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From a98589711da5e9d935e8d690cfca92892e86d557 Mon Sep 17 00:00:00 2001
From: Roland Shoemaker <roland@golang.org>
Date: Wed, 9 Jun 2021 11:31:27 -0700
Subject: [PATCH] crypto/tls: test key type when casting
When casting the certificate public key in generateClientKeyExchange,
check the type is appropriate. This prevents a panic when a server
agrees to a RSA based key exchange, but then sends an ECDSA (or
other) certificate.
Fixes #47143
Fixes CVE-2021-34558
Thanks to Imre Rad for reporting this issue.
Change-Id: Iabccacca6052769a605cccefa1216a9f7b7f6aea
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1116723
Reviewed-by: Filippo Valsorda <valsorda@google.com>
Reviewed-by: Katie Hockman <katiehockman@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/334031
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Upstream-Status: Backport
https://github.com/golang/go/commit/a98589711da5e9d935e8d690cfca92892e86d557
CVE: CVE-2021-34558
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
src/crypto/tls/key_agreement.go | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
Index: go/src/crypto/tls/key_agreement.go
===================================================================
--- go.orig/src/crypto/tls/key_agreement.go
+++ go/src/crypto/tls/key_agreement.go
@@ -67,7 +67,11 @@ func (ka rsaKeyAgreement) generateClient
return nil, nil, err
}
- encrypted, err := rsa.EncryptPKCS1v15(config.rand(), cert.PublicKey.(*rsa.PublicKey), preMasterSecret)
+ rsaKey, ok := cert.PublicKey.(*rsa.PublicKey)
+ if !ok {
+ return nil, nil, errors.New("tls: server certificate contains incorrect key type for selected ciphersuite")
+ }
+ encrypted, err := rsa.EncryptPKCS1v15(config.rand(), rsaKey, preMasterSecret)
if err != nil {
return nil, nil, err
}
|
