]> git.saurik.com Git - apt.git/blobdiff - cmdline/apt-key.in
Fix lzma write support to handle "try again" case
[apt.git] / cmdline / apt-key.in
index 779872b4c3184f7defff598932ddaf2e278bf17b..3ed2a70cec9f62a4f35202619bc8ea1febaf0199 100644 (file)
@@ -2,66 +2,69 @@
 
 set -e
 unset GREP_OPTIONS
-
-GPG_CMD="gpg --ignore-time-conflict --no-options --no-default-keyring"
-
-# gpg needs a trustdb to function, but it can't be invalid (not even empty)
-# so we create a temporary directory to store our fresh readable trustdb in
-TRUSTDBDIR="$(mktemp -d)"
-CURRENTTRAP="${CURRENTTRAP} rm -rf '${TRUSTDBDIR}';"
-trap "${CURRENTTRAP}" 0 HUP INT QUIT ILL ABRT FPE SEGV PIPE TERM
-chmod 700 "$TRUSTDBDIR"
-# We also don't use a secret keyring, of course, but gpg panics and
-# implodes if there isn't one available - and writeable for imports
-SECRETKEYRING="${TRUSTDBDIR}/secring.gpg"
-touch $SECRETKEYRING
-GPG_CMD="$GPG_CMD --secret-keyring $SECRETKEYRING"
-GPG_CMD="$GPG_CMD --trustdb-name ${TRUSTDBDIR}/trustdb.gpg"
-
-# now create the trustdb with an (empty) dummy keyring
-$GPG_CMD --quiet --check-trustdb --keyring $SECRETKEYRING
-# and make sure that gpg isn't trying to update the file
-GPG_CMD="$GPG_CMD --no-auto-check-trustdb --trust-model always"
-
-GPG="$GPG_CMD"
+export IFS="$(printf "\n\b")"
 
 MASTER_KEYRING='&keyring-master-filename;'
-eval $(apt-config shell MASTER_KEYRING APT::Key::MasterKeyring)
+eval "$(apt-config shell MASTER_KEYRING APT::Key::MasterKeyring)"
 ARCHIVE_KEYRING='&keyring-filename;'
-eval $(apt-config shell ARCHIVE_KEYRING APT::Key::ArchiveKeyring)
+eval "$(apt-config shell ARCHIVE_KEYRING APT::Key::ArchiveKeyring)"
 REMOVED_KEYS='&keyring-removed-filename;'
-eval $(apt-config shell REMOVED_KEYS APT::Key::RemovedKeys)
+eval "$(apt-config shell REMOVED_KEYS APT::Key::RemovedKeys)"
 ARCHIVE_KEYRING_URI='&keyring-uri;'
-eval $(apt-config shell ARCHIVE_KEYRING_URI APT::Key::ArchiveKeyringURI)
-TMP_KEYRING=/var/lib/apt/keyrings/maybe-import-keyring.gpg
+eval "$(apt-config shell ARCHIVE_KEYRING_URI APT::Key::ArchiveKeyringURI)"
+
+aptkey_echo() { echo "$@"; }
 
 requires_root() {
        if [ "$(id -u)" -ne 0 ]; then
-               echo >&1 "ERROR: This command can only be used by root."
+               echo >&2 "ERROR: This command can only be used by root."
                exit 1
        fi
 }
 
-# gpg defaults to mode 0600 for new keyrings. Create one with 0644 instead.
-init_keyring() {
-    for path; do
-        if ! [ -e "$path" ]; then
-            touch -- "$path"
-            chmod 0644 -- "$path"
-        fi
+command_available() {
+    # command -v "$1" >/dev/null 2>&1 # not required by policy, see #747320
+    # which "$1" >/dev/null 2>&1 # is in debianutils (essential) but not on non-debian systems
+    local OLDIFS="$IFS"
+    IFS=:
+    for p in $PATH; do
+       if [ -x "${p}/${1}" ]; then
+           IFS="$OLDIFS"
+           return 0
+       fi
     done
+    IFS="$OLDIFS"
+    return 1
+}
+
+escape_shell() {
+    echo "$@" | sed -e "s#'#'\"'\"'#g"
+}
+
+get_fingerprints_of_keyring() {
+    aptkey_execute "$GPG_SH" --keyring "$1" --with-colons --fingerprint | while read publine; do
+       # search for a public key
+       if [ "${publine%%:*}" != 'pub' ]; then continue; fi
+       # search for the associated fingerprint (should be the very next line)
+       while read fprline; do
+          if [ "${fprline%%:*}" = 'sub' ]; then break; # should never happen
+          elif [ "${fprline%%:*}" != 'fpr' ]; then continue; fi
+          echo "$fprline" | cut -d':' -f 10
+       done
+       # order in the keyring shouldn't be important
+    done | sort
 }
 
 add_keys_with_verify_against_master_keyring() {
-    ADD_KEYRING=$1
-    MASTER=$2
+    ADD_KEYRING="$1"
+    MASTER="$2"
 
     if [ ! -f "$ADD_KEYRING" ]; then
-       echo "ERROR: '$ADD_KEYRING' not found"
+       echo >&2 "ERROR: '$ADD_KEYRING' not found"
        return
-    fi 
+    fi
     if [ ! -f "$MASTER" ]; then
-       echo "ERROR: '$MASTER' not found"
+       echo >&2 "ERROR: '$MASTER' not found"
        return
     fi
 
@@ -69,9 +72,9 @@ add_keys_with_verify_against_master_keyring() {
     # is honored. so:
     #   all keys that are exported must have a valid signature
     #   from a key in the $distro-master-keyring
-    add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^pub | cut -d: -f5`
-    all_add_keys=`$GPG_CMD --keyring $ADD_KEYRING --with-colons --list-keys | grep ^[ps]ub | cut -d: -f5`
-    master_keys=`$GPG_CMD --keyring $MASTER --with-colons --list-keys | grep ^pub | cut -d: -f5`
+    add_keys="$(get_fingerprints_of_keyring "$ADD_KEYRING")"
+    all_add_keys="$(aptkey_execute "$GPG_SH" --keyring "$ADD_KEYRING" --with-colons --list-keys | grep ^[ps]ub | cut -d: -f5)"
+    master_keys="$(aptkey_execute "$GPG_SH" --keyring "$MASTER" --with-colons --list-keys | grep ^pub | cut -d: -f5)"
 
     # ensure there are no colisions LP: #857472
     for all_add_key in $all_add_keys; do
@@ -82,70 +85,81 @@ add_keys_with_verify_against_master_keyring() {
             fi
         done
     done
-    
+
     for add_key in $add_keys; do
         # export the add keyring one-by-one
-        rm -f $TMP_KEYRING
-        $GPG_CMD --keyring $ADD_KEYRING --output $TMP_KEYRING --export $add_key 
-        # check if signed with the master key and only add in this case
-        ADDED=0
+       local TMP_KEYRING="${GPGHOMEDIR}/tmp-keyring.gpg"
+       aptkey_execute "$GPG_SH" --batch --yes --keyring "$ADD_KEYRING" --output "$TMP_KEYRING" --export "$add_key"
+       if ! aptkey_execute "$GPG_SH" --batch --yes --keyring "$TMP_KEYRING" --import "$MASTER" > "${GPGHOMEDIR}/gpgoutput.log" 2>&1; then
+           cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+           false
+       fi
+       # check if signed with the master key and only add in this case
+       ADDED=0
        for master_key in $master_keys; do
-           if $GPG_CMD --keyring $MASTER --keyring $TMP_KEYRING --check-sigs --with-colons $add_key | grep '^sig:!:' | cut -d: -f5 | grep -q $master_key; then
-               $GPG --import $TMP_KEYRING
+           if aptkey_execute "$GPG_SH" --keyring "$TMP_KEYRING" --check-sigs --with-colons "$add_key" \
+              | grep '^sig:!:' | cut -d: -f5 | grep -q "$master_key"; then
+               aptkey_execute "$GPG_SH" --batch --yes --keyring "$ADD_KEYRING" --export "$add_key" \
+                  | aptkey_execute "$GPG" --batch --yes --import
                ADDED=1
            fi
        done
        if [ $ADDED = 0 ]; then
            echo >&2 "Key '$add_key' not added. It is not signed with a master key"
        fi
+       rm -f "${TMP_KEYRING}"
     done
-    rm -f $TMP_KEYRING
 }
 
 # update the current archive signing keyring from a network URI
 # the archive-keyring keys needs to be signed with the master key
 # (otherwise it does not make sense from a security POV)
 net_update() {
+    local APT_DIR='/'
+    eval $(apt-config shell APT_DIR Dir)
+
     # Disabled for now as code is insecure (LP: #1013639 (and 857472, 1013128))
-    exit 1
+    APT_KEY_NET_UPDATE_ENABLED=""
+    eval $(apt-config shell APT_KEY_NET_UPDATE_ENABLED APT::Key::Net-Update-Enabled)
+    if [ -z "$APT_KEY_NET_UPDATE_ENABLED" ]; then
+        exit 1
+    fi
 
     if [ -z "$ARCHIVE_KEYRING_URI" ]; then
        echo >&2 "ERROR: Your distribution is not supported in net-update as no uri for the archive-keyring is set"
        exit 1
     fi
-    requires_root
     # in theory we would need to depend on wget for this, but this feature
     # isn't useable in debian anyway as we have no keyring uri nor a master key
-    if ! which wget >/dev/null 2>&1; then
+    if ! command_available 'wget'; then
        echo >&2 "ERROR: an installed wget is required for a network-based update"
        exit 1
     fi
-    if [ ! -d /var/lib/apt/keyrings ]; then
-       mkdir -p /var/lib/apt/keyrings
+    if [ ! -d "${APT_DIR}/var/lib/apt/keyrings" ]; then
+       mkdir -p "${APT_DIR}/var/lib/apt/keyrings"
     fi
-    keyring=/var/lib/apt/keyrings/$(basename $ARCHIVE_KEYRING)
+    keyring="${APT_DIR}/var/lib/apt/keyrings/$(basename "$ARCHIVE_KEYRING_URI")"
     old_mtime=0
     if [ -e $keyring ]; then
-       old_mtime=$(stat -c %Y $keyring)
+       old_mtime=$(stat -c %Y "$keyring")
     fi
-    (cd  /var/lib/apt/keyrings; wget --timeout=90 -q -N $ARCHIVE_KEYRING_URI)
-    if [ ! -e $keyring ]; then
+    (cd  "${APT_DIR}/var/lib/apt/keyrings"; wget --timeout=90 -q -N "$ARCHIVE_KEYRING_URI")
+    if [ ! -e "$keyring" ]; then
        return
     fi
-    new_mtime=$(stat -c %Y $keyring)
+    new_mtime=$(stat -c %Y "$keyring")
     if [ $new_mtime -ne $old_mtime ]; then
-       echo "Checking for new archive signing keys now"
-       add_keys_with_verify_against_master_keyring $keyring $MASTER_KEYRING
+       aptkey_echo "Checking for new archive signing keys now"
+       add_keys_with_verify_against_master_keyring "$keyring" "$MASTER_KEYRING"
     fi
 }
 
 update() {
-    if [ ! -f $ARCHIVE_KEYRING ]; then
+    if [ ! -f "$ARCHIVE_KEYRING" ]; then
        echo >&2 "ERROR: Can't find the archive-keyring"
        echo >&2 "Is the &keyring-package; package installed?"
        exit 1
     fi
-    requires_root
 
     # add new keys from the package;
 
@@ -154,75 +168,239 @@ update() {
     # attacker might as well replace the master-archive-keyring file
     # in the package and add his own keys. so this check wouldn't
     # add any security. we *need* this check on net-update though
-    $GPG_CMD --quiet --batch --keyring $ARCHIVE_KEYRING --export | $GPG --import
+    import_keyring_into_keyring "$ARCHIVE_KEYRING" '' && cat "${GPGHOMEDIR}/gpgoutput.log"
 
     if [ -r "$REMOVED_KEYS" ]; then
        # remove no-longer supported/used keys
-       keys=`$GPG_CMD --keyring $REMOVED_KEYS --with-colons --list-keys | grep ^pub | cut -d: -f5`
-       for key in $keys; do
-           if $GPG --list-keys --with-colons | grep ^pub | cut -d: -f5 | grep -q $key; then
-               $GPG --quiet --batch --delete-key --yes ${key}
-           fi
+       get_fingerprints_of_keyring "$REMOVED_KEYS" | while read key; do
+           foreach_keyring_do 'remove_key_from_keyring' "$key"
        done
     else
-       echo "Warning: removed keys keyring  $REMOVED_KEYS missing or not readable" >&2
+       echo >&2 "Warning: removed keys keyring  $REMOVED_KEYS missing or not readable"
     fi
 }
 
 remove_key_from_keyring() {
-    local GPG="$GPG_CMD --keyring $1"
-    # check if the key is in this keyring: the key id is in the 5 column at the end
-    if ! $GPG --with-colons --list-keys 2>&1 | grep -q "^pub:[^:]*:[^:]*:[^:]*:[0-9A-F]\+$2:"; then
-       return
-    fi
-    if [ ! -w "$1" ]; then
-       echo >&2 "Key ${2} is in keyring ${1}, but can't be removed as it is read only."
-       return
+    local KEYRINGFILE="$1"
+    shift
+    # non-existent keyrings have by definition no keys
+    if [ ! -e "$KEYRINGFILE" ]; then
+       return
     fi
-    # check if it is the only key in the keyring and if so remove the keyring alltogether
-    if [ '1' = "$($GPG --with-colons --list-keys | grep "^pub:[^:]*:[^:]*:[^:]*:[0-9A-F]\+:" | wc -l)" ]; then
-       mv -f "$1" "${1}~" # behave like gpg
-       return
+
+    for KEY in "$@"; do
+       local FINGERPRINTS="${GPGHOMEDIR}/keyringfile.keylst"
+       get_fingerprints_of_keyring "$KEYRINGFILE" > "$FINGERPRINTS"
+
+        # strip leading 0x, if present:
+        KEY="${KEY#0x}"
+
+       # check if the key is in this keyring
+       if ! grep -iq "^[0-9A-F]*${KEY}$" "$FINGERPRINTS"; then
+           continue
+       fi
+       if [ ! -w "$KEYRINGFILE" ]; then
+           echo >&2 "Key ${KEY} is in keyring ${KEYRINGFILE}, but can't be removed as it is read only."
+           continue
+       fi
+       # check if it is the only key in the keyring and if so remove the keyring altogether
+       if [ '1' = "$(uniq "$FINGERPRINTS" | wc -l)" ]; then
+           mv -f "$KEYRINGFILE" "${KEYRINGFILE}~" # behave like gpg
+           return
+       fi
+       # we can't just modify pointed to files as these might be in /usr or something
+       local REALTARGET
+       if [ -L "$KEYRINGFILE" ]; then
+           REALTARGET="$(readlink -f "$KEYRINGFILE")"
+           mv -f "$KEYRINGFILE" "${KEYRINGFILE}.dpkg-tmp"
+           cp -a "$REALTARGET" "$KEYRINGFILE"
+       fi
+       # delete the key from the keyring
+       aptkey_execute "$GPG_SH" --keyring "$KEYRINGFILE" --batch --delete-keys --yes "$KEY"
+       if [ -n "$REALTARGET" ]; then
+           # the real backup is the old link, not the copy we made
+           mv -f "${KEYRINGFILE}.dpkg-tmp" "${KEYRINGFILE}~"
+       fi
+    done
+}
+
+foreach_keyring_do() {
+   local ACTION="$1"
+   shift
+   # if a --keyring was given, just work on this one
+   if [ -n "$FORCED_KEYRING" ]; then
+       $ACTION "$FORCED_KEYRING" "$@"
+   else
+       # otherwise all known keyrings are up for inspection
+       if [ -s "$TRUSTEDFILE" ]; then
+           $ACTION "$TRUSTEDFILE" "$@"
+       fi
+       local TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
+       eval "$(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)"
+       if [ -d "$TRUSTEDPARTS" ]; then
+           # strip / suffix as gpg will double-slash in that case (#665411)
+           local STRIPPED_TRUSTEDPARTS="${TRUSTEDPARTS%/}"
+           if [ "${STRIPPED_TRUSTEDPARTS}/" = "$TRUSTEDPARTS" ]; then
+               TRUSTEDPARTS="$STRIPPED_TRUSTEDPARTS"
+           fi
+           for trusted in $(find "$TRUSTEDPARTS" -mindepth 1 -maxdepth 1 -regex '^.*\.gpg$' | sort); do
+               if [ -s "$trusted" ]; then
+                   $ACTION "$trusted" "$@"
+               fi
+           done
+       fi
+   fi
+}
+
+run_cmd_on_keyring() {
+    local KEYRINGFILE="$1"
+    shift
+    # fingerprint and co will fail if key isn't in this keyring
+    aptkey_execute "$GPG_SH" --keyring "$KEYRINGFILE" --batch "$@" 2>/dev/null || true
+}
+
+import_keyring_into_keyring() {
+    local FROM="${1:-${GPGHOMEDIR}/pubring.gpg}"
+    local TO="${2:-${GPGHOMEDIR}/pubring.gpg}"
+    shift 2
+    rm -f "${GPGHOMEDIR}/gpgoutput.log"
+    # the idea is simple: We take keys from one keyring and copy it to another
+    # we do this with so many checks in between to ensure that WE control the
+    # creation, so we know that the (potentially) created $TO keyring is a
+    # simple keyring rather than a keybox as gpg2 would create it which in turn
+    # can't be read by gpgv.
+    # BEWARE: This is designed more in the way to work with the current
+    # callers, than to have a well defined it would be easy to add new callers to.
+    if [ ! -s "$TO" ]; then
+       if [ -s "$FROM" ]; then
+           if [ -z "$2" ]; then
+               if ! aptkey_execute "$GPG_SH" --keyring "$FROM" --export ${1:+"$1"} > "$TO" 2> "${GPGHOMEDIR}/gpgoutput.log"; then
+                   cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+                   false
+               else
+                   chmod 0644 -- "$TO"
+               fi
+           else
+               create_new_keyring "$TO"
+           fi
+       else
+           create_new_keyring "$TO"
+       fi
+    elif [ -s "$FROM" ]; then
+       local EXPORTLIMIT="$1"
+       if [ -n "$1$2" ]; then shift; fi
+       if ! aptkey_execute "$GPG_SH" --keyring "$FROM" --export ${EXPORTLIMIT:+"$EXPORTLIMIT"} \
+          | aptkey_execute "$GPG_SH" --keyring "$TO" --batch --import "$@" > "${GPGHOMEDIR}/gpgoutput.log" 2>&1; then
+           cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+           false
+       fi
     fi
-    # we can't just modify pointed to files as these might be in /usr or something
-    local REALTARGET
-    if [ -L "$1" ]; then
-       REALTARGET="$(readlink -f "$1")"
-       mv -f "$1" "${1}.dpkg-tmp"
-       cp -a "$REALTARGET" "$1"
-       ls "$(dirname $1)"
+}
+
+merge_all_trusted_keyrings_into_pubring() {
+    # does the same as:
+    # foreach_keyring_do 'import_keys_from_keyring' "${GPGHOMEDIR}/pubring.gpg"
+    # but without using gpg, just cat and find
+    local PUBRING="${GPGHOMEDIR}/pubring.gpg"
+    # if a --keyring was given, just use this one
+    if [ -n "$FORCED_KEYRING" ]; then
+       if [ -s "$FORCED_KEYRING" ]; then
+           cp --dereference "$FORCED_KEYRING" "$PUBRING"
+       fi
+    else
+       # otherwise all known keyrings are merged
+       local TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
+       eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
+       if [ -d "$TRUSTEDPARTS" ]; then
+           # ignore errors mostly for non-existing $TRUSTEDFILE
+           {
+              cat "$TRUSTEDFILE" || true
+              for parts in $(find -L "$TRUSTEDPARTS" -type f -name '*.gpg'); do
+                 cat "$parts" || true
+              done
+           } > "$PUBRING" 2>/dev/null
+       elif [ -s "$TRUSTEDFILE" ]; then
+           cp --dereference "$TRUSTEDFILE" "$PUBRING"
+       fi
     fi
-    # delete the key from the keyring
-    $GPG --batch --delete-key --yes "$2"
-    if [ -n "$REALTARGET" ]; then
-       # the real backup is the old link, not the copy we made
-       mv -f "${1}.dpkg-tmp" "${1}~"
+
+    if [ ! -s "$PUBRING" ]; then
+       touch "$PUBRING"
     fi
 }
 
-remove_key() {
-    requires_root
+import_keys_from_keyring() {
+    import_keyring_into_keyring "$1" "$2"
+}
 
-    # if a --keyring was given, just remove from there
+merge_keys_into_keyrings() {
+    import_keyring_into_keyring "$2" "$1" '' --import-options 'merge-only'
+}
+
+merge_back_changes() {
     if [ -n "$FORCED_KEYRING" ]; then
-       remove_key_from_keyring "$FORCED_KEYRING" "$1"
+       # if the keyring was forced merge is already done
+       return
+    fi
+    if [ -s "${GPGHOMEDIR}/pubring.gpg" ]; then
+       # merge all updated keys
+       foreach_keyring_do 'merge_keys_into_keyrings' "${GPGHOMEDIR}/pubring.gpg"
+    fi
+    # look for keys which were added or removed
+    get_fingerprints_of_keyring "${GPGHOMEDIR}/pubring.orig.gpg" > "${GPGHOMEDIR}/pubring.orig.keylst"
+    get_fingerprints_of_keyring "${GPGHOMEDIR}/pubring.gpg" > "${GPGHOMEDIR}/pubring.keylst"
+    comm -3 "${GPGHOMEDIR}/pubring.keylst" "${GPGHOMEDIR}/pubring.orig.keylst" > "${GPGHOMEDIR}/pubring.diff"
+    # key isn't part of new keyring, so remove
+    cut -f 2 "${GPGHOMEDIR}/pubring.diff" | while read key; do
+       if [ -z "$key" ]; then continue; fi
+       foreach_keyring_do 'remove_key_from_keyring' "$key"
+    done
+    # key is only part of new keyring, so we need to import it
+    cut -f 1 "${GPGHOMEDIR}/pubring.diff" | while read key; do
+       if [ -z "$key" ]; then continue; fi
+       import_keyring_into_keyring '' "$TRUSTEDFILE" "$key"
+    done
+}
+
+setup_merged_keyring() {
+    if [ -n "$FORCED_KEYID" ]; then
+       merge_all_trusted_keyrings_into_pubring
+       FORCED_KEYRING="${GPGHOMEDIR}/forcedkeyid.gpg"
+       TRUSTEDFILE="${FORCED_KEYRING}"
+       echo "#!/bin/sh
+exec sh '($(escape_shell "${GPG}")' --keyring '$(escape_shell "${TRUSTEDFILE}")' \"\$@\"" > "${GPGHOMEDIR}/gpg.1.sh"
+       GPG="${GPGHOMEDIR}/gpg.1.sh"
+       # ignore error as this "just" means we haven't found the forced keyid and the keyring will be empty
+       import_keyring_into_keyring '' "$TRUSTEDFILE" "$FORCED_KEYID" || true
+    elif [ -z "$FORCED_KEYRING" ]; then
+       merge_all_trusted_keyrings_into_pubring
+       if [ -r "${GPGHOMEDIR}/pubring.gpg" ]; then
+           cp -a "${GPGHOMEDIR}/pubring.gpg" "${GPGHOMEDIR}/pubring.orig.gpg"
+       else
+          touch "${GPGHOMEDIR}/pubring.gpg" "${GPGHOMEDIR}/pubring.orig.gpg"
+       fi
+       echo "#!/bin/sh
+exec sh '$(escape_shell "${GPG}")' --keyring '$(escape_shell "${GPGHOMEDIR}/pubring.gpg")' \"\$@\"" > "${GPGHOMEDIR}/gpg.1.sh"
+       GPG="${GPGHOMEDIR}/gpg.1.sh"
     else
-       # otherwise all known keyrings are up for inspection
-       local TRUSTEDFILE="/etc/apt/trusted.gpg"
-       eval $(apt-config shell TRUSTEDFILE Apt::GPGV::TrustedKeyring)
-       eval $(apt-config shell TRUSTEDFILE Dir::Etc::Trusted/f)
-       remove_key_from_keyring "$TRUSTEDFILE" "$1"
-       TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
-       eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
-       if [ -d "$TRUSTEDPARTS" ]; then
-           for trusted in $(run-parts --list "$TRUSTEDPARTS" --regex '^.*\.gpg$'); do
-               remove_key_from_keyring "$trusted" "$1"
-           done
+       create_new_keyring "$TRUSTEDFILE"
+       echo "#!/bin/sh
+exec sh '$(escape_shell "${GPG}")' --keyring '$(escape_shell "${TRUSTEDFILE}")' \"\$@\"" > "${GPGHOMEDIR}/gpg.1.sh"
+       GPG="${GPGHOMEDIR}/gpg.1.sh"
+    fi
+}
+
+create_new_keyring() {
+    # gpg defaults to mode 0600 for new keyrings. Create one with 0644 instead.
+    if ! [ -e "$TRUSTEDFILE" ]; then
+       if [ -w "$(dirname "$TRUSTEDFILE")" ]; then
+           touch -- "$TRUSTEDFILE"
+           chmod 0644 -- "$TRUSTEDFILE"
        fi
     fi
-    echo "OK"
 }
 
+aptkey_execute() { sh "$@"; }
 
 usage() {
     echo "Usage: apt-key [--keyring file] [command] [arguments]"
@@ -248,18 +426,33 @@ while [ -n "$1" ]; do
         shift
         TRUSTEDFILE="$1"
         FORCED_KEYRING="$1"
-        if [ -r "$TRUSTEDFILE" ] || [ "$2" = 'add' ] || [ "$2" = 'adv' ]; then
-           GPG="$GPG --keyring $TRUSTEDFILE --primary-keyring $TRUSTEDFILE"
-        else
-           echo >&2 "Error: The specified keyring »$TRUSTEDFILE« is missing or not readable"
-           exit 1
-        fi
+        ;;
+      --keyid)
         shift
+        FORCED_KEYID="$1"
+        ;;
+      --secret-keyring)
+        shift
+        FORCED_SECRET_KEYRING="$1"
+        ;;
+      --readonly)
+        merge_back_changes() { true; }
+        create_new_keyring() { if [ ! -r "$FORCED_KEYRING" ]; then TRUSTEDFILE='/dev/null'; FORCED_KEYRING="$TRUSTEDFILE"; fi; }
         ;;
       --fakeroot)
         requires_root() { true; }
-        shift
         ;;
+      --quiet)
+        aptkey_echo() { true; }
+        ;;
+      --debug1)
+        # some cmds like finger redirect stderr to /dev/null …
+       aptkey_execute() { echo 'EXEC:' "$@"; sh "$@"; }
+       ;;
+      --debug2)
+        # … other more complicated ones pipe gpg into gpg.
+       aptkey_execute() { echo >&2 'EXEC:' "$@"; sh "$@"; }
+       ;;
       --*)
         echo >&2 "Unknown option: $1"
         usage
@@ -267,28 +460,13 @@ while [ -n "$1" ]; do
       *)
         break;;
    esac
+   shift
 done
 
 if [ -z "$TRUSTEDFILE" ]; then
    TRUSTEDFILE="/etc/apt/trusted.gpg"
    eval $(apt-config shell TRUSTEDFILE Apt::GPGV::TrustedKeyring)
    eval $(apt-config shell TRUSTEDFILE Dir::Etc::Trusted/f)
-   if [ -r "$TRUSTEDFILE" ]; then
-      GPG="$GPG --keyring $TRUSTEDFILE"
-   fi
-   GPG="$GPG --primary-keyring $TRUSTEDFILE"
-   TRUSTEDPARTS="/etc/apt/trusted.gpg.d"
-   eval $(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)
-   if [ -d "$TRUSTEDPARTS" ]; then
-      # strip / suffix as gpg will double-slash in that case (#665411)
-      STRIPPED_TRUSTEDPARTS="${TRUSTEDPARTS%/}"
-      if [ "${STRIPPED_TRUSTEDPARTS}/" = "$TRUSTEDPARTS" ]; then
-        TRUSTEDPARTS="$STRIPPED_TRUSTEDPARTS"
-      fi
-      for trusted in $(run-parts --list "$TRUSTEDPARTS" --regex '^.*\.gpg$'); do
-        GPG="$GPG --keyring $trusted"
-      done
-   fi
 fi
 
 command="$1"
@@ -298,52 +476,142 @@ if [ -z "$command" ]; then
 fi
 shift
 
-if [ "$command" != "help" ] && ! which gpg >/dev/null 2>&1; then
-    echo >&2 "Warning: gnupg does not seem to be installed."
-    echo >&2 "Warning: apt-key requires gnupg for most operations."
-    echo >&2
+create_gpg_home() {
+    # gpg needs (in different versions more or less) files to function correctly,
+    # so we give it its own homedir and generate some valid content for it later on
+    if [ -n "$TMPDIR" ]; then
+       # tmpdir is a directory and current user has rwx access to it
+       # same tests as in apt-pkg/contrib/fileutl.cc GetTempDir()
+       if [ ! -d "$TMPDIR" ] || [ ! -r "$TMPDIR" ] || [ ! -w "$TMPDIR" ] || [ ! -x "$TMPDIR" ]; then
+           unset TMPDIR
+       fi
+    fi
+    GPGHOMEDIR="$(mktemp -d)"
+    CURRENTTRAP="${CURRENTTRAP} rm -rf '$(escape_shell "${GPGHOMEDIR}")';"
+    trap "${CURRENTTRAP}" 0 HUP INT QUIT ILL ABRT FPE SEGV PIPE TERM
+    chmod 700 "$GPGHOMEDIR"
+}
+
+prepare_gpg_home() {
+    eval "$(apt-config shell GPG_EXE Apt::Key::gpgcommand)"
+
+    if [ -n "$GPG_EXE" ] && command_available "$GPG_EXE"; then
+       true
+    elif command_available 'gpg'; then
+       GPG_EXE="gpg"
+    elif command_available 'gpg2'; then
+       GPG_EXE="gpg2"
+    else
+       echo >&2 "Error: gnupg or gnupg2 do not seem to be installed,"
+       echo >&2 "Error: but apt-key requires gnupg or gnupg2 for this operation."
+       echo >&2
+       exit 255
+    fi
+
+    create_gpg_home
+
+    # create the trustdb with an (empty) dummy keyring
+    # older gpgs required it, newer gpgs even warn that it isn't needed,
+    # but require it nonetheless for some commands, so we just play safe
+    # here for the foreseeable future and create a dummy one
+    touch "${GPGHOMEDIR}/empty.gpg"
+    if ! "$GPG_EXE" --ignore-time-conflict --no-options --no-default-keyring \
+       --homedir "$GPGHOMEDIR" --quiet --check-trustdb --keyring "${GPGHOMEDIR}/empty.gpg" >"${GPGHOMEDIR}/gpgoutput.log" 2>&1; then
+       cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+       false
+    fi
+
+    # now tell gpg that it shouldn't try to maintain this trustdb file
+    echo "#!/bin/sh
+exec '$(escape_shell "${GPG_EXE}")' --ignore-time-conflict --no-options --no-default-keyring \\
+--homedir '$(escape_shell "${GPGHOMEDIR}")' --no-auto-check-trustdb --trust-model always \"\$@\"" > "${GPGHOMEDIR}/gpg.0.sh"
+    GPG_SH="${GPGHOMEDIR}/gpg.0.sh"
+    GPG="$GPG_SH"
+
+    # We don't usually need a secret keyring, of course, but
+    # for advanced operations, we might really need a secret keyring after all
+    if [ -n "$FORCED_SECRET_KEYRING" ] && [ -r "$FORCED_SECRET_KEYRING" ]; then
+       if ! aptkey_execute "$GPG" -v --batch --import "$FORCED_SECRET_KEYRING" >"${GPGHOMEDIR}/gpgoutput.log" 2>&1; then
+           cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+           false
+       fi
+    else
+       # and then, there are older versions of gpg which panic and implode
+       # if there isn't one available - and writeable for imports
+       # and even if not output is littered with the creation of a secring,
+       # so lets call import once to have it create what it wants in silence
+       echo -n | aptkey_execute "$GPG" --batch --import >/dev/null 2>&1 || true
+    fi
+}
+
+if [ "$command" != 'help' ] && [ "$command" != 'verify' ]; then
+    prepare_gpg_home
 fi
 
 case "$command" in
     add)
-        requires_root
-        init_keyring "$TRUSTEDFILE"
-        $GPG --quiet --batch --import "$1"
-        echo "OK"
+       requires_root
+       setup_merged_keyring
+       aptkey_execute "$GPG" --quiet --batch --import "$@"
+       merge_back_changes
+       aptkey_echo "OK"
         ;;
     del|rm|remove)
-        init_keyring "$TRUSTEDFILE"
-       remove_key "$1"
+       requires_root
+       foreach_keyring_do 'remove_key_from_keyring' "$@"
+       aptkey_echo "OK"
         ;;
     update)
-        init_keyring "$TRUSTEDFILE"
+       requires_root
+       setup_merged_keyring
        update
+       merge_back_changes
        ;;
     net-update)
-        init_keyring "$TRUSTEDFILE"
+       requires_root
+       setup_merged_keyring
        net_update
+       merge_back_changes
        ;;
     list)
-        init_keyring "$TRUSTEDFILE"
-        $GPG --batch --list-keys
-        ;;
+       foreach_keyring_do 'run_cmd_on_keyring' --list-keys "$@"
+       ;;
     finger*)
-        init_keyring "$TRUSTEDFILE"
-        $GPG --batch --fingerprint
-        ;;
-    export)
-        init_keyring "$TRUSTEDFILE"
-        $GPG --armor --export "$1"
-        ;;
-    exportall)
-        init_keyring "$TRUSTEDFILE"
-        $GPG --armor --export
-        ;;
+       foreach_keyring_do 'run_cmd_on_keyring' --fingerprint "$@"
+       ;;
+    export|exportall)
+       merge_all_trusted_keyrings_into_pubring
+       aptkey_execute "$GPG_SH" --keyring "${GPGHOMEDIR}/pubring.gpg" --armor --export "$@"
+       ;;
     adv*)
-        init_keyring "$TRUSTEDFILE"
-        echo "Executing: $GPG $*"
-        $GPG $*
-        ;;
+       setup_merged_keyring
+       aptkey_echo "Executing: $GPG $*"
+       aptkey_execute "$GPG" "$@"
+       merge_back_changes
+       ;;
+    verify)
+       GPGV=''
+       eval $(apt-config shell GPGV Apt::Key::gpgvcommand)
+       if [ -n "$GPGV" ] && command_available "$GPGV"; then true;
+       elif command_available 'gpgv'; then GPGV='gpgv';
+       elif command_available 'gpgv2'; then GPGV='gpgv2';
+       else
+          echo >&2 'ERROR: gpgv or gpgv2 required for verification'
+          exit 29
+       fi
+       # for a forced keyid we need gpg --export, so full wrapping required
+       if [ -n "$FORCED_KEYID" ]; then
+           prepare_gpg_home
+       else
+           create_gpg_home
+       fi
+       setup_merged_keyring
+       if [ -n "$FORCED_KEYRING" ]; then
+           "$GPGV" --homedir "${GPGHOMEDIR}" --keyring "${FORCED_KEYRING}" --ignore-time-conflict "$@"
+       else
+           "$GPGV" --homedir "${GPGHOMEDIR}" --keyring "${GPGHOMEDIR}/pubring.gpg" --ignore-time-conflict "$@"
+       fi
+       ;;
     help)
         usage
         ;;