fix: add SSRF protection to validate-model endpoint (#357)

Block private IPs, localhost, cloud metadata endpoints (169.254.169.254),
and internal hostnames in custom baseUrl parameter to prevent server-side
request forgery attacks.

app/api/validate-model/route.ts

@@ -11,6 +11,66 @@ import { createOllama } from "ollama-ai-provider-v2"
 
 export const runtime = "nodejs"
 
+/**
+ * SECURITY: Check if URL points to private/internal network (SSRF protection)
+ * Blocks: localhost, private IPs, link-local, AWS metadata service
+ */
+function isPrivateUrl(urlString: string): boolean {
+    try {
+        const url = new URL(urlString)
+        const hostname = url.hostname.toLowerCase()
+
+        // Block localhost
+        if (
+            hostname === "localhost" ||
+            hostname === "127.0.0.1" ||
+            hostname === "::1"
+        ) {
+            return true
+        }
+
+        // Block AWS/cloud metadata endpoints
+        if (
+            hostname === "169.254.169.254" ||
+            hostname === "metadata.google.internal"
+        ) {
+            return true
+        }
+
+        // Check for private IPv4 ranges
+        const ipv4Match = hostname.match(
+            /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/,
+        )
+        if (ipv4Match) {
+            const [, a, b] = ipv4Match.map(Number)
+            // 10.0.0.0/8
+            if (a === 10) return true
+            // 172.16.0.0/12
+            if (a === 172 && b >= 16 && b <= 31) return true
+            // 192.168.0.0/16
+            if (a === 192 && b === 168) return true
+            // 169.254.0.0/16 (link-local)
+            if (a === 169 && b === 254) return true
+            // 127.0.0.0/8 (loopback)
+            if (a === 127) return true
+        }
+
+        // Block common internal hostnames
+        if (
+            hostname.endsWith(".local") ||
+            hostname.endsWith(".internal") ||
+            hostname.endsWith(".localhost")
+        ) {
+            return true
+        }
+
+        return false
+    } catch {
+        // Invalid URL - block it
+        return true
+    }
+}
+
 interface ValidateRequest {
     provider: string
     apiKey: string
@@ -42,6 +102,14 @@ export async function POST(req: Request) {
             )
         }
 
+        // SECURITY: Block SSRF attacks via custom baseUrl
+        if (baseUrl && isPrivateUrl(baseUrl)) {
+            return NextResponse.json(
+                { valid: false, error: "Invalid base URL" },
+                { status: 400 },
+            )
+        }
+
         // Validate credentials based on provider
         if (provider === "bedrock") {
             if (!awsAccessKeyId || !awsSecretAccessKey || !awsRegion) {