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/**
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* Hachette injecting policy to page using webRequest
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*
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* Copyright (C) 2021 Wojtek Kosior
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* Copyright (C) 2021 jahoti
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* Redistribution terms are gathered in the `copyright' file.
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*/
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/*
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* IMPORTS_START
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* IMPORT sign_data
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* IMPORT extract_signed
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* IMPORT sanitize_csp_header
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* IMPORT csp_rule
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* IMPORT is_csp_header_name
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* IMPORTS_END
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*/
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function inject_csp_headers(headers, policy)
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{
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let csp_headers;
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let old_signature;
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let hachette_header;
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for (const header of headers.filter(h => h.name === "x-hachette")) {
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/* x-hachette header has format: <signature>_0_<data> */
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const match = /^([^_]+)_(0_.*)$/.exec(header.value);
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if (!match)
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continue;
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const result = extract_signed(...match.slice(1, 3));
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if (result.fail)
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continue;
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/* This should succeed - it's our self-produced valid JSON. */
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const old_data = JSON.parse(decodeURIComponent(result.data));
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/* Confirmed- it's the originals, smuggled in! */
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csp_headers = old_data.csp_headers;
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old_signature = old_data.policy_sig;
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hachette_header = header;
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break;
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}
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if (!hachette_header) {
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hachette_header = {name: "x-hachette"};
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headers.push(hachette_header);
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}
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csp_headers = csp_headers ||
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headers.filter(h => is_csp_header_name(h.name));
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/* When blocking remove report-only CSP headers that snitch on us. */
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headers = headers.filter(h => !is_csp_header_name(h.name, !policy.allow));
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if (old_signature)
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headers = headers.filter(h => h.value.search(old_signature) === -1);
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headers.push(...csp_headers.map(h => sanitize_csp_header(h, policy)));
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const policy_str = encodeURIComponent(JSON.stringify(policy));
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const signed_policy = sign_data(policy_str, new Date().getTime());
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const later_30sec = new Date(new Date().getTime() + 30000).toGMTString();
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headers.push({
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name: "Set-Cookie",
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value: `hachette-${signed_policy.join("=")}; Expires=${later_30sec};`
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});
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/*
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* Smuggle in the signature and the original CSP headers for future use.
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* These are signed with a time of 0, as it's not clear there is a limit on
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* how long Firefox might retain headers in the cache.
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*/
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let hachette_data = {csp_headers, policy_sig: signed_policy[0]};
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hachette_data = encodeURIComponent(JSON.stringify(hachette_data));
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hachette_header.value = sign_data(hachette_data, 0).join("_");
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/* To ensure there is a CSP header if required */
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if (!policy.allow)
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headers.push({
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name: "content-security-policy",
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value: csp_rule(policy.nonce)
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});
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return headers;
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}
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/*
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* EXPORTS_START
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* EXPORT inject_csp_headers
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* EXPORTS_END
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*/
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