Add script to sign arbitrary files using the key stored in Secrets Ma…

…nager

sign.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+set -euo pipefail
+
+if [[ "${1:-}" == "" ]]; then
+    echo "Usage: sign.sh FILE" >&2
+    exit 1
+fi
+
+
+tmpdir=$(mktemp -d)
+trap "shred $tmpdir/* && rm -rf $tmpdir" EXIT
+
+SECRET=CDK/SigningKey
+
+# Use secrets manager to obtain the key and passphrase into a JSON file
+echo "Retrieving key..." >&2
+aws --region us-east-1 secretsmanager get-secret-value --secret-id "$SECRET" --output text --query SecretString > $tmpdir/secret.txt
+passphrase=$(python -c "import json; print(json.load(file('$tmpdir/secret.txt'))['Passphrase'])")
+
+echo "Importing key..." >&2
+gpg --homedir $tmpdir --import <(python -c "import json; print(json.load(file('$tmpdir/secret.txt'))['PrivateKey'])")
+
+echo "Signing $1..." >&2
+echo $passphrase | gpg \
+    --homedir $tmpdir \
+    --local-user [email protected] \
+    --batch --yes \
+    --passphrase-fd 0 \
+    --output $1.sig \
+    --detach-sign $1
+
+echo "Done!" >&2