add apt-key support for armored GPG key files (*.asc)

Having binary files in /etc is kinda annoying – not that the armored
files are much better – but it is hard to keep tabs on which format the
file has ("simple" or "keybox") and different gnupg versions have
different default binary formats which can be confusing for users to
work with (beside that it is binary).

Adding support for this now will enable us in some distant future to
move to armored later on, much like we added trusted.gpg.d years before
the world picked it up.

1 files changed, 106 insertions, 30 deletions

diff --git a/cmdline/apt-key.in b/cmdline/apt-key.in
index 5e8332bcb..c9ff4b3f4 100644
--- a/cmdline/apt-key.in
+++ b/cmdline/apt-key.in
@@ -179,7 +179,7 @@ update() {
 
     if [ -r "$REMOVED_KEYS" ]; then
 	# remove no-longer supported/used keys
-	get_fingerprints_of_keyring "$REMOVED_KEYS" | while read key; do
+	get_fingerprints_of_keyring "$(dearmor_filename "$REMOVED_KEYS")" | while read key; do
 	    foreach_keyring_do 'remove_key_from_keyring' "$key"
 	done
     else
@@ -195,10 +195,11 @@ remove_key_from_keyring() {
        return
     fi
 
-    for KEY in "$@"; do
-	local FINGERPRINTS="${GPGHOMEDIR}/keyringfile.keylst"
-	get_fingerprints_of_keyring "$KEYRINGFILE" > "$FINGERPRINTS"
+    local FINGERPRINTS="${GPGHOMEDIR}/keyringfile.keylst"
+    local DEARMOR="$(dearmor_filename "$KEYRINGFILE")"
+    get_fingerprints_of_keyring "$DEARMOR" > "$FINGERPRINTS"
 
+    for KEY in "$@"; do
 	# strip leading 0x, if present:
 	KEY="$(echo "${KEY#0x}" | tr -d ' ')"
 
@@ -207,7 +208,7 @@ remove_key_from_keyring() {
 	    continue
 	fi
 	if [ ! -w "$KEYRINGFILE" ]; then
-	    echo >&2 "Key ${KEY} is in keyring ${KEYRINGFILE}, but can't be removed as it is read only."
+	    apt_warn "Key ${KEY} is in keyring ${KEYRINGFILE}, but can't be removed as it is read only."
 	    continue
 	fi
 	# check if it is the only key in the keyring and if so remove the keyring altogether
@@ -217,17 +218,23 @@ remove_key_from_keyring() {
 	fi
 	# we can't just modify pointed to files as these might be in /usr or something
 	local REALTARGET
-	if [ -L "$KEYRINGFILE" ]; then
-	    REALTARGET="$(readlink -f "$KEYRINGFILE")"
-	    mv -f "$KEYRINGFILE" "${KEYRINGFILE}.dpkg-tmp"
-	    cp -a "$REALTARGET" "$KEYRINGFILE"
+	if [ -L "$DEARMOR" ]; then
+	    REALTARGET="$(readlink -f "$DEARMOR")"
+	    mv -f "$DEARMOR" "${DEARMOR}.dpkg-tmp"
+	    cp -a "$REALTARGET" "$DEARMOR"
 	fi
 	# delete the key from the keyring
-	aptkey_execute "$GPG_SH" --keyring "$KEYRINGFILE" --batch --delete-keys --yes "$KEY"
+	aptkey_execute "$GPG_SH" --keyring "$DEARMOR" --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}~"
+	    mv -f "${DEARMOR}.dpkg-tmp" "${DEARMOR}~"
+	fi
+	if [ "$DEARMOR" != "$KEYRINGFILE" ]; then
+	    mv -f "$KEYRINGFILE" "${KEYRINGFILE}~"
+	    create_new_keyring "$KEYRINGFILE"
+	    aptkey_execute "$GPG_SH" --keyring "$DEARMOR" --armor --export > "$KEYRINGFILE"
 	fi
+	get_fingerprints_of_keyring "$DEARMOR" > "$FINGERPRINTS"
     done
 }
 
@@ -247,7 +254,7 @@ foreach_keyring_do() {
    shift
    # if a --keyring was given, just work on this one
    if [ -n "$FORCED_KEYRING" ]; then
-	$ACTION "$FORCED_KEYRING" "$@"
+	$ACTION "$TRUSTEDFILE" "$@"
    else
 	# otherwise all known keyrings are up for inspection
 	if accessible_file_exists "$TRUSTEDFILE"; then
@@ -257,7 +264,7 @@ foreach_keyring_do() {
 	eval "$(apt-config shell TRUSTEDPARTS Dir::Etc::TrustedParts/d)"
 	if [ -d "$TRUSTEDPARTS" ]; then
 	    TRUSTEDPARTS="$(readlink -f "$TRUSTEDPARTS")"
-	    local TRUSTEDPARTSLIST="$(cd /; find "$TRUSTEDPARTS" -mindepth 1 -maxdepth 1 -name '*.gpg')"
+	    local TRUSTEDPARTSLIST="$(cd /; find "$TRUSTEDPARTS" -mindepth 1 -maxdepth 1 \( -name '*.gpg' -o -name '*.asc' \))"
 	    for trusted in $(echo "$TRUSTEDPARTSLIST" | sort); do
 		if accessible_file_exists "$trusted"; then
 		    $ACTION "$trusted" "$@"
@@ -267,11 +274,41 @@ foreach_keyring_do() {
    fi
 }
 
-run_cmd_on_keyring() {
+list_keys_in_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
+    aptkey_execute "$GPG_SH" --keyring "$(dearmor_filename "$KEYRINGFILE")" "$@" > "${GPGHOMEDIR}/gpgoutput.log" 2> "${GPGHOMEDIR}/gpgoutput.err" || true
+    if [ ! -s "${GPGHOMEDIR}/gpgoutput.log" ]; then
+	return
+    fi
+    # we fake gpg header here to refer to the real asc file rather than a temp file
+    if [ "${KEYRINGFILE##*.}" = 'asc' ]; then
+	if expr match "$(sed -n '2p' "${GPGHOMEDIR}/gpgoutput.log")" '^-\+$' >/dev/null 2>&1; then
+	    echo "$KEYRINGFILE"
+	    echo "$KEYRINGFILE" | sed 's#[^-]#-#g'
+	    sed '1,2d' "${GPGHOMEDIR}/gpgoutput.log" || true
+	else
+	    cat "${GPGHOMEDIR}/gpgoutput.log"
+	fi
+    else
+	cat "${GPGHOMEDIR}/gpgoutput.log"
+    fi
+    if [ -s "${GPGHOMEDIR}/gpgoutput.err" ]; then
+	cat >&2 "${GPGHOMEDIR}/gpgoutput.err"
+    fi
+}
+
+export_key_from_to() {
+    local FROM="$1"
+    local TO="$2"
+    shift 2
+    if ! aptkey_execute "$GPG_SH" --keyring "$(dearmor_filename "$FROM")" --export "$@" > "$TO" 2> "${GPGHOMEDIR}/gpgoutput.log"; then
+	cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
+	false
+    else
+	chmod 0644 -- "$TO"
+    fi
 }
 
 import_keyring_into_keyring() {
@@ -289,12 +326,11 @@ import_keyring_into_keyring() {
     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 -- "$TO"
+		local OPTS
+		if [ "${TO##*.}" = 'asc' ]; then
+		    OPTS='--armor'
 		fi
+		export_key_from_to "$(dearmor_filename "$FROM")" "$TO" $OPTS ${1:+"$1"}
 	    else
 		create_new_keyring "$TO"
 	    fi
@@ -304,16 +340,51 @@ import_keyring_into_keyring() {
     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
+	local DEARMORTO="$(dearmor_filename "$TO")"
+	if ! aptkey_execute "$GPG_SH" --keyring "$(dearmor_filename "$FROM")" --export ${EXPORTLIMIT:+"$EXPORTLIMIT"} \
+	   | aptkey_execute "$GPG_SH" --keyring "$DEARMORTO" --batch --import "$@" > "${GPGHOMEDIR}/gpgoutput.log" 2>&1; then
 	    cat >&2 "${GPGHOMEDIR}/gpgoutput.log"
 	    false
 	fi
+	if [ "$DEARMORTO" != "$TO" ]; then
+	    export_key_from_to "$DEARMORTO" "${DEARMORTO}.asc" --armor
+	    if ! cmp -s "$TO" "${DEARMORTO}.asc" 2>/dev/null; then
+		cp -a "$TO" "${TO}~"
+		mv -f "${DEARMORTO}.asc" "$TO"
+	    fi
+	fi
     fi
 }
 
+dearmor_keyring() {
+    # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=831409#67
+    # The awk script is more complex through to skip surrounding garbage and
+    # to support multiple keys in one file (old gpgs generate version headers
+    # which get printed with the original and hence result in garbage input for base64
+    awk '/^-----BEGIN/{ x = 1; }
+/^$/{ if (x == 1) { x = 2; }; }
+/^[^=-]/{ if (x == 2) { print $0; }; }
+/^-----END/{ x = 0; }' | base64 -d
+}
+dearmor_filename() {
+    if [ "${1##*.}" = 'asc' ]; then
+	local trusted="${GPGHOMEDIR}/${1##*/}.gpg"
+	if [ -s "$1" ]; then
+	    dearmor_keyring < "$1" > "$trusted"
+	fi
+	echo "$trusted"
+    elif [ "${1##*.}" = 'gpg' ]; then
+	echo "$1"
+    elif [ "$(head -n 1 "$1" 2>/dev/null)" = '-----BEGIN PGP PUBLIC KEY BLOCK-----' ]; then
+	local trusted="${GPGHOMEDIR}/${1##*/}.gpg"
+	dearmor_keyring < "$1" > "$trusted"
+	echo "$trusted"
+    else
+	echo "$1"
+    fi
+}
 catfile() {
-   cat "$1" >> "$2"
+    cat "$(dearmor_filename "$1")" >> "$2"
 }
 
 merge_all_trusted_keyrings_into_pubring() {
@@ -337,6 +408,10 @@ merge_keys_into_keyrings() {
 merge_back_changes() {
     if [ -n "$FORCED_KEYRING" ]; then
 	# if the keyring was forced merge is already done
+	if [ "$FORCED_KEYRING" != "$TRUSTEDFILE" ]; then
+	    mv -f "$FORCED_KEYRING" "${FORCED_KEYRING}~"
+	    export_key_from_to "$TRUSTEDFILE" "$FORCED_KEYRING" --armor
+	fi
 	return
     fi
     if [ -s "${GPGHOMEDIR}/pubring.gpg" ]; then
@@ -380,6 +455,7 @@ exec sh '($(escape_shell "${GPG}")' --keyring '$(escape_shell "${TRUSTEDFILE}")'
 exec sh '$(escape_shell "${GPG}")' --keyring '$(escape_shell "${GPGHOMEDIR}/pubring.gpg")' \"\$@\"" > "${GPGHOMEDIR}/gpg.1.sh"
 	GPG="${GPGHOMEDIR}/gpg.1.sh"
     else
+	TRUSTEDFILE="$(dearmor_filename "$FORCED_KEYRING")"
 	create_new_keyring "$TRUSTEDFILE"
 	echo "#!/bin/sh
 exec sh '$(escape_shell "${GPG}")' --keyring '$(escape_shell "${TRUSTEDFILE}")' \"\$@\"" > "${GPGHOMEDIR}/gpg.1.sh"
@@ -389,10 +465,10 @@ exec sh '$(escape_shell "${GPG}")' --keyring '$(escape_shell "${TRUSTEDFILE}")'
 
 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"
+    if ! [ -e "$1" ]; then
+	if [ -w "$(dirname "$1")" ]; then
+	    touch -- "$1"
+	    chmod 0644 -- "$1"
 	fi
     fi
 }
@@ -648,7 +724,7 @@ case "$command" in
 	;;
     list|finger*)
 	warn_on_script_usage
-	foreach_keyring_do 'run_cmd_on_keyring' --fingerprint "$@"
+	foreach_keyring_do 'list_keys_in_keyring' --fingerprint "$@"
 	;;
     export|exportall)
 	warn_on_script_usage
@@ -658,7 +734,7 @@ case "$command" in
     adv*)
 	warn_on_script_usage
 	setup_merged_keyring
-	aptkey_echo "Executing: $GPG $*"
+	aptkey_echo "Executing: $GPG" "$@"
 	aptkey_execute "$GPG" "$@"
 	merge_back_changes
 	;;
@@ -681,7 +757,7 @@ case "$command" in
 	fi
 	setup_merged_keyring
 	if [ -n "$FORCED_KEYRING" ]; then
-	    "$GPGV" --homedir "${GPGHOMEDIR}" --keyring "${FORCED_KEYRING}" --ignore-time-conflict "$@"
+	    "$GPGV" --homedir "${GPGHOMEDIR}" --keyring "$(dearmor_filename "${FORCED_KEYRING}")" --ignore-time-conflict "$@"
 	else
 	    "$GPGV" --homedir "${GPGHOMEDIR}" --keyring "${GPGHOMEDIR}/pubring.gpg" --ignore-time-conflict "$@"
 	fi