fleetd #519: test policy probe guards

scripts/probe-member-credentials.sh

@@ -64,6 +64,59 @@
 # The two outputs side by side are the finding: any name whose hash matches between them is a
 # credential the member holds in full.
 #
+parse_policy_fields() {
+  if command -v jq >/dev/null 2>&1; then
+    _FIELDS_RAW="$(printf '%s' "$POLICY_JSON" | jq -r '
+        (.present | tostring),
+        (.policy // ""),
+        (.knownCount // 0 | tostring),
+        (.allowedCount // 0 | tostring),
+        (.blockedCount // 0 | tostring),
+        (.known[]? // empty)')"
+    _PARSE_STATUS=$?
+    _PARSER_NAME="jq"
+  else
+    _FIELDS_RAW="$(printf '%s' "$POLICY_JSON" | python3 - <<'PY'
+import json, sys
+data = json.load(sys.stdin)
+print(str(data.get("present")))
+print(data.get("policy") or "")
+print(data.get("knownCount") if data.get("knownCount") is not None else 0)
+print(data.get("allowedCount") if data.get("allowedCount") is not None else 0)
+print(data.get("blockedCount") if data.get("blockedCount") is not None else 0)
+for n in (data.get("known") or []):
+    print(n)
+PY
+    )"
+    _PARSE_STATUS=$?
+    _PARSER_NAME="python3"
+  fi
+
+  if [ "$_PARSE_STATUS" -ne 0 ]; then
+    echo "refusing to run: could not parse the policy fetched from $POLICY_URL — $_PARSER_NAME exited" \
+         "non-zero (status $_PARSE_STATUS). That is a parser failure, not a claim about the policy" \
+         "itself; the policy response has not been read." >&2
+    return 4
+  fi
+
+  # A herestring adds a newline, so mapfile would turn an empty parser result into one empty field.
+  # Keep that case separate so the refusal reports what the parser actually returned: zero fields.
+  if [ -z "$_FIELDS_RAW" ]; then
+    _FIELDS=()
+  else
+    mapfile -t _FIELDS <<< "$_FIELDS_RAW"
+  fi
+
+  if (( ${#_FIELDS[@]} < 5 )); then
+    echo "refusing to run: the policy parser ($_PARSER_NAME) returned ${#_FIELDS[@]} field(s); at" \
+         "least 5 are required (present, policy mode, knownCount, allowedCount, blockedCount). The" \
+         "parse ran but its shape is wrong — this is not a claim about how many names the policy" \
+         "knows." >&2
+    return 5
+  fi
+}
+
+main() {
 set -uo pipefail
 # `pipefail` is not what catches the parser failure handled below (fleetd #500): in
 # `printf '%s' "$POLICY_JSON" | jq -r '...'`, jq is the LAST element of the pipe, so the pipeline's
@@ -159,42 +212,6 @@ fi
 # materialises the whole string in memory first, where `< <(...)` would stream it. That only
 # matters for a large producer; this one is a short credential-name policy response, so the
 # tradeoff is irrelevant here — noted because it would not be for every producer.
-if command -v jq >/dev/null 2>&1; then
-  _FIELDS_RAW="$(printf '%s' "$POLICY_JSON" | jq -r '
-      (.present | tostring),
-      (.policy // ""),
-      (.knownCount // 0 | tostring),
-      (.allowedCount // 0 | tostring),
-      (.blockedCount // 0 | tostring),
-      (.known[]? // empty)')"
-  _PARSE_STATUS=$?
-  _PARSER_NAME="jq"
-else
-  _FIELDS_RAW="$(printf '%s' "$POLICY_JSON" | python3 - <<'PY'
-import json, sys
-data = json.load(sys.stdin)
-print(str(data.get("present")))
-print(data.get("policy") or "")
-print(data.get("knownCount") if data.get("knownCount") is not None else 0)
-print(data.get("allowedCount") if data.get("allowedCount") is not None else 0)
-print(data.get("blockedCount") if data.get("blockedCount") is not None else 0)
-for n in (data.get("known") or []):
-    print(n)
-PY
-  )"
-  _PARSE_STATUS=$?
-  _PARSER_NAME="python3"
-fi
-
-if [ "$_PARSE_STATUS" -ne 0 ]; then
-  echo "refusing to run: could not parse the policy fetched from $POLICY_URL — $_PARSER_NAME exited" \
-       "non-zero (status $_PARSE_STATUS). That is a parser failure, not a claim about the policy" \
-       "itself; the policy response has not been read." >&2
-  exit 4
-fi
-
-mapfile -t _FIELDS <<< "$_FIELDS_RAW"
-
 # Arity check — the CORRECTNESS fix (fleetd #500). A parser that exits 0 can still return fewer
 # than the 5 fixed fields (present, policy mode, 3 counts) that every line below this expects,
 # whatever the reason: a producer that printed nothing, malformed JSON that jq/python3 still
@@ -203,13 +220,7 @@ mapfile -t _FIELDS <<< "$_FIELDS_RAW"
 # without this check a short `_FIELDS` reaches the "0 known names" guard further down with the
 # same look as a policy that genuinely has 0 names. Check the count here, at the one point the
 # fact is still present, before the slice consumes it.
-if (( ${#_FIELDS[@]} < 5 )); then
-  echo "refusing to run: the policy parser ($_PARSER_NAME) returned ${#_FIELDS[@]} field(s); at" \
-       "least 5 are required (present, policy mode, knownCount, allowedCount, blockedCount). The" \
-       "parse ran but its shape is wrong — this is not a claim about how many names the policy" \
-       "knows." >&2
-  exit 5
-fi
+parse_policy_fields || exit $?
 
 PRESENT="${_FIELDS[0]:-null}"
 POLICY_MODE="${_FIELDS[1]:-}"
@@ -317,3 +328,8 @@ How to read this:
     hardcoded list did. If the daemon's policy changes, the next run of this script reflects it
     with no edit to this file.
 EOF
+}
+
+if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
+  main "$@"
+fi

scripts/test-probe-member-credentials.sh

@@ -0,0 +1,109 @@
+#!/usr/bin/env bash
+# Self-contained checks for the policy parsing guards in probe-member-credentials.sh.
+
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+PROBE="$ROOT/scripts/probe-member-credentials.sh"
+TMP="$(mktemp -d "$ROOT/.probe-member-credentials-test.XXXXXX")"
+trap 'rm -rf "$TMP"' EXIT
+
+# The SOURCED guard exposes this pure parser without contacting POLICY_URL.
+source "$PROBE"
+
+fail() {
+  printf 'FAIL: %s\n' "$*" >&2
+  return 1
+}
+
+assert_equals() {
+  local expected="$1" actual="$2" description="$3"
+  [ "$expected" = "$actual" ] || fail "$description: expected $expected, got $actual"
+}
+
+assert_contains() {
+  local needle="$1" text="$2" description="$3"
+  printf '%s' "$text" | grep -qF "$needle" || fail "$description: missing $needle"
+}
+
+make_jq() {
+  local body="$1"
+  mkdir -p "$TMP/bin"
+  printf '%s\n' '#!/usr/bin/env bash' "$body" > "$TMP/bin/jq"
+  chmod +x "$TMP/bin/jq"
+}
+
+run_parser() {
+  local output rc=0
+  POLICY_JSON="$(< "$TMP/policy.json")"
+  POLICY_URL="fixture://member-credentials"
+  output="$(PATH="$TMP/bin:$PATH" parse_policy_fields 2>&1)" || rc=$?
+  PARSER_OUTPUT="$output"
+  PARSER_RC="$rc"
+}
+
+test_bash_older_than_four_refuses() {
+  local output rc=0 version
+  version="$(/bin/bash -c 'printf %s "$BASH_VERSION"')"
+  output="$(/bin/bash "$PROBE" 2>&1)" || rc=$?
+  assert_equals 3 "$rc" "bash 3 refusal status"
+  assert_contains 'This shell is bash' "$output" "bash 3 refusal"
+  assert_contains "$version" "$output" "bash 3 refusal version"
+}
+
+test_parser_non_zero_refuses() {
+  make_jq 'exit 17'
+  run_parser
+  assert_equals 4 "$PARSER_RC" "parser failure status"
+  assert_contains 'jq exited non-zero (status 17)' "$PARSER_OUTPUT" "parser failure message"
+}
+
+test_short_parser_output_refuses() {
+  make_jq "printf '%s\\n' true enforce 3 2"
+  run_parser
+  assert_equals 5 "$PARSER_RC" "short parser output status"
+  assert_contains 'jq) returned 4 field(s)' "$PARSER_OUTPUT" "short parser output count"
+}
+
+test_empty_parser_output_reports_zero_fields() {
+  make_jq ':'
+  run_parser
+  assert_equals 5 "$PARSER_RC" "empty parser output status"
+  assert_contains 'jq) returned 0 field(s)' "$PARSER_OUTPUT" "empty parser output count"
+}
+
+test_well_formed_policy_prints_name_table() {
+  local output rc=0
+  make_jq "cat '$TMP/policy.fields'"
+  # Shell functions cannot be passed in an environment assignment. Run the executable through bash.
+  output="$(BRIDGED_MEMBER=1 FIXTURE="$TMP/policy.json" PROBE="$PROBE" PATH="$TMP/bin:$PATH" bash -c '
+    curl() { cat "$FIXTURE"; }
+    export -f curl
+    exec "$PROBE"
+  ' 2>&1)" || rc=$?
+  assert_equals 0 "$rc" "well-formed policy status"
+  assert_contains 'ALPHA_TOKEN' "$output" "name table"
+  assert_contains 'BETA_TOKEN' "$output" "name table"
+  assert_contains 'GAMMA_TOKEN' "$output" "name table"
+}
+
+cat > "$TMP/policy.json" <<'JSON'
+{"present":true,"policy":"enforce","knownCount":3,"allowedCount":2,"blockedCount":1,"known":["ALPHA_TOKEN","BETA_TOKEN","GAMMA_TOKEN"]}
+JSON
+cat > "$TMP/policy.fields" <<'FIELDS'
+true
+enforce
+3
+2
+1
+ALPHA_TOKEN
+BETA_TOKEN
+GAMMA_TOKEN
+FIELDS
+
+test_bash_older_than_four_refuses
+test_parser_non_zero_refuses
+test_short_parser_output_refuses
+test_empty_parser_output_reports_zero_fields
+test_well_formed_policy_prints_name_table
+printf 'PASS: probe member credentials guards\n'