openssh/auth2-methods.c

135 lines
3.3 KiB
C

/*
* Copyright (c) 2012,2023 Damien Miller <djm@mindrot.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include "log.h"
#include "misc.h"
#include "servconf.h"
#include "xmalloc.h"
#include "hostfile.h"
#include "auth.h"
extern ServerOptions options;
/*
* Configuration of enabled authentication methods. Separate to the rest of
* auth2-*.c because we want to query it during server configuration validity
* checking in the sshd listener process without pulling all the auth code in
* too.
*/
/* "none" is allowed only one time and it cleared by userauth_none() later */
int none_enabled = 1;
struct authmethod_cfg methodcfg_none = {
"none",
NULL,
&none_enabled
};
struct authmethod_cfg methodcfg_pubkey = {
"publickey",
"publickey-hostbound-v00@openssh.com",
&options.pubkey_authentication
};
#ifdef GSSAPI
struct authmethod_cfg methodcfg_gssapi = {
"gssapi-with-mic",
NULL,
&options.gss_authentication
};
#endif
struct authmethod_cfg methodcfg_passwd = {
"password",
NULL,
&options.password_authentication
};
struct authmethod_cfg methodcfg_kbdint = {
"keyboard-interactive",
NULL,
&options.kbd_interactive_authentication
};
struct authmethod_cfg methodcfg_hostbased = {
"hostbased",
NULL,
&options.hostbased_authentication
};
static struct authmethod_cfg *authmethod_cfgs[] = {
&methodcfg_none,
&methodcfg_pubkey,
#ifdef GSSAPI
&methodcfg_gssapi,
#endif
&methodcfg_passwd,
&methodcfg_kbdint,
&methodcfg_hostbased,
NULL
};
/*
* Check a comma-separated list of methods for validity. Is need_enable is
* non-zero, then also require that the methods are enabled.
* Returns 0 on success or -1 if the methods list is invalid.
*/
int
auth2_methods_valid(const char *_methods, int need_enable)
{
char *methods, *omethods, *method, *p;
u_int i, found;
int ret = -1;
const struct authmethod_cfg *cfg;
if (*_methods == '\0') {
error("empty authentication method list");
return -1;
}
omethods = methods = xstrdup(_methods);
while ((method = strsep(&methods, ",")) != NULL) {
for (found = i = 0; !found && authmethod_cfgs[i] != NULL; i++) {
cfg = authmethod_cfgs[i];
if ((p = strchr(method, ':')) != NULL)
*p = '\0';
if (strcmp(method, cfg->name) != 0)
continue;
if (need_enable) {
if (cfg->enabled == NULL ||
*(cfg->enabled) == 0) {
error("Disabled method \"%s\" in "
"AuthenticationMethods list \"%s\"",
method, _methods);
goto out;
}
}
found = 1;
break;
}
if (!found) {
error("Unknown authentication method \"%s\" in list",
method);
goto out;
}
}
ret = 0;
out:
free(omethods);
return ret;
}