fix(examples): stop sign-in redirecting shoppers to other sites - #641
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…n-in The sign-in actions redirected to whatever returnUrl the query string carried, so a link to /login?returnUrl=https://attacker.example sent a shopper off site straight after a real sign-in. Each example now falls back to its home page unless returnUrl is a path on the same origin, including after dot segments resolve (/.//host becomes //host). Closes #640 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Closes #640.
What was wrong
After sign-in, the example storefronts redirected shoppers to whatever
returnUrlthe login link carried. A link such as/login?returnUrl=https://attacker.exampleshowed the real login page, then sent the shopper to another site straight after a real sign-in. That is an open redirect, a common way to make phishing look legitimate.What changed
Each affected example gets a small
safeReturnPath(returnUrl, fallback)insrc/lib/return-url.ts. Its sign-in action now uses it. The function returnsreturnUrlonly if it is a path on the same site. Anything else goes to the example's home page.It also rejects values that start with
/but still leave the site, such as//attacker.exampleand/.//attacker.example. In the second case, the URL parser resolves the dot segment into//attacker.example.This fixes 12 redirects in 11 examples:
core(password and OIDC sign-in),algolia,analytics-integration,commerce-essentials,next-account-checkout,payments,payments-paypal-express,pdf-viewer,recommendations,shopper-accounts-authenticationandsimple. The guard matches the one already inexamples/commerce-extensions-saved-list, which was reviewed and fuzz-tested in #539.How it was checked
tsc --noEmitis clean in 10 of the 11 examples.next-account-checkouthas 4 type errors, andmainhas the same 4. None are in the changed files.