Oct 9, 2013

Android has never supported revocation checking.

On all platforms that perform revocation checks as a system-level component (eg: on Windows and OS X), we always pass flags to allow cached revocation checks. That is, if another application has caused a revoked certificate to be known, we (Chrome) will treat it as revoked. Additionally, we pass flags to disable online revocation checks. However, in certain circumstances, the OS will ignore those flags and force an online revocation check. In those cases as well, the revocation will be picked up.

Absent both of those cached settings, however, we utilize CRLSets, the contents of which are described at a previous link and, by design, do not contain *every* revoked certificate.

It will also check the revocation of the certificate with OCSP, but currently only if the server provides OCSP stapling (for deeper checks see ocsp_resolver method).

I would encourage you to re-think the Issuer+SerialNumber being the only blocking mechanism. Both CRLSets and Microsoft's Certificate Distrust Lists have found that in the real world of revocations (most notably, DigiNotar), issuer+serial number is NOT sufficient. There are times where you want Subject+Public Key, as a given Subject+PublicKey may have many issuers, some of which the affected CA does not disclose.

> For Chrome, AIUI you already aim to have your CRLSets cover all EV certs, so why demand OCSP Stapling for EV as well?

>

This is not correct, and something we have repeatedly clarified. CRLSets first and foremost has been a means to deal with emergency revocations outside of the binary updates, such as those employed by Firefox, or system updates, such as those employed by Microsoft (prior to certificate distrust lists, which operate comparably) or Apple. Our commitment is to rapid response, and the focus here is on intermediates and certificates with powerful/dangerous capabilities that put a broad base of users at risk.

In the course of developing this, we saw an opportunity to optimize some of the CRL delivery for end-entity certs, but this was merely opportunistic. While we still employ it, especially for CAs that can provide meaningful revocation information, this is a "nice to have", and may be removed in the future. While I'm sure this would kick off a centithread alone, I don't think we should focus on this.

--crlfile <file>

(HTTPS/FTPS) Provide a file using PEM format with a Certificate Revocation List that may specify peer certificates that are to be considered revoked.

Schannel will run CRL checks on certificates unless peer verification is disabled. Secure Transport on iOS will run OCSP checks on certificates unless peer verification is disabled. Secure Transport on OS X will run either OCSP or CRL checks on certificates if those features are enabled, and this behavior can be adjusted in the preferences of Keychain Access.

証明書の失効情報を得るにはなぜか総務大臣の認可が必要だそうなので証明書の検証が必要な場合は面倒ですが申請するしかないですね。

問題の発端となったのは、グローバルサインが10月7日に発行した証明書失効リスト(CRL)。CRLは有効期限が過ぎた証明書を失効させるためのリストなのだが、その中に含まれていたクロスルート証明書と同じ公開鍵、同じサブジェクトネームを持つルート証明書が存在し、「より最近の有効期間開始日を持つクロスルート証明書について、元のルート証明書(R1)に対する置き換えであるとみなしてしまうような実装がされていた」たためにそのルート証明書が失効扱いとなり、このルート証明書に依存する中間CA証明書がすべて無効となってしまったという。

10月7日時点では問題は発生していなかったのだが、10月13日に証明書失効情報を提供するためのOnline Certificate Status Protocol(OCSP)で使われるデータベースが更新され、10月7日に発行されたCRLの情報を取り込んだために問題が発覚した模様。