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Diffstat (limited to 'readpass.c')
-rw-r--r-- | readpass.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/readpass.c b/readpass.c new file mode 100644 index 000000000..3031825e5 --- /dev/null +++ b/readpass.c | |||
@@ -0,0 +1,114 @@ | |||
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: readpass.c,v 1.1 1999/10/27 03:42:44 damien Exp $"); | ||
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 | } | ||