tree 7d8e67694cfd94ef61dd6f0299acffe1d8a9309d
parent 7e71c9c3edbf5b7a8608d6f739c20420a618e0ab
author Katie Hockman <katie@golang.org> 1571085741 -0400
committer Katie Hockman <katie@golang.org> 1572985294 +0000

crypto/dsa: prevent bad public keys from causing panic

dsa.Verify might currently use a nil s inverse in a
multiplication if the public key contains a non-prime Q,
causing a panic. Change this to check that the mod
inverse exists before using it.

Fixes CVE-2019-17596

Fixes #34960

Change-Id: I94d5f3cc38f1b5d52d38dcb1d253c71b7fd1cae7
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/572809
Reviewed-by: Filippo Valsorda <valsorda@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/205441
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>