,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>          } else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
>              /* ops set to 3.0 by default for default so update */
>              ses->server->ops = &smb21_operations;
> -        }
> +        } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
> +            ses->server->ops = &smb311_operations;
>      } else if (le16_to_cpu(rsp->DialectRevision) !=
>                  ses->server->vals->protocol_id) {
>          /* if requested single dialect ensure returned dialect matched */
> @@ -947,7 +960,8 @@ int smb3_validate_negotiate(const unsigned int
> xid, struct cifs_tcon *tcon)
>          pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
>          pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
>          pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
> -        pneg_inbuf->DialectCount = cpu_to_le16(3);
> +        pneg_inbuf->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
> +        pneg_inbuf->DialectCount = cpu_to_le16(4);
>          /* structure is big enough for 3 dialects */
>          inbuflen = sizeof(*pneg_inbuf);
>      } else {
> --
>
>
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve
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