cifs_writev(struct kiocb *iocb, const struct iovec *iov,
	    unsigned long nr_segs, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
	struct inode *inode = file->f_mapping->host;
	struct cifsInodeInfo *cinode = CIFS_I(inode);
	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
	ssize_t rc = -EACCES;

	BUG_ON(iocb->ki_pos != pos);

	/*
	 * We need to hold the sem to be sure nobody modifies lock list
	 * with a brlock that prevents writing.
	 */
	down_read(&cinode->lock_sem);
	if (!cifs_find_lock_conflict(cfile, pos, iov_length(iov, nr_segs),
				     server->vals->exclusive_lock_type, NULL,
				     CIFS_WRITE_OP)) {
		mutex_lock(&inode->i_mutex);
		rc = __generic_file_aio_write(iocb, iov, nr_segs,
					       &iocb->ki_pos);
		mutex_unlock(&inode->i_mutex);
	}

	if (rc > 0) {
		ssize_t err;

		err = generic_write_sync(file, pos, rc);
		if (err < 0 && rc > 0)
			rc = err;
	}

	up_read(&cinode->lock_sem);
	return rc;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.