git.distorted.org.uk Git - u/mdw/putty/blob - unix/uxcons.c

   1 /*
   2  * uxcons.c: various interactive-prompt routines shared between the
   3  * Unix console PuTTY tools
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <stdarg.h>
   9 #include <assert.h>
  10 #include <termios.h>
  11 #include <unistd.h>
  12
  13 #include "putty.h"
  14 #include "storage.h"
  15 #include "ssh.h"
  16
  17 int console_batch_mode = FALSE;
  18
  19 static void *console_logctx = NULL;
  20
  21 /*
  22  * Clean up and exit.
  23  */
  24 void cleanup_exit(int code)
  25 {
  26     /*
  27      * Clean up.
  28      */
  29     sk_cleanup();
  30     random_save_seed();
  31     exit(code);
  32 }
  33
  34 void set_busy_status(void *frontend, int status)
  35 {
  36 }
  37
  38 void update_specials_menu(void *frontend)
  39 {
  40 }
  41
  42 void notify_remote_exit(void *frontend)
  43 {
  44 }
  45
  46 void timer_change_notify(long next)
  47 {
  48 }
  49
  50 int verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
  51                         char *keystr, char *fingerprint,
  52                         void (*callback)(void *ctx, int result), void *ctx)
  53 {
  54     int ret;
  55
  56     static const char absentmsg_batch[] =
  57         "The server's host key is not cached. You have no guarantee\n"
  58         "that the server is the computer you think it is.\n"
  59         "The server's %s key fingerprint is:\n"
  60         "%s\n"
  61         "Connection abandoned.\n";
  62     static const char absentmsg[] =
  63         "The server's host key is not cached. You have no guarantee\n"
  64         "that the server is the computer you think it is.\n"
  65         "The server's %s key fingerprint is:\n"
  66         "%s\n"
  67         "If you trust this host, enter \"y\" to add the key to\n"
  68         "PuTTY's cache and carry on connecting.\n"
  69         "If you want to carry on connecting just once, without\n"
  70         "adding the key to the cache, enter \"n\".\n"
  71         "If you do not trust this host, press Return to abandon the\n"
  72         "connection.\n"
  73         "Store key in cache? (y/n) ";
  74
  75     static const char wrongmsg_batch[] =
  76         "WARNING - POTENTIAL SECURITY BREACH!\n"
  77         "The server's host key does not match the one PuTTY has\n"
  78         "cached. This means that either the server administrator\n"
  79         "has changed the host key, or you have actually connected\n"
  80         "to another computer pretending to be the server.\n"
  81         "The new %s key fingerprint is:\n"
  82         "%s\n"
  83         "Connection abandoned.\n";
  84     static const char wrongmsg[] =
  85         "WARNING - POTENTIAL SECURITY BREACH!\n"
  86         "The server's host key does not match the one PuTTY has\n"
  87         "cached. This means that either the server administrator\n"
  88         "has changed the host key, or you have actually connected\n"
  89         "to another computer pretending to be the server.\n"
  90         "The new %s key fingerprint is:\n"
  91         "%s\n"
  92         "If you were expecting this change and trust the new key,\n"
  93         "enter \"y\" to update PuTTY's cache and continue connecting.\n"
  94         "If you want to carry on connecting but without updating\n"
  95         "the cache, enter \"n\".\n"
  96         "If you want to abandon the connection completely, press\n"
  97         "Return to cancel. Pressing Return is the ONLY guaranteed\n"
  98         "safe choice.\n"
  99         "Update cached key? (y/n, Return cancels connection) ";
 100
 101     static const char abandoned[] = "Connection abandoned.\n";
 102
 103     char line[32];
 104
 105     /*
 106      * Verify the key.
 107      */
 108     ret = verify_host_key(host, port, keytype, keystr);
 109
 110     if (ret == 0)                      /* success - key matched OK */
 111         return 1;
 112
 113     if (ret == 2) {                    /* key was different */
 114         if (console_batch_mode) {
 115             fprintf(stderr, wrongmsg_batch, keytype, fingerprint);
 116             return 0;
 117         }
 118         fprintf(stderr, wrongmsg, keytype, fingerprint);
 119         fflush(stderr);
 120     }
 121     if (ret == 1) {                    /* key was absent */
 122         if (console_batch_mode) {
 123             fprintf(stderr, absentmsg_batch, keytype, fingerprint);
 124             return 0;
 125         }
 126         fprintf(stderr, absentmsg, keytype, fingerprint);
 127         fflush(stderr);
 128     }
 129
 130     {
 131         struct termios oldmode, newmode;
 132         tcgetattr(0, &oldmode);
 133         newmode = oldmode;
 134         newmode.c_lflag |= ECHO | ISIG | ICANON;
 135         tcsetattr(0, TCSANOW, &newmode);
 136         line[0] = '\0';
 137         read(0, line, sizeof(line) - 1);
 138         tcsetattr(0, TCSANOW, &oldmode);
 139     }
 140
 141     if (line[0] != '\0' && line[0] != '\r' && line[0] != '\n') {
 142         if (line[0] == 'y' || line[0] == 'Y')
 143             store_host_key(host, port, keytype, keystr);
 144         return 1;
 145     } else {
 146         fprintf(stderr, abandoned);
 147         return 0;
 148     }
 149 }
 150
 151 /*
 152  * Ask whether the selected algorithm is acceptable (since it was
 153  * below the configured 'warn' threshold).
 154  */
 155 int askalg(void *frontend, const char *algtype, const char *algname,
 156            void (*callback)(void *ctx, int result), void *ctx)
 157 {
 158     static const char msg[] =
 159         "The first %s supported by the server is\n"
 160         "%s, which is below the configured warning threshold.\n"
 161         "Continue with connection? (y/n) ";
 162     static const char msg_batch[] =
 163         "The first %s supported by the server is\n"
 164         "%s, which is below the configured warning threshold.\n"
 165         "Connection abandoned.\n";
 166     static const char abandoned[] = "Connection abandoned.\n";
 167
 168     char line[32];
 169
 170     if (console_batch_mode) {
 171         fprintf(stderr, msg_batch, algtype, algname);
 172         return 0;
 173     }
 174
 175     fprintf(stderr, msg, algtype, algname);
 176     fflush(stderr);
 177
 178     {
 179         struct termios oldmode, newmode;
 180         tcgetattr(0, &oldmode);
 181         newmode = oldmode;
 182         newmode.c_lflag |= ECHO | ISIG | ICANON;
 183         tcsetattr(0, TCSANOW, &newmode);
 184         line[0] = '\0';
 185         read(0, line, sizeof(line) - 1);
 186         tcsetattr(0, TCSANOW, &oldmode);
 187     }
 188
 189     if (line[0] == 'y' || line[0] == 'Y') {
 190         return 1;
 191     } else {
 192         fprintf(stderr, abandoned);
 193         return 0;
 194     }
 195 }
 196
 197 /*
 198  * Ask whether to wipe a session log file before writing to it.
 199  * Returns 2 for wipe, 1 for append, 0 for cancel (don't log).
 200  */
 201 int askappend(void *frontend, Filename filename,
 202               void (*callback)(void *ctx, int result), void *ctx)
 203 {
 204     static const char msgtemplate[] =
 205         "The session log file \"%.*s\" already exists.\n"
 206         "You can overwrite it with a new session log,\n"
 207         "append your session log to the end of it,\n"
 208         "or disable session logging for this session.\n"
 209         "Enter \"y\" to wipe the file, \"n\" to append to it,\n"
 210         "or just press Return to disable logging.\n"
 211         "Wipe the log file? (y/n, Return cancels logging) ";
 212
 213     static const char msgtemplate_batch[] =
 214         "The session log file \"%.*s\" already exists.\n"
 215         "Logging will not be enabled.\n";
 216
 217     char line[32];
 218
 219     if (console_batch_mode) {
 220         fprintf(stderr, msgtemplate_batch, FILENAME_MAX, filename.path);
 221         fflush(stderr);
 222         return 0;
 223     }
 224     fprintf(stderr, msgtemplate, FILENAME_MAX, filename.path);
 225     fflush(stderr);
 226
 227     {
 228         struct termios oldmode, newmode;
 229         tcgetattr(0, &oldmode);
 230         newmode = oldmode;
 231         newmode.c_lflag |= ECHO | ISIG | ICANON;
 232         tcsetattr(0, TCSANOW, &newmode);
 233         line[0] = '\0';
 234         read(0, line, sizeof(line) - 1);
 235         tcsetattr(0, TCSANOW, &oldmode);
 236     }
 237
 238     if (line[0] == 'y' || line[0] == 'Y')
 239         return 2;
 240     else if (line[0] == 'n' || line[0] == 'N')
 241         return 1;
 242     else
 243         return 0;
 244 }
 245
 246 /*
 247  * Warn about the obsolescent key file format.
 248  *
 249  * Uniquely among these functions, this one does _not_ expect a
 250  * frontend handle. This means that if PuTTY is ported to a
 251  * platform which requires frontend handles, this function will be
 252  * an anomaly. Fortunately, the problem it addresses will not have
 253  * been present on that platform, so it can plausibly be
 254  * implemented as an empty function.
 255  */
 256 void old_keyfile_warning(void)
 257 {
 258     static const char message[] =
 259         "You are loading an SSH-2 private key which has an\n"
 260         "old version of the file format. This means your key\n"
 261         "file is not fully tamperproof. Future versions of\n"
 262         "PuTTY may stop supporting this private key format,\n"
 263         "so we recommend you convert your key to the new\n"
 264         "format.\n"
 265         "\n"
 266         "Once the key is loaded into PuTTYgen, you can perform\n"
 267         "this conversion simply by saving it again.\n";
 268
 269     fputs(message, stderr);
 270 }
 271
 272 void console_provide_logctx(void *logctx)
 273 {
 274     console_logctx = logctx;
 275 }
 276
 277 void logevent(void *frontend, const char *string)
 278 {
 279     if (console_logctx)
 280         log_eventlog(console_logctx, string);
 281 }
 282
 283 static void console_data_untrusted(const char *data, int len)
 284 {
 285     int i;
 286     for (i = 0; i < len; i++)
 287         if ((data[i] & 0x60) || (data[i] == '\n'))
 288             fputc(data[i], stdout);
 289     fflush(stdout);
 290 }
 291
 292 int console_get_userpass_input(prompts_t *p, unsigned char *in, int inlen)
 293 {
 294     size_t curr_prompt;
 295
 296     /*
 297      * Zero all the results, in case we abort half-way through.
 298      */
 299     {
 300         int i;
 301         for (i = 0; i < p->n_prompts; i++)
 302             memset(p->prompts[i]->result, 0, p->prompts[i]->result_len);
 303     }
 304
 305     if (console_batch_mode)
 306         return 0;
 307
 308     /*
 309      * Preamble.
 310      */
 311     /* We only print the `name' caption if we have to... */
 312     if (p->name_reqd && p->name) {
 313         size_t l = strlen(p->name);
 314         console_data_untrusted(p->name, l);
 315         if (p->name[l-1] != '\n')
 316             console_data_untrusted("\n", 1);
 317     }
 318     /* ...but we always print any `instruction'. */
 319     if (p->instruction) {
 320         size_t l = strlen(p->instruction);
 321         console_data_untrusted(p->instruction, l);
 322         if (p->instruction[l-1] != '\n')
 323             console_data_untrusted("\n", 1);
 324     }
 325
 326     for (curr_prompt = 0; curr_prompt < p->n_prompts; curr_prompt++) {
 327
 328         struct termios oldmode, newmode;
 329         int i;
 330         prompt_t *pr = p->prompts[curr_prompt];
 331
 332         tcgetattr(0, &oldmode);
 333         newmode = oldmode;
 334         newmode.c_lflag |= ISIG | ICANON;
 335         if (!pr->echo)
 336             newmode.c_lflag &= ~ECHO;
 337         else
 338             newmode.c_lflag |= ECHO;
 339         tcsetattr(0, TCSANOW, &newmode);
 340
 341         console_data_untrusted(pr->prompt, strlen(pr->prompt));
 342
 343         i = read(0, pr->result, pr->result_len - 1);
 344
 345         tcsetattr(0, TCSANOW, &oldmode);
 346
 347         if (i > 0 && pr->result[i-1] == '\n')
 348             i--;
 349         pr->result[i] = '\0';
 350
 351         if (!pr->echo)
 352             fputs("\n", stdout);
 353
 354     }
 355
 356     return 1; /* success */
 357
 358 }
 359
 360 void frontend_keypress(void *handle)
 361 {
 362     /*
 363      * This is nothing but a stub, in console code.
 364      */
 365     return;
 366 }
 367
 368 int is_interactive(void)
 369 {
 370     return isatty(0);
 371 }
 372
 373 /*
 374  * X11-forwarding-related things suitable for console.
 375  */
 376
 377 const char platform_x11_best_transport[] = "unix";
 378
 379 char *platform_get_x_display(void) {
 380     return dupstr(getenv("DISPLAY"));
 381 }