Files
next-ai-draw-io/lib/ssrf-protection.ts
chaochaoweb3 410993a3bf fix: block private IPv6 URLs (#858)
* fix: block private IPv6 URLs

* fix: cover full fe80::/10 link-local range and :: unspecified

- Replace startsWith("fe80:") with a check covering the full fe80::/10
  range (fe80 through febf) per RFC 4291.
- Add :: (unspecified) to the localhost block.
- Drop the dead 0:0:0:0:0:0:0:1 branch (URL parser normalizes it to ::1).
- Add tests for fe9f::1, febf::1, and ::.

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>
2026-06-06 00:30:20 +09:00

87 lines
2.7 KiB
TypeScript

/**
* SSRF (Server-Side Request Forgery) protection utilities
*/
/**
* Check if URL points to private/internal network
* Blocks: localhost, private IPs, link-local, AWS metadata service
*/
export function isPrivateUrl(urlString: string): boolean {
try {
const url = new URL(urlString)
// Strip a trailing dot so FQDN forms like "localhost." (which still
// resolve to 127.0.0.1) cannot bypass the equality checks below.
const hostname = url.hostname
.toLowerCase()
.replace(/^\[|\]$/g, "")
.replace(/\.$/, "")
// Block localhost
if (
hostname === "localhost" ||
hostname === "127.0.0.1" ||
hostname === "::1" ||
hostname === "::"
) {
return true
}
// Block IPv6 unique-local (fc00::/7), link-local (fe80::/10),
// and IPv4-mapped (::ffff:0:0/96) hosts.
if (hostname.includes(":")) {
if (
hostname.startsWith("fc") ||
hostname.startsWith("fd") ||
hostname.startsWith("::ffff:")
) {
return true
}
const linkLocal = hostname.match(/^fe([0-9a-f]{2}):/)
if (linkLocal) {
const high = parseInt(linkLocal[1], 16)
if (high >= 0x80 && high <= 0xbf) 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)
if (a === 10) return true // 10.0.0.0/8
if (a === 172 && b >= 16 && b <= 31) return true // 172.16.0.0/12
if (a === 192 && b === 168) return true // 192.168.0.0/16
if (a === 169 && b === 254) return true // 169.254.0.0/16 (link-local)
if (a === 127) return true // 127.0.0.0/8 (loopback)
}
// Block common internal hostnames
if (
hostname.endsWith(".local") ||
hostname.endsWith(".internal") ||
hostname.endsWith(".localhost")
) {
return true
}
return false
} catch {
return true // Invalid URL - block it
}
}
/**
* Whether private URLs are allowed (defaults to true)
* Set ALLOW_PRIVATE_URLS=false to block private URLs
*/
export const allowPrivateUrls = process.env.ALLOW_PRIVATE_URLS !== "false"