tree 205d54add175a3c5c90c80d786702ad2ec368a9e
parent 6c15c7cce718e1e9a47f4f0ab1bd70923b04557b
author Katie Hockman <katie@golang.org> 1571085741 -0400
committer Katie Hockman <katiehockman@google.com> 1571261087 +0000

[release-branch.go1.12-security] 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

Change-Id: I94d5f3cc38f1b5d52d38dcb1d253c71b7fd1cae7
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/572809
Reviewed-by: Filippo Valsorda <valsorda@google.com>
(cherry picked from commit 9119dfb0511326d4485b248b83d4fde19c95d0f7)
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/575232