From 24444eb396759b24f35dc9d2382a249dd9211990 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Sun, 22 Nov 2020 08:40:38 +0000
Subject: [PATCH] Expose a global list of known host key algorithms.

The information was already centralised in find_pubkey_alg, but that
had a query-based API that couldn't enumerate the key types. Now I
expose an underlying array so that it's possible to iterate over them.

Also, I'd forgotten to add the two new rsa-sha2-* algorithms to
find_pubkey_alg. That's also done as part of this commit.
---
 ssh.h     |  2 ++
 sshpubk.c | 34 ++++++++++++++++++----------------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/ssh.h b/ssh.h
index 1cdfe3b8..fe9eb394 100644
--- a/ssh.h
+++ b/ssh.h
@@ -1230,6 +1230,8 @@ int rsa1_loadpub_s(BinarySource *src, BinarySink *bs,
 int rsa1_loadpub_f(const Filename *filename, BinarySink *bs,
                    char **commentptr, const char **errorstr);
 
+extern const ssh_keyalg *const all_keyalgs[];
+extern const size_t n_keyalgs;
 const ssh_keyalg *find_pubkey_alg(const char *name);
 const ssh_keyalg *find_pubkey_alg_len(ptrlen name);
 
diff --git a/sshpubk.c b/sshpubk.c
index 4675eec1..b8d7ffb2 100644
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -634,24 +634,26 @@ static bool read_blob(BinarySource *src, int nlines, BinarySink *bs)
  */
 ssh2_userkey ssh2_wrong_passphrase = { NULL, NULL };
 
+const ssh_keyalg *const all_keyalgs[] = {
+    &ssh_rsa,
+    &ssh_rsa_sha256,
+    &ssh_rsa_sha512,
+    &ssh_dss,
+    &ssh_ecdsa_nistp256,
+    &ssh_ecdsa_nistp384,
+    &ssh_ecdsa_nistp521,
+    &ssh_ecdsa_ed25519,
+    &ssh_ecdsa_ed448,
+};
+const size_t n_keyalgs = lenof(all_keyalgs);
+
 const ssh_keyalg *find_pubkey_alg_len(ptrlen name)
 {
-    if (ptrlen_eq_string(name, "ssh-rsa"))
-        return &ssh_rsa;
-    else if (ptrlen_eq_string(name, "ssh-dss"))
-        return &ssh_dss;
-    else if (ptrlen_eq_string(name, "ecdsa-sha2-nistp256"))
-        return &ssh_ecdsa_nistp256;
-    else if (ptrlen_eq_string(name, "ecdsa-sha2-nistp384"))
-        return &ssh_ecdsa_nistp384;
-    else if (ptrlen_eq_string(name, "ecdsa-sha2-nistp521"))
-        return &ssh_ecdsa_nistp521;
-    else if (ptrlen_eq_string(name, "ssh-ed25519"))
-        return &ssh_ecdsa_ed25519;
-    else if (ptrlen_eq_string(name, "ssh-ed448"))
-        return &ssh_ecdsa_ed448;
-    else
-        return NULL;
+    for (size_t i = 0; i < n_keyalgs; i++)
+        if (ptrlen_eq_string(name, all_keyalgs[i]->ssh_id))
+            return all_keyalgs[i];
+
+    return NULL;
 }
 
 const ssh_keyalg *find_pubkey_alg(const char *name)