mirror of git://anongit.mindrot.org/openssh.git
650 lines
16 KiB
C
650 lines
16 KiB
C
/* $OpenBSD: auth-options.c,v 1.54 2010/12/24 21:41:48 djm Exp $ */
|
|
/*
|
|
* Author: Tatu Ylonen <ylo@cs.hut.fi>
|
|
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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".
|
|
*/
|
|
|
|
#include "includes.h"
|
|
|
|
#include <sys/types.h>
|
|
|
|
#include <netdb.h>
|
|
#include <pwd.h>
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <stdarg.h>
|
|
|
|
#include "openbsd-compat/sys-queue.h"
|
|
#include "xmalloc.h"
|
|
#include "match.h"
|
|
#include "log.h"
|
|
#include "canohost.h"
|
|
#include "buffer.h"
|
|
#include "channels.h"
|
|
#include "servconf.h"
|
|
#include "misc.h"
|
|
#include "key.h"
|
|
#include "auth-options.h"
|
|
#include "hostfile.h"
|
|
#include "auth.h"
|
|
#ifdef GSSAPI
|
|
#include "ssh-gss.h"
|
|
#endif
|
|
#include "monitor_wrap.h"
|
|
|
|
/* Flags set authorized_keys flags */
|
|
int no_port_forwarding_flag = 0;
|
|
int no_agent_forwarding_flag = 0;
|
|
int no_x11_forwarding_flag = 0;
|
|
int no_pty_flag = 0;
|
|
int no_user_rc = 0;
|
|
int key_is_cert_authority = 0;
|
|
|
|
/* "command=" option. */
|
|
char *forced_command = NULL;
|
|
|
|
/* "environment=" options. */
|
|
struct envstring *custom_environment = NULL;
|
|
|
|
/* "tunnel=" option. */
|
|
int forced_tun_device = -1;
|
|
|
|
/* "principals=" option. */
|
|
char *authorized_principals = NULL;
|
|
|
|
extern ServerOptions options;
|
|
|
|
void
|
|
auth_clear_options(void)
|
|
{
|
|
no_agent_forwarding_flag = 0;
|
|
no_port_forwarding_flag = 0;
|
|
no_pty_flag = 0;
|
|
no_x11_forwarding_flag = 0;
|
|
no_user_rc = 0;
|
|
key_is_cert_authority = 0;
|
|
while (custom_environment) {
|
|
struct envstring *ce = custom_environment;
|
|
custom_environment = ce->next;
|
|
xfree(ce->s);
|
|
xfree(ce);
|
|
}
|
|
if (forced_command) {
|
|
xfree(forced_command);
|
|
forced_command = NULL;
|
|
}
|
|
if (authorized_principals) {
|
|
xfree(authorized_principals);
|
|
authorized_principals = NULL;
|
|
}
|
|
forced_tun_device = -1;
|
|
channel_clear_permitted_opens();
|
|
}
|
|
|
|
/*
|
|
* return 1 if access is granted, 0 if not.
|
|
* side effect: sets key option flags
|
|
*/
|
|
int
|
|
auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
|
|
{
|
|
const char *cp;
|
|
int i;
|
|
|
|
/* reset options */
|
|
auth_clear_options();
|
|
|
|
if (!opts)
|
|
return 1;
|
|
|
|
while (*opts && *opts != ' ' && *opts != '\t') {
|
|
cp = "cert-authority";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
key_is_cert_authority = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "no-port-forwarding";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
auth_debug_add("Port forwarding disabled.");
|
|
no_port_forwarding_flag = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "no-agent-forwarding";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
auth_debug_add("Agent forwarding disabled.");
|
|
no_agent_forwarding_flag = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "no-X11-forwarding";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
auth_debug_add("X11 forwarding disabled.");
|
|
no_x11_forwarding_flag = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "no-pty";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
auth_debug_add("Pty allocation disabled.");
|
|
no_pty_flag = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "no-user-rc";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
auth_debug_add("User rc file execution disabled.");
|
|
no_user_rc = 1;
|
|
opts += strlen(cp);
|
|
goto next_option;
|
|
}
|
|
cp = "command=\"";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
opts += strlen(cp);
|
|
if (forced_command != NULL)
|
|
xfree(forced_command);
|
|
forced_command = xmalloc(strlen(opts) + 1);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
if (*opts == '\\' && opts[1] == '"') {
|
|
opts += 2;
|
|
forced_command[i++] = '"';
|
|
continue;
|
|
}
|
|
forced_command[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
xfree(forced_command);
|
|
forced_command = NULL;
|
|
goto bad_option;
|
|
}
|
|
forced_command[i] = '\0';
|
|
auth_debug_add("Forced command.");
|
|
opts++;
|
|
goto next_option;
|
|
}
|
|
cp = "principals=\"";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
opts += strlen(cp);
|
|
if (authorized_principals != NULL)
|
|
xfree(authorized_principals);
|
|
authorized_principals = xmalloc(strlen(opts) + 1);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
if (*opts == '\\' && opts[1] == '"') {
|
|
opts += 2;
|
|
authorized_principals[i++] = '"';
|
|
continue;
|
|
}
|
|
authorized_principals[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
xfree(authorized_principals);
|
|
authorized_principals = NULL;
|
|
goto bad_option;
|
|
}
|
|
authorized_principals[i] = '\0';
|
|
auth_debug_add("principals: %.900s",
|
|
authorized_principals);
|
|
opts++;
|
|
goto next_option;
|
|
}
|
|
cp = "environment=\"";
|
|
if (options.permit_user_env &&
|
|
strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
char *s;
|
|
struct envstring *new_envstring;
|
|
|
|
opts += strlen(cp);
|
|
s = xmalloc(strlen(opts) + 1);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
if (*opts == '\\' && opts[1] == '"') {
|
|
opts += 2;
|
|
s[i++] = '"';
|
|
continue;
|
|
}
|
|
s[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
xfree(s);
|
|
goto bad_option;
|
|
}
|
|
s[i] = '\0';
|
|
auth_debug_add("Adding to environment: %.900s", s);
|
|
debug("Adding to environment: %.900s", s);
|
|
opts++;
|
|
new_envstring = xmalloc(sizeof(struct envstring));
|
|
new_envstring->s = s;
|
|
new_envstring->next = custom_environment;
|
|
custom_environment = new_envstring;
|
|
goto next_option;
|
|
}
|
|
cp = "from=\"";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
const char *remote_ip = get_remote_ipaddr();
|
|
const char *remote_host = get_canonical_hostname(
|
|
options.use_dns);
|
|
char *patterns = xmalloc(strlen(opts) + 1);
|
|
|
|
opts += strlen(cp);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
if (*opts == '\\' && opts[1] == '"') {
|
|
opts += 2;
|
|
patterns[i++] = '"';
|
|
continue;
|
|
}
|
|
patterns[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
xfree(patterns);
|
|
goto bad_option;
|
|
}
|
|
patterns[i] = '\0';
|
|
opts++;
|
|
switch (match_host_and_ip(remote_host, remote_ip,
|
|
patterns)) {
|
|
case 1:
|
|
xfree(patterns);
|
|
/* Host name matches. */
|
|
goto next_option;
|
|
case -1:
|
|
debug("%.100s, line %lu: invalid criteria",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: "
|
|
"invalid criteria", file, linenum);
|
|
/* FALLTHROUGH */
|
|
case 0:
|
|
xfree(patterns);
|
|
logit("Authentication tried for %.100s with "
|
|
"correct key but not from a permitted "
|
|
"host (host=%.200s, ip=%.200s).",
|
|
pw->pw_name, remote_host, remote_ip);
|
|
auth_debug_add("Your host '%.200s' is not "
|
|
"permitted to use this key for login.",
|
|
remote_host);
|
|
break;
|
|
}
|
|
/* deny access */
|
|
return 0;
|
|
}
|
|
cp = "permitopen=\"";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
char *host, *p;
|
|
int port;
|
|
char *patterns = xmalloc(strlen(opts) + 1);
|
|
|
|
opts += strlen(cp);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
if (*opts == '\\' && opts[1] == '"') {
|
|
opts += 2;
|
|
patterns[i++] = '"';
|
|
continue;
|
|
}
|
|
patterns[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing "
|
|
"end quote", file, linenum);
|
|
xfree(patterns);
|
|
goto bad_option;
|
|
}
|
|
patterns[i] = '\0';
|
|
opts++;
|
|
p = patterns;
|
|
host = hpdelim(&p);
|
|
if (host == NULL || strlen(host) >= NI_MAXHOST) {
|
|
debug("%.100s, line %lu: Bad permitopen "
|
|
"specification <%.100s>", file, linenum,
|
|
patterns);
|
|
auth_debug_add("%.100s, line %lu: "
|
|
"Bad permitopen specification", file,
|
|
linenum);
|
|
xfree(patterns);
|
|
goto bad_option;
|
|
}
|
|
host = cleanhostname(host);
|
|
if (p == NULL || (port = a2port(p)) <= 0) {
|
|
debug("%.100s, line %lu: Bad permitopen port "
|
|
"<%.100s>", file, linenum, p ? p : "");
|
|
auth_debug_add("%.100s, line %lu: "
|
|
"Bad permitopen port", file, linenum);
|
|
xfree(patterns);
|
|
goto bad_option;
|
|
}
|
|
if (options.allow_tcp_forwarding)
|
|
channel_add_permitted_opens(host, port);
|
|
xfree(patterns);
|
|
goto next_option;
|
|
}
|
|
cp = "tunnel=\"";
|
|
if (strncasecmp(opts, cp, strlen(cp)) == 0) {
|
|
char *tun = NULL;
|
|
opts += strlen(cp);
|
|
tun = xmalloc(strlen(opts) + 1);
|
|
i = 0;
|
|
while (*opts) {
|
|
if (*opts == '"')
|
|
break;
|
|
tun[i++] = *opts++;
|
|
}
|
|
if (!*opts) {
|
|
debug("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: missing end quote",
|
|
file, linenum);
|
|
xfree(tun);
|
|
forced_tun_device = -1;
|
|
goto bad_option;
|
|
}
|
|
tun[i] = '\0';
|
|
forced_tun_device = a2tun(tun, NULL);
|
|
xfree(tun);
|
|
if (forced_tun_device == SSH_TUNID_ERR) {
|
|
debug("%.100s, line %lu: invalid tun device",
|
|
file, linenum);
|
|
auth_debug_add("%.100s, line %lu: invalid tun device",
|
|
file, linenum);
|
|
forced_tun_device = -1;
|
|
goto bad_option;
|
|
}
|
|
auth_debug_add("Forced tun device: %d", forced_tun_device);
|
|
opts++;
|
|
goto next_option;
|
|
}
|
|
next_option:
|
|
/*
|
|
* Skip the comma, and move to the next option
|
|
* (or break out if there are no more).
|
|
*/
|
|
if (!*opts)
|
|
fatal("Bugs in auth-options.c option processing.");
|
|
if (*opts == ' ' || *opts == '\t')
|
|
break; /* End of options. */
|
|
if (*opts != ',')
|
|
goto bad_option;
|
|
opts++;
|
|
/* Process the next option. */
|
|
}
|
|
|
|
/* grant access */
|
|
return 1;
|
|
|
|
bad_option:
|
|
logit("Bad options in %.100s file, line %lu: %.50s",
|
|
file, linenum, opts);
|
|
auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
|
|
file, linenum, opts);
|
|
|
|
/* deny access */
|
|
return 0;
|
|
}
|
|
|
|
#define OPTIONS_CRITICAL 1
|
|
#define OPTIONS_EXTENSIONS 2
|
|
static int
|
|
parse_option_list(u_char *optblob, size_t optblob_len, struct passwd *pw,
|
|
u_int which, int crit,
|
|
int *cert_no_port_forwarding_flag,
|
|
int *cert_no_agent_forwarding_flag,
|
|
int *cert_no_x11_forwarding_flag,
|
|
int *cert_no_pty_flag,
|
|
int *cert_no_user_rc,
|
|
char **cert_forced_command,
|
|
int *cert_source_address_done)
|
|
{
|
|
char *command, *allowed;
|
|
const char *remote_ip;
|
|
u_char *name = NULL, *data_blob = NULL;
|
|
u_int nlen, dlen, clen;
|
|
Buffer c, data;
|
|
int ret = -1, found;
|
|
|
|
buffer_init(&data);
|
|
|
|
/* Make copy to avoid altering original */
|
|
buffer_init(&c);
|
|
buffer_append(&c, optblob, optblob_len);
|
|
|
|
while (buffer_len(&c) > 0) {
|
|
if ((name = buffer_get_cstring_ret(&c, &nlen)) == NULL ||
|
|
(data_blob = buffer_get_string_ret(&c, &dlen)) == NULL) {
|
|
error("Certificate options corrupt");
|
|
goto out;
|
|
}
|
|
buffer_append(&data, data_blob, dlen);
|
|
debug3("found certificate option \"%.100s\" len %u",
|
|
name, dlen);
|
|
if (strlen(name) != nlen) {
|
|
error("Certificate constraint name contains \\0");
|
|
goto out;
|
|
}
|
|
found = 0;
|
|
if ((which & OPTIONS_EXTENSIONS) != 0) {
|
|
if (strcmp(name, "permit-X11-forwarding") == 0) {
|
|
*cert_no_x11_forwarding_flag = 0;
|
|
found = 1;
|
|
} else if (strcmp(name,
|
|
"permit-agent-forwarding") == 0) {
|
|
*cert_no_agent_forwarding_flag = 0;
|
|
found = 1;
|
|
} else if (strcmp(name,
|
|
"permit-port-forwarding") == 0) {
|
|
*cert_no_port_forwarding_flag = 0;
|
|
found = 1;
|
|
} else if (strcmp(name, "permit-pty") == 0) {
|
|
*cert_no_pty_flag = 0;
|
|
found = 1;
|
|
} else if (strcmp(name, "permit-user-rc") == 0) {
|
|
*cert_no_user_rc = 0;
|
|
found = 1;
|
|
}
|
|
}
|
|
if (!found && (which & OPTIONS_CRITICAL) != 0) {
|
|
if (strcmp(name, "force-command") == 0) {
|
|
if ((command = buffer_get_cstring_ret(&data,
|
|
&clen)) == NULL) {
|
|
error("Certificate constraint \"%s\" "
|
|
"corrupt", name);
|
|
goto out;
|
|
}
|
|
if (strlen(command) != clen) {
|
|
error("force-command constraint "
|
|
"contains \\0");
|
|
goto out;
|
|
}
|
|
if (*cert_forced_command != NULL) {
|
|
error("Certificate has multiple "
|
|
"force-command options");
|
|
xfree(command);
|
|
goto out;
|
|
}
|
|
*cert_forced_command = command;
|
|
found = 1;
|
|
}
|
|
if (strcmp(name, "source-address") == 0) {
|
|
if ((allowed = buffer_get_cstring_ret(&data,
|
|
&clen)) == NULL) {
|
|
error("Certificate constraint "
|
|
"\"%s\" corrupt", name);
|
|
goto out;
|
|
}
|
|
if (strlen(allowed) != clen) {
|
|
error("source-address constraint "
|
|
"contains \\0");
|
|
goto out;
|
|
}
|
|
if ((*cert_source_address_done)++) {
|
|
error("Certificate has multiple "
|
|
"source-address options");
|
|
xfree(allowed);
|
|
goto out;
|
|
}
|
|
remote_ip = get_remote_ipaddr();
|
|
switch (addr_match_cidr_list(remote_ip,
|
|
allowed)) {
|
|
case 1:
|
|
/* accepted */
|
|
xfree(allowed);
|
|
break;
|
|
case 0:
|
|
/* no match */
|
|
logit("Authentication tried for %.100s "
|
|
"with valid certificate but not "
|
|
"from a permitted host "
|
|
"(ip=%.200s).", pw->pw_name,
|
|
remote_ip);
|
|
auth_debug_add("Your address '%.200s' "
|
|
"is not permitted to use this "
|
|
"certificate for login.",
|
|
remote_ip);
|
|
xfree(allowed);
|
|
goto out;
|
|
case -1:
|
|
error("Certificate source-address "
|
|
"contents invalid");
|
|
xfree(allowed);
|
|
goto out;
|
|
}
|
|
found = 1;
|
|
}
|
|
}
|
|
|
|
if (!found) {
|
|
if (crit) {
|
|
error("Certificate critical option \"%s\" "
|
|
"is not supported", name);
|
|
goto out;
|
|
} else {
|
|
logit("Certificate extension \"%s\" "
|
|
"is not supported", name);
|
|
}
|
|
} else if (buffer_len(&data) != 0) {
|
|
error("Certificate option \"%s\" corrupt "
|
|
"(extra data)", name);
|
|
goto out;
|
|
}
|
|
buffer_clear(&data);
|
|
xfree(name);
|
|
xfree(data_blob);
|
|
name = data_blob = NULL;
|
|
}
|
|
/* successfully parsed all options */
|
|
ret = 0;
|
|
|
|
out:
|
|
if (ret != 0 &&
|
|
cert_forced_command != NULL &&
|
|
*cert_forced_command != NULL) {
|
|
xfree(*cert_forced_command);
|
|
*cert_forced_command = NULL;
|
|
}
|
|
if (name != NULL)
|
|
xfree(name);
|
|
if (data_blob != NULL)
|
|
xfree(data_blob);
|
|
buffer_free(&data);
|
|
buffer_free(&c);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Set options from critical certificate options. These supersede user key
|
|
* options so this must be called after auth_parse_options().
|
|
*/
|
|
int
|
|
auth_cert_options(Key *k, struct passwd *pw)
|
|
{
|
|
int cert_no_port_forwarding_flag = 1;
|
|
int cert_no_agent_forwarding_flag = 1;
|
|
int cert_no_x11_forwarding_flag = 1;
|
|
int cert_no_pty_flag = 1;
|
|
int cert_no_user_rc = 1;
|
|
char *cert_forced_command = NULL;
|
|
int cert_source_address_done = 0;
|
|
|
|
if (key_cert_is_legacy(k)) {
|
|
/* All options are in the one field for v00 certs */
|
|
if (parse_option_list(buffer_ptr(&k->cert->critical),
|
|
buffer_len(&k->cert->critical), pw,
|
|
OPTIONS_CRITICAL|OPTIONS_EXTENSIONS, 1,
|
|
&cert_no_port_forwarding_flag,
|
|
&cert_no_agent_forwarding_flag,
|
|
&cert_no_x11_forwarding_flag,
|
|
&cert_no_pty_flag,
|
|
&cert_no_user_rc,
|
|
&cert_forced_command,
|
|
&cert_source_address_done) == -1)
|
|
return -1;
|
|
} else {
|
|
/* Separate options and extensions for v01 certs */
|
|
if (parse_option_list(buffer_ptr(&k->cert->critical),
|
|
buffer_len(&k->cert->critical), pw,
|
|
OPTIONS_CRITICAL, 1, NULL, NULL, NULL, NULL, NULL,
|
|
&cert_forced_command,
|
|
&cert_source_address_done) == -1)
|
|
return -1;
|
|
if (parse_option_list(buffer_ptr(&k->cert->extensions),
|
|
buffer_len(&k->cert->extensions), pw,
|
|
OPTIONS_EXTENSIONS, 1,
|
|
&cert_no_port_forwarding_flag,
|
|
&cert_no_agent_forwarding_flag,
|
|
&cert_no_x11_forwarding_flag,
|
|
&cert_no_pty_flag,
|
|
&cert_no_user_rc,
|
|
NULL, NULL) == -1)
|
|
return -1;
|
|
}
|
|
|
|
no_port_forwarding_flag |= cert_no_port_forwarding_flag;
|
|
no_agent_forwarding_flag |= cert_no_agent_forwarding_flag;
|
|
no_x11_forwarding_flag |= cert_no_x11_forwarding_flag;
|
|
no_pty_flag |= cert_no_pty_flag;
|
|
no_user_rc |= cert_no_user_rc;
|
|
/* CA-specified forced command supersedes key option */
|
|
if (cert_forced_command != NULL) {
|
|
if (forced_command != NULL)
|
|
xfree(forced_command);
|
|
forced_command = cert_forced_command;
|
|
}
|
|
return 0;
|
|
}
|
|
|