PATCH] smb3: include current dialect (SMB3.1.1) when version 3 or greater requested on mount

[Pavel Shilovsky]

пн, 1 февр. 2021 г. в 22:15, Steve French <smfrench at gmail.com>:
>
> SMB3.1.1 is the newest, and preferred dialect, and is included in
> the requested dialect list by default (ie if no vers= is specified
> on mount) but it should also be requested if SMB3 or later is requested
> (vers=3 instead of a specific dialect: vers=2.1, vers=3.02 or vers=3.0).
>
> Currently specifying "vers=3" only requests smb3.0 and smb3.02 but this
> patch fixes it to also request smb3.1.1 dialect, as it is the newest
> and most secure dialect and is a "version 3 or later" dialect (the intent
> of "vers=3").
>
> Signed-off-by: Steve French <stfrench at microsoft.com>
> Suggested-by: Pavel Shilovsky <pshilov at microsoft.com>
> ---
>  fs/cifs/fs_context.c |  2 +-
>  fs/cifs/smb2pdu.c    | 19 +++++++++++++------
>  2 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
> index 5111aadfdb6b..479c24695281 100644
> --- a/fs/cifs/fs_context.c
> +++ b/fs/cifs/fs_context.c
> @@ -391,7 +391,7 @@ cifs_parse_smb_version(char *value, struct
> smb3_fs_context *ctx, bool is_smb3)
>   ctx->vals = &smb3any_values;
>   break;
>   case Smb_default:
> - ctx->ops = &smb30_operations; /* currently identical with 3.0 */
> + ctx->ops = &smb30_operations;
>   ctx->vals = &smbdefault_values;
>   break;
>   default:
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 794fc3b68b4f..52625549c3b5 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -814,8 +814,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>      SMB3ANY_VERSION_STRING) == 0) {
>   req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
>   req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> - req->DialectCount = cpu_to_le16(2);
> - total_len += 4;
> + req->Dialects[2] = cpu_to_le16(SMB311_PROT_ID);
> + req->DialectCount = cpu_to_le16(3);
> + total_len += 6;
>   } else if (strcmp(server->vals->version_string,
>      SMBDEFAULT_VERSION_STRING) == 0) {
>   req->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> @@ -848,6 +849,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>   memcpy(req->ClientGUID, server->client_guid,
>   SMB2_CLIENT_GUID_SIZE);
>   if ((server->vals->protocol_id == SMB311_PROT_ID) ||
> +     (strcmp(server->vals->version_string,
> +      SMB3ANY_VERSION_STRING) == 0) ||
>       (strcmp(server->vals->version_string,
>        SMBDEFAULT_VERSION_STRING) == 0))
>   assemble_neg_contexts(req, server, &total_len);
> @@ -883,6 +886,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>   cifs_server_dbg(VFS,
>   "SMB2.1 dialect returned but not requested\n");
>   return -EIO;
> + } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {

I think we should include comment "/* ops set to 3.0 by default for
default so update */" as in smbdefault case to improve readability.

> + server->ops = &smb311_operations;
> + server->vals = &smb311_values;
>   }
>   } else if (strcmp(server->vals->version_string,
>      SMBDEFAULT_VERSION_STRING) == 0) {
> @@ -1042,10 +1048,11 @@ int smb3_validate_negotiate(const unsigned int
> xid, struct cifs_tcon *tcon)
>   SMB3ANY_VERSION_STRING) == 0) {
>   pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
>   pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
> - pneg_inbuf->DialectCount = cpu_to_le16(2);
> - /* structure is big enough for 3 dialects, sending only 2 */
> + pneg_inbuf->Dialects[2] = cpu_to_le16(SMB311_PROT_ID);
> + pneg_inbuf->DialectCount = cpu_to_le16(3);
> + /* SMB 2.1 not included so subtract one dialect from len */
>   inbuflen = sizeof(*pneg_inbuf) -
> - (2 * sizeof(pneg_inbuf->Dialects[0]));
> + (sizeof(pneg_inbuf->Dialects[0]));
>   } else if (strcmp(server->vals->version_string,
>   SMBDEFAULT_VERSION_STRING) == 0) {
>   pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
> @@ -1053,7 +1060,7 @@ int smb3_validate_negotiate(const unsigned int
> xid, struct cifs_tcon *tcon)
>   pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
>   pneg_inbuf->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
>   pneg_inbuf->DialectCount = cpu_to_le16(4);
> - /* structure is big enough for 3 dialects */
> + /* structure is big enough for 4 dialects */
>   inbuflen = sizeof(*pneg_inbuf);
>   } else {
>   /* otherwise specific dialect was requested */
>
> --
> Thanks,
>
> Steve

Looks good overall.

Reviewed-by: Pavel Shilovsky <pshilov at microsoft.com>
--
Best regards,
Pavel Shilovsky