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Commit | Line | Data |
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8efc0c15 | 1 | /* |
2 | ||
3 | readpass.c | |
4 | ||
5 | Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | ||
7 | Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | All rights reserved | |
9 | ||
10 | Created: Mon Jul 10 22:08:59 1995 ylo | |
11 | ||
12 | Functions for reading passphrases and passwords. | |
13 | ||
14 | */ | |
15 | ||
16 | #include "includes.h" | |
17 | RCSID("$Id$"); | |
18 | ||
19 | #include "xmalloc.h" | |
20 | #include "ssh.h" | |
21 | ||
22 | /* Saved old terminal mode for read_passphrase. */ | |
23 | static struct termios saved_tio; | |
24 | ||
25 | /* Old interrupt signal handler for read_passphrase. */ | |
26 | static void (*old_handler)(int sig) = NULL; | |
27 | ||
28 | /* Interrupt signal handler for read_passphrase. */ | |
29 | ||
30 | void intr_handler(int sig) | |
31 | { | |
32 | /* Restore terminal modes. */ | |
33 | tcsetattr(fileno(stdin), TCSANOW, &saved_tio); | |
34 | /* Restore the old signal handler. */ | |
35 | signal(sig, old_handler); | |
36 | /* Resend the signal, with the old handler. */ | |
37 | kill(getpid(), sig); | |
38 | } | |
39 | ||
40 | /* Reads a passphrase from /dev/tty with echo turned off. Returns the | |
41 | passphrase (allocated with xmalloc). Exits if EOF is encountered. | |
42 | The passphrase if read from stdin if from_stdin is true (as is the | |
43 | case with ssh-keygen). */ | |
44 | ||
45 | char *read_passphrase(const char *prompt, int from_stdin) | |
46 | { | |
47 | char buf[1024], *cp; | |
48 | struct termios tio; | |
49 | FILE *f; | |
50 | ||
51 | if (from_stdin) | |
52 | f = stdin; | |
53 | else | |
54 | { | |
55 | /* Read the passphrase from /dev/tty to make it possible to ask it even | |
56 | when stdin has been redirected. */ | |
57 | f = fopen("/dev/tty", "r"); | |
58 | if (!f) | |
59 | { | |
60 | /* No controlling terminal and no DISPLAY. Nowhere to read. */ | |
61 | fprintf(stderr, "You have no controlling tty and no DISPLAY. Cannot read passphrase.\n"); | |
62 | exit(1); | |
63 | } | |
64 | } | |
65 | ||
66 | /* Display the prompt (on stderr because stdout might be redirected). */ | |
67 | fflush(stdout); | |
68 | fprintf(stderr, "%s", prompt); | |
69 | fflush(stderr); | |
70 | ||
71 | /* Get terminal modes. */ | |
72 | tcgetattr(fileno(f), &tio); | |
73 | saved_tio = tio; | |
74 | /* Save signal handler and set the new handler. */ | |
75 | old_handler = signal(SIGINT, intr_handler); | |
76 | ||
77 | /* Set new terminal modes disabling all echo. */ | |
78 | tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL); | |
79 | tcsetattr(fileno(f), TCSANOW, &tio); | |
80 | ||
81 | /* Read the passphrase from the terminal. */ | |
82 | if (fgets(buf, sizeof(buf), f) == NULL) | |
83 | { | |
84 | /* Got EOF. Just exit. */ | |
85 | /* Restore terminal modes. */ | |
86 | tcsetattr(fileno(f), TCSANOW, &saved_tio); | |
87 | /* Restore the signal handler. */ | |
88 | signal(SIGINT, old_handler); | |
89 | /* Print a newline (the prompt probably didn\'t have one). */ | |
90 | fprintf(stderr, "\n"); | |
91 | /* Close the file. */ | |
92 | if (f != stdin) | |
93 | fclose(f); | |
94 | exit(1); | |
95 | } | |
96 | /* Restore terminal modes. */ | |
97 | tcsetattr(fileno(f), TCSANOW, &saved_tio); | |
98 | /* Restore the signal handler. */ | |
99 | (void)signal(SIGINT, old_handler); | |
100 | /* Remove newline from the passphrase. */ | |
101 | if (strchr(buf, '\n')) | |
102 | *strchr(buf, '\n') = 0; | |
103 | /* Allocate a copy of the passphrase. */ | |
104 | cp = xstrdup(buf); | |
105 | /* Clear the buffer so we don\'t leave copies of the passphrase laying | |
106 | around. */ | |
107 | memset(buf, 0, sizeof(buf)); | |
108 | /* Print a newline since the prompt probably didn\'t have one. */ | |
109 | fprintf(stderr, "\n"); | |
110 | /* Close the file. */ | |
111 | if (f != stdin) | |
112 | fclose(f); | |
113 | return cp; | |
114 | } |