[v8,3/3] cifs: Refactor dialects in validate_negotiate_info_req to variable array

Commit Message

Zhang Xiaoxu Sept. 26, 2022, 3:36 a.m. UTC

The length of the message FSCTL_VALIDATE_NEGOTIATE_INFO is
depends on the count of the dialects, redefine the dialects
to variable array.

Signed-off-by: Zhang Xiaoxu <[e-mail]>
---
 fs/cifs/smb2pdu.c         | 94 ++++++++++++++++++---------------------
 fs/smbfs_common/smb2pdu.h |  3 +-
 2 files changed, 45 insertions(+), 52 deletions(-)

Patch

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 90ccac18f9f3..d0340af845e9 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -847,6 +847,41 @@  add_posix_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode)
 	return 0;
 }
 
+static int neg_dialect_cnt(struct TCP_Server_Info *server)
+{
+	if (!strcmp(server->vals->version_string,
+		    SMB3ANY_VERSION_STRING))
+		return 3;
+	else if (!strcmp(server->vals->version_string,
+			 SMBDEFAULT_VERSION_STRING))
+		return 4;
+
+	/* otherwise specific dialect was requested */
+	return 1;
+}
+
+static int
+build_neg_dialects(struct TCP_Server_Info *server, __le16 *dialects)
+{
+	if (!strcmp(server->vals->version_string,
+		    SMB3ANY_VERSION_STRING)) {
+		dialects[0] = cpu_to_le16(SMB30_PROT_ID);
+		dialects[1] = cpu_to_le16(SMB302_PROT_ID);
+		dialects[2] = cpu_to_le16(SMB311_PROT_ID);
+		return 3;
+	} else if (!strcmp(server->vals->version_string,
+			   SMBDEFAULT_VERSION_STRING)) {
+		dialects[0] = cpu_to_le16(SMB21_PROT_ID);
+		dialects[1] = cpu_to_le16(SMB30_PROT_ID);
+		dialects[2] = cpu_to_le16(SMB302_PROT_ID);
+		dialects[3] = cpu_to_le16(SMB311_PROT_ID);
+		return 4;
+	}
+
+	/* otherwise specific dialect was requested */
+	dialects[0] = cpu_to_le16(server->vals->protocol_id);
+	return 1;
+}
 
 /*
  *
@@ -897,27 +932,9 @@  SMB2_negotiate(const unsigned int xid,
 	memset(server->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
 	memset(ses->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
 
-	if (strcmp(server->vals->version_string,
-		   SMB3ANY_VERSION_STRING) == 0) {
-		req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
-		req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
-		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);
-		req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
-		req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
-		req->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
-		req->DialectCount = cpu_to_le16(4);
-		total_len += 8;
-	} else {
-		/* otherwise send specific dialect */
-		req->Dialects[0] = cpu_to_le16(server->vals->protocol_id);
-		req->DialectCount = cpu_to_le16(1);
-		total_len += 2;
-	}
+	rc = build_neg_dialects(server, req->Dialects);
+	req->DialectCount = cpu_to_le16(rc);
+	total_len += rc * sizeof(req->Dialects[0]);
 
 	/* only one of SMB2 signing flags may be set in SMB2 request */
 	if (ses->sign)
@@ -1124,7 +1141,10 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 	if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
 		cifs_tcon_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");
 
-	pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_NOFS);
+	inbuflen = sizeof(*pneg_inbuf) +
+			sizeof(__le16) * neg_dialect_cnt(server);
+
+	pneg_inbuf = kmalloc(inbuflen, GFP_NOFS);
 	if (!pneg_inbuf)
 		return -ENOMEM;
 
@@ -1145,34 +1165,8 @@  int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 	else
 		pneg_inbuf->SecurityMode = 0;
 
-
-	if (strcmp(server->vals->version_string,
-		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->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) -
-				(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);
-		pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
-		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 4 dialects */
-		inbuflen = sizeof(*pneg_inbuf);
-	} else {
-		/* otherwise specific dialect was requested */
-		pneg_inbuf->Dialects[0] =
-			cpu_to_le16(server->vals->protocol_id);
-		pneg_inbuf->DialectCount = cpu_to_le16(1);
-		/* structure is big enough for 4 dialects, sending only 1 */
-		inbuflen = sizeof(*pneg_inbuf) -
-				sizeof(pneg_inbuf->Dialects[0]) * 3;
-	}
+	rc = build_neg_dialects(server, pneg_inbuf->Dialects);
+	pneg_inbuf->DialectCount = cpu_to_le16(rc);
 
 	rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
 		FSCTL_VALIDATE_NEGOTIATE_INFO,
diff --git a/fs/smbfs_common/smb2pdu.h b/fs/smbfs_common/smb2pdu.h
index 2cab413fffee..4780c72e9b3a 100644
--- a/fs/smbfs_common/smb2pdu.h
+++ b/fs/smbfs_common/smb2pdu.h
@@ -1388,13 +1388,12 @@  struct reparse_symlink_data_buffer {
 } __packed;
 
 /* See MS-FSCC 2.1.2.6 and cifspdu.h for struct reparse_posix_data */
-
 struct validate_negotiate_info_req {
 	__le32 Capabilities;
 	__u8   Guid[SMB2_CLIENT_GUID_SIZE];
 	__le16 SecurityMode;
 	__le16 DialectCount;
-	__le16 Dialects[4]; /* BB expand this if autonegotiate > 4 dialects */
+	__le16 Dialects[];
 } __packed;
 
 struct validate_negotiate_info_rsp {