cmdline/apt-key.in

   1 #!/bin/sh
   2
   3 set -e
   4 unset GREP_OPTIONS
   5
   6 GPG_CMD="gpg --ignore-time-conflict --no-options --no-default-keyring"
   7
   8 # gpg needs (in different versions more or less) files to function correctly,
   9 # so we give it its own homedir and generate some valid content for it
  10 GPGHOMEDIR="$(mktemp -d)"
  11 CURRENTTRAP="${CURRENTTRAP} rm -rf '${GPGHOMEDIR}';"
  12 trap "${CURRENTTRAP}" 0 HUP INT QUIT ILL ABRT FPE SEGV PIPE TERM
  13 chmod 700 "$GPGHOMEDIR"
  14 # We don't use a secret keyring, of course, but gpg panics and
  15 # implodes if there isn't one available - and writeable for imports
  16 SECRETKEYRING="${GPGHOMEDIR}/secring.gpg"
  17 touch $SECRETKEYRING
  18 GPG_CMD="$GPG_CMD --homedir $GPGHOMEDIR"
  19 # create the trustdb with an (empty) dummy keyring
  20 # older gpgs required it, newer gpgs even warn that it isn't needed,
  21 # but require it nonetheless for some commands, so we just play safe
  22 # here for the foreseeable future and create a dummy one
  23 $GPG_CMD --quiet --check-trustdb --keyring $SECRETKEYRING >/dev/null 2>&1
  24 # tell gpg that it shouldn't try to maintain a trustdb file
  25 GPG_CMD="$GPG_CMD --no-auto-check-trustdb --trust-model always"
  26
  27 GPG="$GPG_CMD"
  28
  29 APT_DIR="/"
  30 eval $(apt-config shell APT_DIR Dir)
  31
  32 MASTER_KEYRING='&keyring-master-filename;'
  33 eval $(apt-config shell MASTER_KEYRING APT::Key::MasterKeyring)
  34 ARCHIVE_KEYRING='&keyring-filename;'
  35 eval $(apt-config shell ARCHIVE_KEYRING APT::Key::ArchiveKeyring)
  36 REMOVED_KEYS='&keyring-removed-filename;'
  37 eval $(apt-config shell REMOVED_KEYS APT::Key::RemovedKeys)
  38 ARCHIVE_KEYRING_URI='&keyring-uri;'
  39 eval $(apt-config shell ARCHIVE_KEYRING_URI APT::Key::ArchiveKeyringURI)
  40 TMP_KEYRING=${APT_DIR}/var/lib/apt/keyrings/maybe-import-keyring.gpg
  41
  42 aptkey_echo() { echo "$@"; }
  43
  44 requires_root() {
  45         if [ "$(id -u)" -ne 0 ]; then
  46                 echo >&2 "ERROR: This command can only be used by root."
  47                 exit 1
  48         fi
  49 }
  50
  51 add_keys_with_verify_against_master_keyring() {
  52     ADD_KEYRING=$1
  53     MASTER=$2
  54
  55     if [ ! -f "$ADD_KEYRING" ]; then
  56         echo >&2 "ERROR: '$ADD_KEYRING' not found"
  57         return
  58     fi
  59     if [ ! -f "$MASTER" ]; then
  60         echo >&2 "ERROR: '$MASTER' not found"
  61         return
  62     fi
  63
  64     # when adding new keys, make sure that the archive-master-keyring
  65     # is honored. so:
  66     #   all keys that are exported must have a valid signature
  67     #   from a key in the $distro-master-keyring
  68     add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^pub | cut -d: -f5`
  69     all_add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^[ps]ub | cut -d: -f5`
  70     master_keys=`$GPG_CMD --keyring $MASTER --with-colons --list-keys | grep ^pub | cut -d: -f5`
  71
  72     # ensure there are no colisions LP: #857472
  73     for all_add_key in $all_add_keys; do
  74         for master_key in $master_keys; do
  75             if [ "$all_add_key" = "$master_key" ]; then
  76                 echo >&2 "Keyid collision for '$all_add_key' detected, operation aborted"
  77                 return 1
  78             fi
  79         done
  80     done
  81
  82     for add_key in $add_keys; do
  83         # export the add keyring one-by-one
  84         rm -f $TMP_KEYRING
  85         $GPG_CMD --keyring $ADD_KEYRING --output $TMP_KEYRING --export $add_key
  86         # check if signed with the master key and only add in this case
  87         ADDED=0
  88         for master_key in $master_keys; do
  89             if $GPG_CMD --keyring $MASTER --keyring $TMP_KEYRING --check-sigs --with-colons $add_key | grep '^sig:!:' | cut -d: -f5 | grep -q $master_key; then
  90                 $GPG --import $TMP_KEYRING
  91                 ADDED=1
  92             fi
  93         done
  94         if [ $ADDED = 0 ]; then
  95             echo >&2 "Key '$add_key' not added. It is not signed with a master key"
  96         fi
  97     done
  98     rm -f $TMP_KEYRING
  99 }
 100
 101 # update the current archive signing keyring from a network URI
 102 # the archive-keyring keys needs to be signed with the master key
 103 # (otherwise it does not make sense from a security POV)
 104 net_update() {
 105     # Disabled for now as code is insecure (LP: #1013639 (and 857472, 1013128))
 106     APT_KEY_NET_UPDATE_ENABLED=""
 107     eval $(apt-config shell APT_KEY_NET_UPDATE_ENABLED APT::Key::Net-Update-Enabled)
 108     if [ -z "$APT_KEY_NET_UPDATE_ENABLED" ]; then
 109         exit 1
 110     fi
 111
 112     if [ -z "$ARCHIVE_KEYRING_URI" ]; then
 113         echo >&2 "ERROR: Your distribution is not supported in net-update as no uri for the archive-keyring is set"
 114         exit 1
 115     fi
 116     requires_root
 117     # in theory we would need to depend on wget for this, but this feature
 118     # isn't useable in debian anyway as we have no keyring uri nor a master key
 119     if ! which wget >/dev/null 2>&1; then
 120         echo >&2 "ERROR: an installed wget is required for a network-based update"
 121         exit 1
 122     fi
 123     if [ ! -d ${APT_DIR}/var/lib/apt/keyrings ]; then
 124         mkdir -p ${APT_DIR}/var/lib/apt/keyrings
 125     fi
 126     keyring=${APT_DIR}/var/lib/apt/keyrings/$(basename $ARCHIVE_KEYRING_URI)
 127     old_mtime=0
 128     if [ -e $keyring ]; then
 129         old_mtime=$(stat -c %Y $keyring)
 130     fi
 131     (cd  ${APT_DIR}/var/lib/apt/keyrings; wget --timeout=90 -q -N $ARCHIVE_KEYRING_URI)
 132     if [ ! -e $keyring ]; then
 133         return
 134     fi
 135     new_mtime=$(stat -c %Y $keyring)
 136     if [ $new_mtime -ne $old_mtime ]; then
 137         aptkey_echo "Checking for new archive signing keys now"
 138         add_keys_with_verify_against_master_keyring $keyring $MASTER_KEYRING
 139     fi
 140 }
 141
 142 update() {
 143     if [ ! -f $ARCHIVE_KEYRING ]; then
 144         echo >&2 "ERROR: Can't find the archive-keyring"
 145         echo >&2 "Is the &keyring-package; package installed?"
 146         exit 1
 147     fi
 148     requires_root
 149
 150     # add new keys from the package;
 151
 152     # we do not use add_keys_with_verify_against_master_keyring here,
 153     # because "update" is run on regular package updates.  A
 154     # attacker might as well replace the master-archive-keyring file
 155     # in the package and add his own keys. so this check wouldn't
 156     # add any security. we *need* this check on net-update though
 157     $GPG_CMD --quiet --batch --keyring $ARCHIVE_KEYRING --export | $GPG --import
 158
 159     if [ -r "$REMOVED_KEYS" ]; then
 160         # remove no-longer supported/used keys
 161         keys=`$GPG_CMD --keyring $REMOVED_KEYS --with-colons --list-keys | grep ^pub | cut -d: -f5`
 162         for key in $keys; do
 163             if $GPG --list-keys --with-colons | grep ^pub | cut -d: -f5 | grep -q $key; then
 164                 $GPG --quiet --batch --delete-key --yes ${key}
 165             fi
 166         done
 167     else
 168         echo >&2 "Warning: removed keys keyring  $REMOVED_KEYS missing or not readable"
 169     fi
 170 }
 171
 172 remove_key_from_keyring() {
 173     local GPG="$GPG_CMD --keyring $1"
 174     # check if the key is in this keyring: the key id is in the 5 column at the end
 175     if ! $GPG --with-colons --list-keys 2>&1 | grep -q "^pub:[^:]*:[^:]*:[^:]*:[0-9A-F]\+$2:"; then
 176         return
 177     fi
 178     if [ ! -w "$1" ]; then
 179         echo >&2 "Key ${2} is in keyring ${1}, but can't be removed as it is read only."
 180         return
 181     fi
 182     # check if it is the only key in the keyring and if so remove the keyring altogether
 183     if [ '1' = "$($GPG --with-colons --list-keys | grep "^pub:[^:]*:[^:]*:[^:]*:[0-9A-F]\+:" | wc -l)" ]; then
 184         mv -f "$1" "${1}~" # behave like gpg
 185         return
 186     fi
 187     # we can't just modify pointed to files as these might be in /usr or something
 188     local REALTARGET
 189     if [ -L "$1" ]; then
 190         REALTARGET="$(readlink -f "$1")"
 191         mv -f "$1" "${1}.dpkg-tmp"
 192         cp -a "$REALTARGET" "$1"
 193     fi
 194     # delete the key from the keyring
 195     $GPG --batch --delete-key --yes "$2"
 196     if [ -n "$REALTARGET" ]; then
 197         # the real backup is the old link, not the copy we made
 198         mv -f "${1}.dpkg-tmp" "${1}~"
 199     fi
 200 }
 201
 202 remove_key() {
 203     requires_root
 204
 205     while [ -n "$1" ]; do
 206         # if a --keyring was given, just remove from there
 207         if [ -n "$FORCED_KEYRING" ]; then
 208             remove_key_from_keyring "$FORCED_KEYRING" "$1"
 209         else
 210             # otherwise all known keyrings are up for inspection
 211             local TRUSTEDFILE="/etc/apt/trusted.gpg"
 212             eval $(apt-config shell TRUSTEDFILE Apt::GPGV::TrustedKeyring)
 213             eval $(apt-config shell TRUSTEDFILE Dir::Etc::Trusted/f)
 214             remove_key_from_keyring "$TRUSTEDFILE" "$1"
 215             TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
 216             eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
 217             if [ -d "$TRUSTEDPARTS" ]; then
 218                 for trusted in $(run-parts --list "$TRUSTEDPARTS" --regex '^.*\.gpg$'); do
 219                     remove_key_from_keyring "$trusted" "$1"
 220                 done
 221             fi
 222         fi
 223         aptkey_echo "OK"
 224         shift
 225     done
 226 }
 227
 228
 229 usage() {
 230     echo "Usage: apt-key [--keyring file] [command] [arguments]"
 231     echo
 232     echo "Manage apt's list of trusted keys"
 233     echo
 234     echo "  apt-key add <file>          - add the key contained in <file> ('-' for stdin)"
 235     echo "  apt-key del <keyid>         - remove the key <keyid>"
 236     echo "  apt-key export <keyid>      - output the key <keyid>"
 237     echo "  apt-key exportall           - output all trusted keys"
 238     echo "  apt-key update              - update keys using the keyring package"
 239     echo "  apt-key net-update          - update keys using the network"
 240     echo "  apt-key list                - list keys"
 241     echo "  apt-key finger              - list fingerprints"
 242     echo "  apt-key adv                 - pass advanced options to gpg (download key)"
 243     echo
 244     echo "If no specific keyring file is given the command applies to all keyring files."
 245 }
 246
 247 while [ -n "$1" ]; do
 248    case "$1" in
 249       --keyring)
 250          shift
 251          TRUSTEDFILE="$1"
 252          FORCED_KEYRING="$1"
 253          if [ -r "$TRUSTEDFILE" ] || [ "$2" = 'add' ] || [ "$2" = 'adv' ]; then
 254             GPG="$GPG --keyring $TRUSTEDFILE --primary-keyring $TRUSTEDFILE"
 255          else
 256             echo >&2 "Error: The specified keyring »$TRUSTEDFILE« is missing or not readable"
 257             exit 1
 258          fi
 259          shift
 260          ;;
 261       --fakeroot)
 262          requires_root() { true; }
 263          shift
 264          ;;
 265       --quiet)
 266          aptkey_echo() { true; }
 267          shift
 268          ;;
 269       --*)
 270          echo >&2 "Unknown option: $1"
 271          usage
 272          exit 1;;
 273       *)
 274          break;;
 275    esac
 276 done
 277
 278 if [ -z "$TRUSTEDFILE" ]; then
 279    TRUSTEDFILE="/etc/apt/trusted.gpg"
 280    eval $(apt-config shell TRUSTEDFILE Apt::GPGV::TrustedKeyring)
 281    eval $(apt-config shell TRUSTEDFILE Dir::Etc::Trusted/f)
 282    if [ -r "$TRUSTEDFILE" ]; then
 283       GPG="$GPG --keyring $TRUSTEDFILE"
 284       GPG="$GPG --primary-keyring $TRUSTEDFILE"
 285    fi
 286    TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
 287    eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
 288    if [ -d "$TRUSTEDPARTS" ]; then
 289       # strip / suffix as gpg will double-slash in that case (#665411)
 290       STRIPPED_TRUSTEDPARTS="${TRUSTEDPARTS%/}"
 291       if [ "${STRIPPED_TRUSTEDPARTS}/" = "$TRUSTEDPARTS" ]; then
 292          TRUSTEDPARTS="$STRIPPED_TRUSTEDPARTS"
 293       fi
 294       for trusted in $(run-parts --list "$TRUSTEDPARTS" --regex '^.*\.gpg$'); do
 295          GPG="$GPG --keyring $trusted"
 296       done
 297    fi
 298 fi
 299
 300 command="$1"
 301 if [ -z "$command" ]; then
 302     usage
 303     exit 1
 304 fi
 305 shift
 306
 307 if [ "$command" != "help" ]; then
 308     if ! which gpg >/dev/null 2>&1; then
 309         echo >&2 "Warning: gnupg does not seem to be installed."
 310         echo >&2 "Warning: apt-key requires gnupg for most operations."
 311         echo >&2
 312     fi
 313
 314     # gpg defaults to mode 0600 for new keyrings. Create one with 0644 instead.
 315     if ! [ -e "$TRUSTEDFILE" ]; then
 316         if [ -w "$(dirname "$TRUSTEDFILE")" ]; then
 317            touch -- "$TRUSTEDFILE"
 318            chmod 0644 -- "$TRUSTEDFILE"
 319            GPG="$GPG --keyring $TRUSTEDFILE"
 320            GPG="$GPG --primary-keyring $TRUSTEDFILE"
 321         fi
 322     fi
 323 fi
 324
 325 case "$command" in
 326     add)
 327         requires_root
 328         $GPG --quiet --batch --import "$@"
 329         aptkey_echo "OK"
 330         ;;
 331     del|rm|remove)
 332         remove_key "$@"
 333         ;;
 334     update)
 335         update
 336         ;;
 337     net-update)
 338         net_update
 339         ;;
 340     list)
 341         $GPG --batch --list-keys "$@"
 342         ;;
 343     finger*)
 344         $GPG --batch --fingerprint "$@"
 345         ;;
 346     export|exportall)
 347         $GPG --armor --export "$@"
 348         ;;
 349     adv*)
 350         aptkey_echo "Executing: $GPG $*"
 351         $GPG "$@"
 352         ;;
 353     help)
 354         usage
 355         ;;
 356     *)
 357         usage
 358         exit 1
 359         ;;
 360 esac