Re: [PATCH v3 13/32] CIFS: Make demultiplex_thread work with SMB2 code

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On Fri, 13 Jul 2012 11:53:26 +0400
Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:

> From: Pavel Shilovsky <piastryyy@xxxxxxxxx>
> 
> Now we can process SMB2 messages: check message, get message id
> and wakeup awaiting routines.
> 
> Signed-off-by: Pavel Shilovsky <piastryyy@xxxxxxxxx>
> ---
>  fs/cifs/Makefile     |    2 +-
>  fs/cifs/cifs_debug.c |    2 +-
>  fs/cifs/smb2misc.c   |  307 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/cifs/smb2ops.c    |   37 ++++++
>  fs/cifs/smb2pdu.h    |   36 ++++++
>  fs/cifs/smb2proto.h  |    2 +
>  6 files changed, 384 insertions(+), 2 deletions(-)
>  create mode 100644 fs/cifs/smb2misc.c
> 
> diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
> index a73d7f8..b77e9ec 100644
> --- a/fs/cifs/Makefile
> +++ b/fs/cifs/Makefile
> @@ -16,4 +16,4 @@ cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o
>  
>  cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o cache.o
>  
> -cifs-$(CONFIG_CIFS_SMB2) += smb2ops.o smb2maperror.o smb2transport.o
> +cifs-$(CONFIG_CIFS_SMB2) += smb2ops.o smb2maperror.o smb2transport.o smb2misc.o
> diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
> index e814052..8aa8693 100644
> --- a/fs/cifs/cifs_debug.c
> +++ b/fs/cifs/cifs_debug.c
> @@ -65,7 +65,7 @@ void cifs_dump_detail(void *buf)
>  	cERROR(1, "Cmd: %d Err: 0x%x Flags: 0x%x Flgs2: 0x%x Mid: %d Pid: %d",
>  		  smb->Command, smb->Status.CifsError,
>  		  smb->Flags, smb->Flags2, smb->Mid, smb->Pid);
> -	cERROR(1, "smb buf %p len %d", smb, smbCalcSize(smb));
> +	cERROR(1, "smb buf %p len %u", smb, smbCalcSize(smb));
>  #endif /* CONFIG_CIFS_DEBUG2 */
>  }
>  
> diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
> new file mode 100644
> index 0000000..d422678
> --- /dev/null
> +++ b/fs/cifs/smb2misc.c
> @@ -0,0 +1,307 @@
> +/*
> + *   fs/cifs/smb2misc.c
> + *
> + *   Copyright (C) International Business Machines  Corp., 2002,2011
> + *                 Etersoft, 2012
> + *   Author(s): Steve French (sfrench@xxxxxxxxxx)
> + *              Pavel Shilovsky (pshilovsky@xxxxxxxxx) 2012
> + *
> + *   This library is free software; you can redistribute it and/or modify
> + *   it under the terms of the GNU Lesser General Public License as published
> + *   by the Free Software Foundation; either version 2.1 of the License, or
> + *   (at your option) any later version.
> + *
> + *   This library is distributed in the hope that it will be useful,
> + *   but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> + *   the GNU Lesser General Public License for more details.
> + *
> + *   You should have received a copy of the GNU Lesser General Public License
> + *   along with this library; if not, write to the Free Software
> + *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +#include <linux/ctype.h>
> +#include "smb2pdu.h"
> +#include "cifsglob.h"
> +#include "cifsproto.h"
> +#include "smb2proto.h"
> +#include "cifs_debug.h"
> +#include "cifs_unicode.h"
> +#include "smb2status.h"
> +
> +static int
> +check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
> +{
> +	/*
> +	 * Make sure that this really is an SMB, that it is a response,
> +	 * and that the message ids match.
> +	 */
> +	if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
> +	    (mid == hdr->MessageId)) {
> +		if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
> +			return 0;
> +		else {
> +			/* only one valid case where server sends us request */
> +			if (hdr->Command == SMB2_OPLOCK_BREAK)
> +				return 0;
> +			else
> +				cERROR(1, "Received Request not response");
> +		}
> +	} else { /* bad signature or mid */
> +		if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
> +			cERROR(1, "Bad protocol string signature header %x",
> +				  *(unsigned int *) hdr->ProtocolId);
> +		if (mid != hdr->MessageId)
> +			cERROR(1, "Mids do not match");

			This error message isn't as helpful as it could
			be. Perhaps you could print the mid and the
			hdr->MessageId?

> +	}
> +	cERROR(1, "Bad SMB detected. The Mid=%llu", hdr->MessageId);
> +	return 1;
> +}
> +
> +/*
> + *  The following table defines the expected "StructureSize" of SMB2 responses
> + *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS responses.
> + *
> + *  Note that commands are defined in smb2pdu.h in le16 but the array below is
> + *  indexed by command in host byte order
> + */
> +static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
> +	/* SMB2_NEGOTIATE */ __constant_cpu_to_le16(65),
> +	/* SMB2_SESSION_SETUP */ __constant_cpu_to_le16(9),
> +	/* SMB2_LOGOFF */ __constant_cpu_to_le16(4),
> +	/* SMB2_TREE_CONNECT */ __constant_cpu_to_le16(16),
> +	/* SMB2_TREE_DISCONNECT */ __constant_cpu_to_le16(4),
> +	/* SMB2_CREATE */ __constant_cpu_to_le16(89),
> +	/* SMB2_CLOSE */ __constant_cpu_to_le16(60),
> +	/* SMB2_FLUSH */ __constant_cpu_to_le16(4),
> +	/* SMB2_READ */ __constant_cpu_to_le16(17),
> +	/* SMB2_WRITE */ __constant_cpu_to_le16(17),
> +	/* SMB2_LOCK */ __constant_cpu_to_le16(4),
> +	/* SMB2_IOCTL */ __constant_cpu_to_le16(49),
> +	/* BB CHECK this ... not listed in documentation */
> +	/* SMB2_CANCEL */ __constant_cpu_to_le16(0),
> +	/* SMB2_ECHO */ __constant_cpu_to_le16(4),
> +	/* SMB2_QUERY_DIRECTORY */ __constant_cpu_to_le16(9),
> +	/* SMB2_CHANGE_NOTIFY */ __constant_cpu_to_le16(9),
> +	/* SMB2_QUERY_INFO */ __constant_cpu_to_le16(9),
> +	/* SMB2_SET_INFO */ __constant_cpu_to_le16(2),
> +	/* BB FIXME can also be 44 for lease break */
> +	/* SMB2_OPLOCK_BREAK */ __constant_cpu_to_le16(24)
> +};
> +
> +int
> +smb2_check_message(char *buf, unsigned int length)
> +{
> +	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
> +	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
> +	__u64 mid = hdr->MessageId;
> +	__u32 len = get_rfc1002_length(buf);
> +	__u32 clc_len;  /* calculated length */
> +	int command;
> +
> +	/* BB disable following printk later */
> +	cFYI(1, "%s length: 0x%x, smb_buf_length: 0x%x", __func__, length, len);
> +
> +	/*
> +	 * Add function to do table lookup of StructureSize by command
> +	 * ie Validate the wct via smb2_struct_sizes table above
> +	 */
> +
> +	if (length < 2 + sizeof(struct smb2_hdr)) {

	Why 2 here? In the SMB1 code, the 2 is the width of the BCC
	field. Here, I'm not sure I understand what it's for. Is it the
	StructureSize2? If so, why not just use sizeof(struct smb2_pdu) ?

> +		if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
> +			pdu->StructureSize2 = 0;
> +			/*
> +			 * As with SMB/CIFS, on some error cases servers may
> +			 * not return wct properly
> +			 */
> +			return 0;
> +		} else {
> +			cERROR(1, "Length less than SMB header size");
> +		}
> +		return 1;
> +	}
> +	if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
> +		cERROR(1, "SMB length greater than maximum, mid=%lld", mid);
> +		return 1;
> +	}
> +
> +	if (check_smb2_hdr(hdr, mid))
> +		return 1;
> +
> +	if (hdr->StructureSize != SMB2_HEADER_SIZE) {
> +		cERROR(1, "Illegal structure size %d",
> +			  le16_to_cpu(hdr->StructureSize));
> +		return 1;
> +	}
> +

The name SMB2_HEADER_SIZE is confusing since it's not the header size,
but the fixed value of hdr->StructureSize for SMB2. Renaming that would
be nice.

> +	command = le16_to_cpu(hdr->Command);
> +	if (command >= NUMBER_OF_SMB2_COMMANDS) {
> +		cERROR(1, "Illegal SMB2 command %d", command);
> +		return 1;
> +	}
> +
> +	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
> +		if (hdr->Status == 0 ||
> +		    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2) {
> +			/* error packets have 9 byte structure size */
> +			cERROR(1, "Illegal response size %u for command %d",
> +				   le16_to_cpu(pdu->StructureSize2), command);
> +			return 1;
> +		}
> +	}
> +
> +	if (4 + len != length) {
> +		cERROR(1, "Total length %u RFC1002 length %u mismatch mid %llu",
> +			  length, 4 + len, mid);
> +		return 1;
> +	}
> +
> +	clc_len = smb2_calc_size(hdr);
> +
> +	if (4 + len != clc_len) {
> +		cFYI(1, "Calculated size %u length %u mismatch mid %llu",
> +			clc_len, 4 + len, mid);
> +		if (clc_len == 4 + len + 1) /* BB FIXME (fix samba) */
> +			return 0; /* BB workaround Samba 3 bug SessSetup rsp */

If it's only for SessSetup, then might it make sense to limit the above
workaround to only when command == SMB2_SESSION_SETUP?

> +		return 1;
> +	}
> +	return 0;
> +}
> +
> +/*
> + * The size of the variable area depends on the offset and length fields
> + * located in different fields for various SMB2 responses. SMB2 responses
> + * with no variable length info, show an offset of zero for the offset field.
> + */
> +static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
> +	/* SMB2_NEGOTIATE */ true,
> +	/* SMB2_SESSION_SETUP */ true,
> +	/* SMB2_LOGOFF */ false,
> +	/* SMB2_TREE_CONNECT */	false,
> +	/* SMB2_TREE_DISCONNECT */ false,
> +	/* SMB2_CREATE */ true,
> +	/* SMB2_CLOSE */ false,
> +	/* SMB2_FLUSH */ false,
> +	/* SMB2_READ */	true,
> +	/* SMB2_WRITE */ false,
> +	/* SMB2_LOCK */	false,
> +	/* SMB2_IOCTL */ true,
> +	/* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
> +	/* SMB2_ECHO */ false,
> +	/* SMB2_QUERY_DIRECTORY */ true,
> +	/* SMB2_CHANGE_NOTIFY */ true,
> +	/* SMB2_QUERY_INFO */ true,
> +	/* SMB2_SET_INFO */ false,
> +	/* SMB2_OPLOCK_BREAK */ false
> +};
> +
> +/*
> + * Returns the pointer to the beginning of the data area. Length of the data
> + * area and the offset to it (from the beginning of the smb are also returned.
> + */
> +static char *
> +smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
> +{
> +	*off = 0;
> +	*len = 0;
> +
> +	/* error responses do not have data area */
> +	if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
> +	    (((struct smb2_err_rsp *)hdr)->StructureSize) ==
> +						SMB2_ERROR_STRUCTURE_SIZE2)
> +		return NULL;
> +

I'm not sure I understand the logic in the above statement.

Why the need to check the StructureSize above? Is it ever the case that
you'll have Status set to something besides
STATUS_MORE_PROCESSING_REQUIRED or 0, and the StructureSize is
something besides SMB2_ERROR_STRUCTURE_SIZE2?

If so, then you're treating it as a non-error response?

> +	/*
> +	 * Following commands have data areas so we have to get the location
> +	 * of the data buffer offset and data buffer length for the particular
> +	 * command.
> +	 */
> +	switch (hdr->Command) {
> +	case SMB2_NEGOTIATE:
> +	case SMB2_SESSION_SETUP:
> +	case SMB2_CREATE:
> +	case SMB2_READ:
> +	case SMB2_QUERY_INFO:
> +	case SMB2_QUERY_DIRECTORY:
> +	case SMB2_IOCTL:
> +	case SMB2_CHANGE_NOTIFY:
> +	default:
> +		/* BB FIXME for unimplemented cases above */
> +		cERROR(1, "no length check for command");
> +		break;
> +	}

Doesn't the above switch always end up doing the same thing? Print a
cERROR? I guess you flesh this out in the later patches?

> +
> +	/*
> +	 * Invalid length or offset probably means data area is invalid, but
> +	 * we have little choice but to ignore the data area in this case.
> +	 */
> +	if (*off > 4096) {
> +		cERROR(1, "offset %d too large, data area ignored", *off);
> +		*len = 0;
> +		*off = 0;
> +	} else if (*off < 0) {
> +		cERROR(1, "negative offset %d to data invalid ignore data area",
> +			  *off);
> +		*off = 0;
> +		*len = 0;
> +	} else if (*len < 0) {
> +		cERROR(1, "negative data length %d invalid, data area ignored",
> +			  *len);
> +		*len = 0;
> +	} else if (*len > 128 * 1024) {
> +		cERROR(1, "data area larger than 128K: %d", *len);
> +		*len = 0;
> +	}
> +
> +	/* return pointer to beginning of data area, ie offset from SMB start */
> +	if ((*off != 0) && (*len != 0))
> +		return hdr->ProtocolId + *off;
> +	else
> +		return NULL;
> +}
> +
> +/*
> + * Calculate the size of the SMB message based on the fixed header
> + * portion, the number of word parameters and the data portion of the message.
> + */
> +unsigned int
> +smb2_calc_size(struct smb2_hdr *hdr)
> +{
> +	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
> +	int offset; /* the offset from the beginning of SMB to data area */
> +	int data_length; /* the length of the variable length data area */
> +	/* Structure Size has already been checked to make sure it is 64 */
> +	int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
> +
> +	/*
> +	 * StructureSize2, ie length of fixed parameter area has already
> +	 * been checked to make sure it is the correct length.
> +	 */
> +	len += le16_to_cpu(pdu->StructureSize2);
> +
> +	if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
> +		goto calc_size_exit;
> +
> +	smb2_get_data_area_len(&offset, &data_length, hdr);
> +	cFYI(1, "SMB2 data length %d offset %d", data_length, offset);
> +
> +	if (data_length > 0) {
> +		/*
> +		 * Check to make sure that data area begins after fixed area,
> +		 * Note that last byte of the fixed area is part of data area
> +		 * for some commands, typically those with odd StructureSize,
> +		 * so we must add one to the calculation (and 4 to account for
> +		 * the size of the RFC1001 hdr.
> +		 */
> +		if (offset + 4 + 1 < len) {
> +			cERROR(1, "data area offset %d overlaps SMB2 header %d",
> +				  offset + 4 + 1, len);
> +			data_length = 0;
> +		} else {
> +			len = 4 + offset + data_length;
> +		}
> +	}
> +calc_size_exit:
> +	cFYI(1, "SMB2 len %d", len);
> +	return len;
> +}
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 67a0598..c6f8154 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -107,6 +107,38 @@ smb2_get_next_mid(struct TCP_Server_Info *server)
>  	return mid;
>  }
>  
> +static struct mid_q_entry *
> +smb2_find_mid(struct TCP_Server_Info *server, char *buf)
> +{
> +	struct mid_q_entry *mid;
> +	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
> +
> +	spin_lock(&GlobalMid_Lock);
> +	list_for_each_entry(mid, &server->pending_mid_q, qhead) {
> +		if ((mid->mid == hdr->MessageId) &&
> +		    (mid->mid_state == MID_REQUEST_SUBMITTED) &&
> +		    (mid->command == hdr->Command)) {
> +			spin_unlock(&GlobalMid_Lock);
> +			return mid;
> +		}
> +	}
> +	spin_unlock(&GlobalMid_Lock);
> +	return NULL;
> +}
> +
> +static void
> +smb2_dump_detail(void *buf)
> +{
> +#ifdef CONFIG_CIFS_DEBUG2
> +	struct smb2_hdr *smb = (struct smb2_hdr *)buf;
> +
> +	cERROR(1, "Cmd: %d Err: 0x%x Flags: 0x%x Mid: %llu Pid: %d",
> +		  smb->Command, smb->Status, smb->Flags, smb->MessageId,
> +		  smb->ProcessId);
> +	cERROR(1, "smb buf %p len %u", smb, smb2_calc_size(smb));
> +#endif
> +}
> +
>  struct smb_version_operations smb21_operations = {
>  	.setup_request = smb2_setup_request,
>  	.check_receive = smb2_check_receive,
> @@ -115,9 +147,14 @@ struct smb_version_operations smb21_operations = {
>  	.get_credits_field = smb2_get_credits_field,
>  	.get_credits = smb2_get_credits,
>  	.get_next_mid = smb2_get_next_mid,
> +	.find_mid = smb2_find_mid,
> +	.check_message = smb2_check_message,
> +	.dump_detail = smb2_dump_detail,
>  };
>  
>  struct smb_version_values smb21_values = {
>  	.version_string = SMB21_VERSION_STRING,
> +	.header_size = sizeof(struct smb2_hdr),
> +	.max_header_size = MAX_SMB2_HDR_SIZE,
>  	.lock_cmd = SMB2_LOCK,
>  };
> diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
> index c7f52e3..b08a277 100644
> --- a/fs/cifs/smb2pdu.h
> +++ b/fs/cifs/smb2pdu.h
> @@ -85,6 +85,12 @@
>  /* BB FIXME - analyze following length BB */
>  #define MAX_SMB2_HDR_SIZE 0x78 /* 4 len + 64 hdr + (2*24 wct) + 2 bct + 2 pad */
>  
> +#define SMB2_PROTO_NUMBER __constant_cpu_to_le32(0x424d53fe)
> +
> +#define SMB2_HEADER_SIZE __constant_le16_to_cpu(64)
> +
> +#define SMB2_ERROR_STRUCTURE_SIZE2 __constant_le16_to_cpu(9)
> +
>  /*
>   * SMB2 Header Definition
>   *
> @@ -112,4 +118,34 @@ struct smb2_hdr {
>  	__u8   Signature[16];
>  } __packed;
>  
> +struct smb2_pdu {
> +	struct smb2_hdr hdr;
> +	__le16 StructureSize2; /* size of wct area (varies, request specific) */
> +} __packed;
> +
> +/*
> + *	SMB2 flag definitions
> + */
> +#define SMB2_FLAGS_SERVER_TO_REDIR	__constant_cpu_to_le32(0x00000001)
> +#define SMB2_FLAGS_ASYNC_COMMAND	__constant_cpu_to_le32(0x00000002)
> +#define SMB2_FLAGS_RELATED_OPERATIONS	__constant_cpu_to_le32(0x00000004)
> +#define SMB2_FLAGS_SIGNED		__constant_cpu_to_le32(0x00000008)
> +#define SMB2_FLAGS_DFS_OPERATIONS	__constant_cpu_to_le32(0x10000000)
> +
> +/*
> + *	Definitions for SMB2 Protocol Data Units (network frames)
> + *
> + *  See MS-SMB2.PDF specification for protocol details.
> + *  The Naming convention is the lower case version of the SMB2
> + *  command code name for the struct. Note that structures must be packed.
> + *
> + */
> +struct smb2_err_rsp {
> +	struct smb2_hdr hdr;
> +	__le16 StructureSize;
> +	__le16 Reserved; /* MBZ */
> +	__le32 ByteCount;  /* even if zero, at least one byte follows */
> +	__u8   ErrorData[1];  /* variable length */
> +} __packed;
> +
>  #endif				/* _SMB2PDU_H */
> diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
> index 0e59afb..19bf987 100644
> --- a/fs/cifs/smb2proto.h
> +++ b/fs/cifs/smb2proto.h
> @@ -33,6 +33,8 @@ struct statfs;
>   *****************************************************************
>   */
>  extern int map_smb2_to_linux_error(char *buf, bool log_err);
> +extern int smb2_check_message(char *buf, unsigned int length);
> +extern unsigned int smb2_calc_size(struct smb2_hdr *hdr);
>  
>  extern int smb2_check_receive(struct mid_q_entry *mid,
>  			      struct TCP_Server_Info *server, bool log_error);


-- 
Jeff Layton <jlayton@xxxxxxxxxx>
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