git.scottworley.com Git - overonion/blob - overonion

   1 #!/bin/bash
   2
   3 umask 077
   4
   5 hash_dir=$(mktemp -d)
   6
   7 function die() {
   8   echo "$*" >&2
   9   exit 1
  10 }
  11
  12 if (( $# != 2));then
  13   die "usage: overonion e|d keyfile"
  14 fi
  15 mode=$1
  16 if [[ "$mode" != e && "$mode" != d ]];then
  17   die "Use 'e' for encrypt or 'd' for decrypt"
  18 fi
  19 keyfile=$2
  20 if [[ ! -e "$keyfile" ]];then
  21   die "Keyfile not found"
  22 fi
  23 if [[ ! -r "$keyfile" ]];then
  24   die "Cannot read keyfile"
  25 fi
  26
  27 num_layers=$(wc -l < "$keyfile")
  28 if (( num_layers < 20 ));then
  29   die "Keyfile doesn't have enough layers to be an onion"
  30 fi
  31
  32 hash_fields=$(awk '/^openssl-dgst / { print NF }' "$keyfile" | uniq )
  33
  34 if [[ "$mode" == e ]];then
  35   first_layer=$num_layers
  36   next_layer=-1
  37   openssl_decrypt=""
  38   if [[ "$hash_fields" != 4 ]];then
  39     die "Refusing to encrypt with already-used key"
  40   fi
  41 else
  42   first_layer=1
  43   next_layer=1
  44   openssl_decrypt="-d"
  45   if [[ "$hash_fields" != 5 ]];then
  46     die "Key does not appear to have been used for encryption (it has no embedded hashes).  Refusing to decrypt."
  47   fi
  48 fi
  49
  50 function go() {
  51   layer=$1
  52   if (( layer == 0 || layer > num_layers ));then
  53     cat
  54   else
  55     operation=$(sed -n "${layer}{;s/ .*//;p;}" "$keyfile")
  56     if [[ "$operation" == openssl-enc ]];then
  57       openssl enc $openssl_decrypt "-$(sed -rn "${layer}s/[^ ]+ ([^ ]+) .*/\\1/p" "$keyfile")" \
  58               -nosalt -pass fd:37 37< <(sed -rn "${layer}s/^[^ ]+ [^ ]+ //p" "$keyfile")
  59     elif [[ "$operation" == reverse ]];then
  60       reverse
  61     elif [[ "$operation" == openssl-dgst ]];then
  62       tee >(echo "$(sed -n "${layer}p" "$keyfile") $(
  63             {
  64               awk -vlayer="$layer" 'NR == layer { print $3 }' "$keyfile" | base64 -d
  65               cat
  66               awk -vlayer="$layer" 'NR == layer { print $4 }' "$keyfile" | base64 -d
  67             } |
  68               openssl dgst -binary "-$(sed -rn "${layer}s/^[^ ]+ ([^ ]+).*/\\1/p" "$keyfile")" |
  69               base64 --wrap=0)" > "$hash_dir/$layer")
  70     else
  71       die "Unknown operation"
  72     fi |
  73       go $(( layer + next_layer ))
  74   fi
  75 }
  76
  77 go "$first_layer"
  78
  79 for hash_result in "$hash_dir"/*;do
  80   layer=$(basename "$hash_result")
  81   if [[ "$mode" == e ]];then
  82     # Add the hashes to keyfile
  83     key_aside_dir=$(mktemp -d "$keyfile.XXXXXXXXXX")
  84     key_aside="$key_aside_dir/key.orig"
  85     mv "$keyfile" "$key_aside"
  86     sed "${layer}s,.*,$(< "$hash_result")," "$key_aside" > "$keyfile"
  87     shred -u "$key_aside"
  88     rmdir "$key_aside_dir"
  89   else
  90     # Verify the hashes
  91     if [[ "$(awk '{ print $5 == $6 ? "hash ok" : "mismatch" }' "$hash_result")" != "hash ok" ]];then
  92       die "Hash check $layer failed"
  93     fi
  94   fi
  95 done
  96
  97 rm -r "$hash_dir"