| commit | 2017d88dbc096381d4f348d2fb08bfb3c2b7ed73 | [log] [tgz] |
|---|---|---|
| author | Katie Hockman <katie@golang.org> | Mon Oct 14 16:42:21 2019 -0400 |
| committer | Katie Hockman <katiehockman@google.com> | Wed Oct 16 21:24:47 2019 +0000 |
| tree | 205d54add175a3c5c90c80d786702ad2ec368a9e | |
| parent | 6c15c7cce718e1e9a47f4f0ab1bd70923b04557b [diff] |
[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
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 @@ } w := new(big.Int).ModInverse(s, pub.Q) + if w == nil { + return false + } n := pub.Q.BitLen() if n&7 != 0 {