Fix cornercase crash in weird pdfsig setups

This fixes a potential crash in setups where at least one cryptographic
signature backend is compiled in, but none is functional.

1 files changed, 7 insertions, 1 deletions

diff --git a/utils/pdfsig.cc b/utils/pdfsig.cc
index b78169d8..0baf0d09 100644
--- a/utils/pdfsig.cc
+++ b/utils/pdfsig.cc
@@ -202,7 +202,13 @@ static std::vector<std::unique_ptr<X509CertificateInfo>> getAvailableSigningCert
         }
     };
     NSSSignatureConfiguration::setNSSPasswordCallback(passwordCallback);
-    std::vector<std::unique_ptr<X509CertificateInfo>> vCerts = CryptoSign::Factory::createActive()->getAvailableSigningCertificates();
+    auto backend = CryptoSign::Factory::createActive();
+    if (!backend) {
+        *error = true;
+        printf("No backends for cryptographic signatures available");
+        return {};
+    }
+    std::vector<std::unique_ptr<X509CertificateInfo>> vCerts = backend->getAvailableSigningCertificates();
     NSSSignatureConfiguration::setNSSPasswordCallback({});
     if (passwordNeeded) {
         *error = true;