unsubscribe: prevent decrypt from showing random crap

Wow, I don't know crypto at all.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/Unsubscribe.pm b/lib/PublicInbox/Unsubscribe.pm
index 4ccdb7e0..97ff97f6 100644
--- a/lib/PublicInbox/Unsubscribe.pm
+++ b/lib/PublicInbox/Unsubscribe.pm
@@ -77,7 +77,7 @@ sub _user_list_addr {
                         'Missing mailing list name in path component');
         }
         my $user = eval { $self->{cipher}->decrypt(decode_base64url($u)) };
-        if (!defined $user || $user eq '') {
+        if (!defined $user || index($user, '@') <= 1) {
                 my $err = quotemeta($@);
                 my $errors = $env->{'psgi.errors'};
                 $errors->print("error decrypting: $u\n");