Final fixes to keyboard-interactive so it now works with packets

containing more than one prompt instead of less than one, and also
correctly enables echo on prompts that the server requests it for.
In the process I've moved the whole username/password input routine
out into its own function, where it's called independently of which
SSH protocol we're using, so this should even have _saved_ code
size. Rock!

[originally from svn r1830]

diff --git a/ssh.c b/ssh.c
index 7cc9d20e2d176c9f4e89aca9165f9574cad74529..0edaf932427f6a5465200bd874547d4d9b75c779 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -2048,6 +2048,76 @@ static void ssh_throttle_all(int enable, int bufsize)
     }
 }
 
+/*
+ * Username and password input, abstracted off into reusable
+ * routines (hopefully even reusable between SSH1 and SSH2!).
+ */
+static char *ssh_userpass_input_buffer;
+static int ssh_userpass_input_buflen;
+static int ssh_userpass_input_bufpos;
+static int ssh_userpass_input_echo;
+
+/* Set up a username or password input loop on a given buffer. */
+void setup_userpass_input(char *buffer, int buflen, int echo)
+{
+    ssh_userpass_input_buffer = buffer;
+    ssh_userpass_input_buflen = buflen;
+    ssh_userpass_input_bufpos = 0;
+    ssh_userpass_input_echo = echo;
+}
+
+/*
+ * Process some terminal data in the course of username/password
+ * input. Returns >0 for success (line of input returned in
+ * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
+ * for inconclusive (keep waiting for more input please).
+ */
+int process_userpass_input(unsigned char *in, int inlen)
+{
+    char c;
+
+    while (inlen--) {
+       switch (c = *in++) {
+         case 10:
+         case 13:
+           ssh_userpass_input_buffer[ssh_userpass_input_bufpos] = 0;
+           ssh_userpass_input_buffer[ssh_userpass_input_buflen-1] = 0;
+           return +1;
+           break;
+         case 8:
+         case 127:
+           if (ssh_userpass_input_bufpos > 0) {
+               if (ssh_userpass_input_echo)
+                   c_write_str("\b \b");
+               ssh_userpass_input_bufpos--;
+           }
+           break;
+         case 21:
+         case 27:
+           while (ssh_userpass_input_bufpos > 0) {
+               if (ssh_userpass_input_echo)
+                   c_write_str("\b \b");
+               ssh_userpass_input_bufpos--;
+           }
+           break;
+         case 3:
+         case 4:
+           return -1;
+           break;
+         default:
+           if (((c >= ' ' && c <= '~') ||
+                ((unsigned char) c >= 160))
+               && ssh_userpass_input_bufpos < ssh_userpass_input_buflen-1) {
+               ssh_userpass_input_buffer[ssh_userpass_input_bufpos++] = c;
+               if (ssh_userpass_input_echo)
+                   c_write(&c, 1);
+           }
+           break;
+       }
+    }
+    return 0;
+}
+
 /*
  * Handle the key exchange and user authentication phases.
  */
@@ -2233,8 +2303,6 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
 
     fflush(stdout);
     {
-       static int pos = 0;
-       static char c;
        if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
            if (ssh_get_line && !ssh_getline_pw_only) {
                if (!ssh_get_line("login as: ",
@@ -2248,47 +2316,18 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
                    crReturn(1);
                }
            } else {
+               static int ret;
                c_write_str("login as: ");
                ssh_send_ok = 1;
-               while (pos >= 0) {
+
+               setup_userpass_input(username, sizeof(username), 1);
+               do {
                    crWaitUntil(!ispkt);
-                   while (inlen--)
-                       switch (c = *in++) {
-                         case 10:
-                         case 13:
-                           username[pos] = 0;
-                           pos = -1;
-                           break;
-                         case 8:
-                         case 127:
-                           if (pos > 0) {
-                               c_write_str("\b \b");
-                               pos--;
-                           }
-                           break;
-                         case 21:
-                         case 27:
-                           while (pos > 0) {
-                               c_write_str("\b \b");
-                               pos--;
-                           }
-                           break;
-                         case 3:
-                         case 4:
-                           cleanup_exit(0);
-                           break;
-                         default:
-                           if (((c >= ' ' && c <= '~') ||
-                                ((unsigned char) c >= 160))
-                               && pos < sizeof(username)-1) {
-                               username[pos++] = c;
-                               c_write(&c, 1);
-                           }
-                           break;
-                       }
-               }
+                   ret = process_userpass_input(in, inlen);
+               } while (ret == 0);
+               if (ret < 0)
+                   cleanup_exit(0);
                c_write_str("\r\n");
-               username[strcspn(username, "\n\r")] = '\0';
            }
        } else {
            strncpy(username, cfg.username, 99);
@@ -2572,37 +2611,17 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
        } else {
            /* Prompt may have come from server. We've munged it a bit, so
             * we know it to be zero-terminated at least once. */
+           static int ret;
            c_write_untrusted(prompt, strlen(prompt));
            pos = 0;
-           ssh_send_ok = 1;
-           while (pos >= 0) {
+
+           setup_userpass_input(password, sizeof(password), 0);
+           do {
                crWaitUntil(!ispkt);
-               while (inlen--)
-                   switch (c = *in++) {
-                     case 10:
-                     case 13:
-                       password[pos] = 0;
-                       pos = -1;
-                       break;
-                     case 8:
-                     case 127:
-                       if (pos > 0)
-                           pos--;
-                       break;
-                     case 21:
-                     case 27:
-                       pos = 0;
-                       break;
-                     case 3:
-                     case 4:
-                       cleanup_exit(0);
-                       break;
-                     default:
-                       if (pos < sizeof(password)-1)
-                           password[pos++] = c;
-                       break;
-                   }
-           }
+               ret = process_userpass_input(in, inlen);
+           } while (ret == 0);
+           if (ret < 0)
+               cleanup_exit(0);
            c_write_str("\r\n");
        }
 
@@ -4092,13 +4111,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
     username[0] = '\0';
     got_username = FALSE;
     do {
-       static int pos;
-       static char c;
-
        /*
         * Get a username.
         */
-       pos = 0;
        if (got_username && !cfg.change_username) {
            /*
             * We got a username last time round this loop, and
@@ -4118,45 +4133,16 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
                    crReturnV;
                }
            } else {
+               static int ret;
                c_write_str("login as: ");
                ssh_send_ok = 1;
-               while (pos >= 0) {
+               setup_userpass_input(username, sizeof(username), 1);
+               do {
                    crWaitUntilV(!ispkt);
-                   while (inlen--)
-                       switch (c = *in++) {
-                         case 10:
-                         case 13:
-                           username[pos] = 0;
-                           pos = -1;
-                           break;
-                         case 8:
-                         case 127:
-                           if (pos > 0) {
-                               c_write_str("\b \b");
-                               pos--;
-                           }
-                           break;
-                         case 21:
-                         case 27:
-                           while (pos > 0) {
-                               c_write_str("\b \b");
-                               pos--;
-                           }
-                           break;
-                         case 3:
-                         case 4:
-                           cleanup_exit(0);
-                           break;
-                         default:
-                           if (((c >= ' ' && c <= '~') ||
-                                ((unsigned char) c >= 160))
-                               && pos < sizeof(username)-1) {
-                               username[pos++] = c;
-                               c_write(&c, 1);
-                           }
-                           break;
-                       }
-               }
+                   ret = process_userpass_input(in, inlen);
+               } while (ret == 0);
+               if (ret < 0)
+                   cleanup_exit(0);
            }
            c_write_str("\r\n");
            username[strcspn(username, "\n\r")] = '\0';
@@ -4325,6 +4311,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
            method = 0;
            ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
 
+           /*
+            * Most password/passphrase prompts will be
+            * non-echoing, so we set this to 0 by default.
+            * Exception is that some keyboard-interactive prompts
+            * can be echoing, in which case we'll set this to 1.
+            */
+           echo = 0;
+
            if (!method && can_pubkey && agent_exists() && !tried_agent) {
                /*
                 * Attempt public-key authentication using Pageant.
@@ -4579,11 +4573,11 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
                    ssh2_pkt_getstring(&lang, &lang_len);
                    if (name_len > 0) {
                        c_write_untrusted(name, name_len);
-                       c_write_str("\n");
+                       c_write_str("\r\n");
                    }
                    if (inst_len > 0) {
                        c_write_untrusted(inst, inst_len);
-                       c_write_str("\n");
+                       c_write_str("\r\n");
                    }
                    num_prompts = ssh2_pkt_getuint32();
                }
@@ -4642,41 +4636,17 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
                        crReturnV;
                    }
                } else {
-                   static int pos = 0;
-                   static char c;
-
+                   static int ret;
                    c_write_untrusted(pwprompt, strlen(pwprompt));
                    ssh_send_ok = 1;
 
-                   pos = 0;
-                   while (pos >= 0) {
+                   setup_userpass_input(password, sizeof(password), echo);
+                   do {
                        crWaitUntilV(!ispkt);
-                       while (inlen--)
-                           switch (c = *in++) {
-                             case 10:
-                             case 13:
-                               password[pos] = 0;
-                               pos = -1;
-                               break;
-                             case 8:
-                             case 127:
-                               if (pos > 0)
-                                   pos--;
-                               break;
-                             case 21:
-                             case 27:
-                               pos = 0;
-                               break;
-                             case 3:
-                             case 4:
-                               cleanup_exit(0);
-                               break;
-                             default:
-                               if (pos < sizeof(password)-1)
-                                   password[pos++] = c;
-                               break;
-                           }
-                   }
+                       ret = process_userpass_input(in, inlen);
+                   } while (ret == 0);
+                   if (ret < 0)
+                       cleanup_exit(0);
                    c_write_str("\r\n");
                }
            }