crypto: fix builtin qcrypto_cipher_free

This was dereferencing a pointer before checking if it was NULL.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reported-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/crypto/cipher-builtin.c b/crypto/cipher-builtin.c
index c625cb40f7..912c1b947d 100644
--- a/crypto/cipher-builtin.c
+++ b/crypto/cipher-builtin.c
@@ -354,11 +354,13 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 
 void qcrypto_cipher_free(QCryptoCipher *cipher)
 {
-    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+    QCryptoCipherBuiltin *ctxt;
+
     if (!cipher) {
         return;
     }
 
+    ctxt = cipher->opaque;
     ctxt->free(cipher);
     g_free(cipher);
 }