2 files changed, 39 insertions, 0 deletions
diff --git a/src/net/mail/message.go b/src/net/mail/message.go
index 01290bc65b..571c95ddc9 100644
--- a/src/net/mail/message.go
+++ b/src/net/mail/message.go
@@ -234,6 +234,12 @@ func (a *Address) String() string {
 		return b.String()
 	}
 
+	// Text in an encoded-word in a display-name must not contain certain
+	// characters like quotes or parentheses (see RFC 2047 section 5.3).
+	// When this is the case encode the name using base64 encoding.
+	if strings.ContainsAny(a.Name, "\"#$%&'(),.:;<>@[]^`{|}~") {
+		return mime.BEncoding.Encode("utf-8", a.Name) + " " + s
+	}
 	return mime.QEncoding.Encode("utf-8", a.Name) + " " + s
 }
 
diff --git a/src/net/mail/message_test.go b/src/net/mail/message_test.go
index e05af6c6ba..9fd7923c34 100644
--- a/src/net/mail/message_test.go
+++ b/src/net/mail/message_test.go
@@ -499,6 +499,10 @@ func TestAddressFormatting(t *testing.T) {
 			&Address{Name: "Rob", Address: "@"},
 			`"Rob" <@>`,
 		},
+		{
+			&Address{Name: "Böb, Jacöb", Address: "bob@example.com"},
+			`=?utf-8?b?QsO2YiwgSmFjw7Zi?= <bob@example.com>`,
+		},
 	}
 	for _, test := range tests {
 		s := test.addr.String()
@@ -594,3 +598,32 @@ func TestAddressParsingAndFormatting(t *testing.T) {
 	}
 
 }
+
+func TestAddressFormattingAndParsing(t *testing.T) {
+	tests := []*Address{
+		&Address{Name: "@lïce", Address: "alice@example.com"},
+		&Address{Name: "Böb O'Connor", Address: "bob@example.com"},
+		&Address{Name: "???", Address: "bob@example.com"},
+		&Address{Name: "Böb ???", Address: "bob@example.com"},
+		&Address{Name: "Böb (Jacöb)", Address: "bob@example.com"},
+		&Address{Name: "à#$%&'(),.:;<>@[]^`{|}~'", Address: "bob@example.com"},
+		// https://golang.org/issue/11292
+		&Address{Name: "\"\\\x1f,\"", Address: "0@0"},
+		// https://golang.org/issue/12782
+		&Address{Name: "naé, mée", Address: "test.mail@gmail.com"},
+	}
+
+	for _, test := range tests {
+		parsed, err := ParseAddress(test.String())
+		if err != nil {
+			t.Errorf("ParseAddr(%q) error: %v", test.String(), err)
+			continue
+		}
+		if parsed.Name != test.Name {
+			t.Errorf("Parsed name = %q; want %q", parsed.Name, test.Name)
+		}
+		if parsed.Address != test.Address {
+			t.Errorf("Parsed address = %q; want %q", parsed.Address, test.Address)
+		}
+	}
+}