cmdline/apt-key

   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 a trustdb to function, but it can't be invalid (not even empty)
   9 # so we create a temporary directory to store our fresh readable trustdb in
  10 TRUSTDBDIR="$(mktemp -d)"
  11 CURRENTTRAP="${CURRENTTRAP} rm -rf '${TRUSTDBDIR}';"
  12 trap "${CURRENTTRAP}" 0 HUP INT QUIT ILL ABRT FPE SEGV PIPE TERM
  13 chmod 700 "$TRUSTDBDIR"
  14 # We also don't use a secret keyring, of course, but gpg panics and
  15 # implodes if there isn't one available - and writeable for imports
  16 SECRETKEYRING="${TRUSTDBDIR}/secring.gpg"
  17 touch $SECRETKEYRING
  18 GPG_CMD="$GPG_CMD --secret-keyring $SECRETKEYRING"
  19 GPG_CMD="$GPG_CMD --trustdb-name ${TRUSTDBDIR}/trustdb.gpg"
  20
  21 # now create the trustdb with an (empty) dummy keyring
  22 $GPG_CMD --quiet --check-trustdb --keyring $SECRETKEYRING
  23 # and make sure that gpg isn't trying to update the file
  24 GPG_CMD="$GPG_CMD --no-auto-check-trustdb --trust-model always"
  25
  26 GPG="$GPG_CMD"
  27
  28 MASTER_KEYRING=''
  29 eval $(apt-config shell MASTER_KEYRING APT::Key::MasterKeyring)
  30 ARCHIVE_KEYRING='/usr/share/keyrings/debian-archive-keyring.gpg'
  31 eval $(apt-config shell ARCHIVE_KEYRING APT::Key::ArchiveKeyring)
  32 REMOVED_KEYS='/usr/share/keyrings/debian-archive-removed-keys.gpg'
  33 eval $(apt-config shell REMOVED_KEYS APT::Key::RemovedKeys)
  34 ARCHIVE_KEYRING_URI=''
  35 eval $(apt-config shell ARCHIVE_KEYRING_URI APT::Key::ArchiveKeyringURI)
  36 TMP_KEYRING=/var/lib/apt/keyrings/maybe-import-keyring.gpg
  37
  38 requires_root() {
  39         if [ "$(id -u)" -ne 0 ]; then
  40                 echo >&1 "ERROR: This command can only be used by root."
  41                 exit 1
  42         fi
  43 }
  44
  45 # gpg defaults to mode 0600 for new keyrings. Create one with 0644 instead.
  46 init_keyring() {
  47     for path; do
  48         if ! [ -e "$path" ]; then
  49             touch -- "$path"
  50             chmod 0644 -- "$path"
  51         fi
  52     done
  53 }
  54
  55 add_keys_with_verify_against_master_keyring() {
  56     ADD_KEYRING=$1
  57     MASTER=$2
  58
  59     if [ ! -f "$ADD_KEYRING" ]; then
  60         echo "ERROR: '$ADD_KEYRING' not found"
  61         return
  62     fi
  63     if [ ! -f "$MASTER" ]; then
  64         echo "ERROR: '$MASTER' not found"
  65         return
  66     fi
  67
  68     # when adding new keys, make sure that the archive-master-keyring
  69     # is honored. so:
  70     #   all keys that are exported must have a valid signature
  71     #   from a key in the $distro-master-keyring
  72     add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^pub | cut -d: -f5`
  73     all_add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^[ps]ub | cut -d: -f5`
  74     master_keys=`$GPG_CMD --keyring $MASTER --with-colons --list-keys | grep ^pub | cut -d: -f5`
  75
  76     # ensure there are no colisions LP: #857472
  77     for all_add_key in $all_add_keys; do
  78         for master_key in $master_keys; do
  79             if [ "$all_add_key" = "$master_key" ]; then
  80                 echo >&2 "Keyid collision for '$all_add_key' detected, operation aborted"
  81                 return 1
  82             fi
  83         done
  84     done
  85
  86     for add_key in $add_keys; do
  87         # export the add keyring one-by-one
  88         rm -f $TMP_KEYRING
  89         $GPG_CMD --keyring $ADD_KEYRING --output $TMP_KEYRING --export $add_key
  90         # check if signed with the master key and only add in this case
  91         ADDED=0
  92         for master_key in $master_keys; do
  93             if $GPG_CMD --keyring $MASTER --keyring $TMP_KEYRING --check-sigs --with-colons $add_key | grep '^sig:!:' | cut -d: -f5 | grep -q $master_key; then
  94                 $GPG --import $TMP_KEYRING
  95                 ADDED=1
  96             fi
  97         done
  98         if [ $ADDED = 0 ]; then
  99             echo >&2 "Key '$add_key' not added. It is not signed with a master key"
 100         fi
 101     done
 102     rm -f $TMP_KEYRING
 103 }
 104
 105 # update the current archive signing keyring from a network URI
 106 # the archive-keyring keys needs to be signed with the master key
 107 # (otherwise it does not make sense from a security POV)
 108 net_update() {
 109     # Disabled for now as code is insecure (LP: #1013639 (and 857472, 1013128))
 110     exit 1
 111
 112     if [ -z "$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 /var/lib/apt/keyrings ]; then
 124         mkdir -p /var/lib/apt/keyrings
 125     fi
 126     keyring=/var/lib/apt/keyrings/$(basename $ARCHIVE_KEYRING)
 127     old_mtime=0
 128     if [ -e $keyring ]; then
 129         old_mtime=$(stat -c %Y $keyring)
 130     fi
 131     (cd  /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         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 debian-archive-keyring 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 "Warning: removed keys keyring  $REMOVED_KEYS missing or not readable" >&2
 169     fi
 170 }
 171
 172 remove_key_from_keyring() {
 173     local GPG="$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 ${1}, but can't be removed as it is read only."
 180         return
 181     fi
 182     # check if it is the only key in the keyring and if so remove the keyring alltogether
 183     if [ '1' = "$($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" "$1"
 193         ls "$(dirname $1)"
 194     fi
 195     # delete the key from the keyring
 196     $GPG --batch --delete-key --yes "$2"
 197     if [ -n "$REALTARGET" ]; then
 198         # the real backup is the old link, not the copy we made
 199         mv -f "${1}.dpkg-tmp" "${1}~"
 200     fi
 201 }
 202
 203 remove_key() {
 204     requires_root
 205
 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     echo "OK"
 224 }
 225
 226
 227 usage() {
 228     echo "Usage: apt-key [--keyring file] [command] [arguments]"
 229     echo
 230     echo "Manage apt's list of trusted keys"
 231     echo
 232     echo "  apt-key add <file>          - add the key contained in <file> ('-' for stdin)"
 233     echo "  apt-key del <keyid>         - remove the key <keyid>"
 234     echo "  apt-key export <keyid>      - output the key <keyid>"
 235     echo "  apt-key exportall           - output all trusted keys"
 236     echo "  apt-key update              - update keys using the keyring package"
 237     echo "  apt-key net-update          - update keys using the network"
 238     echo "  apt-key list                - list keys"
 239     echo "  apt-key finger              - list fingerprints"
 240     echo "  apt-key adv                 - pass advanced options to gpg (download key)"
 241     echo
 242     echo "If no specific keyring file is given the command applies to all keyring files."
 243 }
 244
 245 while [ -n "$1" ]; do
 246    case "$1" in
 247       --keyring)
 248          shift
 249          TRUSTEDFILE="$1"
 250          FORCED_KEYRING="$1"
 251          if [ -r "$TRUSTEDFILE" ] || [ "$2" = 'add' ] || [ "$2" = 'adv' ]; then
 252             GPG="$GPG --keyring $TRUSTEDFILE --primary-keyring $TRUSTEDFILE"
 253          else
 254             echo >&2 "Error: The specified keyring »$TRUSTEDFILE« is missing or not readable"
 255             exit 1
 256          fi
 257          shift
 258          ;;
 259       --fakeroot)
 260          requires_root() { true; }
 261          shift
 262          ;;
 263       --*)
 264          echo >&2 "Unknown option: $1"
 265          usage
 266          exit 1;;
 267       *)
 268          break;;
 269    esac
 270 done
 271
 272 if [ -z "$TRUSTEDFILE" ]; then
 273    TRUSTEDFILE="/etc/apt/trusted.gpg"
 274    eval $(apt-config shell TRUSTEDFILE Apt::GPGV::TrustedKeyring)
 275    eval $(apt-config shell TRUSTEDFILE Dir::Etc::Trusted/f)
 276    if [ -r "$TRUSTEDFILE" ]; then
 277       GPG="$GPG --keyring $TRUSTEDFILE"
 278    fi
 279    GPG="$GPG --primary-keyring $TRUSTEDFILE"
 280    TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
 281    eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
 282    if [ -d "$TRUSTEDPARTS" ]; then
 283       # strip / suffix as gpg will double-slash in that case (#665411)
 284       STRIPPED_TRUSTEDPARTS="${TRUSTEDPARTS%/}"
 285       if [ "${STRIPPED_TRUSTEDPARTS}/" = "$TRUSTEDPARTS" ]; then
 286          TRUSTEDPARTS="$STRIPPED_TRUSTEDPARTS"
 287       fi
 288       for trusted in $(run-parts --list "$TRUSTEDPARTS" --regex '^.*\.gpg$'); do
 289          GPG="$GPG --keyring $trusted"
 290       done
 291    fi
 292 fi
 293
 294 command="$1"
 295 if [ -z "$command" ]; then
 296     usage
 297     exit 1
 298 fi
 299 shift
 300
 301 if [ "$command" != "help" ] && ! which gpg >/dev/null 2>&1; then
 302     echo >&2 "Warning: gnupg does not seem to be installed."
 303     echo >&2 "Warning: apt-key requires gnupg for most operations."
 304     echo >&2
 305 fi
 306
 307 case "$command" in
 308     add)
 309         requires_root
 310         init_keyring "$TRUSTEDFILE"
 311         $GPG --quiet --batch --import "$1"
 312         echo "OK"
 313         ;;
 314     del|rm|remove)
 315         init_keyring "$TRUSTEDFILE"
 316         remove_key "$1"
 317         ;;
 318     update)
 319         init_keyring "$TRUSTEDFILE"
 320         update
 321         ;;
 322     net-update)
 323         init_keyring "$TRUSTEDFILE"
 324         net_update
 325         ;;
 326     list)
 327         init_keyring "$TRUSTEDFILE"
 328         $GPG --batch --list-keys
 329         ;;
 330     finger*)
 331         init_keyring "$TRUSTEDFILE"
 332         $GPG --batch --fingerprint
 333         ;;
 334     export)
 335         init_keyring "$TRUSTEDFILE"
 336         $GPG --armor --export "$1"
 337         ;;
 338     exportall)
 339         init_keyring "$TRUSTEDFILE"
 340         $GPG --armor --export
 341         ;;
 342     adv*)
 343         init_keyring "$TRUSTEDFILE"
 344         echo "Executing: $GPG $*"
 345         $GPG $*
 346         ;;
 347     help)
 348         usage
 349         ;;
 350     *)
 351         usage
 352         exit 1
 353         ;;
 354 esac