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Fix exchange url injection - #104
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Exchange URLs in Web Bundles were constructed by string-concatenating baseURL with relative asset paths derived from on-disk filenames. Because ':' is a legal character in POSIX directory and filenames, an attacker placing a directory structure like 'static/https:/attacker.test/p.js' with an empty baseURL (the default) caused the plugin to add an exchange for 'https:/attacker.test/p.js'. Under WHATWG URL parsing rules, this normalizes to 'https://attacker.test/p.js', embedding an arbitrary foreign-origin exchange into the emitted (and developer-signed) bundle. This patch adds assertExchangeUrlOrigin(exchangeUrl, baseURL) to ensure: - Any exchange URL that parses as an absolute URL has its origin verified against baseURL. - If baseURL is empty or relative, absolute exchange URLs are rejected. - If baseURL is an absolute URL, the protocol, host, and port must match (supporting both standard web schemes and non-standard schemes like isolated-app:). - Relative exchange URLs remain allowed when baseURL is relative or empty. Unit tests are added across shared utilities, rollup plugin, and webpack plugin. Bug: https://b.corp.google.com/issues/530773137
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Validate exchange URL origin to prevent injection into signed bundles
Exchange URLs in Web Bundles were constructed by string-concatenating
baseURL with relative asset paths derived from on-disk filenames.
Because ':' is a legal character in POSIX directory and filenames, an
attacker placing a directory structure like 'static/https:/attacker.test/p.js'
with an empty baseURL (the default) caused the plugin to add an exchange
for 'https:/attacker.test/p.js'. Under WHATWG URL parsing rules, this
normalizes to 'https://attacker.test/p.js', embedding an arbitrary
foreign-origin exchange into the emitted (and developer-signed) bundle.
This patch adds assertExchangeUrlOrigin(exchangeUrl, baseURL) to ensure:
against baseURL.
(supporting both standard web schemes and non-standard schemes like
isolated-app:).
Unit tests are added across shared utilities, rollup plugin, and webpack plugin.
Bug: 530773137