SBOM scraper script

Problem:
Extract SBOM from docker image and upload to archivist

Solution:
sbom_scraper.sh using app registrations flow.

Signed-off-by: Paul Hewlett <[email protected]>

Author: Paul Hewlett

scripts/sbom_scraper.sh

@@ -0,0 +1,177 @@
+#!/usr/bin/env bash
+#
+# Scrape a docker image and upload as SBOM file
+#
+# Preparation:
+#
+# Install syft  - https://github.com/anchore/syft
+# 
+#    Read the docs on syft usage.
+#
+# Create App registration called "SBOM scraper" following the flow described in
+# https://docs.rkvst.com/docs/setup-and-administration/getting-access-tokens-using-app-registrations/#using-the-rkvst-ui-(required-for-first-time-setup)
+# and note down the CLIENT_ID and SECRET.
+#
+# Copy the SECRET generated to the file specified by ${CLIENTSECRET_FILE} below. This
+# file should reside in a subdirectory with 0600 permissions.
+#
+# Use the CLIENT_ID as the first fixed argument to this script.
+# 
+
+SCRIPTNAME=$(basename "$0")
+
+SYFT=$(which syft)
+if [ -z "${SYFT}" ]
+then
+    echo "syft command not found"
+    exit 10
+fi
+
+set -e
+set -u
+
+LOGTAG=$$
+log() {
+    echo "${LOGTAG}:$(date --rfc-3339=seconds):$* ..."
+}
+
+# defaults
+FORMAT=cyclonedx
+
+# credentials directory has 0600 permissions
+CLIENTSECRET_FILE=credentials/client_secret
+SBOM=false
+
+URL=https://app.rkvst.io
+
+usage() {
+    cat >&2 <<EOF
+
+Scrape an SBOM from a docker image
+
+Usage: $SCRIPTNAME [-c clientsecretfile] [-o output format] [-s sbomFile ] [-u url] client_id [docker-image|sbom file]
+
+   -c clientsecretfile containing client secret (default ${CLIENTSECRET_FILE})
+   -o FORMAT           default ($FORMAT) [cyclonedx]
+   -s                  default ($SBOM) if specified the second argument is an sbom file
+                       and -o is ignored.
+   -u URL              URL Default ($URL)
+
+Example:
+
+    $0 -o spdx 29b48af4-45ca-465b-b136-206674f8aa9b ubuntu:21.10
+
+EOF
+
+    exit 1
+}
+
+while getopts "c:ho:su:" o; do
+    case "${o}" in
+        c) CLIENTSECRET_FILE="${OPTARG}"
+           ;;
+        o) FORMAT=${OPTARG}
+           ;;
+        s) SBOM=true
+           ;;
+        u) URL=$OPTARG
+           ;;
+        *)
+           usage
+           ;;
+    esac
+done
+shift $((OPTIND-1))
+
+[ $# -lt 1 ] && usage
+CLIENT_ID=$1
+shift 1
+[ $# -lt 1 ] && usage
+DOCKER_IMAGE=$1
+shift 1
+
+[ $# -ge 1 ] && usage
+
+# ----------------------------------------------------------------------------
+# Setup exit handling and temporary directory
+# ----------------------------------------------------------------------------
+TEMPDIR=$( mktemp -d /tmp/.sbom_scraper.XXXXXXXX )
+
+# report on exit
+function finalise {
+    CODE=$?
+    rm -rf "$TEMPDIR"
+    exit $CODE
+}
+trap finalise EXIT INT TERM
+
+OUTFILE=$(echo "${DOCKER_IMAGE}" | tr '/:' '-').${FORMAT}.sbom
+
+# ----------------------------------------------------------------------------
+# Extract client secrets
+# ----------------------------------------------------------------------------
+if [ ! -s "${CLIENTSECRET_FILE}" ]
+then
+    log "${CLIENTSECRET_FILE} does not exist or is empty"
+    exit 1
+fi
+SECRET=$(cat "${CLIENTSECRET_FILE}")
+
+# ----------------------------------------------------------------------------
+# Extract SBOM
+# ----------------------------------------------------------------------------
+if [ "${SBOM}" = "false" ]
+then
+    log "Scrape ${FORMAT} SBOM from ${DOCKER_IMAGE} to ${OUTFILE}..."
+    OUTPUT="${TEMPDIR}/${OUTFILE}"
+    ${SYFT} -q packages -o "${FORMAT}" "${DOCKER_IMAGE}"> "${OUTPUT}"
+else
+    OUTPUT="${DOCKER_IMAGE}"
+fi
+
+# ----------------------------------------------------------------------------
+# Handle client id and secrets for SBOM scraper via App registrations
+# ----------------------------------------------------------------------------
+HTTP_STATUS=""
+# get token
+log "Get token"
+HTTP_STATUS=$(curl -sS -w "%{http_code}" \
+    -o "${TEMPDIR}/access_token" \
+    --data-urlencode "grant_type=client_credentials" \
+    --data-urlencode "client_id=${CLIENT_ID}" \
+    --data-urlencode "client_secret=${SECRET}" \
+    "${URL}/archivist/iam/v1/appidp/token")
+if [ "${HTTP_STATUS}" != "200" ]
+then
+    log "Get token failure ${HTTP_STATUS}"
+    exit 2
+fi
+
+TOKEN=$(jq -r .access_token "${TEMPDIR}"/access_token )
+
+# create token file
+BEARER_TOKEN_FILE=${TEMPDIR}/token
+cat > "${BEARER_TOKEN_FILE}" <<EOF
+Authorization: Bearer $TOKEN
+EOF
+#
+# ----------------------------------------------------------------------------
+# Upload SBOM
+# ----------------------------------------------------------------------------
+log "Upload ${OUTPUT}"
+
+HTTP_STATUS=$(curl -s -w "%{http_code}" -X POST \
+    -o "${TEMPDIR}/upload" \
+    -H "@${BEARER_TOKEN_FILE}" \
+    -H "content_type=text/xml" \
+    -F "sbom=@${OUTPUT}" \
+    "${URL}/archivist/v1/sboms")
+
+if [ "${HTTP_STATUS}" != "200" ]
+then
+    log "Upload failure ${HTTP_STATUS}"
+    exit 4
+fi
+UUID=$(cat "${TEMPDIR}/upload")
+log "Upload success: uuid=${UUID}"
+exit 0