Bash profile file for "GIT for Windows" to run ssh-agent automatically and use Windows Credential Manager.

git-for-windows-bash-profile

#
# Description: Bash profile file for "GIT for Windows" to run ssh-agent
#              automatically and use Windows Credential Manager.
#      Author: Vincent Lauria <vincent@lauria.ch>
#        Data: 20170330
#     Version: 0.2
#
# Dependency:
#
#   - GIT for Windows
#   - Powershell and CredentialManager packages
#
# Usage example:
#
#   1. Run Powershell as Administrator:
#      PS > Install-Module CredentialManager -force
#      PS > exit
#
#   2. Run Git Bash for Windows and copy this script:
#      cp git-for-windows-bash-profile ~/.profile
#      source ~/.profile
#

# SSH ask password
if [ "$#" -eq 1 ]; then
	exec cat
	exit 1
fi

SSH_AGENT_ENV=$HOME/.ssh_agent_env

function get_credential
{
	powershell.exe -ExecutionPolicy RemoteSigned \
		-Command "Get-StoredCredential -Target $1 -AsCredentialObject | % {\$_.Password}"
}

function set_credential
{
	local PASSWORD

	while true; do
		read -s -p "Enter password for key '$1': " PASSWORD

		if ssh_add "$PASSWORD" "$1"; then
			powershell.exe -ExecutionPolicy RemoteSigned \
				-Command "New-StoredCredential -Target $1 -Persist LocalMachine -Username \$ENV:Username -Pass '$PASSWORD'"
			break
		else
			echo
		fi
	done
}

function ssh_has_identity
{
	local IDENTITY=$(echo $1 | sed 's/.*\/.ssh/.ssh/')

	if [[ $(ssh-add -l | grep "$IDENTITY") == "" ]]; then
		return 1
	else
		return 0
	fi
}

function ssh_add
{
	echo "$1" | SSH_ASKPASS="$HOME/.profile" ssh-add "$2" 2> /dev/null

	if ! ssh_has_identity "$2"; then
		return 1
	fi
}

if [[ $(ps ax | grep -c ssh-agent) = "0" ]]; then
	eval $(ssh-agent -s) > /dev/null

	# Save ssh agent environment variables
	cat <<-EOL > ${SSH_AGENT_ENV}
	export SSH_AGENT_PID=$SSH_AGENT_PID
	export SSH_AUTH_SOCK=$SSH_AUTH_SOCK
	EOL
else
	. ${SSH_AGENT_ENV}
fi

for FILE in $(find $HOME/.ssh -maxdepth 1 -type f ! -name '*.pub' -name 'id_*'); do
	if ssh_has_identity "$FILE" ; then
		continue
	fi

	CREDENTIAL=$(get_credential "$FILE")

	if [[ $CREDENTIAL = "" ]]; then
		set_credential "$FILE"

	else
		if ! ssh_add "$CREDENTIAL" "$FILE"; then
			set_credential "$FILE"
		fi
	fi
done