I'd like to access SSL certificate information from a Google Chrome extension.
I took a look at the APIs here: http://code.google.com/chrome/extensions/api_index.html, but didn't see anything that would get the job done.
Ideally I'd like to get access to Issuer, Validity Period, Subject, Serial Number, etc...
This seems to be possible in Mozilla/Firefox:
https://developer.mozilla.org/En/How_to_check_the_security_state_of_an_XMLHTTPRequest_over_SSL
You'll need to make a WebExtension, which is also called a browser extension.
See accessing security information on MDN
You can also check out the docs for:
You'll need Firefox 62.
Here's a working background.js
var log = console.log.bind(console)
log(`\n\nTLS browser extension loaded`)
// https://developer.chrome.com/extensions/match_patterns
var ALL_SITES = { urls: ['<all_urls>'] }
// Mozilla doesn't use tlsInfo in extraInfoSpec
var extraInfoSpec = ['blocking'];
// https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/webRequest/onHeadersReceived
browser.webRequest.onHeadersReceived.addListener(async function(details){
log(`\n\nGot a request for ${details.url} with ID ${details.requestId}`)
// Yeah this is a String, even though the content is a Number
var requestId = details.requestId
var securityInfo = await browser.webRequest.getSecurityInfo(requestId, {
certificateChain: true,
rawDER: false
});
log(`securityInfo: ${JSON.stringify(securityInfo, null, 2)}`)
}, ALL_SITES, extraInfoSpec)
log('Added listener')
manifest.json:
{
"manifest_version": 2,
"name": "Test extension",
"version": "1.0",
"description": "Test extension.",
"icons": {
"48": "icons/border-48.png"
},
"background": {
"scripts": ["background.js"]
},
"permissions": [
"webRequest",
"webRequestBlocking",
"<all_urls>"
]
}
It also may be implemented in Chromium once this code is merged.
It is currently not available, but there's the Chromium API proposal webRequest SSL Hooks (from 02/27/2012) which treats this topic.
You can use a NPAPI plugin to do that.
