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authorDamien Miller <djm@mindrot.org>1999-10-27 13:42:43 +1000
committerDamien Miller <djm@mindrot.org>1999-10-27 13:42:43 +1000
commitd4a8b7e34dd619a4debf9a206c81db26d1402ea6 (patch)
treea47d770a2f790f40d18b0982d4e55fa7cfb1fa3b /readpass.c
Initial revision
Diffstat (limited to 'readpass.c')
-rw-r--r--readpass.c114
1 files changed, 114 insertions, 0 deletions
diff --git a/readpass.c b/readpass.c
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+++ b/readpass.c
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+/*
+
+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 1.1 1999/10/27 03:42:44 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;
+}