Revamp interface to verify_ssh_host_key() and askalg(). Each of them
[u/mdw/putty] / unix / uxcons.c
CommitLineData
c5e438ec 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
17int console_batch_mode = FALSE;
18
b51259f6 19static void *console_logctx = NULL;
20
c5e438ec 21/*
22 * Clean up and exit.
23 */
24void cleanup_exit(int code)
25{
26 /*
27 * Clean up.
28 */
29 sk_cleanup();
e85da6a5 30 random_save_seed();
c5e438ec 31 exit(code);
32}
33
755e0524 34void set_busy_status(void *frontend, int status)
35{
36}
37
125105d1 38void update_specials_menu(void *frontend)
39{
40}
41
39934deb 42void notify_remote_exit(void *frontend)
43{
44}
45
46void timer_change_notify(long next)
47{
48}
49
3d9449a1 50int 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)
c5e438ec 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"
65f66c88 59 "The server's %s key fingerprint is:\n"
c5e438ec 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"
65f66c88 65 "The server's %s key fingerprint is:\n"
c5e438ec 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"
65f66c88 81 "The new %s key fingerprint is:\n"
c5e438ec 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"
65f66c88 90 "The new %s key fingerprint is:\n"
c5e438ec 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 */
3d9449a1 111 return 1;
c5e438ec 112
113 if (ret == 2) { /* key was different */
114 if (console_batch_mode) {
65f66c88 115 fprintf(stderr, wrongmsg_batch, keytype, fingerprint);
3d9449a1 116 return 0;
c5e438ec 117 }
65f66c88 118 fprintf(stderr, wrongmsg, keytype, fingerprint);
c5e438ec 119 fflush(stderr);
120 }
121 if (ret == 1) { /* key was absent */
122 if (console_batch_mode) {
65f66c88 123 fprintf(stderr, absentmsg_batch, keytype, fingerprint);
3d9449a1 124 return 0;
c5e438ec 125 }
65f66c88 126 fprintf(stderr, absentmsg, keytype, fingerprint);
c5e438ec 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);
3d9449a1 144 return 1;
c5e438ec 145 } else {
146 fprintf(stderr, abandoned);
3d9449a1 147 return 0;
c5e438ec 148 }
149}
150
151/*
83e7d008 152 * Ask whether the selected algorithm is acceptable (since it was
c5e438ec 153 * below the configured 'warn' threshold).
c5e438ec 154 */
3d9449a1 155int askalg(void *frontend, const char *algtype, const char *algname,
156 void (*callback)(void *ctx, int result), void *ctx)
c5e438ec 157{
158 static const char msg[] =
83e7d008 159 "The first %s supported by the server is\n"
c5e438ec 160 "%s, which is below the configured warning threshold.\n"
161 "Continue with connection? (y/n) ";
162 static const char msg_batch[] =
83e7d008 163 "The first %s supported by the server is\n"
c5e438ec 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) {
83e7d008 171 fprintf(stderr, msg_batch, algtype, algname);
3d9449a1 172 return 0;
c5e438ec 173 }
174
83e7d008 175 fprintf(stderr, msg, algtype, algname);
c5e438ec 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') {
3d9449a1 190 return 1;
c5e438ec 191 } else {
192 fprintf(stderr, abandoned);
3d9449a1 193 return 0;
c5e438ec 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 */
9a30e26b 201int askappend(void *frontend, Filename filename)
c5e438ec 202{
203 static const char msgtemplate[] =
204 "The session log file \"%.*s\" already exists.\n"
205 "You can overwrite it with a new session log,\n"
206 "append your session log to the end of it,\n"
207 "or disable session logging for this session.\n"
208 "Enter \"y\" to wipe the file, \"n\" to append to it,\n"
209 "or just press Return to disable logging.\n"
210 "Wipe the log file? (y/n, Return cancels logging) ";
211
212 static const char msgtemplate_batch[] =
213 "The session log file \"%.*s\" already exists.\n"
214 "Logging will not be enabled.\n";
215
216 char line[32];
217
c5e438ec 218 if (console_batch_mode) {
9a30e26b 219 fprintf(stderr, msgtemplate_batch, FILENAME_MAX, filename.path);
c5e438ec 220 fflush(stderr);
221 return 0;
222 }
9a30e26b 223 fprintf(stderr, msgtemplate, FILENAME_MAX, filename.path);
c5e438ec 224 fflush(stderr);
225
226 {
227 struct termios oldmode, newmode;
228 tcgetattr(0, &oldmode);
229 newmode = oldmode;
230 newmode.c_lflag |= ECHO | ISIG | ICANON;
231 tcsetattr(0, TCSANOW, &newmode);
232 line[0] = '\0';
233 read(0, line, sizeof(line) - 1);
234 tcsetattr(0, TCSANOW, &oldmode);
235 }
236
237 if (line[0] == 'y' || line[0] == 'Y')
238 return 2;
239 else if (line[0] == 'n' || line[0] == 'N')
240 return 1;
241 else
242 return 0;
243}
244
245/*
246 * Warn about the obsolescent key file format.
247 *
248 * Uniquely among these functions, this one does _not_ expect a
249 * frontend handle. This means that if PuTTY is ported to a
250 * platform which requires frontend handles, this function will be
251 * an anomaly. Fortunately, the problem it addresses will not have
252 * been present on that platform, so it can plausibly be
253 * implemented as an empty function.
254 */
255void old_keyfile_warning(void)
256{
257 static const char message[] =
258 "You are loading an SSH 2 private key which has an\n"
259 "old version of the file format. This means your key\n"
260 "file is not fully tamperproof. Future versions of\n"
261 "PuTTY may stop supporting this private key format,\n"
262 "so we recommend you convert your key to the new\n"
263 "format.\n"
264 "\n"
265 "Once the key is loaded into PuTTYgen, you can perform\n"
266 "this conversion simply by saving it again.\n";
267
268 fputs(message, stderr);
269}
270
b51259f6 271void console_provide_logctx(void *logctx)
272{
273 console_logctx = logctx;
274}
275
cbe2d68f 276void logevent(void *frontend, const char *string)
c5e438ec 277{
b51259f6 278 if (console_logctx)
279 log_eventlog(console_logctx, string);
c5e438ec 280}
281
282int console_get_line(const char *prompt, char *str,
283 int maxlen, int is_pw)
284{
285 struct termios oldmode, newmode;
286 int i;
287
288 if (console_batch_mode) {
289 if (maxlen > 0)
290 str[0] = '\0';
a21a6a9a 291 return 0;
c5e438ec 292 } else {
293 tcgetattr(0, &oldmode);
294 newmode = oldmode;
295 newmode.c_lflag |= ISIG | ICANON;
296 if (is_pw)
297 newmode.c_lflag &= ~ECHO;
298 else
299 newmode.c_lflag |= ECHO;
300 tcsetattr(0, TCSANOW, &newmode);
301
302 fputs(prompt, stdout);
303 fflush(stdout);
304 i = read(0, str, maxlen - 1);
305
306 tcsetattr(0, TCSANOW, &oldmode);
307
308 if (i > 0 && str[i-1] == '\n')
309 i--;
310 str[i] = '\0';
311
312 if (is_pw)
8d69b472 313 fputs("\n", stdout);
a21a6a9a 314
315 return 1;
c5e438ec 316 }
c5e438ec 317}
318
319void frontend_keypress(void *handle)
320{
321 /*
322 * This is nothing but a stub, in console code.
323 */
324 return;
325}
47a6b94c 326
327int is_interactive(void)
328{
329 return isatty(0);
330}
46ed7b64 331
332/*
333 * X11-forwarding-related things suitable for console.
334 */
335
336const char platform_x11_best_transport[] = "unix";
337
338char *platform_get_x_display(void) {
339 return dupstr(getenv("DISPLAY"));
340}