Introduce a sane interface function, from_backend(), for backends to

[u/mdw/putty] / scp.c

diff --git a/scp.c b/scp.c
index 53db80a..3c3369f 100644 (file)
--- a/scp.c
+++ b/scp.c
@@ -26,6 +26,8 @@
 
 #define PUTTY_DO_GLOBALS
 #include "putty.h"
+#include "winstuff.h"
+#include "storage.h"
 
 #define TIME_POSIX_TO_WIN(t, ft) (*(LONGLONG*)&(ft) = \
        ((LONGLONG) (t) + (LONGLONG) 11644473600) * (LONGLONG) 10000000)
@@ -72,13 +74,76 @@ static void send_char_msg(unsigned int msg_id, char c);
 static void send_str_msg(unsigned int msg_id, char *str);
 static void gui_update_stats(char *name, unsigned long size, int percentage, time_t elapsed);
 
-/*
- * These functions are needed to link with other modules, but
- * (should) never get called.
- */
 void begin_session(void) { }
-void write_clip (void *data, int len, int must_deselect) { }
-void term_deselect(void) { }
+void logevent(char *string) { }
+
+void verify_ssh_host_key(char *host, int port, char *keytype,
+                         char *keystr, char *fingerprint) {
+    int ret;
+
+    static const char absentmsg[] =
+        "The server's host key is not cached in the registry. You\n"
+        "have no guarantee that the server is the computer you\n"
+        "think it is.\n"
+        "The server's key fingerprint is:\n"
+        "%s\n"
+        "If you trust this host, enter \"y\" to add the key to\n"
+        "PuTTY's cache and carry on connecting.\n"
+        "If you do not trust this host, enter \"n\" to abandon the\n"
+        "connection.\n"
+        "Continue connecting? (y/n) ";
+
+    static const char wrongmsg[] =
+        "WARNING - POTENTIAL SECURITY BREACH!\n"
+        "The server's host key does not match the one PuTTY has\n"
+        "cached in the registry. This means that either the\n"
+        "server administrator has changed the host key, or you\n"
+        "have actually connected to another computer pretending\n"
+        "to be the server.\n"
+        "The new key fingerprint is:\n"
+        "%s\n"
+        "If you were expecting this change and trust the new key,\n"
+        "enter Yes to update PuTTY's cache and continue connecting.\n"
+        "If you want to carry on connecting but without updating\n"
+        "the cache, enter No.\n"
+        "If you want to abandon the connection completely, press\n"
+        "Return to cancel. Pressing Return is the ONLY guaranteed\n"
+        "safe choice.\n"
+        "Update cached key? (y/n, Return cancels connection) ";
+
+    static const char abandoned[] = "Connection abandoned.\n";
+
+    char line[32];
+
+    /*
+     * Verify the key against the registry.
+     */
+    ret = verify_host_key(host, port, keytype, keystr);
+
+    if (ret == 0)                      /* success - key matched OK */
+        return;
+    if (ret == 2) {                    /* key was different */
+        fprintf(stderr, wrongmsg, fingerprint);
+        if (fgets(line, sizeof(line), stdin) &&
+            line[0] != '\0' && line[0] != '\n') {
+            if (line[0] == 'y' || line[0] == 'Y')
+                store_host_key(host, port, keytype, keystr);
+        } else {
+            fprintf(stderr, abandoned);
+            exit(0);
+        }
+    }
+    if (ret == 1) {                    /* key was absent */
+        fprintf(stderr, absentmsg, fingerprint);
+        if (fgets(line, sizeof(line), stdin) &&
+            (line[0] == 'y' || line[0] == 'Y'))
+            store_host_key(host, port, keytype, keystr);
+        else {
+            fprintf(stderr, abandoned);
+            exit(0);
+        }
+    }
+}
 
 /* GUI Adaptation - Sept 2000 */
 static void send_msg(HWND h, UINT message, WPARAM wParam)
@@ -181,20 +246,25 @@ void connection_fatal(char *fmt, ...)
  * is available.
  *
  * To do this, we repeatedly call the SSH protocol module, with our
- * own trap in term_out() to catch the data that comes back. We do
- * this until we have enough data.
+ * own trap in from_backend() to catch the data that comes back. We
+ * do this until we have enough data.
  */
 static unsigned char *outptr;          /* where to put the data */
 static unsigned outlen;                /* how much data required */
 static unsigned char *pending = NULL;  /* any spare data */
 static unsigned pendlen=0, pendsize=0; /* length and phys. size of buffer */
-void term_out(void) {
+void from_backend(int is_stderr, char *data, int datalen) {
+    unsigned char *p = (unsigned char *)data;
+    unsigned len = (unsigned)datalen;
+
     /*
-     * Here we must deal with a block of data, in `inbuf', size
-     * `inbuf_head'.
+     * stderr data is just spouted to local stderr and otherwise
+     * ignored.
      */
-    unsigned char *p = inbuf;
-    unsigned len = inbuf_head;
+    if (is_stderr) {
+       fwrite(data, 1, len, stderr);
+       return;
+    }
 
     inbuf_head = 0;
 
@@ -264,7 +334,6 @@ static int ssh_scp_recv(unsigned char *buf, int len) {
         if (select(1, &readfds, NULL, NULL, NULL) < 0)
             return 0;                  /* doom */
         back->msg(0, FD_READ);
-        term_out();
     }
 
     return len;
@@ -286,7 +355,6 @@ static void ssh_scp_init(void) {
         if (select(1, &readfds, NULL, NULL, NULL) < 0)
             return;                    /* doom */
         back->msg(0, FD_READ);
-        term_out();
     }
 }
 
@@ -368,7 +436,7 @@ static void do_cmd(char *host, char *user, char *cmd)
        bump("Empty host name");
 
     /* Try to load settings for this host */
-    do_defaults(host);
+    do_defaults(host, &cfg);
     if (cfg.host[0] == '\0') {
        /* No settings for this host; use defaults */
        strncpy(cfg.host, host, sizeof(cfg.host)-1);