Initial commit of script and Dockerfile

Dockerfile

@@ -0,0 +1,14 @@
+FROM alpine:3.20
+
+ARG DROPBEAR_VERSION_PREFIX=2024.85
+
+RUN apk add --no-cache \
+    dropbear-scp=~${DROPBEAR_VERSION_PREFIX} \
+    dropbear-dbclient=~${DROPBEAR_VERSION_PREFIX} \
+    dropbear-convert=~${DROPBEAR_VERSION_PREFIX} && \
+    addgroup -S plugin && \
+    adduser -S plugin -G plugin
+COPY --chown=root:plugin --chmod=770 copy.sh /bin/plugin_scp
+USER plugin
+
+ENTRYPOINT ["/bin/plugin_scp"]

copy.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env sh
+
+fatal() {
+    echo "[ERROR] $1"
+    [ -n "$2" ] && exit "$2" || exit 1
+}
+
+info() {
+    echo "[INFO] $1"
+}
+
+# dropbear SSH uses a whacky private key format. I can't imagine anyone likes this, so read a normal
+# one from the input (which needs to be a string anyways) and let dropbear figure it out
+create_key_from_env() {
+    if [ ! -d "$HOME"/.ssh ]; then
+        mkdir "$HOME"/.ssh
+    fi
+
+    echo "${PLUGIN_SSH_PRIVATE_KEY}" >"$HOME"/.ssh/id_rsa
+    chmod 600 "$HOME"/.ssh/id_rsa
+    dropbearconvert openssh dropbear "$HOME"/.ssh/id_rsa "$HOME"/.ssh/id_dropbear
+    chmod 600 "$HOME"/.ssh/id_dropbear
+}
+
+if [ -z "${PLUGIN_REMOTE_USER}" ]; then
+    fatal "Must specify remote user" 1
+fi
+
+if [ -z "${PLUGIN_REMOTE_HOST}" ]; then
+    fatal "Must specify remote host" 2
+fi
+
+if [ -z "${PLUGIN_REMOTE_PORT}" ]; then
+    PLUGIN_REMOTE_PORT=22
+fi
+
+if [ -z "${PLUGIN_REMOTE_PATH}" ]; then
+    fatal "Must specify remote path" 3
+fi
+
+if [ -z "$PLUGIN_SSH_PRIVATE_KEY" ]; then
+    fatal "Must provide private key for authentication" 4
+fi
+
+if [ -z "$PLUGIN_FILE" ]; then
+    fatal "Must provide source file for transfer" 5
+fi
+
+create_key_from_env
+scp -o StrictHostKeyChecking=accept-new \
+    -P "${PLUGIN_REMOTE_PORT}" \
+    -i "$HOME"/.ssh/id_dropbear \
+    "${PLUGIN_FILE}" \
+    "${PLUGIN_REMOTE_USER}"@"${PLUGIN_REMOTE_HOST}":"${PLUGIN_REMOTE_PATH}"
+scp_status=$?
+
+rm -r "$HOME"/.ssh
+
+if [ "$scp_status" -ne 0 ]; then
+    fatal "Transfer failed with exit code $scp_status" $scp_status
+fi
+
+info "Transfer completed"