git-sig/siglog

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2020-11-12 22:56:38 +00:00
#! /usr/bin/env bash
set -e
die() {
echo "$@" >&2
exit 1
}
gpg_env(){
GNUPGHOME=$(mktemp -d -p /dev/shm/); export GNUPGHOME
killall gpg-agent 2> /dev/null
gpg-agent --daemon --extra-socket "$GNUPGHOME/S.gpg-agent" 2> /dev/null
echo "export PATH=$GNUPGHOME:$PATH \
export GNUPGHOME=$GNUPGHOME; \
export GPG_AGENT_INFO=$GNUPGHOME/S.gpg-agent"
}
gpg_cleanup(){
gpgconf --kill gpg-agent
rm -rf "$GNUPGHOME"
}
verify_file() {
filename="${1?}"
sig_count=0
seen_fingerprints=""
for sig_filename in "${filename%.*}".*.asc; do
gpg --verify "${sig_filename}" "${filename}" >/dev/null 2>&1 || {
echo "Invalid signature: ${sig_filename}";
exit 1;
}
fingerprint=$( \
gpg --list-packets "${sig_filename}" \
| grep keyid \
| sed 's/.*keyid //g'
)
signer=$( \
gpg \
--list-keys \
--with-colons "${fingerprint}" 2>&1 \
| awk -F: '$1 == "uid" {print $10}' \
| head -n1 \
)
[[ "${seen_fingerprints}" == *"${fingerprint}"* ]] && {
echo "Duplicate signature: ${sig_filename}";
exit 1;
}
echo "Verified signature by \"${signer}\""
seen_fingerprints="${seen_fingerprints} ${fingerprint}"
((sig_count=sig_count+1))
done
[[ "$sig_count" -ge "$threshold" ]] || {
echo "Minimum number of signatures not met: ${sig_count}/${threshold}";
exit 1;
}
}
cmd_manifest() {
mkdir -p .siglog
find . \
-type f \
-not -path "./.git/*" \
-not -path "./.siglog/*" \
-exec openssl sha256 -r {} \; \
| sed 's/ \*/ /g' \
| LC_ALL=C sort -k2 \
> .siglog/manifest.txt
}
cmd_detach-verify() {
[ $# -lt 3 ] || die \
"Usage: detach-verify <threshold> <pubkey_dir> <file> (, <file, ...)"
threshold="${1}"
pubkey_dir="${2}"
target_files="${*:3}"
eval "$(gpg_env)"
gpg --import "${pubkey_dir}"/*.asc 2>/dev/null
for target_file in ${target_files}; do
verify_file "${target_file}"
done
gpg_cleanup
}
cmd_verify() {
cmd_manifest
for file in .siglog/*.asc; do
gpg --verify "$file" signatures/manifest.txt
done
}
cmd_version() {
cat <<-_EOF
============================================
= siglog: simple multisig trust toolchain =
= =
= v0.0.1 =
= =
= https://gitlab.com/pchq/siglog =
============================================
_EOF
}
cmd_usage() {
cmd_version
echo
cat <<-_EOF
Usage:
$PROGRAM detach-verify [<threshold> <pubkey_dir> <file> (, <file, ...)
Verify detached signatures of the provided file by m-of-n keys
$PROGRAM verify
Verify all signing policies for this directory are met
$PROGRAM manifest
Generate hash manifest for this directory
$PROGRAM sign
Add signature to manifest for this directory
$PROGRAM help
Show this text.
$PROGRAM version
Show version information.
_EOF
}
checktools(){
for cmd in "$@"; do
if ! command -v "$1" >/dev/null; then
printf "not found!\n";
return 1;
fi
done
}
PROGRAM="${0##*/}"
COMMAND="$1"
checktools gpg openssl
case "$1" in
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detach-verify) shift; cmd_detach-verify "$@" ;;
verify) shift; cmd_verify "$@" ;;
manifest) shift; cmd_manifest "$@" ;;
sign) shift; cmd_sign "$@" ;;
version|--version) shift; cmd_version "$@" ;;
help|--help) shift; cmd_usage "$@" ;;
*) cmd_usage "$@" ;;
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esac
exit 0