crypto/tls: don't use CN in BuildNameToCertificate if SANs are present
Change-Id: I18d5b9fc392a6a52fbdd240254d6d9db838073a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/266540
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
diff --git a/src/crypto/tls/common.go b/src/crypto/tls/common.go
index 66d2c00..86dc0dd 100644
--- a/src/crypto/tls/common.go
+++ b/src/crypto/tls/common.go
@@ -1263,7 +1263,9 @@
if err != nil {
continue
}
- if len(x509Cert.Subject.CommonName) > 0 {
+ // If SANs are *not* present, some clients will consider the certificate
+ // valid for the name in the Common Name.
+ if x509Cert.Subject.CommonName != "" && len(x509Cert.DNSNames) == 0 {
c.NameToCertificate[x509Cert.Subject.CommonName] = cert
}
for _, san := range x509Cert.DNSNames {
