Utility function ssh_key_clone().

This makes a second independent copy of an existing ssh_key, for
situations where one piece of code is going to want to keep it after
its current owner frees it.

In order to have it work on an arbitrary ssh_key, whether public-only
or a full public+private key pair, I've had to add an ssh_key query
method to ask whether a private key is known. I'm surprised I haven't
found a need for that before! But I suppose in most situations in an
SSH client you statically know which kind of key you're dealing with.

1 files changed, 6 insertions, 0 deletions

diff --git a/ssh.h b/ssh.h
index 3bd90dfc..b703945f 100644
--- a/ssh.h
+++ b/ssh.h
@@ -841,6 +841,7 @@ struct ssh_keyalg {
     void (*public_blob)(ssh_key *key, BinarySink *);
     void (*private_blob)(ssh_key *key, BinarySink *);
     void (*openssh_blob) (ssh_key *key, BinarySink *);
+    bool (*has_private) (ssh_key *key);
     char *(*cache_str) (ssh_key *key);
     key_components *(*components) (ssh_key *key);
 
@@ -878,6 +879,8 @@ static inline void ssh_key_private_blob(ssh_key *key, BinarySink *bs)
 { key->vt->private_blob(key, bs); }
 static inline void ssh_key_openssh_blob(ssh_key *key, BinarySink *bs)
 { key->vt->openssh_blob(key, bs); }
+static inline bool ssh_key_has_private(ssh_key *key)
+{ return key->vt->has_private(key); }
 static inline char *ssh_key_cache_str(ssh_key *key)
 { return key->vt->cache_str(key); }
 static inline key_components *ssh_key_components(ssh_key *key)
@@ -902,6 +905,9 @@ static inline const char *ssh_keyalg_alternate_ssh_id(
 unsigned nullkey_supported_flags(const ssh_keyalg *self);
 const char *nullkey_alternate_ssh_id(const ssh_keyalg *self, unsigned flags);
 
+/* Utility functions implemented centrally */
+ssh_key *ssh_key_clone(ssh_key *key);
+
 /*
  * SSH2 ECDH key exchange vtable
  */