Give a better error message if a PuTTY private key file has a version

number we don't understand. It's nicer to report 'format too new' than
'not a PuTTY key file'.

git-svn-id: svn://svn.tartarus.org/sgt/putty@9763 cda61777-01e9-0310-a592-d414129be87e

diff --git a/cmdgen.c b/cmdgen.c
index 254ae6a..33662c3 100644 (file)
--- a/cmdgen.c
+++ b/cmdgen.c
@@ -779,11 +779,13 @@ int main(int argc, char **argv)
            if (!load_encrypted) {
                ssh2blob = ssh2_userkey_loadpub(infilename, &ssh2alg,
                                                &ssh2bloblen, NULL, &error);
-               ssh2algf = find_pubkey_alg(ssh2alg);
-               if (ssh2algf)
-                   bits = ssh2algf->pubkey_bits(ssh2blob, ssh2bloblen);
-               else
-                   bits = -1;
+                if (ssh2blob) {
+                    ssh2algf = find_pubkey_alg(ssh2alg);
+                    if (ssh2algf)
+                        bits = ssh2algf->pubkey_bits(ssh2blob, ssh2bloblen);
+                    else
+                        bits = -1;
+                }
            } else {
                ssh2key = ssh2_load_userkey(infilename, passphrase, &error);
            }

diff --git a/sshpubk.c b/sshpubk.c
index c29d8a5..76aa343 100644 (file)
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -647,6 +647,11 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
        /* this is an old key file; warn and then continue */
        old_keyfile_warning();
        old_fmt = 1;
+    } else if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) {
+       /* this is a key file FROM THE FUTURE; refuse it, but with a
+         * more specific error message than the generic one below */
+       error = "PuTTY key format too new";
+       goto error;
     } else {
        error = "not a PuTTY SSH-2 private key";
        goto error;
@@ -891,7 +896,10 @@ unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
     if (!read_header(fp, header)
        || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
            0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
-       error = "not a PuTTY SSH-2 private key";
+        if (0 == strncmp(header, "PuTTY-User-Key-File-", 20))
+            error = "PuTTY key format too new";
+        else
+            error = "not a PuTTY SSH-2 private key";
        goto error;
     }
     error = "file format error";