From 6e80d3f130773fc9a9123c5c4c2e97d63e90fa2a Mon Sep 17 00:00:00 2001 From: hackademix Date: Sun, 26 Aug 2018 17:43:01 +0200 Subject: Let content script inject failsafe CSP in the DOM. --- src/content/DocumentCSP.js | 26 ++++++++++++++++++++++++++ src/content/content.js | 11 +++++++++-- 2 files changed, 35 insertions(+), 2 deletions(-) create mode 100644 src/content/DocumentCSP.js (limited to 'src/content') diff --git a/src/content/DocumentCSP.js b/src/content/DocumentCSP.js new file mode 100644 index 0000000..228b2a2 --- /dev/null +++ b/src/content/DocumentCSP.js @@ -0,0 +1,26 @@ +'use strict'; + +class DocumentCSP { + constructor(document) { + this.document = document; + this.builder = new CapsCSP(); + } + + apply(capabilities) { + let csp = this.builder; + let blocker = csp.buildFromCapabilities(capabilities); + if (!blocker) return; + + let document = this.document; + let header = csp.asHeader(blocker); + let meta = document.createElementNS("http://www.w3.org/1999/xhtml", "meta"); + meta.setAttribute("http-equiv", header.name); + meta.setAttribute("content", header.value); + let parent = document.head || document.documentElement; + try { + parent.insertBefore(meta, parent.firstChild); + } catch (e) { + error(e, "Error inserting CSP %s in the DOM", header && header.value); + } + } +} diff --git a/src/content/content.js b/src/content/content.js index 8ab3654..a5d996d 100644 --- a/src/content/content.js +++ b/src/content/content.js @@ -61,14 +61,21 @@ if (!this.perms.DEFAULT || this.perms.tabInfo.unrestricted) { this.allows = () => true; + this.capabilities = Object.assign( + new Set(["script"]), { has() { return true; } }); + } else { + let perms = this.perms.CURRENT || this.perms.DEFAULT; + this.capabilities = new Set(perms.capabilities); + new DocumentCSP(document).apply(this.capabilities); } ns.fire("perms"); }, perms: { DEFAULT: null, CURRENT: null, tabInfo: {}, MARKER: "" }, + allows(cap) { - let perms = this.perms.CURRENT; - return perms && perms.capabilities.includes(cap); + return this.capabilities && this.capabilities.has(cap); }, + getWindowName() { return top !== window || !this.perms.MARKER ? window.name : window.name.split(this.perms.MARKER + ",").pop(); -- cgit v1.2.3