ksmbd: implement error handling for STATUS_INFO_LENGTH_MISMATCH in smb server

Add STATUS_INFO_LENGTH_MISMATCH mapping to EMSGSIZE.
Currently, STATUS_INFO_LENGTH_MISMATCH has no mapping to any error code,
making it difficult to distinguish between invalid parameters and length
mismatch.

Map STATUS_INFO_LENGTH_MISMATCH to EMSGSIZE while keeping the EINVAL for
invalid parameters. Although the buf_len check only checks for buf_size
being less than required, there was no error code for lower buf_size.
Hence, EMSGSIZE is used.

Signed-off-by: Aaditya Kansal <aadityakansal390@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Nightfire390

fs/smb/server/smb2pdu.c

@@ -6383,7 +6383,6 @@ static int set_file_mode_info(struct ksmbd_file *fp,
  * @share:	ksmbd_share_config pointer
  *
  * Return:	0 on success, otherwise error
- * TODO: need to implement an error handling for STATUS_INFO_LENGTH_MISMATCH
  */
 static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 			      struct smb2_set_info_req *req,
@@ -6396,30 +6395,30 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 	case FILE_BASIC_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_basic_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_file_basic_info(fp, (struct smb2_file_basic_info *)buffer, share);
 	}
 	case FILE_ALLOCATION_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_alloc_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_file_allocation_info(work, fp,
 						(struct smb2_file_alloc_info *)buffer);
 	}
 	case FILE_END_OF_FILE_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_eof_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_end_of_file_info(work, fp,
 					    (struct smb2_file_eof_info *)buffer);
 	}
 	case FILE_RENAME_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_rename_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_rename_info(work, fp,
 				       (struct smb2_file_rename_info *)buffer,
@@ -6428,7 +6427,7 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 	case FILE_LINK_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_link_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return smb2_create_link(work, work->tcon->share_conf,
 					(struct smb2_file_link_info *)buffer,
@@ -6438,7 +6437,7 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 	case FILE_DISPOSITION_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_disposition_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_file_disposition_info(fp,
 						 (struct smb2_file_disposition_info *)buffer);
@@ -6452,22 +6451,22 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp,
 		}
 
 		if (buf_len < sizeof(struct smb2_ea_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return smb2_set_ea((struct smb2_ea_info *)buffer,
 				   buf_len, &fp->filp->f_path, true);
 	}
 	case FILE_POSITION_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_pos_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_file_position_info(fp, (struct smb2_file_pos_info *)buffer);
 	}
 	case FILE_MODE_INFORMATION:
 	{
 		if (buf_len < sizeof(struct smb2_file_mode_info))
-			return -EINVAL;
+			return -EMSGSIZE;
 
 		return set_file_mode_info(fp, (struct smb2_file_mode_info *)buffer);
 	}
@@ -6574,6 +6573,8 @@ int smb2_set_info(struct ksmbd_work *work)
 		rsp->hdr.Status = STATUS_ACCESS_DENIED;
 	else if (rc == -EINVAL)
 		rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+	else if (rc == -EMSGSIZE)
+		rsp->hdr.Status = STATUS_INFO_LENGTH_MISMATCH;
 	else if (rc == -ESHARE)
 		rsp->hdr.Status = STATUS_SHARING_VIOLATION;
 	else if (rc == -ENOENT)