1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
/*
*
* readpass.c
*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* Created: Mon Jul 10 22:08:59 1995 ylo
*
* Functions for reading passphrases and passwords.
*
*/
#include "includes.h"
RCSID("$Id: readpass.c,v 1.3 1999/11/25 00:54:59 damien Exp $");
#include "xmalloc.h"
#include "ssh.h"
/* Saved old terminal mode for read_passphrase. */
static struct termios saved_tio;
/* Old interrupt signal handler for read_passphrase. */
static void (*old_handler) (int sig) = NULL;
/* Interrupt signal handler for read_passphrase. */
void
intr_handler(int sig)
{
/* Restore terminal modes. */
tcsetattr(fileno(stdin), TCSANOW, &saved_tio);
/* Restore the old signal handler. */
signal(sig, old_handler);
/* Resend the signal, with the old handler. */
kill(getpid(), sig);
}
/*
* Reads a passphrase from /dev/tty with echo turned off. Returns the
* passphrase (allocated with xmalloc). Exits if EOF is encountered. The
* passphrase if read from stdin if from_stdin is true (as is the case with
* ssh-keygen).
*/
char *
read_passphrase(const char *prompt, int from_stdin)
{
char buf[1024], *cp;
struct termios tio;
FILE *f;
if (from_stdin)
f = stdin;
else {
/*
* Read the passphrase from /dev/tty to make it possible to
* ask it even when stdin has been redirected.
*/
f = fopen("/dev/tty", "r");
if (!f) {
/* No controlling terminal and no DISPLAY. Nowhere to read. */
fprintf(stderr, "You have no controlling tty and no DISPLAY. Cannot read passphrase.\n");
exit(1);
}
}
/* Display the prompt (on stderr because stdout might be redirected). */
fflush(stdout);
fprintf(stderr, "%s", prompt);
fflush(stderr);
/* Get terminal modes. */
tcgetattr(fileno(f), &tio);
saved_tio = tio;
/* Save signal handler and set the new handler. */
old_handler = signal(SIGINT, intr_handler);
/* Set new terminal modes disabling all echo. */
tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
tcsetattr(fileno(f), TCSANOW, &tio);
/* Read the passphrase from the terminal. */
if (fgets(buf, sizeof(buf), f) == NULL) {
/* Got EOF. Just exit. */
/* Restore terminal modes. */
tcsetattr(fileno(f), TCSANOW, &saved_tio);
/* Restore the signal handler. */
signal(SIGINT, old_handler);
/* Print a newline (the prompt probably didn\'t have one). */
fprintf(stderr, "\n");
/* Close the file. */
if (f != stdin)
fclose(f);
exit(1);
}
/* Restore terminal modes. */
tcsetattr(fileno(f), TCSANOW, &saved_tio);
/* Restore the signal handler. */
(void) signal(SIGINT, old_handler);
/* Remove newline from the passphrase. */
if (strchr(buf, '\n'))
*strchr(buf, '\n') = 0;
/* Allocate a copy of the passphrase. */
cp = xstrdup(buf);
/*
* Clear the buffer so we don\'t leave copies of the passphrase
* laying around.
*/
memset(buf, 0, sizeof(buf));
/* Print a newline since the prompt probably didn\'t have one. */
fprintf(stderr, "\n");
/* Close the file. */
if (f != stdin)
fclose(f);
return cp;
}
|
