Pass more information to interactive host key check.

Now we pass the whole set of fingerprints, and also a displayable
format for the full host public key.

NFC: this commit doesn't modify any of the host key prompts to _use_
any of the new information. That's coming next.

misc.c

@@ -378,8 +378,8 @@ void nullseat_update_specials_menu(Seat *seat) {}
 char *nullseat_get_ttymode(Seat *seat, const char *mode) { return NULL; }
 void nullseat_set_busy_status(Seat *seat, BusyStatus status) {}
 int nullseat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *key_fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **key_fingerprints,
     void (*callback)(void *ctx, int result), void *ctx) { return 0; }
 int nullseat_confirm_weak_crypto_primitive(
     Seat *seat, const char *algtype, const char *algname,

putty.h

@@ -972,8 +972,8 @@ struct SeatVtable {
      *    or +1'.
      */
     int (*verify_ssh_host_key)(
-        Seat *seat, const char *host, int port,
-        const char *keytype, char *keystr, char *key_fingerprint,
+        Seat *seat, const char *host, int port, const char *keytype,
+        char *keystr, const char *keydisp, char **key_fingerprints,
         void (*callback)(void *ctx, int result), void *ctx);
 
     /*
@@ -1095,8 +1095,9 @@ static inline void seat_set_busy_status(Seat *seat, BusyStatus status)
 { seat->vt->set_busy_status(seat, status); }
 static inline int seat_verify_ssh_host_key(
     Seat *seat, const char *h, int p, const char *ktyp, char *kstr,
-    char *fp, void (*cb)(void *ctx, int result), void *ctx)
-{ return seat->vt->verify_ssh_host_key(seat, h, p, ktyp, kstr, fp, cb, ctx); }
+    const char *kdsp, char **fps, void (*cb)(void *ctx, int result), void *ctx)
+{ return seat->vt->verify_ssh_host_key(seat, h, p, ktyp, kstr, kdsp, fps,
+                                       cb, ctx); }
 static inline int seat_confirm_weak_crypto_primitive(
     Seat *seat, const char *atyp, const char *aname,
     void (*cb)(void *ctx, int result), void *ctx)
@@ -1159,8 +1160,8 @@ void nullseat_update_specials_menu(Seat *seat);
 char *nullseat_get_ttymode(Seat *seat, const char *mode);
 void nullseat_set_busy_status(Seat *seat, BusyStatus status);
 int nullseat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *key_fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **key_fingerprints,
     void (*callback)(void *ctx, int result), void *ctx);
 int nullseat_confirm_weak_crypto_primitive(
     Seat *seat, const char *algtype, const char *algname,
@@ -1191,8 +1192,8 @@ bool nullseat_get_cursor_position(Seat *seat, int *x, int *y);
 
 void console_connection_fatal(Seat *seat, const char *message);
 int console_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *key_fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **key_fingerprints,
     void (*callback)(void *ctx, int result), void *ctx);
 int console_confirm_weak_crypto_primitive(
     Seat *seat, const char *algtype, const char *algname,

ssh1login.c

@@ -256,10 +256,11 @@ static void ssh1_login_process_queue(PacketProtocolLayer *ppl)
                             "configured list");
             return;
         } else if (s->dlgret < 0) { /* none configured; use standard handling */
+            char *keydisp = ssh1_pubkey_str(&s->hostkey);
             s->dlgret = seat_verify_ssh_host_key(
-                s->ppl.seat, s->savedhost, s->savedport,
-                "rsa", keystr, fingerprints[SSH_FPTYPE_DEFAULT],
-                ssh1_login_dialog_callback, s);
+                s->ppl.seat, s->savedhost, s->savedport, "rsa", keystr,
+                keydisp, fingerprints, ssh1_login_dialog_callback, s);
+            sfree(keydisp);
             ssh2_free_all_fingerprints(fingerprints);
             sfree(keystr);
 #ifdef FUZZING

ssh2kex-client.c

@@ -858,11 +858,13 @@ void ssh2kex_coroutine(struct ssh2_transport_state *s, bool *aborted)
                 *aborted = true;
                 return;
             } else if (s->dlgret < 0) { /* none configured; use standard handling */
+                ssh2_userkey uk = { .key = s->hkey, .comment = NULL };
+                char *keydisp = ssh2_pubkey_openssh_str(&uk);
                 s->dlgret = seat_verify_ssh_host_key(
                     s->ppl.seat, s->savedhost, s->savedport,
-                    ssh_key_cache_id(s->hkey), s->keystr,
-                    fingerprints[SSH_FPTYPE_DEFAULT],
-                    ssh2_transport_dialog_callback, s);
+                    ssh_key_cache_id(s->hkey), s->keystr, keydisp,
+                    fingerprints, ssh2_transport_dialog_callback, s);
+                sfree(keydisp);
                 ssh2_free_all_fingerprints(fingerprints);
 #ifdef FUZZING
                 s->dlgret = 1;
@@ -875,6 +877,7 @@ void ssh2kex_coroutine(struct ssh2_transport_state *s, bool *aborted)
                     return;
                 }
             }
+
             /*
              * Save this host key, to check against the one presented in
              * subsequent rekeys.

unix/gtkdlg.c

@@ -31,6 +31,7 @@
 #include "dialog.h"
 #include "tree234.h"
 #include "licence.h"
+#include "ssh.h"
 
 #if GTK_CHECK_VERSION(2,0,0)
 /* Decide which of GtkFileChooserDialog and GtkFileSelection to use */
@@ -3461,8 +3462,8 @@ static void verify_ssh_host_key_result_callback(void *vctx, int result)
 }
 
 int gtk_seat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **fingerprints,
     void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char absenttxt[] =
@@ -3513,7 +3514,11 @@ int gtk_seat_verify_ssh_host_key(
     if (ret == 0)                      /* success - key matched OK */
         return 1;
 
-    text = dupprintf((ret == 2 ? wrongtxt : absenttxt), keytype, fingerprint);
+    FingerprintType fptype_default =
+        ssh2_pick_default_fingerprint(fingerprints);
+
+    text = dupprintf((ret == 2 ? wrongtxt : absenttxt), keytype,
+                     fingerprints[fptype_default]);
 
     result_ctx = snew(struct verify_ssh_host_key_result_ctx);
     result_ctx->callback = callback;
@@ -3526,7 +3531,8 @@ int gtk_seat_verify_ssh_host_key(
 
     mainwin = GTK_WIDGET(gtk_seat_get_window(seat));
     msgbox = create_message_box(
-        mainwin, "PuTTY Security Alert", text, string_width(fingerprint), true,
+        mainwin, "PuTTY Security Alert", text,
+        string_width(fingerprints[fptype_default]), true,
         &buttons_hostkey, verify_ssh_host_key_result_callback, result_ctx);
     register_dialog(seat, DIALOG_SLOT_NETWORK_PROMPT, msgbox);
 

unix/unix.h

@@ -218,8 +218,8 @@ void logevent_dlg(eventlog_stuff *estuff, const char *string);
 int gtkdlg_askappend(Seat *seat, Filename *filename,
                      void (*callback)(void *ctx, int result), void *ctx);
 int gtk_seat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **fingerprints,
     void (*callback)(void *ctx, int result), void *ctx);
 int gtk_seat_confirm_weak_crypto_primitive(
     Seat *seat, const char *algtype, const char *algname,

unix/uxcons.c

@@ -103,8 +103,8 @@ static int block_and_read(int fd, void *buf, size_t len)
 }
 
 int console_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **fingerprints,
     void (*callback)(void *ctx, int result), void *ctx)
 {
     int ret;
@@ -132,7 +132,10 @@ int console_verify_ssh_host_key(
         prompt = hk_absentmsg_interactive_prompt;
     }
 
-    fprintf(stderr, common_fmt, keytype, fingerprint);
+    FingerprintType fptype_default =
+        ssh2_pick_default_fingerprint(fingerprints);
+
+    fprintf(stderr, common_fmt, keytype, fingerprints[fptype_default]);
     if (console_batch_mode) {
         fputs(console_abandoned_msg, stderr);
         return 0;

windows/wincons.c

@@ -33,8 +33,8 @@ void console_print_error_msg(const char *prefix, const char *msg)
 }
 
 int console_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **fingerprints,
     void (*callback)(void *ctx, int result), void *ctx)
 {
     int ret;
@@ -62,7 +62,10 @@ int console_verify_ssh_host_key(
         prompt = hk_absentmsg_interactive_prompt;
     }
 
-    fprintf(stderr, common_fmt, keytype, fingerprint);
+    FingerprintType fptype_default =
+        ssh2_pick_default_fingerprint(fingerprints);
+
+    fprintf(stderr, common_fmt, keytype, fingerprints[fptype_default]);
     if (console_batch_mode) {
         fputs(console_abandoned_msg, stderr);
         return 0;

windows/windlg.c

@@ -939,8 +939,8 @@ static INT_PTR CALLBACK HostKeyDialogProc(HWND hwnd, UINT msg,
 }
 
 int win_seat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **fingerprints,
     void (*callback)(void *ctx, int result), void *ctx)
 {
     int ret;
@@ -965,7 +965,8 @@ int win_seat_verify_ssh_host_key(
         struct hostkey_dialog_ctx ctx[1];
         ctx->keywords = keywords;
         ctx->values = values;
-        ctx->fingerprint = fingerprint;
+        ctx->fingerprint = fingerprints[
+            ssh2_pick_default_fingerprint(fingerprints)];
         ctx->iconid = (ret == 2 ? IDI_WARNING : IDI_QUESTION);
         ctx->helpctx = (ret == 2 ? WINHELP_CTX_errors_hostkey_changed :
                         WINHELP_CTX_errors_hostkey_absent);

windows/winstuff.h

@@ -218,8 +218,8 @@ int has_embedded_chm(void);            /* 1 = yes, 0 = no, -1 = N/A */
  * window.c can refer to them.
  */
 int win_seat_verify_ssh_host_key(
-    Seat *seat, const char *host, int port,
-    const char *keytype, char *keystr, char *key_fingerprint,
+    Seat *seat, const char *host, int port, const char *keytype,
+    char *keystr, const char *keydisp, char **key_fingerprints,
     void (*callback)(void *ctx, int result), void *ctx);
 int win_seat_confirm_weak_crypto_primitive(
     Seat *seat, const char *algtype, const char *algname,