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smb3: send NTLMSSP version information
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For improved debugging it can be helpful to send version information
as other clients do during NTLMSSP negotiation. See protocol document
MS-NLMP section 2.2.1.1

Set the major and minor versions based on the kernel version, and the
BuildNumber based on the internal cifs.ko module version number,
and following the recommendation in the protocol documentation
(MS-NLMP section 2.2.10) we set the NTLMRevisionCurrent field to 15.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Steve French committed Jan 20, 2022
1 parent 70431bf commit 52d0053
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Showing 4 changed files with 101 additions and 2 deletions.
1 change: 1 addition & 0 deletions fs/cifs/cifsfs.h
Original file line number Diff line number Diff line change
Expand Up @@ -152,5 +152,6 @@ extern struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type,
extern const struct export_operations cifs_export_ops;
#endif /* CONFIG_CIFS_NFSD_EXPORT */

#define SMB3_PRODUCT_BUILD 34
#define CIFS_VERSION "2.34"
#endif /* _CIFSFS_H */
30 changes: 29 additions & 1 deletion fs/cifs/ntlmssp.h
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@
#define NTLMSSP_REQUEST_NON_NT_KEY 0x400000
#define NTLMSSP_NEGOTIATE_TARGET_INFO 0x800000
/* #define reserved4 0x1000000 */
#define NTLMSSP_NEGOTIATE_VERSION 0x2000000 /* we do not set */
#define NTLMSSP_NEGOTIATE_VERSION 0x2000000 /* we only set for SMB2+ */
/* #define reserved3 0x4000000 */
/* #define reserved2 0x8000000 */
/* #define reserved1 0x10000000 */
Expand Down Expand Up @@ -87,6 +87,30 @@ typedef struct _NEGOTIATE_MESSAGE {
/* followed by WorkstationString */
} __attribute__((packed)) NEGOTIATE_MESSAGE, *PNEGOTIATE_MESSAGE;

#define NTLMSSP_REVISION_W2K3 0x0F

/* See MS-NLMP section 2.2.2.10 */
struct ntlmssp_version {
__u8 ProductMajorVersion;
__u8 ProductMinorVersion;
__le16 ProductBuild; /* we send the cifs.ko module version here */
__u8 Reserved[3];
__u8 NTLMRevisionCurrent; /* currently 0x0F */
} __packed;

/* see MS-NLMP section 2.2.1.1 */
struct negotiate_message {
__u8 Signature[sizeof(NTLMSSP_SIGNATURE)];
__le32 MessageType; /* NtLmNegotiate = 1 */
__le32 NegotiateFlags;
SECURITY_BUFFER DomainName; /* RFC 1001 style and ASCII */
SECURITY_BUFFER WorkstationName; /* RFC 1001 and ASCII */
struct ntlmssp_version Version;
/* SECURITY_BUFFER */
char DomainString[0];
/* followed by WorkstationString */
} __packed;

typedef struct _CHALLENGE_MESSAGE {
__u8 Signature[sizeof(NTLMSSP_SIGNATURE)];
__le32 MessageType; /* NtLmChallenge = 2 */
Expand Down Expand Up @@ -123,6 +147,10 @@ int build_ntlmssp_negotiate_blob(unsigned char **pbuffer, u16 *buflen,
struct cifs_ses *ses,
struct TCP_Server_Info *server,
const struct nls_table *nls_cp);
int build_ntlmssp_smb3_negotiate_blob(unsigned char **pbuffer, u16 *buflen,
struct cifs_ses *ses,
struct TCP_Server_Info *server,
const struct nls_table *nls_cp);
int build_ntlmssp_auth_blob(unsigned char **pbuffer, u16 *buflen,
struct cifs_ses *ses,
struct TCP_Server_Info *server,
Expand Down
70 changes: 70 additions & 0 deletions fs/cifs/sess.c
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@
#include "nterr.h"
#include <linux/utsname.h>
#include <linux/slab.h>
#include <linux/version.h>
#include "cifsfs.h"
#include "cifs_spnego.h"
#include "smb2proto.h"
#include "fs_context.h"
Expand Down Expand Up @@ -809,6 +811,74 @@ int build_ntlmssp_negotiate_blob(unsigned char **pbuffer,
return rc;
}

/*
* Build ntlmssp blob with additional fields, such as version,
* supported by modern servers. For safety limit to SMB3 or later
* See notes in MS-NLMP Section 2.2.2.1 e.g.
*/
int build_ntlmssp_smb3_negotiate_blob(unsigned char **pbuffer,
u16 *buflen,
struct cifs_ses *ses,
struct TCP_Server_Info *server,
const struct nls_table *nls_cp)
{
int rc = 0;
struct negotiate_message *sec_blob;
__u32 flags;
unsigned char *tmp;
int len;

len = size_of_ntlmssp_blob(ses, sizeof(struct negotiate_message));
*pbuffer = kmalloc(len, GFP_KERNEL);
if (!*pbuffer) {
rc = -ENOMEM;
cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
*buflen = 0;
goto setup_ntlm_smb3_neg_ret;
}
sec_blob = (struct negotiate_message *)*pbuffer;

memset(*pbuffer, 0, sizeof(struct negotiate_message));
memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
sec_blob->MessageType = NtLmNegotiate;

/* BB is NTLMV2 session security format easier to use here? */
flags = NTLMSSP_NEGOTIATE_56 | NTLMSSP_REQUEST_TARGET |
NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
NTLMSSP_NEGOTIATE_ALWAYS_SIGN | NTLMSSP_NEGOTIATE_SEAL |
NTLMSSP_NEGOTIATE_SIGN | NTLMSSP_NEGOTIATE_VERSION;
if (!server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
flags |= NTLMSSP_NEGOTIATE_KEY_XCH;

sec_blob->Version.ProductMajorVersion = LINUX_VERSION_MAJOR;
sec_blob->Version.ProductMinorVersion = LINUX_VERSION_PATCHLEVEL;
sec_blob->Version.ProductBuild = cpu_to_le16(SMB3_PRODUCT_BUILD);
sec_blob->Version.NTLMRevisionCurrent = NTLMSSP_REVISION_W2K3;

tmp = *pbuffer + sizeof(struct negotiate_message);
ses->ntlmssp->client_flags = flags;
sec_blob->NegotiateFlags = cpu_to_le32(flags);

/* these fields should be null in negotiate phase MS-NLMP 3.1.5.1.1 */
cifs_security_buffer_from_str(&sec_blob->DomainName,
NULL,
CIFS_MAX_DOMAINNAME_LEN,
*pbuffer, &tmp,
nls_cp);

cifs_security_buffer_from_str(&sec_blob->WorkstationName,
NULL,
CIFS_MAX_WORKSTATION_LEN,
*pbuffer, &tmp,
nls_cp);

*buflen = tmp - *pbuffer;
setup_ntlm_smb3_neg_ret:
return rc;
}


int build_ntlmssp_auth_blob(unsigned char **pbuffer,
u16 *buflen,
struct cifs_ses *ses,
Expand Down
2 changes: 1 addition & 1 deletion fs/cifs/smb2pdu.c
Original file line number Diff line number Diff line change
Expand Up @@ -1506,7 +1506,7 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
if (rc)
goto out_err;

rc = build_ntlmssp_negotiate_blob(&ntlmssp_blob,
rc = build_ntlmssp_smb3_negotiate_blob(&ntlmssp_blob,
&blob_length, ses, server,
sess_data->nls_cp);
if (rc)
Expand Down

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