From: Dr. Tobias Quathamer <toddy@debian.org>
Date: Sat, 19 Oct 2019 12:03:22 +0000 (+0200)
Subject: Fix CVE-2019-17596
X-Git-Tag: archive/raspbian/1.11.6-1+rpi1+deb10u3^2~1
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=4bf0804e28d0a93c10b941e890ea91878dd2c46d;p=golang-1.11.git

Fix CVE-2019-17596

Cherry-picked from upstream:
https://github.com/golang/go/commit/2017d88dbc096381d4f348d2fb08bfb3c2b7ed73

Gbp-Pq: Name 0008-Fix-CVE-2019-17596.patch
---

diff --git a/src/crypto/dsa/dsa.go b/src/crypto/dsa/dsa.go
index 575314b..2fc4f1f 100644
--- a/src/crypto/dsa/dsa.go
+++ b/src/crypto/dsa/dsa.go
@@ -279,6 +279,9 @@ func Verify(pub *PublicKey, hash []byte, r, s *big.Int) bool {
 	}
 
 	w := new(big.Int).ModInverse(s, pub.Q)
+	if w == nil {
+		return false
+	}
 
 	n := pub.Q.BitLen()
 	if n&7 != 0 {