tree 49be0108054034a92c417ee51ca22aa3a6260391
parent ace25f82df0a27eb26a518e1883eb56c1bec6c5e
author Filippo Valsorda <filippo@golang.org> 1579635915 -0500
committer Filippo Valsorda <filippo@golang.org> 1579818685 +0000

crypto/x509: mitigate CVE-2020-0601 verification bypass on Windows

An attacker can trick the Windows system verifier to use a poisoned set
of elliptic curve parameters for a trusted root, allowing it to generate
spoofed signatures. When this happens, the returned chain will present
the unmodified original root, so the actual signatures won't verify (as
they are invalid for the correct parameters). Simply double check them
as a safety measure and mitigation.

Windows users should still install the system security patch ASAP.

This is the same mitigation adopted by Chromium:

https://chromium-review.googlesource.com/c/chromium/src/+/1994434

Change-Id: I2c734f6fb2cb51d906c7fd77034318ffeeb3e146
Reviewed-on: https://go-review.googlesource.com/c/go/+/215905
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ryan Sleevi <sleevi@google.com>
Reviewed-by: Katie Hockman <katie@golang.org>