Commit d592a915 authored by Namjae Jeon's avatar Namjae Jeon Committed by Steve French
Browse files

ksmbd: don't allow O_TRUNC open on read-only share 



When file is changed using notepad on read-only share(read_only = yes in
ksmbd.conf), There is a problem where existing data is truncated.
notepad in windows try to O_TRUNC open(FILE_OVERWRITE_IF) and all data
in file is truncated. This patch don't allow  O_TRUNC open on read-only
share and add KSMBD_TREE_CONN_FLAG_WRITABLE check in smb2_set_info().

Cc: stable@vger.kernel.org
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 8d99c113

fs/smb/server/smb2pdu.c

+9 −14
Original line number Diff line number Diff line
@@ -2972,7 +2972,7 @@ int smb2_open(struct ksmbd_work *work) 
					    &may_flags);



	if (!test_tree_conn_flag(tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {

		if (open_flags & O_CREAT) {

		if (open_flags & (O_CREAT | O_TRUNC)) {

			ksmbd_debug(SMB,

				    "User does not have write permission\n");

			rc = -EACCES;
@@ -5944,12 +5944,6 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp, 
	}

	case FILE_RENAME_INFORMATION:

	{

		if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {

			ksmbd_debug(SMB,

				    "User does not have write permission\n");

			return -EACCES;

		}



		if (buf_len < sizeof(struct smb2_file_rename_info))

			return -EINVAL;
@@ -5969,12 +5963,6 @@ static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_file *fp, 
	}

	case FILE_DISPOSITION_INFORMATION:

	{

		if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {

			ksmbd_debug(SMB,

				    "User does not have write permission\n");

			return -EACCES;

		}



		if (buf_len < sizeof(struct smb2_file_disposition_info))

			return -EINVAL;
@@ -6036,7 +6024,7 @@ int smb2_set_info(struct ksmbd_work *work) 
{

	struct smb2_set_info_req *req;

	struct smb2_set_info_rsp *rsp;

	struct ksmbd_file *fp;

	struct ksmbd_file *fp = NULL;

	int rc = 0;

	unsigned int id = KSMBD_NO_FID, pid = KSMBD_NO_FID;
@@ -6056,6 +6044,13 @@ int smb2_set_info(struct ksmbd_work *work) 
		rsp = smb2_get_msg(work->response_buf);

	}



	if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {

		ksmbd_debug(SMB, "User does not have write permission\n");

		pr_err("User does not have write permission\n");

		rc = -EACCES;

		goto err_out;

	}



	if (!has_file_id(id)) {

		id = req->VolatileFileId;

		pid = req->PersistentFileId;