feat: validate script mapping paths

src/Service/PathNormalizer.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Service;
+
+use InvalidArgumentException;
+
+final class PathNormalizer
+{
+    public function publicPath(string $path): string
+    {
+        $normalized = $this->relativePath($path);
+
+        if (!str_ends_with($normalized, '.sh')) {
+            throw new InvalidArgumentException('Public path must end with .sh.');
+        }
+
+        return $normalized;
+    }
+
+    public function repositoryPath(string $path): string
+    {
+        return $this->relativePath($path);
+    }
+
+    private function relativePath(string $path): string
+    {
+        $path = trim(str_replace('\\', '/', $path));
+        $path = ltrim($path, '/');
+
+        if ($path === '') {
+            throw new InvalidArgumentException('Path cannot be empty.');
+        }
+
+        $segments = explode('/', $path);
+
+        foreach ($segments as $segment) {
+            if ($segment === '' || $segment === '.' || $segment === '..') {
+                throw new InvalidArgumentException('Path contains an invalid segment.');
+            }
+        }
+
+        return implode('/', $segments);
+    }
+}

tests/Service/PathNormalizerTest.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace App\Tests\Service;
+
+use App\Service\PathNormalizer;
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+
+final class PathNormalizerTest extends TestCase
+{
+    private PathNormalizer $normalizer;
+
+    protected function setUp(): void
+    {
+        $this->normalizer = new PathNormalizer();
+    }
+
+    public function testPublicPathIsNormalized(): void
+    {
+        self::assertSame('mcp/graylog/install.sh', $this->normalizer->publicPath('/mcp/graylog/install.sh'));
+    }
+
+    public function testPublicPathMustEndWithShellExtension(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        $this->normalizer->publicPath('mcp/graylog/install.txt');
+    }
+
+    public function testPublicPathRejectsTraversal(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        $this->normalizer->publicPath('mcp/../install.sh');
+    }
+
+    public function testRepositoryPathAllowsNestedFileWithoutShellRequirement(): void
+    {
+        self::assertSame('scripts/install', $this->normalizer->repositoryPath('/scripts/install'));
+    }
+
+    public function testRepositoryPathRejectsTraversal(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        $this->normalizer->repositoryPath('../install.sh');
+    }
+}