fix(openfeature): isolate malformed flag configuration

Author: leoromanovsky

.github/dependabot.yml

@@ -402,3 +402,8 @@ updates:
         applies-to: security-updates
         patterns:
           - "*"
+
+  - package-ecosystem: "gitsubmodule"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/openfeature.yml

@@ -23,6 +23,8 @@ jobs:
       id-token: write
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          submodules: true
       - uses: ./.github/actions/node
         with:
           version: ${{ matrix.version }}

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "packages/dd-trace/test/openfeature/ffe-system-test-data"]
+  path = packages/dd-trace/test/openfeature/ffe-system-test-data
+  url = https://github.com/DataDog/ffe-system-test-data.git

packages/dd-trace/src/openfeature/ffe-evaluator.js

@@ -0,0 +1,276 @@
+'use strict'
+
+const SEMVER_OPERATORS = new Set([
+  'SEMVER_EQ', 'SEMVER_NEQ', 'SEMVER_LT', 'SEMVER_LTE', 'SEMVER_GT', 'SEMVER_GTE',
+])
+const OPERATORS = new Set([
+  'LT', 'LTE', 'GT', 'GTE', 'MATCHES', 'NOT_MATCHES', 'ONE_OF', 'NOT_ONE_OF', 'IS_NULL',
+  ...SEMVER_OPERATORS,
+])
+const SEMVER = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[A-Za-z-][0-9A-Za-z-]*)(?:\.(?:0|[1-9]\d*|\d*[A-Za-z-][0-9A-Za-z-]*))*))?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$/
+const UINT64_MAX = '18446744073709551615'
+
+/**
+ * Validates flags independently and converts SemVer conditions into rules the
+ * upstream evaluator can execute with per-request synthetic attributes.
+ *
+ * @param {import('@datadog/openfeature-node-server').UniversalFlagConfigurationV1 | undefined} [configuration]
+ * @returns {{
+ *   configuration: import('@datadog/openfeature-node-server').UniversalFlagConfigurationV1 | undefined,
+ *   rejected: Set<string>,
+ *   semverConditions: Map<string, Array<{
+ *     attribute: string,
+ *     comparand: string,
+ *     operator: string,
+ *     syntheticAttribute: string
+ *   }>>
+ * }}
+ */
+function sanitizeConfiguration (configuration) {
+  const rejected = new Set()
+  const semverConditions = new Map()
+  if (!configuration?.flags || typeof configuration.flags !== 'object' || Array.isArray(configuration.flags)) {
+    return { configuration, rejected, semverConditions }
+  }
+
+  const flags = { ...configuration.flags }
+  for (const [key, flag] of Object.entries(configuration.flags)) {
+    try {
+      const conditions = []
+      flags[key] = prepareFlag(key, flag, conditions)
+      if (conditions.length) semverConditions.set(key, conditions)
+    } catch {
+      rejected.add(key)
+    }
+  }
+
+  return {
+    configuration: rejected.size || semverConditions.size ? { ...configuration, flags } : configuration,
+    rejected,
+    semverConditions,
+  }
+}
+
+/**
+ * Adds the precomputed attributes used by transformed SemVer rules.
+ *
+ * @param {Array<{
+ *   attribute: string,
+ *   comparand: string,
+ *   operator: string,
+ *   syntheticAttribute: string
+ * }> | undefined} conditions
+ * @param {import('@openfeature/server-sdk').EvaluationContext} context
+ * @returns {import('@openfeature/server-sdk').EvaluationContext}
+ */
+function addSemverContext (conditions, context) {
+  if (!conditions) return context
+
+  const semverContext = { ...context }
+  for (const condition of conditions) {
+    const matches = compareSemverOperator(
+      condition.operator,
+      context?.[condition.attribute],
+      condition.comparand
+    )
+    semverContext[condition.syntheticAttribute] = matches ? 'true' : 'false'
+  }
+  return semverContext
+}
+
+function prepareFlag (key, flag, semverConditions) {
+  if (!flag || flag.key !== key || typeof flag.enabled !== 'boolean' ||
+      !['BOOLEAN', 'INTEGER', 'NUMERIC', 'STRING', 'JSON'].includes(flag.variationType)) {
+    throw new Error('invalid flag')
+  }
+  if (!flag.variations || typeof flag.variations !== 'object' || Array.isArray(flag.variations)) {
+    throw new Error('missing variations')
+  }
+  for (const [variationKey, variation] of Object.entries(flag.variations)) {
+    if (!variation || variation.key !== variationKey || !matchesType(variation.value, flag.variationType)) {
+      throw new Error('invalid variation')
+    }
+  }
+  if (!Array.isArray(flag.allocations)) throw new Error('invalid allocations')
+
+  let transformed = false
+  const allocations = []
+  for (const allocation of flag.allocations) {
+    if (!allocation || !Array.isArray(allocation.splits)) throw new Error('invalid allocation')
+    for (const split of allocation.splits) validateSplit(split, flag.variations)
+
+    if (allocation.rules === undefined) {
+      allocations.push(allocation)
+      continue
+    }
+    if (!Array.isArray(allocation.rules)) throw new Error('invalid rules')
+
+    let allocationTransformed = false
+    const rules = []
+    for (const rule of allocation.rules) {
+      if (!rule || !Array.isArray(rule.conditions)) throw new Error('invalid rule')
+
+      let ruleTransformed = false
+      const conditions = []
+      for (const condition of rule.conditions) {
+        validateCondition(condition)
+        if (!SEMVER_OPERATORS.has(condition.operator)) {
+          conditions.push(condition)
+          continue
+        }
+
+        const syntheticAttribute = `__datadog_semver_condition_${semverConditions.length}`
+        semverConditions.push({
+          attribute: condition.attribute,
+          comparand: condition.value,
+          operator: condition.operator,
+          syntheticAttribute,
+        })
+        conditions.push({
+          ...condition,
+          attribute: syntheticAttribute,
+          operator: 'ONE_OF',
+          value: ['true'],
+        })
+        ruleTransformed = true
+      }
+      rules.push(ruleTransformed ? { ...rule, conditions } : rule)
+      allocationTransformed ||= ruleTransformed
+    }
+    allocations.push(allocationTransformed ? { ...allocation, rules } : allocation)
+    transformed ||= allocationTransformed
+  }
+
+  return transformed ? { ...flag, allocations } : flag
+}
+
+function validateSplit (split, variations) {
+  if (!split || !Array.isArray(split.shards) || !Object.hasOwn(variations, split.variationKey)) {
+    throw new Error('invalid split')
+  }
+  for (const shard of split.shards) {
+    if (!shard || !Number.isSafeInteger(shard.totalShards) || shard.totalShards <= 0 ||
+        shard.totalShards > 0xFF_FF_FF_FF || !Array.isArray(shard.ranges)) {
+      throw new Error('invalid shard')
+    }
+    for (const range of shard.ranges) {
+      if (!range || !Number.isSafeInteger(range.start) || !Number.isSafeInteger(range.end) ||
+          range.start < 0 || range.start >= range.end || range.end > shard.totalShards) {
+        throw new Error('invalid shard range')
+      }
+    }
+  }
+}
+
+function validateCondition (condition) {
+  if (!condition || typeof condition.attribute !== 'string' || !OPERATORS.has(condition.operator)) {
+    throw new Error('invalid condition')
+  }
+  switch (condition.operator) {
+    case 'MATCHES':
+    case 'NOT_MATCHES':
+      if (typeof condition.value !== 'string') throw new Error('invalid regex')
+      compileRegex(condition.value)
+      break
+    case 'LT':
+    case 'LTE':
+    case 'GT':
+    case 'GTE':
+      if (typeof condition.value !== 'number' || !Number.isFinite(condition.value)) throw new Error('invalid number')
+      break
+    case 'ONE_OF':
+    case 'NOT_ONE_OF':
+      if (!Array.isArray(condition.value) || condition.value.some(value => typeof value !== 'string')) {
+        throw new Error('invalid membership')
+      }
+      break
+    case 'IS_NULL':
+      if (typeof condition.value !== 'boolean') throw new Error('invalid null check')
+      break
+    default:
+      parseSemver(condition.value)
+  }
+}
+
+function matchesType (value, type) {
+  if (type === 'BOOLEAN') return typeof value === 'boolean'
+  if (type === 'STRING') return typeof value === 'string'
+  if (type === 'INTEGER') return Number.isSafeInteger(value)
+  if (type === 'NUMERIC') return typeof value === 'number' && Number.isFinite(value)
+  return value !== undefined
+}
+
+function compileRegex (pattern) {
+  const inlineFlags = pattern.match(/^\(\?([imsu]+)\)/)
+  const flags = inlineFlags ? [...new Set(inlineFlags[1])].join('') : ''
+  const source = (inlineFlags ? pattern.slice(inlineFlags[0].length) : pattern)
+    .replaceAll('[:alnum:]', 'A-Za-z0-9')
+  return new RegExp(source, flags)
+}
+
+function parseSemver (value) {
+  if (typeof value !== 'string') throw new Error('invalid semantic version')
+  const match = SEMVER.exec(value)
+  if (!match) throw new Error('invalid semantic version')
+
+  const core = match.slice(1, 4)
+  if (core.some(part => compareNumeric(part, UINT64_MAX) > 0)) throw new Error('invalid semantic version')
+  const prerelease = match[4]?.split('.')
+  if (prerelease?.some(part => /^\d+$/.test(part) && compareNumeric(part, UINT64_MAX) > 0)) {
+    throw new Error('invalid semantic version')
+  }
+  return { core, prerelease }
+}
+
+function compareSemverOperator (operator, left, right) {
+  let comparison
+  try {
+    comparison = compareSemver(parseSemver(left), parseSemver(right))
+  } catch {
+    return false
+  }
+  if (operator === 'SEMVER_EQ') return comparison === 0
+  if (operator === 'SEMVER_NEQ') return comparison !== 0
+  if (operator === 'SEMVER_LT') return comparison < 0
+  if (operator === 'SEMVER_LTE') return comparison <= 0
+  if (operator === 'SEMVER_GT') return comparison > 0
+  return comparison >= 0
+}
+
+function compareSemver (left, right) {
+  for (let index = 0; index < 3; index++) {
+    const result = compareNumeric(left.core[index], right.core[index])
+    if (result) return result
+  }
+  if (!left.prerelease && !right.prerelease) return 0
+  if (!left.prerelease) return 1
+  if (!right.prerelease) return -1
+  for (let index = 0; index < Math.min(left.prerelease.length, right.prerelease.length); index++) {
+    const leftPart = left.prerelease[index]
+    const rightPart = right.prerelease[index]
+    const leftNumeric = /^\d+$/.test(leftPart)
+    const rightNumeric = /^\d+$/.test(rightPart)
+    let result
+    if (leftNumeric && rightNumeric) {
+      result = compareNumeric(leftPart, rightPart)
+    } else if (leftNumeric) {
+      result = -1
+    } else if (rightNumeric) {
+      result = 1
+    } else {
+      result = compareLexical(leftPart, rightPart)
+    }
+    if (result) return result
+  }
+  return Math.sign(left.prerelease.length - right.prerelease.length)
+}
+
+function compareNumeric (left, right) {
+  return Math.sign(left.length - right.length) || compareLexical(left, right)
+}
+
+function compareLexical (left, right) {
+  return left === right ? 0 : left < right ? -1 : 1
+}
+
+module.exports = { addSemverContext, sanitizeConfiguration }