On 28/11/2024 05.32, Eli Schwartz wrote:
The current state of verify-sig support is a bit awkward. We rely on validating distfiles against a known trusted keyring, but creating the known trusted keyring is basically all manual verification. We somehow decide an ascii armored key is good enough without any portage assistance, then arrange to download it and trust it by Manifest hash. How do we know when updating a key is actually safe?This eclass handles the problem in a manner inspired in part by pacman. We require an eclass variable that lists all permitted PGP fingerprints, and the eclass is responsible checking that list against the keys we will install. It comes with a mechanism for computing SRC_URI for a couple of well known locations, or you can append your own in the ebuild. Key rotations, both expected and malicious, are easily detected by checking the git log for changes to declared fingerprints in a bump. The former can be rationalized in the commit message. So can the latter, but in most cases those will be rejected during peer review. Signed-off-by: Eli Schwartz <eschwa...@gentoo.org> --- eclass/sec-keys.eclass | 197 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 197 insertions(+) create mode 100644 eclass/sec-keys.eclass diff --git a/eclass/sec-keys.eclass b/eclass/sec-keys.eclass new file mode 100644 index 000000000000..7ea4d34a8c1c --- /dev/null +++ b/eclass/sec-keys.eclass @@ -0,0 +1,197 @@ +# Copyright 2024 Gentoo Authors +# Distributed under the terms of the GNU General Public License v2 + +# @ECLASS: sec-keys.eclass +# @MAINTAINER: +# Eli Schwartz <eschwa...@gentoo.org> +# @AUTHOR: +# Eli Schwartz <eschwa...@gentoo.org> +# @SUPPORTED_EAPIS: 8 +# @BLURB: Provides a uniform way of handling ebuilds which package PGP key material +# @DESCRIPTION: +# This eclass provides a streamlined approach to finding suitable source material +# for OpenPGP keys used by the verify-sig eclass. Its primary purpose is to permit +# developers to easily and securely package new sec-keys/* packages. The eclass +# removes the risk of developers accidentally packaging malformed key material, or +# neglecting to notice when PGP identities have changed. +# +# To use the eclass, define SEC_KEYS_VALIDPGPKEYS to contain the fingerprint of +# the key and the short name of the key's owner. +# +# @EXAMPLE: +# Example use: +# +# @CODE +# SEC_KEYS_VALIDPGPKEYS=( +# # implicit Ubuntu +# '3DB7F3CA6C1D90B99FE25B38D4B476A4D175C54F:bjones:' +# '4EC8A4DB7D2E01C00AF36C49E5C587B5E286C65A:jsmith:github,openpgp' +# # key only available on personal website, use manual SRC_URI +# '5FD9B5EC8E3F12D11BA47D50F6D698C6F397D76B:awhite:none' +# ) +# +# inherit sec-keys +# +# SRC_URI+="https://awhite.com/awhite.gpg -> awhite-${PV}.gpg" +# @CODE + +case ${EAPI} in + 8) ;; + *) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;; +esac + +if [[ ! ${_SEC_KEYS_ECLASS} ]]; then +_SEC_KEYS_ECLASS=1 + +inherit edo + +# @ECLASS_VARIABLE: SEC_KEYS_VALIDPGPKEYS +# @PRE_INHERIT +# @DEFAULT_UNSET +# @DESCRIPTION: +# Mapping of fingerprints, name, and optional location of PGP keys to include, +# separated by colons. The allowed values for a location are: +# +# - gentoo -- fetch key by fingerprint from https://keys.gentoo.org +# +# - github -- fetch key from github.com/${name}.pgp +# +# - openpgp -- fetch key by fingerprint from https://keys.openpgp.org +# +# - ubuntu -- fetch key by fingerprint from http://keyserver.ubuntu.com (the default) +# +# - none -- do not add to SRC_URI, the ebuild will provide a custom download location +_sec_keys_set_globals() { + if [[ ${SEC_KEYS_VALIDPGPKEYS[*]} ]]; then
The function's body is already pretty wide, therefore maybe consider using an early return here.
+ local key fingerprint name loc locations=() remote
+ for key in "${SEC_KEYS_VALIDPGPKEYS[@]}"; do
+ fingerprint=${key%%:*}
+ name=${key#${fingerprint}:}; name=${name%%:*}
+ IFS=, read -r -a locations <<<"${key##*:}"
+ [[ ${locations[@]} ]] || locations=(ubuntu)
+ for loc in "${locations[@]}"; do
+ case ${loc} in
+ gentoo)
remote="https://keys.gentoo.org/pks/lookup?op=get&search=0x${fingerprint}";;;
+ github)
remote="https://github.com/${name}.gpg";;;
+ openpgp)
remote="https://keys.openpgp.org/vks/v1/by-fingerprint/${fingerprint}";;;
+ ubuntu)
remote="https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x${fingerprint}";;;
+ # provided via manual SRC_URI
+ none) continue;;
+ *) die "${ECLASS}: unknown PGP key remote:
${loc}";;
+
+ esac
+ SRC_URI+="
+ ${remote} ->
openpgp-keys-${name}-${loc}-${PV}.asc
+ "
+ done
+ done
+ fi
+}
+_sec_keys_set_globals
+unset -f _sec_keys_set_globals
+
+IUSE="test"
+PROPERTIES="test_network"
+RESTRICT="test"
+
+BDEPEND="
+ app-crypt/gnupg
+ test? ( app-crypt/pgpdump )
+"
+S=${WORKDIR}
+
+LICENSE="public-domain"
+SLOT="0"
+
+
+# @FUNCTION: sec-keys_src_compile
+# @DESCRIPTION:
+# Default src_compile override that imports all public keys into a keyring,
+# and validates that they are listed in SEC_KEYS_VALIDPGPKEYS.
+sec-keys_src_compile() {
+ local -x GNUPGHOME=${WORKDIR}/gnupg
+ mkdir -m700 -p "${GNUPGHOME}" || die
+
+ pushd "${DISTDIR}" >/dev/null || die
+ gpg --import ${A} || die
+ popd >/dev/null || die
+
+ local line imported_keys=() found=0
+ while IFS=: read -r -a line; do
+ if [[ ${line[0]} = pub ]]; then
+ # new key
+ found=0
+ elif [[ ${found} = 0 && ${line[0]} = fpr ]]; then
+ # primary fingerprint
+ imported_keys+=("${line[9]}")
+ found=1
+ fi
+ done < <(gpg --batch --list-keys --keyid-format=long --with-colons ||
die)
+
+ printf '%s\n' "${imported_keys[@]}" | sort > imported_keys.list || die
+ printf '%s\n' "${SEC_KEYS_VALIDPGPKEYS[@]%%:*}" | sort >
allowed_keys.list || die
+
+ local extra_keys=($(comm -23 imported_keys.list allowed_keys.list ||
die))
+ local missing_keys=($(comm -13 imported_keys.list allowed_keys.list ||
die))
+
+ if [[ ${#extra_keys[@]} != 0 ]]; then
+ die "too many keys found. Suspicious keys: ${extra_keys[@]}"
+ fi
+ if [[ ${#missing_keys[@]} != 0 ]]; then
+ die "too few keys found. Unavailable keys: ${missing_keys[@]}"
+ fi
+}
+
+
+sec-keys_src_test() {
+ local -x GNUPGHOME=${WORKDIR}/gnupg
+ local key fingerprint name server
+ local gpg_command=(gpg --export-options export-minimal)
+
+ for fingerprint in "${SEC_KEYS_VALIDPGPKEYS[@]%%:*}"; do
+ "${gpg_command[@]}" --export "${fingerprint}" | pgpdump >
"${fingerprint}.pgpdump" || die
+ done
+
+ # Best-effort attempt to check for updates. keyservers can and usually
do
+ # fail for weird reasons, (such as being unable to import a key without
a
+ # uid) as well as normal reasons, like the key being exclusive to a
+ # different keyserver. this isn't a reason to fail src_test.
+ for server in keys.gentoo.org keys.openpgp.org keyserver.ubuntu.com; do
+ gpg --refresh-keys --keyserver "hkps://${server}"
+ done
+ for key in "${SEC_KEYS_VALIDPGPKEYS[@]}"; do
+ if [[ ${key##*:} = *github* ]]; then
+ name=${key#*:}; name=${name%%:*}
+ wget -qO- https://github.com/${name}.gpg | gpg --import
|| die
+ fi
+ done
+
+ for fingerprint in "${SEC_KEYS_VALIDPGPKEYS[@]%%:*}"; do
+ "${gpg_command[@]}" --export "${fingerprint}" | pgpdump >
"${fingerprint}.pgpdump.new" || die
+ diff -u "${fingerprint}.pgpdump" "${fingerprint}.pgpdump.new" || die
"updates available for PGP key: ${fingerprint}"
+ done
+
+}
+
+# @FUNCTION: sec-keys_src_install
+# @DESCRIPTION:
+# Default src_install override that minifies and exports all PGP public keys
+# into an ascii-armored keyfile installed to the standard
/usr/share/openpgp-keys.
+sec-keys_src_install() {
+ local -x GNUPGHOME=${WORKDIR}/gnupg
+ local fingerprint
+ local gpg_command=(gpg --no-permission-warning --export-options
export-minimal)
+
+ for fingerprint in "${SEC_KEYS_VALIDPGPKEYS[@]%%:*}"; do
+ local uids=()
+ mapfile -t uids < <("${gpg_command[@]}" --list-key
--with-colons ${fingerprint} | awk -F: '/^uid/{print $10}' || die)
+ edo "${gpg_command[@]}" "${uids[@]/#/--comment=}" --export --armor
"${fingerprint}" >> ${PN#openpgp-keys-}.asc
+ done
+
+ insinto /usr/share/openpgp-keys
+ doins ${PN#openpgp-keys-}.asc
+}
+
+fi
+
+EXPORT_FUNCTIONS src_compile src_test src_install
OpenPGP_0x8CAC2A9678548E35.asc
Description: OpenPGP public key
OpenPGP_signature.asc
Description: OpenPGP digital signature
