b6dc13c2d3
The current password checking is unable to distinguish between the user entering an empty password or pressing Control-D. As a result, an empty password always results in normal startup. We modify bb_ask to return NULL if Control-D is pressed without entering a password. The sulogin applet is then modified to only proceed to normal startup if bb_ask returns NULL. This covers EOF with no password, interrupt by timeout and ^C. Signed-off-by: Jonathan Liu <net147@gmail.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
93 lines
1.9 KiB
C
93 lines
1.9 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Ask for a password
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* I use a static buffer in this function. Plan accordingly.
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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/* do nothing signal handler */
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static void askpass_timeout(int UNUSED_PARAM ignore)
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{
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}
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char* FAST_FUNC bb_ask_stdin(const char *prompt)
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{
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return bb_ask(STDIN_FILENO, 0, prompt);
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}
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char* FAST_FUNC bb_ask(const int fd, int timeout, const char *prompt)
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{
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/* Was static char[BIGNUM] */
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enum { sizeof_passwd = 128 };
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static char *passwd;
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char *ret;
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int i;
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struct sigaction sa, oldsa;
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struct termios tio, oldtio;
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fputs(prompt, stdout);
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fflush_all();
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tcflush(fd, TCIFLUSH);
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tcgetattr(fd, &oldtio);
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tio = oldtio;
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#if 0
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/* Switch off UPPERCASE->lowercase conversion (never used since 198x)
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* and XON/XOFF (why we want to mess with this??)
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*/
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# ifndef IUCLC
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# define IUCLC 0
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# endif
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tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
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#endif
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/* Switch off echo */
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tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL);
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tcsetattr(fd, TCSANOW, &tio);
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memset(&sa, 0, sizeof(sa));
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/* sa.sa_flags = 0; - no SA_RESTART! */
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/* SIGINT and SIGALRM will interrupt reads below */
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sa.sa_handler = askpass_timeout;
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sigaction(SIGINT, &sa, &oldsa);
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if (timeout) {
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sigaction_set(SIGALRM, &sa);
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alarm(timeout);
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}
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if (!passwd)
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passwd = xmalloc(sizeof_passwd);
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ret = passwd;
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i = 0;
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while (1) {
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int r = read(fd, &ret[i], 1);
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if ((i == 0 && r == 0) /* EOF (^D) with no password */
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|| r < 0
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) {
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/* read is interrupted by timeout or ^C */
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ret = NULL;
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break;
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}
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if (r == 0 /* EOF */
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|| ret[i] == '\r' || ret[i] == '\n' /* EOL */
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|| ++i == sizeof_passwd-1 /* line limit */
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) {
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ret[i] = '\0';
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break;
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}
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}
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if (timeout) {
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alarm(0);
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}
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sigaction_set(SIGINT, &oldsa);
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tcsetattr(fd, TCSANOW, &oldtio);
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bb_putchar('\n');
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fflush_all();
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return ret;
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}
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