Mercurial > dropbear
view svr-authpubkeyoptions.c @ 1306:34e6127ef02e
merge fixes from PuTTY import.c
toint() from misc.c
(revids are from hggit conversion)
changeset: 4620:60a336a6c85c
user: Simon Tatham <[email protected]>
date: Thu Feb 25 20:26:33 2016 +0000
files: import.c
description:
Fix potential segfaults in reading OpenSSH's ASN.1 key format.
The length coming back from ber_read_id_len might have overflowed, so
treat it as potentially negative. Also, while I'm here, accumulate it
inside ber_read_id_len as an unsigned, so as to avoid undefined
behaviour on integer overflow, and toint() it before return.
Thanks to Hanno Böck for spotting this, with the aid of AFL.
(cherry picked from commit 5b7833cd474a24ec098654dcba8cb9509f3bf2c1)
Conflicts:
import.c
(cherry-picker's note: resolving the conflict involved removing an
entire section of the original commit which fixed ECDSA code not
present on this branch)
changeset: 4619:9c6c638d98d8
user: Simon Tatham <[email protected]>
date: Sun Jul 14 10:45:54 2013 +0000
files: import.c ssh.c sshdss.c sshpubk.c sshrsa.c
description:
Tighten up a lot of casts from unsigned to int which are read by one
of the GET_32BIT macros and then used as length fields. Missing bounds
checks against zero have been added, and also I've introduced a helper
function toint() which casts from unsigned to int in such a way as to
avoid C undefined behaviour, since I'm not sure I trust compilers any
more to do the obviously sensible thing.
[originally from svn r9918]
changeset: 4618:3957829f24d3
user: Simon Tatham <[email protected]>
date: Mon Jul 08 22:36:04 2013 +0000
files: import.c sshdss.c sshrsa.c
description:
Add an assortment of extra safety checks.
[originally from svn r9896]
changeset: 4617:2cddee0bce12
user: Jacob Nevins <[email protected]>
date: Wed Dec 07 00:24:45 2005 +0000
files: import.c
description:
Institutional failure to memset() things pointed at rather than pointers.
Things should now be zeroed and memory not leaked. Spotted by Brant Thomsen.
[originally from svn r6476]
changeset: 4616:24ac78a9c71d
user: Simon Tatham <[email protected]>
date: Wed Feb 11 13:58:27 2004 +0000
files: import.c
description:
Jacob's last-minute testing found a couple of trivial bugs in
import.c, and my attempts to reproduce them in cmdgen found another
one there :-)
[originally from svn r3847]
changeset: 4615:088d39a73db0
user: Simon Tatham <[email protected]>
date: Thu Jan 22 18:52:49 2004 +0000
files: import.c
description:
Placate some gcc warnings.
[originally from svn r3761]
changeset: 4614:e4288bad4d93
parent: 1758:108b8924593d
user: Simon Tatham <[email protected]>
date: Fri Oct 03 21:21:23 2003 +0000
files: import.c
description:
My ASN.1 decoder returned wrong IDs for anything above 0x1E! Good
job it's never had to yet. Ahem.
[originally from svn r3479]
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Tue, 12 Jul 2016 23:00:01 +0800 |
parents | 5709b15a1b57 |
children | 750ec4ec4cbe ab06e093d1e1 |
line wrap: on
line source
/* * Dropbear - a SSH2 server * * Copyright (c) 2008 Frederic Moulins * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * * This file incorporates work covered by the following copyright and * permission notice: * * Author: Tatu Ylonen <[email protected]> * Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland * All rights reserved * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * This copyright and permission notice applies to the code parsing public keys * options string which can also be found in OpenSSH auth-options.c file * (auth_parse_options). * */ /* Process pubkey options during a pubkey auth request */ #include "includes.h" #include "session.h" #include "dbutil.h" #include "signkey.h" #include "auth.h" #ifdef ENABLE_SVR_PUBKEY_OPTIONS /* Returns 1 if pubkey allows agent forwarding, * 0 otherwise */ int svr_pubkey_allows_agentfwd() { if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->no_agent_forwarding_flag) { return 0; } return 1; } /* Returns 1 if pubkey allows tcp forwarding, * 0 otherwise */ int svr_pubkey_allows_tcpfwd() { if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->no_port_forwarding_flag) { return 0; } return 1; } /* Returns 1 if pubkey allows x11 forwarding, * 0 otherwise */ int svr_pubkey_allows_x11fwd() { if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->no_x11_forwarding_flag) { return 0; } return 1; } /* Returns 1 if pubkey allows pty, 0 otherwise */ int svr_pubkey_allows_pty() { if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->no_pty_flag) { return 0; } return 1; } /* Set chansession command to the one forced * by any 'command' public key option. */ void svr_pubkey_set_forced_command(struct ChanSess *chansess) { if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->forced_command) { if (chansess->cmd) { /* original_command takes ownership */ chansess->original_command = chansess->cmd; } else { chansess->original_command = m_strdup(""); } chansess->cmd = m_strdup(ses.authstate.pubkey_options->forced_command); #ifdef LOG_COMMANDS dropbear_log(LOG_INFO, "Command forced to '%s'", chansess->original_command); #endif } } /* Free potential public key options */ void svr_pubkey_options_cleanup() { if (ses.authstate.pubkey_options) { m_free(ses.authstate.pubkey_options); ses.authstate.pubkey_options = NULL; } } /* helper for svr_add_pubkey_options. returns DROPBEAR_SUCCESS if the option is matched, and increments the options_buf */ static int match_option(buffer *options_buf, const char *opt_name) { const unsigned int len = strlen(opt_name); if (options_buf->len - options_buf->pos < len) { return DROPBEAR_FAILURE; } if (strncasecmp((const char *) buf_getptr(options_buf, len), opt_name, len) == 0) { buf_incrpos(options_buf, len); return DROPBEAR_SUCCESS; } return DROPBEAR_FAILURE; } /* Parse pubkey options and set ses.authstate.pubkey_options accordingly. * Returns DROPBEAR_SUCCESS if key is ok for auth, DROPBEAR_FAILURE otherwise */ int svr_add_pubkey_options(buffer *options_buf, int line_num, const char* filename) { int ret = DROPBEAR_FAILURE; TRACE(("enter addpubkeyoptions")) ses.authstate.pubkey_options = (struct PubKeyOptions*)m_malloc(sizeof( struct PubKeyOptions )); buf_setpos(options_buf, 0); while (options_buf->pos < options_buf->len) { if (match_option(options_buf, "no-port-forwarding") == DROPBEAR_SUCCESS) { dropbear_log(LOG_WARNING, "Port forwarding disabled."); ses.authstate.pubkey_options->no_port_forwarding_flag = 1; goto next_option; } #ifdef ENABLE_SVR_AGENTFWD if (match_option(options_buf, "no-agent-forwarding") == DROPBEAR_SUCCESS) { dropbear_log(LOG_WARNING, "Agent forwarding disabled."); ses.authstate.pubkey_options->no_agent_forwarding_flag = 1; goto next_option; } #endif #ifdef ENABLE_X11FWD if (match_option(options_buf, "no-X11-forwarding") == DROPBEAR_SUCCESS) { dropbear_log(LOG_WARNING, "X11 forwarding disabled."); ses.authstate.pubkey_options->no_x11_forwarding_flag = 1; goto next_option; } #endif if (match_option(options_buf, "no-pty") == DROPBEAR_SUCCESS) { dropbear_log(LOG_WARNING, "Pty allocation disabled."); ses.authstate.pubkey_options->no_pty_flag = 1; goto next_option; } if (match_option(options_buf, "command=\"") == DROPBEAR_SUCCESS) { int escaped = 0; const unsigned char* command_start = buf_getptr(options_buf, 0); while (options_buf->pos < options_buf->len) { const char c = buf_getbyte(options_buf); if (!escaped && c == '"') { const int command_len = buf_getptr(options_buf, 0) - command_start; ses.authstate.pubkey_options->forced_command = m_malloc(command_len); memcpy(ses.authstate.pubkey_options->forced_command, command_start, command_len-1); ses.authstate.pubkey_options->forced_command[command_len-1] = '\0'; dropbear_log(LOG_WARNING, "Forced command '%s'", ses.authstate.pubkey_options->forced_command); goto next_option; } escaped = (!escaped && c == '\\'); } dropbear_log(LOG_WARNING, "Badly formatted command= authorized_keys option"); goto bad_option; } next_option: /* * Skip the comma, and move to the next option * (or break out if there are no more). */ if (options_buf->pos < options_buf->len && buf_getbyte(options_buf) != ',') { goto bad_option; } /* Process the next option. */ } /* parsed all options with no problem */ ret = DROPBEAR_SUCCESS; goto end; bad_option: ret = DROPBEAR_FAILURE; m_free(ses.authstate.pubkey_options); ses.authstate.pubkey_options = NULL; dropbear_log(LOG_WARNING, "Bad public key options at %s:%d", filename, line_num); end: TRACE(("leave addpubkeyoptions")) return ret; } #endif