Automatically set permissions on uploaded files and folders to use in, for example, multi-user FTP environments where different clients set different permissions, or otherwise ignore umask.

inotify-set-permissions.sh

#!/bin/bash
# stig@stigok.com Oct 2019
#
# Reference:
# http://positon.org/a-solution-to-the-umask-problem-inotify-to-force-permissions
set -x

# Take the directory name as argument
inotifywait -mrq -e CREATE --format %w%f "$1" | while read FILE
do
	if [ -d "$FILE" ]
	then
		# $FILE is a directory
		chmod 755 "$FILE"
	else
		# Treat $FILE as a file
		chmod 644 "$FILE"
	fi
done

sftp-permission-guard.service

[Unit]
Description=Sets permissions of all uploaded files (644) and folders (755)
After=sshd.service

[Service]
Type=simple
WorkingDirectory=/srv/sftp
ExecStart=/usr/local/bin/inotify-set-permissions.sh .
Restart=on-failure
RestartSec=5

[Install]
WantedBy=default.target