From ca085a95e36e0cdda56a553f3f7894a30db127b6 Mon Sep 17 00:00:00 2001
From: Shyam Prasad N <sprasad@microsoft.com>
Date: Fri, 5 Nov 2021 19:03:57 +0000
Subject: [PATCH] cifs: send workstation name during ntlmssp session setup

During the ntlmssp session setup (authenticate phases)
send the client workstation info. This can make debugging easier on
servers.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/cifsglob.h   |   4 +
 fs/cifs/connect.c    |   6 ++
 fs/cifs/fs_context.c |  34 +++++++-
 fs/cifs/fs_context.h |   1 +
 fs/cifs/misc.c       |   1 +
 fs/cifs/ntlmssp.h    |   4 +-
 fs/cifs/sess.c       | 188 +++++++++++++++++++++++++++----------------
 fs/cifs/smb2pdu.c    |  17 ++--
 8 files changed, 170 insertions(+), 85 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index eeea520ede0a..41e97df4e0e5 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/mempool.h>
 #include <linux/workqueue.h>
+#include <linux/utsname.h>
 #include "cifs_fs_sb.h"
 #include "cifsacl.h"
 #include <crypto/internal/hash.h>
@@ -99,6 +100,8 @@
 #define XATTR_DOS_ATTRIB "user.DOSATTRIB"
 #endif
 
+#define CIFS_MAX_WORKSTATION_LEN  (__NEW_UTS_LEN + 1)  /* reasonable max for client */
+
 /*
  * CIFS vfs client Status information (based on what we know.)
  */
@@ -909,6 +912,7 @@ struct cifs_ses {
 				   and after mount option parsing we fill it */
 	char *domainName;
 	char *password;
+	char *workstation_name;
 	struct session_key auth_key;
 	struct ntlmssp_auth *ntlmssp; /* ciphertext, flags, server challenge */
 	enum securityEnum sectype; /* what security flavor was specified? */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 24742b7402d1..c45fed4e18ba 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1948,6 +1948,12 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 		if (!ses->domainName)
 			goto get_ses_fail;
 	}
+	if (ctx->workstation_name) {
+		ses->workstation_name = kstrdup(ctx->workstation_name,
+						GFP_KERNEL);
+		if (!ses->workstation_name)
+			goto get_ses_fail;
+	}
 	if (ctx->domainauto)
 		ses->domainAuto = ctx->domainauto;
 	ses->cred_uid = ctx->cred_uid;
diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 38d96a480745..9b29b630c1b3 100644
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -309,6 +309,7 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	new_ctx->username = NULL;
 	new_ctx->password = NULL;
 	new_ctx->domainname = NULL;
+	new_ctx->workstation_name = NULL;
 	new_ctx->UNC = NULL;
 	new_ctx->source = NULL;
 	new_ctx->iocharset = NULL;
@@ -323,6 +324,7 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	DUP_CTX_STR(UNC);
 	DUP_CTX_STR(source);
 	DUP_CTX_STR(domainname);
+	DUP_CTX_STR(workstation_name);
 	DUP_CTX_STR(nodename);
 	DUP_CTX_STR(iocharset);
 
@@ -720,6 +722,11 @@ static int smb3_verify_reconfigure_ctx(struct fs_context *fc,
 		cifs_errorf(fc, "can not change domainname during remount\n");
 		return -EINVAL;
 	}
+	if (new_ctx->workstation_name &&
+	    (!old_ctx->workstation_name || strcmp(new_ctx->workstation_name, old_ctx->workstation_name))) {
+		cifs_errorf(fc, "can not change workstation_name during remount\n");
+		return -EINVAL;
+	}
 	if (new_ctx->nodename &&
 	    (!old_ctx->nodename || strcmp(new_ctx->nodename, old_ctx->nodename))) {
 		cifs_errorf(fc, "can not change nodename during remount\n");
@@ -753,7 +760,8 @@ static int smb3_reconfigure(struct fs_context *fc)
 		return rc;
 
 	/*
-	 * We can not change UNC/username/password/domainname/nodename/iocharset
+	 * We can not change UNC/username/password/domainname/
+	 * workstation_name/nodename/iocharset
 	 * during reconnect so ignore what we have in the new context and
 	 * just use what we already have in cifs_sb->ctx.
 	 */
@@ -762,6 +770,7 @@ static int smb3_reconfigure(struct fs_context *fc)
 	STEAL_STRING(cifs_sb, ctx, username);
 	STEAL_STRING(cifs_sb, ctx, password);
 	STEAL_STRING(cifs_sb, ctx, domainname);
+	STEAL_STRING(cifs_sb, ctx, workstation_name);
 	STEAL_STRING(cifs_sb, ctx, nodename);
 	STEAL_STRING(cifs_sb, ctx, iocharset);
 
@@ -1414,13 +1423,22 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 
 int smb3_init_fs_context(struct fs_context *fc)
 {
+	int rc;
 	struct smb3_fs_context *ctx;
 	char *nodename = utsname()->nodename;
 	int i;
 
 	ctx = kzalloc(sizeof(struct smb3_fs_context), GFP_KERNEL);
-	if (unlikely(!ctx))
-		return -ENOMEM;
+	if (unlikely(!ctx)) {
+		rc = -ENOMEM;
+		goto err_exit;
+	}
+
+	ctx->workstation_name = kstrdup(nodename, GFP_KERNEL);
+	if (unlikely(!ctx->workstation_name)) {
+		rc = -ENOMEM;
+		goto err_exit;
+	}
 
 	/*
 	 * does not have to be perfect mapping since field is
@@ -1493,6 +1511,14 @@ int smb3_init_fs_context(struct fs_context *fc)
 	fc->fs_private = ctx;
 	fc->ops = &smb3_fs_context_ops;
 	return 0;
+
+err_exit:
+	if (ctx) {
+		kfree(ctx->workstation_name);
+		kfree(ctx);
+	}
+
+	return rc;
 }
 
 void
@@ -1518,6 +1544,8 @@ smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
 	ctx->source = NULL;
 	kfree(ctx->domainname);
 	ctx->domainname = NULL;
+	kfree(ctx->workstation_name);
+	ctx->workstation_name = NULL;
 	kfree(ctx->nodename);
 	ctx->nodename = NULL;
 	kfree(ctx->iocharset);
diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index b2d22cf9cb18..e54090d9ef36 100644
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -170,6 +170,7 @@ struct smb3_fs_context {
 	char *server_hostname;
 	char *UNC;
 	char *nodename;
+	char *workstation_name;
 	char *iocharset;  /* local code page for mapping to and from Unicode */
 	char source_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* clnt nb name */
 	char target_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* srvr nb name */
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index ba2c3e897b29..fb76040be4db 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -94,6 +94,7 @@ sesInfoFree(struct cifs_ses *buf_to_free)
 	kfree_sensitive(buf_to_free->password);
 	kfree(buf_to_free->user_name);
 	kfree(buf_to_free->domainName);
+	kfree(buf_to_free->workstation_name);
 	kfree_sensitive(buf_to_free->auth_key.response);
 	kfree(buf_to_free->iface_list);
 	kfree_sensitive(buf_to_free);
diff --git a/fs/cifs/ntlmssp.h b/fs/cifs/ntlmssp.h
index 25a2b8ef88b9..fe707f45da89 100644
--- a/fs/cifs/ntlmssp.h
+++ b/fs/cifs/ntlmssp.h
@@ -119,7 +119,9 @@ typedef struct _AUTHENTICATE_MESSAGE {
  */
 
 int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len, struct cifs_ses *ses);
-void build_ntlmssp_negotiate_blob(unsigned char *pbuffer, struct cifs_ses *ses);
+int build_ntlmssp_negotiate_blob(unsigned char **pbuffer, u16 *buflen,
+				 struct cifs_ses *ses,
+				 const struct nls_table *nls_cp);
 int build_ntlmssp_auth_blob(unsigned char **pbuffer, u16 *buflen,
 			struct cifs_ses *ses,
 			const struct nls_table *nls_cp);
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 23e02db7923f..93a1619d60e6 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -599,18 +599,85 @@ int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
 	return 0;
 }
 
+static int size_of_ntlmssp_blob(struct cifs_ses *ses, int base_size)
+{
+	int sz = base_size + ses->auth_key.len
+		- CIFS_SESS_KEY_SIZE + CIFS_CPHTXT_SIZE + 2;
+
+	if (ses->domainName)
+		sz += sizeof(__le16) * strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
+	else
+		sz += sizeof(__le16);
+
+	if (ses->user_name)
+		sz += sizeof(__le16) * strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
+	else
+		sz += sizeof(__le16);
+
+	sz += sizeof(__le16) * strnlen(ses->workstation_name, CIFS_MAX_WORKSTATION_LEN);
+
+	return sz;
+}
+
+static inline void cifs_security_buffer_from_str(SECURITY_BUFFER *pbuf,
+						 char *str_value,
+						 int str_length,
+						 unsigned char *pstart,
+						 unsigned char **pcur,
+						 const struct nls_table *nls_cp)
+{
+	unsigned char *tmp = pstart;
+	int len;
+
+	if (!pbuf)
+		return;
+
+	if (!pcur)
+		pcur = &tmp;
+
+	if (!str_value) {
+		pbuf->BufferOffset = cpu_to_le32(*pcur - pstart);
+		pbuf->Length = 0;
+		pbuf->MaximumLength = 0;
+		*pcur += sizeof(__le16);
+	} else {
+		len = cifs_strtoUTF16((__le16 *)*pcur,
+				      str_value,
+				      str_length,
+				      nls_cp);
+		len *= sizeof(__le16);
+		pbuf->BufferOffset = cpu_to_le32(*pcur - pstart);
+		pbuf->Length = cpu_to_le16(len);
+		pbuf->MaximumLength = cpu_to_le16(len);
+		*pcur += len;
+	}
+}
+
 /* BB Move to ntlmssp.c eventually */
 
-/* We do not malloc the blob, it is passed in pbuffer, because
-   it is fixed size, and small, making this approach cleaner */
-void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
-					 struct cifs_ses *ses)
+int build_ntlmssp_negotiate_blob(unsigned char **pbuffer,
+				 u16 *buflen,
+				 struct cifs_ses *ses,
+				 const struct nls_table *nls_cp)
 {
+	int rc = 0;
 	struct TCP_Server_Info *server = cifs_ses_server(ses);
-	NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
+	NEGOTIATE_MESSAGE *sec_blob;
 	__u32 flags;
+	unsigned char *tmp;
+	int len;
+
+	len = size_of_ntlmssp_blob(ses, sizeof(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_neg_ret;
+	}
+	sec_blob = (NEGOTIATE_MESSAGE *)*pbuffer;
 
-	memset(pbuffer, 0, sizeof(NEGOTIATE_MESSAGE));
+	memset(*pbuffer, 0, sizeof(NEGOTIATE_MESSAGE));
 	memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
 	sec_blob->MessageType = NtLmNegotiate;
 
@@ -624,34 +691,25 @@ void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
 	if (!server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
 		flags |= NTLMSSP_NEGOTIATE_KEY_XCH;
 
+	tmp = *pbuffer + sizeof(NEGOTIATE_MESSAGE);
 	sec_blob->NegotiateFlags = cpu_to_le32(flags);
 
-	sec_blob->WorkstationName.BufferOffset = 0;
-	sec_blob->WorkstationName.Length = 0;
-	sec_blob->WorkstationName.MaximumLength = 0;
-
-	/* Domain name is sent on the Challenge not Negotiate NTLMSSP request */
-	sec_blob->DomainName.BufferOffset = 0;
-	sec_blob->DomainName.Length = 0;
-	sec_blob->DomainName.MaximumLength = 0;
-}
-
-static int size_of_ntlmssp_blob(struct cifs_ses *ses)
-{
-	int sz = sizeof(AUTHENTICATE_MESSAGE) + ses->auth_key.len
-		- CIFS_SESS_KEY_SIZE + CIFS_CPHTXT_SIZE + 2;
-
-	if (ses->domainName)
-		sz += 2 * strnlen(ses->domainName, CIFS_MAX_DOMAINNAME_LEN);
-	else
-		sz += 2;
+	/* 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);
 
-	if (ses->user_name)
-		sz += 2 * strnlen(ses->user_name, CIFS_MAX_USERNAME_LEN);
-	else
-		sz += 2;
+	cifs_security_buffer_from_str(&sec_blob->WorkstationName,
+				      NULL,
+				      CIFS_MAX_WORKSTATION_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	return sz;
+	*buflen = tmp - *pbuffer;
+setup_ntlm_neg_ret:
+	return rc;
 }
 
 int build_ntlmssp_auth_blob(unsigned char **pbuffer,
@@ -663,6 +721,7 @@ int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 	AUTHENTICATE_MESSAGE *sec_blob;
 	__u32 flags;
 	unsigned char *tmp;
+	int len;
 
 	rc = setup_ntlmv2_rsp(ses, nls_cp);
 	if (rc) {
@@ -670,7 +729,9 @@ int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 		*buflen = 0;
 		goto setup_ntlmv2_ret;
 	}
-	*pbuffer = kmalloc(size_of_ntlmssp_blob(ses), GFP_KERNEL);
+
+	len = size_of_ntlmssp_blob(ses, sizeof(AUTHENTICATE_MESSAGE));
+	*pbuffer = kmalloc(len, GFP_KERNEL);
 	if (!*pbuffer) {
 		rc = -ENOMEM;
 		cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
@@ -686,7 +747,7 @@ int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 		NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
 		NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
 		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
-		NTLMSSP_NEGOTIATE_SEAL;
+		NTLMSSP_NEGOTIATE_SEAL | NTLMSSP_NEGOTIATE_WORKSTATION_SUPPLIED;
 	if (ses->server->sign)
 		flags |= NTLMSSP_NEGOTIATE_SIGN;
 	if (!ses->server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
@@ -719,42 +780,23 @@ int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 		sec_blob->NtChallengeResponse.MaximumLength = 0;
 	}
 
-	if (ses->domainName == NULL) {
-		sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->DomainName.Length = 0;
-		sec_blob->DomainName.MaximumLength = 0;
-		tmp += 2;
-	} else {
-		int len;
-		len = cifs_strtoUTF16((__le16 *)tmp, ses->domainName,
-				      CIFS_MAX_DOMAINNAME_LEN, nls_cp);
-		len *= 2; /* unicode is 2 bytes each */
-		sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->DomainName.Length = cpu_to_le16(len);
-		sec_blob->DomainName.MaximumLength = cpu_to_le16(len);
-		tmp += len;
-	}
+	cifs_security_buffer_from_str(&sec_blob->DomainName,
+				      ses->domainName,
+				      CIFS_MAX_DOMAINNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	if (ses->user_name == NULL) {
-		sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->UserName.Length = 0;
-		sec_blob->UserName.MaximumLength = 0;
-		tmp += 2;
-	} else {
-		int len;
-		len = cifs_strtoUTF16((__le16 *)tmp, ses->user_name,
-				      CIFS_MAX_USERNAME_LEN, nls_cp);
-		len *= 2; /* unicode is 2 bytes each */
-		sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-		sec_blob->UserName.Length = cpu_to_le16(len);
-		sec_blob->UserName.MaximumLength = cpu_to_le16(len);
-		tmp += len;
-	}
+	cifs_security_buffer_from_str(&sec_blob->UserName,
+				      ses->user_name,
+				      CIFS_MAX_USERNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
-	sec_blob->WorkstationName.BufferOffset = cpu_to_le32(tmp - *pbuffer);
-	sec_blob->WorkstationName.Length = 0;
-	sec_blob->WorkstationName.MaximumLength = 0;
-	tmp += 2;
+	cifs_security_buffer_from_str(&sec_blob->WorkstationName,
+				      ses->workstation_name,
+				      CIFS_MAX_WORKSTATION_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
 
 	if (((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) ||
 		(ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_EXTENDED_SEC))
@@ -1230,6 +1272,7 @@ sess_auth_rawntlmssp_negotiate(struct sess_data *sess_data)
 	struct cifs_ses *ses = sess_data->ses;
 	__u16 bytes_remaining;
 	char *bcc_ptr;
+	unsigned char *ntlmsspblob = NULL;
 	u16 blob_len;
 
 	cifs_dbg(FYI, "rawntlmssp session setup negotiate phase\n");
@@ -1253,10 +1296,15 @@ sess_auth_rawntlmssp_negotiate(struct sess_data *sess_data)
 	pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
 
 	/* Build security blob before we assemble the request */
-	build_ntlmssp_negotiate_blob(pSMB->req.SecurityBlob, ses);
-	sess_data->iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
-	sess_data->iov[1].iov_base = pSMB->req.SecurityBlob;
-	pSMB->req.SecurityBlobLength = cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
+	rc = build_ntlmssp_negotiate_blob(&ntlmsspblob,
+				     &blob_len, ses,
+				     sess_data->nls_cp);
+	if (rc)
+		goto out;
+
+	sess_data->iov[1].iov_len = blob_len;
+	sess_data->iov[1].iov_base = ntlmsspblob;
+	pSMB->req.SecurityBlobLength = cpu_to_le16(blob_len);
 
 	rc = _sess_auth_rawntlmssp_assemble_req(sess_data);
 	if (rc)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index d2ecb2ea37c0..5034e53a49e7 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1456,7 +1456,7 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
 	int rc;
 	struct cifs_ses *ses = sess_data->ses;
 	struct smb2_sess_setup_rsp *rsp = NULL;
-	char *ntlmssp_blob = NULL;
+	unsigned char *ntlmssp_blob = NULL;
 	bool use_spnego = false; /* else use raw ntlmssp */
 	u16 blob_length = 0;
 
@@ -1475,22 +1475,17 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
 	if (rc)
 		goto out_err;
 
-	ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
-			       GFP_KERNEL);
-	if (ntlmssp_blob == NULL) {
-		rc = -ENOMEM;
-		goto out;
-	}
+	rc = build_ntlmssp_negotiate_blob(&ntlmssp_blob,
+					  &blob_length, ses,
+					  sess_data->nls_cp);
+	if (rc)
+		goto out_err;
 
-	build_ntlmssp_negotiate_blob(ntlmssp_blob, ses);
 	if (use_spnego) {
 		/* BB eventually need to add this */
 		cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
 		rc = -EOPNOTSUPP;
 		goto out;
-	} else {
-		blob_length = sizeof(struct _NEGOTIATE_MESSAGE);
-		/* with raw NTLMSSP we don't encapsulate in SPNEGO */
 	}
 	sess_data->iov[1].iov_base = ntlmssp_blob;
 	sess_data->iov[1].iov_len = blob_length;
-- 
2.32.0

