Annotation of src/usr.bin/ssh/readpass.c, Revision 1.1
1.1 ! deraadt 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 1.2 1999/05/04 11:59:03 bg Exp $");
! 18:
! 19: #include "xmalloc.h"
! 20: #include "ssh.h"
! 21:
! 22: /* Saved old terminal mode for read_passphrase. */
! 23: #ifdef USING_TERMIOS
! 24: static struct termios saved_tio;
! 25: #endif
! 26: #ifdef USING_SGTTY
! 27: static struct sgttyb saved_tio;
! 28: #endif
! 29:
! 30: /* Old interrupt signal handler for read_passphrase. */
! 31: static RETSIGTYPE (*old_handler)(int sig) = NULL;
! 32:
! 33: /* Interrupt signal handler for read_passphrase. */
! 34:
! 35: RETSIGTYPE intr_handler(int sig)
! 36: {
! 37: /* Restore terminal modes. */
! 38: #ifdef USING_TERMIOS
! 39: tcsetattr(fileno(stdin), TCSANOW, &saved_tio);
! 40: #endif
! 41: #ifdef USING_SGTTY
! 42: ioctl(fileno(stdin), TIOCSETP, &saved_tio);
! 43: #endif
! 44: /* Restore the old signal handler. */
! 45: signal(sig, old_handler);
! 46: /* Resend the signal, with the old handler. */
! 47: kill(getpid(), sig);
! 48: }
! 49:
! 50: /* Reads a passphrase from /dev/tty with echo turned off. Returns the
! 51: passphrase (allocated with xmalloc). Exits if EOF is encountered.
! 52: The passphrase if read from stdin if from_stdin is true (as is the
! 53: case with ssh-keygen). */
! 54:
! 55: char *read_passphrase(const char *prompt, int from_stdin)
! 56: {
! 57: char buf[1024], *cp;
! 58: #ifdef USING_TERMIOS
! 59: struct termios tio;
! 60: #endif
! 61: #ifdef USING_SGTTY
! 62: struct sgttyb tio;
! 63: #endif
! 64: FILE *f;
! 65:
! 66: if (from_stdin)
! 67: f = stdin;
! 68: else
! 69: {
! 70: /* Read the passphrase from /dev/tty to make it possible to ask it even
! 71: when stdin has been redirected. */
! 72: f = fopen("/dev/tty", "r");
! 73: if (!f)
! 74: {
! 75: if (getenv("DISPLAY"))
! 76: {
! 77: char command[512];
! 78: fprintf(stderr,
! 79: "Executing ssh-askpass to query the password...\n");
! 80: fflush(stdout);
! 81: fflush(stderr);
! 82: sprintf(command, "ssh-askpass '%.400s'", prompt);
! 83: f = popen(command, "r");
! 84: if (!fgets(buf, sizeof(buf), f))
! 85: {
! 86: pclose(f);
! 87: fprintf(stderr, "No passphrase supplied. Exiting.\n");
! 88: exit(1);
! 89: }
! 90: pclose(f);
! 91: if (strchr(buf, '\n'))
! 92: *strchr(buf, '\n') = 0;
! 93: return xstrdup(buf);
! 94: }
! 95:
! 96: /* No controlling terminal and no DISPLAY. Nowhere to read. */
! 97: fprintf(stderr, "You have no controlling tty and no DISPLAY. Cannot read passphrase.\n");
! 98: exit(1);
! 99: }
! 100: }
! 101:
! 102: /* Display the prompt (on stderr because stdout might be redirected). */
! 103: fflush(stdout);
! 104: fprintf(stderr, "%s", prompt);
! 105: fflush(stderr);
! 106:
! 107: /* Get terminal modes. */
! 108: #ifdef USING_TERMIOS
! 109: tcgetattr(fileno(f), &tio);
! 110: #endif
! 111: #ifdef USING_SGTTY
! 112: ioctl(fileno(f), TIOCGETP, &tio);
! 113: #endif
! 114: saved_tio = tio;
! 115: /* Save signal handler and set the new handler. */
! 116: old_handler = signal(SIGINT, intr_handler);
! 117:
! 118: /* Set new terminal modes disabling all echo. */
! 119: #ifdef USING_TERMIOS
! 120: tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
! 121: tcsetattr(fileno(f), TCSANOW, &tio);
! 122: #endif
! 123: #ifdef USING_SGTTY
! 124: tio.sg_flags &= ~(ECHO);
! 125: ioctl(fileno(f), TIOCSETP, &tio);
! 126: #endif
! 127:
! 128: /* Read the passphrase from the terminal. */
! 129: if (fgets(buf, sizeof(buf), f) == NULL)
! 130: {
! 131: /* Got EOF. Just exit. */
! 132: /* Restore terminal modes. */
! 133: #ifdef USING_TERMIOS
! 134: tcsetattr(fileno(f), TCSANOW, &saved_tio);
! 135: #endif
! 136: #ifdef USING_SGTTY
! 137: ioctl(fileno(f), TIOCSETP, &saved_tio);
! 138: #endif
! 139: /* Restore the signal handler. */
! 140: signal(SIGINT, old_handler);
! 141: /* Print a newline (the prompt probably didn\'t have one). */
! 142: fprintf(stderr, "\n");
! 143: /* Close the file. */
! 144: if (f != stdin)
! 145: fclose(f);
! 146: exit(1);
! 147: }
! 148: /* Restore terminal modes. */
! 149: #ifdef USING_TERMIOS
! 150: tcsetattr(fileno(f), TCSANOW, &saved_tio);
! 151: #endif
! 152: #ifdef USING_SGTTY
! 153: ioctl(fileno(f), TIOCSETP, &saved_tio);
! 154: #endif
! 155: /* Restore the signal handler. */
! 156: (void)signal(SIGINT, old_handler);
! 157: /* Remove newline from the passphrase. */
! 158: if (strchr(buf, '\n'))
! 159: *strchr(buf, '\n') = 0;
! 160: /* Allocate a copy of the passphrase. */
! 161: cp = xstrdup(buf);
! 162: /* Clear the buffer so we don\'t leave copies of the passphrase laying
! 163: around. */
! 164: memset(buf, 0, sizeof(buf));
! 165: /* Print a newline since the prompt probably didn\'t have one. */
! 166: fprintf(stderr, "\n");
! 167: /* Close the file. */
! 168: if (f != stdin)
! 169: fclose(f);
! 170: return cp;
! 171: }
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