From 2d86a6cc81c8e45b5bca972bbd12f4ebade8d545 Mon Sep 17 00:00:00 2001 From: damien Date: Wed, 8 Dec 1999 23:31:37 +0000 Subject: [PATCH] - OpenBSD CVS updates: - [readpass.c] avoid stdio; based on work by markus, millert, and I - [sshd.c] make sure the client selects a supported cipher - [sshd.c] fix sighup handling. accept would just restart and daemon handled sighup only after the next connection was accepted. use poll on listen sock now. - [sshd.c] make that a fatal --- ChangeLog | 11 ++++ readpass.c | 165 +++++++++++++++++++++++------------------------------ sshd.c | 21 ++++++- 3 files changed, 100 insertions(+), 97 deletions(-) diff --git a/ChangeLog b/ChangeLog index 39304e24..c51d2121 100644 --- a/ChangeLog +++ b/ChangeLog @@ -4,6 +4,17 @@ - "uninstall" rule for Makefile - utmpx support - Should fix PAM problems on Solaris + - OpenBSD CVS updates: + - [readpass.c] + avoid stdio; based on work by markus, millert, and I + - [sshd.c] + make sure the client selects a supported cipher + - [sshd.c] + fix sighup handling. accept would just restart and daemon handled + sighup only after the next connection was accepted. use poll on + listen sock now. + - [sshd.c] + make that a fatal 19991208 - Compile fix for Solaris with /dev/ptmx from diff --git a/readpass.c b/readpass.c index b23959cd..b8f53734 100644 --- a/readpass.c +++ b/readpass.c @@ -1,16 +1,34 @@ /* - * - * readpass.c - * - * Author: Tatu Ylonen - * - * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland - * All rights reserved - * - * Created: Mon Jul 10 22:08:59 1995 ylo - * - * Functions for reading passphrases and passwords. - * + * Copyright (c) 1988, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. */ #include "includes.h" @@ -19,101 +37,58 @@ RCSID("$Id$"); #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). + * passphrase (allocated with xmalloc), being very careful to ensure that + * no other userland buffer is storing the password. */ - char * read_passphrase(const char *prompt, int from_stdin) { - char buf[1024], *cp; - struct termios tio; - FILE *f; + char buf[1024], *p, ch; + struct termios tio, saved_tio; + sigset_t oset, nset; + int input, output, echo = 0; + + if (from_stdin) { + input = STDIN_FILENO; + output = STDERR_FILENO; + } else + input = output = open("/dev/tty", O_RDWR); + + if (input == -1) + fatal("You have no controlling tty. Cannot read passphrase.\n"); - 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); - } + /* block signals, get terminal modes and turn off echo */ + sigemptyset(&nset); + sigaddset(&nset, SIGINT); + sigaddset(&nset, SIGTSTP); + (void) sigprocmask(SIG_BLOCK, &nset, &oset); + + if (tcgetattr(input, &tio) == 0 && (tio.c_lflag & ECHO)) { + echo = 1; + saved_tio = tio; + tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL); + (void) tcsetattr(input, TCSANOW, &tio); } - /* 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); + (void)write(output, prompt, strlen(prompt)); + for (p = buf; read(input, &ch, 1) == 1 && ch != '\n';) + if (p < buf + sizeof(buf) - 1) + *p++ = ch; + *p = '\0'; + (void)write(output, "\n", 1); - /* Set new terminal modes disabling all echo. */ - tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL); - tcsetattr(fileno(f), TCSANOW, &tio); + /* restore terminal modes and allow signals */ + if (echo) + tcsetattr(input, TCSANOW, &saved_tio); + (void) sigprocmask(SIG_SETMASK, &oset, NULL); - /* 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. - */ + if (!from_stdin) + (void)close(input); + p = xstrdup(buf); 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; + return (p); } diff --git a/sshd.c b/sshd.c index 3b4dcd45..d50f7fd7 100644 --- a/sshd.c +++ b/sshd.c @@ -13,6 +13,8 @@ #include "includes.h" RCSID("$Id$"); +#include + #include "xmalloc.h" #include "rsa.h" #include "ssh.h" @@ -419,6 +421,7 @@ main(int ac, char **av) int opt, aux, sock_in, sock_out, newsock, i, pid, on = 1; int remote_major, remote_minor; int silentrsa = 0; + struct pollfd fds; struct sockaddr_in sin; char buf[100]; /* Must not be larger than remote_version. */ char remote_version[100]; /* Must be at least as big as buf. */ @@ -688,7 +691,18 @@ main(int ac, char **av) for (;;) { if (received_sighup) sighup_restart(); - /* Wait in accept until there is a connection. */ + /* Wait in poll until there is a connection. */ + memset(&fds, 0, sizeof(fds)); + fds.fd = listen_sock; + fds.events = POLLIN; + if (poll(&fds, 1, -1) == -1) { + if (errno == EINTR) + continue; + fatal("poll: %.100s", strerror(errno)); + /*NOTREACHED*/ + } + if (fds.revents == 0) + continue; aux = sizeof(sin); newsock = accept(listen_sock, (struct sockaddr *) & sin, &aux); if (received_sighup) @@ -1026,9 +1040,12 @@ do_connection() /* Read clients reply (cipher type and session key). */ packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); - /* Get cipher type. */ + /* Get cipher type and check whether we accept this. */ cipher_type = packet_get_char(); + if (!(cipher_mask() & (1 << cipher_type))) + packet_disconnect("Warning: client selects unsupported cipher."); + /* Get check bytes from the packet. These must match those we sent earlier with the public key packet. */ for (i = 0; i < 8; i++) -- 2.45.2