X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/222d54dc209210b6e43589c798e35e21273b4082..8f1612752a89ea821dbd63491aef858f7f7e5bef:/sshpubk.c?ds=sidebyside

diff --git a/sshpubk.c b/sshpubk.c
index 1659acec..dd06ebd5 100644
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -433,8 +433,7 @@ int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)
  *    data    "putty-private-key-file-mac-key"
  *    data    passphrase
  *
- * Encrypted keys should have a MAC, whereas unencrypted ones must
- * have a hash.
+ * (An empty passphrase is used for unencrypted keys.)
  *
  * If the key is encrypted, the encryption key is derived from the
  * passphrase by means of a succession of SHA-1 hashes. Each hash
@@ -784,7 +783,7 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
 
 	    SHA_Init(&s);
 	    SHA_Bytes(&s, header, sizeof(header)-1);
-	    if (passphrase)
+	    if (cipher && passphrase)
 		SHA_Bytes(&s, passphrase, passlen);
 	    SHA_Final(&s, mackey);
 
@@ -836,7 +835,8 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
     sfree(public_blob);
     sfree(private_blob);
     sfree(encryption);
-    *errorstr = NULL;
+    if (errorstr)
+	*errorstr = NULL;
     return ret;
 
     /*