Shell Programming and Scripting

#!/bin/bash
break_on_injections() { # "$1"
# Pass the first argument, and compare vs malware lists
# 
	[ -z "$1" ] && return 1
	checkthis="${1}"
	malware='; ´ | < & > :'
	#malware2=( '$(' '&&' )
	for mal in $malware #"${malware2[@]}"
	do	mal=$(echo "$mal" | sed s," ","",g)
		echo "$checkthis" | grep "$mal" && \
			printf "%s\t%s\n" \
				"Aborting, injection detected!" "" \
				"Source: " "$(echo ${BASH_SOURCE[@]})" \
				"Function:" "$(echo ${FUNCNAME[@]})" \
				"Pipestatus:" "$(echo ${PIPESTATUS[@]})" && \
				return 0
	done
	return 1
}

break_on_injections "$1" && exit 1

exit
#########################################
#########################################
#
#	Recomended usage:
#
#########################################
#########################################
while arg in "${@}"
do	break_on_injections "$arg" && exit 1
done

0 $ inject.sh "$(hostname)"

0 $ inject.sh || echo hmm
hmm

1 $ inject.sh "|| echo hmm"
|| echo hmm
Aborting, injection detected!	
Source: 	/bin/inject.sh /bin/inject.sh
Function:	break_on_injections main
Pipestatus:	0 0

inject.sh '$(hostname)'

break_on_injections() {
  typeset arg ac=0
  for arg do
    ac=$((ac+=1))
    case $arg in
    (*[';`|<&>:']*|*'$('*)
      printf "%s\n" \
        "Aborting, injection detected! arg${ac}='$arg'"
      return 1
    ;;
    esac
  done
  return 0
}
break_on_injections "$@"