Re: SMB2 dialect negotiation

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2012/9/20 Steve French <smfrench@xxxxxxxxx>:
> Respinning the SMB2/SMB3 mount patch.  As Jeff suggested, if we are
> going to negotiate only one dialect at a time, we will need a change
> something like the following.  In addition, we should pull the
> capabilities out of the structure which contains the default "values"
> for each dialect.  It also adds some missing SMB3 negotiated
> capabilities (which for the moment we don't turn on, but which we will
> need soon).
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index a39e5b7..e94825c 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -179,6 +179,7 @@ struct smb_rqst {
>  enum smb_version {
>         Smb_1 = 1,
>         Smb_21,
> +       Smb_30,
>  };
>
>  struct mid_q_entry;
> @@ -371,6 +372,8 @@ struct smb_version_operations {
>
>  struct smb_version_values {
>         char            *version_string;
> +       __u16           protocol_id;
> +       __u32           req_capabilities;
>         __u32           large_lock_type;
>         __u32           exclusive_lock_type;
>         __u32           shared_lock_type;
> @@ -1495,7 +1498,13 @@ extern mempool_t *cifs_mid_poolp;
>  #define SMB1_VERSION_STRING    "1.0"
>  extern struct smb_version_operations smb1_operations;
>  extern struct smb_version_values smb1_values;
> +#define SMB20_VERSION_STRING   "2.0"
> +/*extern struct smb_version_operations smb20_operations; */ /* not
> needed yet */
> +extern struct smb_version_values smb20_values;
>  #define SMB21_VERSION_STRING   "2.1"
>  extern struct smb_version_operations smb21_operations;
>  extern struct smb_version_values smb21_values;
> +#define SMB30_VERSION_STRING   "3.0"
> +/*extern struct smb_version_operations smb30_operations; */ /* not
> needed yet */
> +extern struct smb_version_values smb30_values;
>  #endif /* _CIFS_GLOB_H */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index a792282..2fdbe08 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -272,6 +272,7 @@ static const match_table_t cifs_cacheflavor_tokens = {
>  static const match_table_t cifs_smb_version_tokens = {
>         { Smb_1, SMB1_VERSION_STRING },
>         { Smb_21, SMB21_VERSION_STRING },
> +       { Smb_30, SMB30_VERSION_STRING },
>  };
>
>  static int ip_connect(struct TCP_Server_Info *server);
> @@ -1074,6 +1075,10 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol)
>                 vol->ops = &smb21_operations;
>                 vol->vals = &smb21_values;
>                 break;
> +       case Smb_30:
> +               vol->ops = &smb21_operations; /* currently identical with 2.1 */
> +               vol->vals = &smb30_values;
> +               break;
>  #endif
>         default:
>                 cERROR(1, "Unknown vers= option specified: %s", value);
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 2183bb3..503c1e8 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -643,8 +643,45 @@ struct smb_version_operations smb21_operations = {
>         .new_lease_key = smb2_new_lease_key,
>  };
>
> +
> +struct smb_version_values smb20_values = {
> +       .version_string = SMB20_VERSION_STRING,
> +       .protocol_id = SMB20_PROT_ID,
> +       .req_capabilities = SMB2_GLOBAL_CAP_DFS,
> +       .large_lock_type = 0,
> +       .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
> +       .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
> +       .unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
> +       .header_size = sizeof(struct smb2_hdr),
> +       .max_header_size = MAX_SMB2_HDR_SIZE,
> +       .read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
> +       .lock_cmd = SMB2_LOCK,
> +       .cap_unix = 0,
> +       .cap_nt_find = SMB2_NT_FIND,
> +       .cap_large_files = SMB2_LARGE_FILES,
> +};

I think we need vers=2.0 mount option to let user choose this structure.

> +
>  struct smb_version_values smb21_values = {
>         .version_string = SMB21_VERSION_STRING,
> +       .protocol_id = SMB21_PROT_ID,
> +       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING |
> SMB2_GLOBAL_CAP_LARGE_MTU,

A client can specify only SMB2_GLOBAL_CAP_DFS in request - other two
are set by the server in a response.

> +       .large_lock_type = 0,
> +       .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
> +       .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
> +       .unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
> +       .header_size = sizeof(struct smb2_hdr),
> +       .max_header_size = MAX_SMB2_HDR_SIZE,
> +       .read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
> +       .lock_cmd = SMB2_LOCK,
> +       .cap_unix = 0,
> +       .cap_nt_find = SMB2_NT_FIND,
> +       .cap_large_files = SMB2_LARGE_FILES,
> +};
> +
> +struct smb_version_values smb30_values = {
> +       .version_string = SMB30_VERSION_STRING,
> +       .protocol_id = SMB30_PROT_ID,
> +       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING |
> SMB2_GLOBAL_CAP_LARGE_MTU,
>         .large_lock_type = 0,
>         .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
>         .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index a7db95f..39d26cb 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -1,7 +1,7 @@
>  /*
>   *   fs/cifs/smb2pdu.c
>   *
> - *   Copyright (C) International Business Machines  Corp., 2009, 2011
> + *   Copyright (C) International Business Machines  Corp., 2009, 2012
>   *                 Etersoft, 2012
>   *   Author(s): Steve French (sfrench@xxxxxxxxxx)
>   *              Pavel Shilovsky (pshilovsky@xxxxxxxxx) 2012
> @@ -304,24 +304,6 @@ free_rsp_buf(int resp_buftype, void *rsp)
>                 cifs_buf_release(rsp);
>  }
>
> -#define SMB2_NUM_PROT 2
> -
> -#define SMB2_PROT   0
> -#define SMB21_PROT  1
> -#define BAD_PROT 0xFFFF
> -
> -#define SMB2_PROT_ID  0x0202
> -#define SMB21_PROT_ID 0x0210
> -#define BAD_PROT_ID   0xFFFF
> -
> -static struct {
> -       int index;
> -       __le16 name;
> -} smb2protocols[] = {
> -       {SMB2_PROT,  cpu_to_le16(SMB2_PROT_ID)},
> -       {SMB21_PROT, cpu_to_le16(SMB21_PROT_ID)},
> -       {BAD_PROT,   cpu_to_le16(BAD_PROT_ID)}
> -};
>
>  /*
>   *
> @@ -348,7 +330,6 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>         int resp_buftype;
>         struct TCP_Server_Info *server;
>         unsigned int sec_flags;
> -       u16 i;
>         u16 temp = 0;
>         int blob_offset, blob_length;
>         char *security_blob;
> @@ -377,11 +358,10 @@ SMB2_negotiate(const unsigned int xid, struct
> cifs_ses *ses)
>
>         req->hdr.SessionId = 0;
>
> -       for (i = 0; i < SMB2_NUM_PROT; i++)
> -               req->Dialects[i] = smb2protocols[i].name;
> +       req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);
>
> -       req->DialectCount = cpu_to_le16(i);
> -       inc_rfc1001_len(req, i * 2);
> +       req->DialectCount = cpu_to_le16(1); /* One vers= at a time for now */
> +       inc_rfc1001_len(req, 2);
>
>         /* only one of SMB2 signing flags may be set in SMB2 request */
>         if ((sec_flags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN)
> @@ -391,7 +371,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
>
>         req->SecurityMode = cpu_to_le16(temp);
>
> -       req->Capabilities = cpu_to_le32(SMB2_GLOBAL_CAP_DFS);
> +       req->Capabilities = cpu_to_le32(ses->server->vals->req_capabilities);

I think we need to separate Negotiate capabilities field and Session
Setup one. So, setting it to SMB2_GLOBAL_CAP_DFS here looks like my
bug: it should be 0 for SMB2.0/SMB2.1 and not 0 for SMB3.0.

The only place where we should set capabilities for SMB2.0/SMB2.1 is
Session Setup capabilities filed that can be 0 or SMB2_GLOBAL_CAP_DFS
for SMB2.0/SMB2.1/SMB3.0.

>
>         memcpy(req->ClientGUID, cifs_client_guid, SMB2_CLIENT_GUID_SIZE);
>
> @@ -416,10 +396,14 @@ SMB2_negotiate(const unsigned int xid, struct
> cifs_ses *ses)
>
>         cFYI(1, "mode 0x%x", rsp->SecurityMode);
>
> -       if (rsp->DialectRevision == smb2protocols[SMB21_PROT].name)
> +       /* BB we may eventually want to match the negotiated vs. requested
> +          dialect, even though we are only requesting one at a time */
> +       if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID))
> +               cFYI(1, "negotiated smb2.0 dialect");
> +       else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID))
>                 cFYI(1, "negotiated smb2.1 dialect");
> -       else if (rsp->DialectRevision == smb2protocols[SMB2_PROT].name)
> -               cFYI(1, "negotiated smb2 dialect");
> +       else if (rsp->DialectRevision == cpu_to_le16(SMB30_PROT_ID))
> +               cFYI(1, "negotiated smb3.0 dialect");
>         else {
>                 cERROR(1, "Illegal dialect returned by server %d",
>                            le16_to_cpu(rsp->DialectRevision));
> diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
> index da09922..4cb4ced 100644
> --- a/fs/cifs/smb2pdu.h
> +++ b/fs/cifs/smb2pdu.h
> @@ -163,9 +163,15 @@ struct smb2_negotiate_req {
>         __le32 Capabilities;
>         __u8   ClientGUID[SMB2_CLIENT_GUID_SIZE];
>         __le64 ClientStartTime; /* MBZ */
> -       __le16 Dialects[2]; /* variable length */
> +       __le16 Dialects[1]; /* One dialect (vers=) at a time for now */
>  } __packed;
>
> +/* Dialects */
> +#define SMB20_PROT_ID 0x0202
> +#define SMB21_PROT_ID 0x0210
> +#define SMB30_PROT_ID 0x0300
> +#define BAD_PROT_ID   0xFFFF
> +
>  /* SecurityMode flags */
>  #define        SMB2_NEGOTIATE_SIGNING_ENABLED  0x0001
>  #define SMB2_NEGOTIATE_SIGNING_REQUIRED        0x0002
> @@ -173,6 +179,10 @@ struct smb2_negotiate_req {
>  #define SMB2_GLOBAL_CAP_DFS            0x00000001
>  #define SMB2_GLOBAL_CAP_LEASING                0x00000002 /* Resp only New to SMB2.1 */
>  #define SMB2_GLOBAL_CAP_LARGE_MTU      0X00000004 /* Resp only New to SMB2.1 */
> +#define SMB2_GLOBAL_CAP_MULTI_CHANNEL  0x00000008 /* New to SMB3 */
> +#define SMB2_GLOBAL_CAP_PERSISTENT_HANDLES 0x00000010 /* New to SMB3 */
> +#define SMB2_GLOBAL_CAP_DIRECTORY_LEASING  0x00000020 /* New to SMB3 */
> +#define SMB2_GLOBAL_CAP_ENCRYPTION     0x00000040 /* New to SMB3 */
>  /* Internal types */
>  #define SMB2_NT_FIND                   0x00100000
>  #define SMB2_LARGE_FILES               0x00200000
>
> --
> Thanks,
>
> Steve



-- 
Best regards,
Pavel Shilovsky.
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