feat(ipuaro): add PathValidator security utility (v0.13.0)

Add centralized path validation to prevent path traversal attacks.

- PathValidator class with sync/async validation methods
- Protects against '..' and '~' traversal patterns
- Validates paths are within project root
- Refactored all 7 file tools to use PathValidator
- 51 new tests for PathValidator

packages/ipuaro/src/infrastructure/index.ts

@@ -3,3 +3,4 @@ export * from "./storage/index.js"
 export * from "./indexer/index.js"
 export * from "./llm/index.js"
 export * from "./tools/index.js"
+export * from "./security/index.js"

packages/ipuaro/src/infrastructure/security/PathValidator.ts

@@ -0,0 +1,293 @@
+import * as path from "node:path"
+import { promises as fs } from "node:fs"
+
+/**
+ * Path validation result classification.
+ */
+export type PathValidationStatus = "valid" | "invalid" | "outside_project"
+
+/**
+ * Result of path validation.
+ */
+export interface PathValidationResult {
+    /** Validation status */
+    status: PathValidationStatus
+    /** Reason for the status */
+    reason: string
+    /** Normalized absolute path (only if valid) */
+    absolutePath?: string
+    /** Normalized relative path (only if valid) */
+    relativePath?: string
+}
+
+/**
+ * Options for path validation.
+ */
+export interface PathValidatorOptions {
+    /** Allow paths that don't exist yet (for create operations) */
+    allowNonExistent?: boolean
+    /** Check if path is a directory */
+    requireDirectory?: boolean
+    /** Check if path is a file */
+    requireFile?: boolean
+    /** Follow symlinks when checking existence */
+    followSymlinks?: boolean
+}
+
+/**
+ * Path validator for ensuring file operations stay within project boundaries.
+ * Prevents path traversal attacks and unauthorized file access.
+ */
+export class PathValidator {
+    private readonly projectRoot: string
+
+    constructor(projectRoot: string) {
+        this.projectRoot = path.resolve(projectRoot)
+    }
+
+    /**
+     * Validate a path and return detailed result.
+     * @param inputPath - Path to validate (relative or absolute)
+     * @param options - Validation options
+     */
+    async validate(
+        inputPath: string,
+        options: PathValidatorOptions = {},
+    ): Promise<PathValidationResult> {
+        if (!inputPath || inputPath.trim() === "") {
+            return {
+                status: "invalid",
+                reason: "Path is empty",
+            }
+        }
+
+        const normalizedInput = inputPath.trim()
+
+        if (this.containsTraversalPatterns(normalizedInput)) {
+            return {
+                status: "invalid",
+                reason: "Path contains traversal patterns",
+            }
+        }
+
+        const absolutePath = path.resolve(this.projectRoot, normalizedInput)
+
+        if (!this.isWithinProject(absolutePath)) {
+            return {
+                status: "outside_project",
+                reason: "Path is outside project root",
+            }
+        }
+
+        const relativePath = path.relative(this.projectRoot, absolutePath)
+
+        if (!options.allowNonExistent) {
+            const existsResult = await this.checkExists(absolutePath, options)
+            if (existsResult) {
+                return existsResult
+            }
+        }
+
+        return {
+            status: "valid",
+            reason: "Path is valid",
+            absolutePath,
+            relativePath,
+        }
+    }
+
+    /**
+     * Synchronous validation for simple checks.
+     * Does not check file existence or type.
+     * @param inputPath - Path to validate (relative or absolute)
+     */
+    validateSync(inputPath: string): PathValidationResult {
+        if (!inputPath || inputPath.trim() === "") {
+            return {
+                status: "invalid",
+                reason: "Path is empty",
+            }
+        }
+
+        const normalizedInput = inputPath.trim()
+
+        if (this.containsTraversalPatterns(normalizedInput)) {
+            return {
+                status: "invalid",
+                reason: "Path contains traversal patterns",
+            }
+        }
+
+        const absolutePath = path.resolve(this.projectRoot, normalizedInput)
+
+        if (!this.isWithinProject(absolutePath)) {
+            return {
+                status: "outside_project",
+                reason: "Path is outside project root",
+            }
+        }
+
+        const relativePath = path.relative(this.projectRoot, absolutePath)
+
+        return {
+            status: "valid",
+            reason: "Path is valid",
+            absolutePath,
+            relativePath,
+        }
+    }
+
+    /**
+     * Quick check if path is within project.
+     * @param inputPath - Path to check (relative or absolute)
+     */
+    isWithin(inputPath: string): boolean {
+        if (!inputPath || inputPath.trim() === "") {
+            return false
+        }
+
+        const normalizedInput = inputPath.trim()
+
+        if (this.containsTraversalPatterns(normalizedInput)) {
+            return false
+        }
+
+        const absolutePath = path.resolve(this.projectRoot, normalizedInput)
+        return this.isWithinProject(absolutePath)
+    }
+
+    /**
+     * Resolve a path relative to project root.
+     * Returns null if path would be outside project.
+     * @param inputPath - Path to resolve
+     */
+    resolve(inputPath: string): string | null {
+        const result = this.validateSync(inputPath)
+        return result.status === "valid" ? (result.absolutePath ?? null) : null
+    }
+
+    /**
+     * Resolve a path or throw an error if invalid.
+     * @param inputPath - Path to resolve
+     * @returns Tuple of [absolutePath, relativePath]
+     * @throws Error if path is invalid
+     */
+    resolveOrThrow(inputPath: string): [absolutePath: string, relativePath: string] {
+        const result = this.validateSync(inputPath)
+        if (result.status !== "valid" || result.absolutePath === undefined) {
+            throw new Error(result.reason)
+        }
+        return [result.absolutePath, result.relativePath ?? ""]
+    }
+
+    /**
+     * Get relative path from project root.
+     * Returns null if path would be outside project.
+     * @param inputPath - Path to make relative
+     */
+    relativize(inputPath: string): string | null {
+        const result = this.validateSync(inputPath)
+        return result.status === "valid" ? (result.relativePath ?? null) : null
+    }
+
+    /**
+     * Get the project root path.
+     */
+    getProjectRoot(): string {
+        return this.projectRoot
+    }
+
+    /**
+     * Check if path contains directory traversal patterns.
+     */
+    private containsTraversalPatterns(inputPath: string): boolean {
+        const normalized = inputPath.replace(/\\/g, "/")
+
+        if (normalized.includes("..")) {
+            return true
+        }
+
+        if (normalized.startsWith("~")) {
+            return true
+        }
+
+        return false
+    }
+
+    /**
+     * Check if absolute path is within project root.
+     */
+    private isWithinProject(absolutePath: string): boolean {
+        const normalizedProject = this.projectRoot.replace(/\\/g, "/")
+        const normalizedPath = absolutePath.replace(/\\/g, "/")
+
+        if (normalizedPath === normalizedProject) {
+            return true
+        }
+
+        const projectWithSep = normalizedProject.endsWith("/")
+            ? normalizedProject
+            : `${normalizedProject}/`
+
+        return normalizedPath.startsWith(projectWithSep)
+    }
+
+    /**
+     * Check file existence and type.
+     */
+    private async checkExists(
+        absolutePath: string,
+        options: PathValidatorOptions,
+    ): Promise<PathValidationResult | null> {
+        try {
+            const statFn = options.followSymlinks ? fs.stat : fs.lstat
+            const stats = await statFn(absolutePath)
+
+            if (options.requireDirectory && !stats.isDirectory()) {
+                return {
+                    status: "invalid",
+                    reason: "Path is not a directory",
+                }
+            }
+
+            if (options.requireFile && !stats.isFile()) {
+                return {
+                    status: "invalid",
+                    reason: "Path is not a file",
+                }
+            }
+
+            return null
+        } catch (error) {
+            if ((error as NodeJS.ErrnoException).code === "ENOENT") {
+                return {
+                    status: "invalid",
+                    reason: "Path does not exist",
+                }
+            }
+
+            return {
+                status: "invalid",
+                reason: `Cannot access path: ${(error as Error).message}`,
+            }
+        }
+    }
+}
+
+/**
+ * Create a path validator for a project.
+ * @param projectRoot - Root directory of the project
+ */
+export function createPathValidator(projectRoot: string): PathValidator {
+    return new PathValidator(projectRoot)
+}
+
+/**
+ * Standalone function for quick path validation.
+ * @param inputPath - Path to validate
+ * @param projectRoot - Project root directory
+ */
+export function validatePath(inputPath: string, projectRoot: string): boolean {
+    const validator = new PathValidator(projectRoot)
+    return validator.isWithin(inputPath)
+}

packages/ipuaro/src/infrastructure/security/index.ts

@@ -0,0 +1,9 @@
+// Security module exports
+export {
+    PathValidator,
+    createPathValidator,
+    validatePath,
+    type PathValidationResult,
+    type PathValidationStatus,
+    type PathValidatorOptions,
+} from "./PathValidator.js"

packages/ipuaro/src/infrastructure/tools/edit/CreateFileTool.ts

@@ -8,6 +8,7 @@ import {
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
 import { hashLines } from "../../../shared/utils/hash.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from create_file tool.
@@ -62,17 +63,18 @@ export class CreateFileTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
+        const inputPath = params.path as string
         const content = params.content as string
 
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/edit/DeleteFileTool.ts

@@ -1,11 +1,11 @@
 import { promises as fs } from "node:fs"
-import * as path from "node:path"
 import type { ITool, ToolContext, ToolParameterSchema } from "../../../domain/services/ITool.js"
 import {
     createErrorResult,
     createSuccessResult,
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from delete_file tool.
@@ -49,15 +49,16 @@ export class DeleteFileTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const inputPath = params.path as string
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/edit/EditLinesTool.ts

@@ -1,5 +1,4 @@
 import { promises as fs } from "node:fs"
-import * as path from "node:path"
 import type { ITool, ToolContext, ToolParameterSchema } from "../../../domain/services/ITool.js"
 import { createFileData } from "../../../domain/value-objects/FileData.js"
 import {
@@ -8,6 +7,7 @@ import {
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
 import { hashLines } from "../../../shared/utils/hash.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from edit_lines tool.
@@ -94,19 +94,20 @@ export class EditLinesTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
+        const inputPath = params.path as string
         const startLine = params.start as number
         const endLine = params.end as number
         const newContent = params.content as string
 
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/read/GetClassTool.ts

@@ -1,5 +1,4 @@
 import { promises as fs } from "node:fs"
-import * as path from "node:path"
 import type { ITool, ToolContext, ToolParameterSchema } from "../../../domain/services/ITool.js"
 import type { ClassInfo } from "../../../domain/value-objects/FileAST.js"
 import {
@@ -7,6 +6,7 @@ import {
     createSuccessResult,
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from get_class tool.
@@ -67,16 +67,17 @@ export class GetClassTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
+        const inputPath = params.path as string
         const className = params.name as string
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/read/GetFunctionTool.ts

@@ -1,5 +1,4 @@
 import { promises as fs } from "node:fs"
-import * as path from "node:path"
 import type { ITool, ToolContext, ToolParameterSchema } from "../../../domain/services/ITool.js"
 import type { FunctionInfo } from "../../../domain/value-objects/FileAST.js"
 import {
@@ -7,6 +6,7 @@ import {
     createSuccessResult,
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from get_function tool.
@@ -65,16 +65,17 @@ export class GetFunctionTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
+        const inputPath = params.path as string
         const functionName = params.name as string
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/read/GetLinesTool.ts

@@ -1,11 +1,11 @@
 import { promises as fs } from "node:fs"
-import * as path from "node:path"
 import type { ITool, ToolContext, ToolParameterSchema } from "../../../domain/services/ITool.js"
 import {
     createErrorResult,
     createSuccessResult,
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Result data from get_lines tool.
@@ -84,15 +84,16 @@ export class GetLinesTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = params.path as string
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const inputPath = params.path as string
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {

packages/ipuaro/src/infrastructure/tools/read/GetStructureTool.ts

@@ -7,6 +7,7 @@ import {
     type ToolResult,
 } from "../../../domain/value-objects/ToolResult.js"
 import { DEFAULT_IGNORE_PATTERNS } from "../../../domain/constants/index.js"
+import { PathValidator } from "../../security/PathValidator.js"
 
 /**
  * Tree node representing a file or directory.
@@ -89,16 +90,17 @@ export class GetStructureTool implements ITool {
         const startTime = Date.now()
         const callId = `${this.name}-${String(startTime)}`
 
-        const relativePath = (params.path as string | undefined) ?? ""
+        const inputPath = (params.path as string | undefined) ?? "."
         const maxDepth = params.depth as number | undefined
-        const absolutePath = path.resolve(ctx.projectRoot, relativePath)
+        const pathValidator = new PathValidator(ctx.projectRoot)
 
-        if (!absolutePath.startsWith(ctx.projectRoot)) {
-            return createErrorResult(
-                callId,
-                "Path must be within project root",
-                Date.now() - startTime,
-            )
+        let absolutePath: string
+        let relativePath: string
+        try {
+            ;[absolutePath, relativePath] = pathValidator.resolveOrThrow(inputPath)
+        } catch (error) {
+            const message = error instanceof Error ? error.message : String(error)
+            return createErrorResult(callId, message, Date.now() - startTime)
         }
 
         try {