Revamp SSH authentication code so that user interaction is more

[u/mdw/putty] / unix / uxcons.c

diff --git a/unix/uxcons.c b/unix/uxcons.c
index 7f05d1f..d4848a6 100644 (file)
--- a/unix/uxcons.c
+++ b/unix/uxcons.c
@@ -47,8 +47,9 @@ void timer_change_notify(long next)
 {
 }
 
-void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
-                        char *keystr, char *fingerprint)
+int verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
+                        char *keystr, char *fingerprint,
+                        void (*callback)(void *ctx, int result), void *ctx)
 {
     int ret;
 
@@ -107,12 +108,12 @@ void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
     ret = verify_host_key(host, port, keytype, keystr);
 
     if (ret == 0)                     /* success - key matched OK */
-       return;
+       return 1;
 
     if (ret == 2) {                   /* key was different */
        if (console_batch_mode) {
            fprintf(stderr, wrongmsg_batch, keytype, fingerprint);
-           cleanup_exit(1);
+           return 0;
        }
        fprintf(stderr, wrongmsg, keytype, fingerprint);
        fflush(stderr);
@@ -120,7 +121,7 @@ void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
     if (ret == 1) {                   /* key was absent */
        if (console_batch_mode) {
            fprintf(stderr, absentmsg_batch, keytype, fingerprint);
-           cleanup_exit(1);
+           return 0;
        }
        fprintf(stderr, absentmsg, keytype, fingerprint);
        fflush(stderr);
@@ -140,9 +141,10 @@ void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
     if (line[0] != '\0' && line[0] != '\r' && line[0] != '\n') {
        if (line[0] == 'y' || line[0] == 'Y')
            store_host_key(host, port, keytype, keystr);
+        return 1;
     } else {
        fprintf(stderr, abandoned);
-       cleanup_exit(0);
+        return 0;
     }
 }
 
@@ -150,7 +152,8 @@ void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
  * Ask whether the selected algorithm is acceptable (since it was
  * below the configured 'warn' threshold).
  */
-void askalg(void *frontend, const char *algtype, const char *algname)
+int askalg(void *frontend, const char *algtype, const char *algname,
+          void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msg[] =
        "The first %s supported by the server is\n"
@@ -166,7 +169,7 @@ void askalg(void *frontend, const char *algtype, const char *algname)
 
     if (console_batch_mode) {
        fprintf(stderr, msg_batch, algtype, algname);
-       cleanup_exit(1);
+       return 0;
     }
 
     fprintf(stderr, msg, algtype, algname);
@@ -184,10 +187,10 @@ void askalg(void *frontend, const char *algtype, const char *algname)
     }
 
     if (line[0] == 'y' || line[0] == 'Y') {
-       return;
+       return 1;
     } else {
        fprintf(stderr, abandoned);
-       cleanup_exit(0);
+       return 0;
     }
 }
 
@@ -195,7 +198,8 @@ void askalg(void *frontend, const char *algtype, const char *algname)
  * Ask whether to wipe a session log file before writing to it.
  * Returns 2 for wipe, 1 for append, 0 for cancel (don't log).
  */
-int askappend(void *frontend, Filename filename)
+int askappend(void *frontend, Filename filename,
+             void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msgtemplate[] =
        "The session log file \"%.*s\" already exists.\n"
@@ -252,7 +256,7 @@ int askappend(void *frontend, Filename filename)
 void old_keyfile_warning(void)
 {
     static const char message[] =
-       "You are loading an SSH 2 private key which has an\n"
+       "You are loading an SSH-2 private key which has an\n"
        "old version of the file format. This means your key\n"
        "file is not fully tamperproof. Future versions of\n"
        "PuTTY may stop supporting this private key format,\n"
@@ -276,41 +280,81 @@ void logevent(void *frontend, const char *string)
        log_eventlog(console_logctx, string);
 }
 
-int console_get_line(const char *prompt, char *str,
-                    int maxlen, int is_pw)
+static void console_data_untrusted(const char *data, int len)
 {
-    struct termios oldmode, newmode;
     int i;
+    for (i = 0; i < len; i++)
+       if ((data[i] & 0x60) || (data[i] == '\n'))
+           fputc(data[i], stdout);
+    fflush(stdout);
+}
 
-    if (console_batch_mode) {
-       if (maxlen > 0)
-           str[0] = '\0';
+int console_get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
+{
+    size_t curr_prompt;
+
+    /*
+     * Zero all the results, in case we abort half-way through.
+     */
+    {
+       int i;
+       for (i = 0; i < p->n_prompts; i++)
+           memset(p->prompts[i]->result, 0, p->prompts[i]->result_len);
+    }
+
+    if (console_batch_mode)
        return 0;
-    } else {
+
+    /*
+     * Preamble.
+     */
+    /* We only print the `name' caption if we have to... */
+    if (p->name_reqd && p->name) {
+       size_t l = strlen(p->name);
+       console_data_untrusted(p->name, l);
+       if (p->name[l-1] != '\n')
+           console_data_untrusted("\n", 1);
+    }
+    /* ...but we always print any `instruction'. */
+    if (p->instruction) {
+       size_t l = strlen(p->instruction);
+       console_data_untrusted(p->instruction, l);
+       if (p->instruction[l-1] != '\n')
+           console_data_untrusted("\n", 1);
+    }
+
+    for (curr_prompt = 0; curr_prompt < p->n_prompts; curr_prompt++) {
+
+       struct termios oldmode, newmode;
+       int i;
+       prompt_t *pr = p->prompts[curr_prompt];
+
        tcgetattr(0, &oldmode);
        newmode = oldmode;
        newmode.c_lflag |= ISIG | ICANON;
-       if (is_pw)
+       if (!pr->echo)
            newmode.c_lflag &= ~ECHO;
        else
            newmode.c_lflag |= ECHO;
        tcsetattr(0, TCSANOW, &newmode);
 
-       fputs(prompt, stdout);
-       fflush(stdout);
-       i = read(0, str, maxlen - 1);
+       console_data_untrusted(pr->prompt, strlen(pr->prompt));
+
+       i = read(0, pr->result, pr->result_len - 1);
 
        tcsetattr(0, TCSANOW, &oldmode);
 
-       if (i > 0 && str[i-1] == '\n')
+       if (i > 0 && pr->result[i-1] == '\n')
            i--;
-       str[i] = '\0';
+       pr->result[i] = '\0';
 
-       if (is_pw)
+       if (!pr->echo)
            fputs("\n", stdout);
 
-       return 1;
     }
+
+    return 1; /* success */
+
 }
 
 void frontend_keypress(void *handle)