New key component type KCT_BINARY.

This stores its data in the same format as the existing KCT_TEXT, but
it displays differently in puttygen --dump, expecting that the data
will be full of horrible control characters, invalid UTF-8, etc.

The displayed data is of the form b64("..."), so you get a hint about
what the encoding is, and can still paste into Python by defining the
identifier 'b64' to be base64.b64decode or equivalent.

cmdgen.c

@@ -1327,6 +1327,38 @@ int main(int argc, char **argv)
                 write_c_string_literal(fp, ptrlen_from_strbuf(comp->str));
                 fputs("\"\n", fp);
                 break;
+              case KCT_BINARY: {
+                /*
+                 * Display format for binary key components is to show
+                 * them as base64, with a wrapper so that the actual
+                 * printed string is along the lines of
+                 * 'b64("aGVsbG8sIHdvcmxkCg==")'.
+                 *
+                 * That's a compromise between not being too verbose
+                 * for a human reader, and still being reasonably
+                 * friendly to people pasting the output of this
+                 * 'puttygen --dump' option into Python code (which
+                 * the format is designed to permit in general).
+                 *
+                 * Python users pasting a dump containing one of these
+                 * will have to define a function 'b64' in advance
+                 * which takes a string, which you can do most easily
+                 * using this import statement, as seen in
+                 * cryptsuite.py:
+                 *
+                 * from base64 import b64decode as b64
+                 */
+                fputs("b64(\"", fp);
+                char b64[4];
+                for (size_t j = 0; j < comp->str->len; j += 3) {
+                    size_t len = comp->str->len - j;
+                    if (len > 3) len = 3;
+                    base64_encode_atom(comp->str->u + j, len, b64);
+                    fwrite(b64, 1, 4, fp);
+                }
+                fputs("\")\n", fp);
+                break;
+              }
               default:
                 unreachable("bad key component type");
             }

ssh.h

@@ -543,13 +543,13 @@ WeierstrassPoint *ecdsa_public(mp_int *private_key, const ssh_keyalg *alg);
 EdwardsPoint *eddsa_public(mp_int *private_key, const ssh_keyalg *alg);
 
 typedef enum KeyComponentType {
-    KCT_TEXT, KCT_MPINT
+    KCT_TEXT, KCT_BINARY, KCT_MPINT
 } KeyComponentType;
 typedef struct key_component {
     char *name;
     KeyComponentType type;
     union {
-        strbuf *str;                   /* used for KCT_TEXT */
+        strbuf *str;                   /* used for KCT_TEXT and KCT_BINARY */
         mp_int *mp;                    /* used for KCT_MPINT */
     };
 } key_component;
@@ -560,6 +560,8 @@ typedef struct key_components {
 key_components *key_components_new(void);
 void key_components_add_text(key_components *kc,
                              const char *name, const char *value);
+void key_components_add_binary(key_components *kc,
+                               const char *name, ptrlen value);
 void key_components_add_mp(key_components *kc,
                            const char *name, mp_int *value);
 void key_components_free(key_components *kc);

test/testcrypt.c

@@ -1231,7 +1231,8 @@ strbuf *key_components_nth_str(key_components *kc, size_t n)
 {
     if (n >= kc->ncomponents)
         return NULL;
-    if (kc->components[n].type != KCT_TEXT)
+    if (kc->components[n].type != KCT_TEXT &&
+        kc->components[n].type != KCT_BINARY)
         return NULL;
     return strbuf_dup(ptrlen_from_strbuf(kc->components[n].str));
 }

utils/key_components.c

@@ -10,14 +10,26 @@ key_components *key_components_new(void)
     return kc;
 }
 
-void key_components_add_text(key_components *kc,
-                             const char *name, const char *value)
+static void key_components_add_str(key_components *kc, const char *name,
+                                   KeyComponentType type, ptrlen data)
 {
     sgrowarray(kc->components, kc->componentsize, kc->ncomponents);
     size_t n = kc->ncomponents++;
     kc->components[n].name = dupstr(name);
-    kc->components[n].type = KCT_TEXT;
-    kc->components[n].str = strbuf_dup_nm(ptrlen_from_asciz(value));
+    kc->components[n].type = type;
+    kc->components[n].str = strbuf_dup_nm(data);
+}
+
+void key_components_add_text(key_components *kc,
+                             const char *name, const char *value)
+{
+    key_components_add_str(kc, name, KCT_TEXT, ptrlen_from_asciz(value));
+}
+
+void key_components_add_binary(key_components *kc,
+                               const char *name, ptrlen value)
+{
+    key_components_add_str(kc, name, KCT_BINARY, value);
 }
 
 void key_components_add_mp(key_components *kc,
@@ -40,6 +52,7 @@ void key_components_free(key_components *kc)
             mp_free(comp->mp);
             break;
           case KCT_TEXT:
+          case KCT_BINARY:
             strbuf_free(comp->str);
             break;
           default: