Add API for getting all of a key's fingerprints.

ssh2_all_fingerprints() and friends will return a small 'char **'
array, containing all the fingerprints of a key that we know how to
generate, indexed by the FingerprintType enum. The result requires
complex freeing, so there's an ssh2_free_all_fingerprints as well.

For SSH-1 RSA keys, we refuse to generate any fingerprint except the
old SSH-1 MD5 version, because there's no other fingerprint type I
know of that anyone else uses. So I've got a function that returns the
same 'char **' for an SSH-1 key, but it only fills in the MD5 slot,
and leaves the rest NULL.

As a result, I also need a dynamic function that takes a fingerprint
list and returns the id of the most preferred fingerprint type in it
_that actually exists_.

NFC: this API is introduced, but not yet used.

1 files changed, 8 insertions, 0 deletions

diff --git a/ssh.h b/ssh.h
index 378dcb90..acffbe32 100644
--- a/ssh.h
+++ b/ssh.h
@@ -567,6 +567,7 @@ mp_int *rsa_ssh1_decrypt(mp_int *input, RSAKey *key);
 bool rsa_ssh1_decrypt_pkcs1(mp_int *input, RSAKey *key, strbuf *outbuf);
 char *rsastr_fmt(RSAKey *key);
 char *rsa_ssh1_fingerprint(RSAKey *key);
+char **rsa_ssh1_fake_all_fingerprints(RSAKey *key);
 bool rsa_verify(RSAKey *key);
 void rsa_ssh1_public_blob(BinarySink *bs, RSAKey *key, RsaSsh1Order order);
 int rsa_ssh1_public_blob_len(ptrlen data);
@@ -1337,6 +1338,10 @@ typedef enum {
 #define SSH_FPTYPE_DEFAULT SSH_FPTYPE_MD5
 #define SSH_N_FPTYPES (SSH_FPTYPE_SHA256 + 1)
 
+FingerprintType ssh2_pick_fingerprint(char **fingerprints,
+                                      FingerprintType preferred_type);
+FingerprintType ssh2_pick_default_fingerprint(char **fingerprints);
+
 char *ssh1_pubkey_str(RSAKey *ssh1key);
 void ssh1_write_pubkey(FILE *fp, RSAKey *ssh1key);
 char *ssh2_pubkey_openssh_str(ssh2_userkey *key);
@@ -1345,6 +1350,9 @@ void ssh2_write_pubkey(FILE *fp, const char *comment,
                        int keytype);
 char *ssh2_fingerprint_blob(ptrlen, FingerprintType);
 char *ssh2_fingerprint(ssh_key *key, FingerprintType);
+char **ssh2_all_fingerprints_for_blob(ptrlen);
+char **ssh2_all_fingerprints(ssh_key *key);
+void ssh2_free_all_fingerprints(char **);
 int key_type(const Filename *filename);
 int key_type_s(BinarySource *src);
 const char *key_type_to_str(int type);