get-deps-from-dockerfile

#!/bin/bash

# You can change these if you want to:
patchers=("patchelf" "pwninit")
blacklist=("linux-vdso.so.1") # do not extract these files from the container
default_outfile="patched"
default_dockerfile="Dockerfile"
patcher="patchelf"
IMAGE_NAME="temp_challenge"
CONTAINER_NAME="temp"
LD="ld-linux-x86-64.so.2"

# Logging functions:
function log()     { echo -e "\e[32m[*]\e[0m $1"; }
function error()   { echo -e "\e[31m[!]\e[0m $1"; [[ ! -z $2 ]] && exit "$2"; }
function warning() { echo -e "\e[33m[?]\e[0m $1"; }
function msg()     { echo -e "\e[34m[+]\e[0m $@"; }

function usage() {
	echo; echo -e "$0 [options]"
	echo -e "\t--binary     | -b - Binary to patch                      [\e[31mREQUIRED\e[0m]"
	echo -e "\t--dockerfile | -d - Dockerfile to extract libraries from [\e[33mDefault\e[0m: \e[32m$default_dockerfile\e[0m]"
	echo -e "\t--outfile    | -o - Output file name                     [\e[33mDefault\e[0m: \e[32m[BINARY]-$default_outfile\e[0m]"
	echo -e "\t--patcher    | -p - The binary to use for patching       [\e[33mDefault\e[0m: \e[32m$patcher\e[0m]"
	echo -e "\t[\e[34m\e[4mAvailable Patchers\e[0m: \e[31m${patchers[@]}\e[0m]"
	[[ ! -z "$1" ]] && exit "$1"
}

function validate() {
	# basic function to validate if the argument is valid and 
	# if the passed file exists or not.
	[[ -z "$1" ]]   && error "No $2 specified!" 1
	[[ ! -f "$1" ]] && error "\e[33m$1\e[0m is not a valid file" 1
	realpath "$1"
}

function set_binary() {
	[[ -z "$1" ]] && error "No binary name specified" 1
	[[ ! -f "$1" ]] && error "\e[33m$1\e[0m is not a valid file" 1
	binary=`realpath "$1"`
}

function set_dockerfile() {
	[[ -z "$1" ]] && dockerfile="$default_dockerfile" || dockerfile="$1"
	[[ ! -f "$dockerfile" ]] && error "\e[33m$1\e[0m is not a valid file" 1
	dockerfile=`realpath $dockerfile`
}

function set_outfile() {
	default="$binary-$default_outfile"
	if [[ -z "$1" && ! -z $out_already ]]; then
		warning "No output file specified. Defaulting to \e[34m$default\e[0m"
		outfile="$default"
	fi

	if [[ -f "$outfile" && ! -z "$1" ]]; then
		warning "\e[31m$1\e[0m is already a file. Defaulting to: \e[34m$default\e[0m"
		outfile="$default"
	fi

	[[ -z "$outfile" ]] && outfile="$default"
}

function set_patcher() {
	[[ ! -z "$1" ]] && patcher="$1"
	searcher="\<${patcher}\>"
	if [[ ${patchers[@]} =~ $searcher ]]; then
		command -v "$patcher" 2>&1 >/dev/null
		[[ $? != 0 ]] && error "$patcher not found in PATH. Please check." 1
	else
		allowed="${patchers[@]}"
		error "Invalid patcher. Only allowed: \e[31m$allowed\e[0m" 1
	fi
}

function get_deps_from_bin() {
	# This function; using ldd will extract the dependencies names.
	deps=()
	files=$(ldd $binary | awk -F ' ' '{print $1}')
	for file in $files; do
		file=`basename $file`
		searcher="\<${file}\>"
		if [[ ${blacklist} =~ $searcher ]]; then
			continue
		fi
		deps+=("$file")
	done
	echo "${deps[@]}"
}

function setup_container() {

	command -v "docker" 2>&1 >/dev/null
	[[ $? != 0 ]] && error "Docker not found. Please install docker to continue" 1

	(docker ps | grep "$CONTAINER_NAME") 2>&1 >/dev/null
	if [[ $? == 0 ]]; then
		warning "Found a container running with name \e[36m$CONTAINER_NAME\e[0m. Stopping it before continuing"
		docker stop "$CONTAINER_NAME" 2>&1 >/dev/null
	fi

	# Extract `FROM` statement, and creating another file with only the IMAGE, and a `sleep` entrypoint:
	# Only get the first result.
	from=$(cat "$dockerfile" | grep -i "^FROM" | cut -d $'\n' -f1)
	# TODO: Make it generic and not specific:
	img_name=`echo "$from" | grep -ioE '((theflash.*|ubuntu.*|debian.*|fedora.*|arch.*|python.*|php.*|apache.*):[^ \n]+)'`
	log "Extracted Image from \"\e[31m$dockerfile\e[0m\": \e[33m$img_name\e[0m"

	tmp_dir=$(mktemp -d)
	tmp_file=$(mktemp "$tmp_dir/temp_Docker_XXX")

	[ -f "$tmp_file" ] && rm -f "$tmp_file"

	echo "FROM $img_name" > "$tmp_file"
	echo 'ENTRYPOINT ["sleep", "1000"]' >> "$tmp_file"

	log "Wrote temporary Dockerfile: \e[33m$tmp_file\e[0m"
	log "Building image \e[36m$IMAGE_NAME\e[0m."
	docker build -f "$tmp_file" -t "$IMAGE_NAME" . 2>&1 >/dev/null

	log "Built image with name: \e[33m$IMAGE_NAME\e[0m"

	container_id=$(docker run -d --rm -q --name "$CONTAINER_NAME" "$IMAGE_NAME")
	msg "Ran container (\e[36m$CONTAINER_NAME\e[0m) with id \e[33m$container_id\e[0m"
}

function find_and_copy() {
	[[ -z "$1" ]] && return
	path=$(docker exec -it "$CONTAINER_NAME" sh -c "find / -name $1 -exec realpath {} \; 2>/dev/null | head -1")
	[[ $? != 0 && $? != 1 ]] && error "Unable to extract \e[33m$1\e[0m path. Possible error: \e[31m$path\e[0m"
	c_path="${path%?}"
	file_path="${c_path//[$'\t\r\n ']}"

	docker cp "$container_id":"$file_path" "$1" 2>&1 >/dev/null
	if [[ $? != 0 ]]; then
		warning "Unable to copy file from the container :("
	else
		msg "Copied from \e[33m\"$file_path\"\e[0m to \e[36m\"$1\"\e[0m"
		chmod +x "$1"
	fi
}

function patch_binary() {

	log "Patching \e[33m$binary\e[0m using \e[36m$patcher\e[0m to \e[31m$outfile\e[0m"

	if [[ "$patcher" == "patchelf" ]]; then
		cp "$binary" "$outfile"
		[[ $? != 0 ]] && error "Unable to make clone of the file. Modifying original." 1
		patchelf --set-interpreter "$LD" --set-rpath . "$outfile"
		[[ $? != 0 ]] && error "An error occurred when running patchelf." 1
	elif [[ "$patcher" == "pwninit" ]]; then
		pwninit --no-template --bin "$binary"
	else
		error "Invalid binary to patch using: \e[31m$patcher\e[0m" 1
	fi
	msg "Done patching!"
}

function cleanup() {
	log "Cleaning up...."
	docker stop "$CONTAINER_NAME" 2>&1 >/dev/null
	msg "Stopped (\e[31m$CONTAINER_NAME\e[0m) \e[33m$container_id\e[0m"

	if [[ $DELETE != 0 ]]; then
		docker rmi "$IMAGE_NAME" 2>&1 >/dev/null
		[[ $? != 0 ]] && error "Unable to delete \e[31m$IMAGE_NAME\e[0m" 1
		msg "Deleted \e[31m$IMAGE_NAME\e[0m"
	fi
}

if [[ $# == 0 ]];  then
	error "No arguments supplied!"
	usage 1
fi

while [[ "$#" -gt 0 ]]; do
    case $1 in
        -b|--binary) set_binary "$2"; shift ;;
        -d|--dockerfile) set_dockerfile "$2"; shift ;;
        -o|--outfile) out_already=1; set_outfile "$2"; shift ;;
        -p|--patcher) set_patcher "$2"; shift ;;
        -h|--help) usage 0 ;;
        *) echo "Invalid parameter: $1"; usage 1;;
    esac
    shift
done

set_binary "$binary"
set_dockerfile "$dockerfile"
set_outfile "$outfile"
set_patcher "$patcher"

deps=$(get_deps_from_bin "$binary")
setup_container

for dep in $deps; do find_and_copy "$dep"; done
patch_binary
cleanup