SFTP Gateway Support

3.0

Create-user bash script

Overview

You can create SFTP users in the web admin portal. But if you need to create many users at once, it might be easier and less error-prone to script this process.

This article goes over how to create an SFTP user via the command line. This involves creating a bash script using the code in this article.

IMPORTANT: If you're on version 3.5.0 or newer of SFTP Gateway, make sure to edit the script on line 119 so the endpoint for generating the OAuth token is set to http://127.0.0.1:8080/login NOT http://127.0.0.1:8080/oauth/token.

Install dependencies

The create-user script relies on jq, which is a command line utility for working with json objects.

SSH into the VM and run the following commands to install this:

sudo su
snap install jq

Create the script

In this section, you will create the bash script.

Paste in the following commands:

cd /usr/local/bin
wget https://thorntech-products.s3.amazonaws.com/sftpgateway/create-user-script/create-user.sh
chmod +x create-user.sh

These commands get the create-user.sh script, and make it executable.

Create a credentials file

The create-user script uses the credentials of your web admin portal user. So you will need to save these credentials in a text file.

First, create a credentials file:

cd /usr/local/bin/
touch credentials.txt
nano credentials.txt

Paste the following properties into the file:

admin.username=
admin.password=

Make sure you populate these values with your web admin credentials. For example:

admin.username=robadmin
admin.password=password

Usage

Run the script to create an SFTP user with a password:

./create-user.sh -f credentials.txt -u user -p password

Note: Replace user and password with the credentials of your SFTP user.

You can create users with an SSH public key:

./create-user.sh -f credentials.txt -u user1 -k "ssh-rsa AAAAB3NzaC1"

The script also supports multiple SSH public keys. Just use the -k flag for each public key you want to add:

./create-user.sh -f credentials.txt -u user1 \
   -k "ssh-rsa AAAAB3NzaC1" \
   -k "ssh-rsa AAAAB3NzaC2"

Video Reference

Home directory

The script creates an SFTP user that points to their default Home Folder location. For example:

/users/robtest

The user creation process attempts to create this Home Folder location.

Note: If this Folder already exists, the user creation process will fail.

Troubleshooting

When you run the script, you will see the following output when successful:

{"createdDate":"2022-09-29T17:50:57.238372Z","credentialsExpired":false,"enabled":true...}

This section covers a few common error scenarios.

  • Make sure you are using sudo, or running as root.
  • Make sure you include the -u or --username parameter, which is required
  • You must specify either a password or SSH key
  • Make sure your credential file exists and contains working values
  • When creating an SFTP user with a password, make sure the password meets complexity requirements
  • Make sure the SFTP user doesn't already exist
  • Make sure the default Home Folder for this username doesn't already exist

Script contents

Here are the contents of the create-user.sh file:

#!/bin/bash

PUBLIC_KEY_ARRAY=()

while [[ $# -gt 0 ]]; do
  key="$1"
  case $key in
    -u|--username)
      SFTP_USERNAME="$2"
      shift
      shift
      ;;
    -p|--password)
      SFTP_PASSWORD="$2"
      shift
      shift
      ;;
     -k|--pubkey)
      PUBLIC_KEY_ARRAY+=("$2")
      shift
      shift
      ;;
    -f|--file)
      CREDENTIAL_FILE="$2"
      shift
      shift
      ;;
    *)
      break
      ;;
  esac
done

USAGE_FLAG=false

function generaterandomstring {
  head /dev/urandom | tr -dc a-zA-Z0-9 | head -c ${1} ; echo ''
}

function usage {
  echo "Usage when setting a password: sudo $0 -f credential.txt -u sftpuser -p $(generaterandomstring 15)"
  echo "Usage when setting public key: sudo $0 -f credential.txt -u sftpuser -k \"ssh-rsa AAAAB3NzaC1\" -k \"ssh-rsa AAAAB3NzaC2\""
  echo ""
  exit 1
}

if [[ `whoami` != "root" ]]; then
  echo ""
  echo "Please run this script using sudo or as root."
  USAGE_FLAG=true
fi

if [[ -z $SFTP_USERNAME ]]; then
  echo ""
  echo "Please provide a username."
  USAGE_FLAG=true
fi

if [[ -z $SFTP_PASSWORD ]] && [[ -z $PUBLIC_KEY_ARRAY ]]; then
  echo ""
  echo "Please provide either a password or public key(s)."
  USAGE_FLAG=true
fi

function credential-file-usage {
  echo ""
  echo "Please provide a path to a valid credential file, which contains the following contents:"
  echo ""
  echo "admin.username=admin"
  echo "admin.password=$(generaterandomstring 15)"
}

function extractPropValueFromSourceFile {
  local prefix="${1}"
  local str=`grep "${prefix}" ${2} 2>/dev/null`
  echo "${str#$prefix}" | xargs
}

if [[ -f $CREDENTIAL_FILE ]]; then
  ADMIN_USERNAME=$(extractPropValueFromSourceFile admin.username= $CREDENTIAL_FILE)
  ADMIN_PASSWORD=$(extractPropValueFromSourceFile admin.password= $CREDENTIAL_FILE)
fi

if [[ ! -f $CREDENTIAL_FILE ]]; then
  credential-file-usage
  USAGE_FLAG=true
elif [[ -z $ADMIN_USERNAME ]] || [[ -z $ADMIN_PASSWORD ]]; then
  credential-file-usage
  USAGE_FLAG=true
fi

if [[ $USAGE_FLAG = true ]]; then
  echo ""
  usage
fi

APPLICATION_PROPERTIES=/opt/sftpgw/application.properties
CLIENT_ID=$(extractPropValueFromSourceFile "security.client-id=" ${APPLICATION_PROPERTIES})
CLIENT_SECRET=$(extractPropValueFromSourceFile "security.client-secret=" ${APPLICATION_PROPERTIES})

CURRENT_JSON=$(jq -n --arg SFTP_USERNAME "${SFTP_USERNAME}" '{username: $SFTP_USERNAME}')

if [[ -n ${SFTP_PASSWORD} ]]; then
  CURRENT_JSON=$(echo $CURRENT_JSON | jq --arg SFTP_PASSWORD "${SFTP_PASSWORD}" '.password |= $SFTP_PASSWORD')
fi

function generaterandomnumber {
  head /dev/urandom | tr -dc 0-9 | head -c ${1} ; echo ''
}

for PUBLIC_KEY in "${PUBLIC_KEY_ARRAY[@]}"; do
  RANDOM_STRING="$(generaterandomnumber 9)"
  KEY_NAME="key-${RANDOM_STRING}"
  CURRENT_JSON=$(echo $CURRENT_JSON | jq --arg KEY_NAME "${KEY_NAME}" --arg PUBLIC_KEY "${PUBLIC_KEY}" '.publicKeys += [{"name": $KEY_NAME, "value": $PUBLIC_KEY}]')
done

#echo $CURRENT_JSON

RESPONSE=$(curl --location --request POST 'http://127.0.0.1:8080/oauth/token' -u ${CLIENT_ID}:${CLIENT_SECRET} --form 'grant_type="password"' --form "username=\"${ADMIN_USERNAME}\"" --form "password=\"${ADMIN_PASSWORD}\"" --form 'scope="read"' --silent)

ACCESS_TOKEN=$(echo $RESPONSE | python3 -c "import sys, json; print(json.load(sys.stdin)['access_token'])")

#echo "ACCESS_TOKEN: $ACCESS_TOKEN"

curl -s --insecure --location --request POST 'https://127.0.0.1:443/backend/3.0.0/users' --header 'Content-Type: application/json' --header "Authorization: Bearer ${ACCESS_TOKEN}" --data-raw "$CURRENT_JSON"

echo ""
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