upstream: Introduce a new API for handling authorized_keys options.
This API parses options to a dedicated structure rather than the old API's approach of setting global state. It also includes support for merging options, e.g. from authorized_keys, authorized_principals and/or certificates. feedback and ok markus@ OpenBSD-Commit-ID: 98badda102cd575210d7802943e93a34232c80a2
This commit is contained in:
djm@openbsd.org
Damien Miller
parent
2607438076
commit
90c4bec8b5
829
auth-options.c
829
auth-options.c
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@ -1,4 +1,4 @@
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/* $OpenBSD: auth-options.c,v 1.74 2017/09/12 06:32:07 djm Exp $ */
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/* $OpenBSD: auth-options.c,v 1.75 2018/03/03 03:06:02 djm Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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@ -9,6 +9,21 @@
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*/
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/*
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* Copyright (c) 2018 Damien Miller <djm@mindrot.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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@ -19,6 +34,8 @@
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#include <string.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <ctype.h>
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#include <limits.h>
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#include "openbsd-compat/sys-queue.h"
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@ -27,6 +44,7 @@
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#include "xmalloc.h"
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#include "match.h"
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#include "ssherr.h"
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#include "ssh2.h"
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#include "log.h"
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#include "canohost.h"
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#include "packet.h"
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@ -661,3 +679,812 @@ auth_cert_options(struct sshkey *k, struct passwd *pw, const char **reason)
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return 0;
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}
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/*
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* authorized_keys options processing.
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*/
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/*
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* Match flag 'opt' in *optsp, and if allow_negate is set then also match
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* 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0
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* if negated option matches.
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* If the option or negated option matches, then *optsp is updated to
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* point to the first character after the option.
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*/
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static int
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opt_flag(const char *opt, int allow_negate, const char **optsp)
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{
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size_t opt_len = strlen(opt);
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const char *opts = *optsp;
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int negate = 0;
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if (allow_negate && strncasecmp(opts, "no-", 3) == 0) {
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opts += 3;
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negate = 1;
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}
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if (strncasecmp(opts, opt, opt_len) == 0) {
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*optsp = opts + opt_len;
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return negate ? 0 : 1;
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}
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return -1;
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}
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static char *
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opt_dequote(const char **sp, const char **errstrp)
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{
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const char *s = *sp;
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char *ret;
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size_t i;
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*errstrp = NULL;
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if (*s != '"') {
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*errstrp = "missing start quote";
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return NULL;
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}
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s++;
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if ((ret = malloc(strlen((s)) + 1)) == NULL) {
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*errstrp = "memory allocation failed";
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return NULL;
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}
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for (i = 0; *s != '\0' && *s != '"';) {
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if (s[0] == '\\' && s[1] == '"')
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s++;
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ret[i++] = *s++;
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}
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if (*s == '\0') {
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*errstrp = "missing end quote";
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free(ret);
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return NULL;
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}
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ret[i] = '\0';
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s++;
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*sp = s;
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return ret;
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}
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static int
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opt_match(const char **opts, const char *term)
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{
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if (strncasecmp((*opts), term, strlen(term)) == 0 &&
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(*opts)[strlen(term)] == '=') {
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*opts += strlen(term) + 1;
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return 1;
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}
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return 0;
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}
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static int
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dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc)
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{
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char **dst;
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size_t i, j;
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*dstp = NULL;
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*ndstp = 0;
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if (nsrc == 0)
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return 0;
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if ((dst = calloc(nsrc, sizeof(*src))) == NULL)
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return -1;
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for (i = 0; i < nsrc; i++) {
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if ((dst[i] = strdup(src[i])) == NULL) {
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for (j = 0; j < i; j++)
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free(dst[j]);
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free(dst);
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return -1;
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}
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}
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/* success */
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*dstp = dst;
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*ndstp = nsrc;
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return 0;
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}
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#define OPTIONS_CRITICAL 1
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#define OPTIONS_EXTENSIONS 2
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static int
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cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob,
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u_int which, int crit)
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{
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char *command, *allowed;
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char *name = NULL;
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struct sshbuf *c = NULL, *data = NULL;
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int r, ret = -1, found;
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if ((c = sshbuf_fromb(oblob)) == NULL) {
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error("%s: sshbuf_fromb failed", __func__);
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goto out;
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}
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while (sshbuf_len(c) > 0) {
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sshbuf_free(data);
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data = NULL;
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if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 ||
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(r = sshbuf_froms(c, &data)) != 0) {
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error("Unable to parse certificate options: %s",
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ssh_err(r));
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goto out;
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}
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debug3("found certificate option \"%.100s\" len %zu",
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name, sshbuf_len(data));
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found = 0;
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if ((which & OPTIONS_EXTENSIONS) != 0) {
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if (strcmp(name, "permit-X11-forwarding") == 0) {
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opts->permit_x11_forwarding_flag = 1;
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found = 1;
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} else if (strcmp(name,
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"permit-agent-forwarding") == 0) {
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opts->permit_agent_forwarding_flag = 1;
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found = 1;
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} else if (strcmp(name,
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"permit-port-forwarding") == 0) {
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opts->permit_port_forwarding_flag = 1;
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found = 1;
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} else if (strcmp(name, "permit-pty") == 0) {
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opts->permit_pty_flag = 1;
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found = 1;
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} else if (strcmp(name, "permit-user-rc") == 0) {
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opts->permit_user_rc = 1;
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found = 1;
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}
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}
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if (!found && (which & OPTIONS_CRITICAL) != 0) {
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if (strcmp(name, "force-command") == 0) {
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if ((r = sshbuf_get_cstring(data, &command,
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NULL)) != 0) {
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error("Unable to parse \"%s\" "
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"section: %s", name, ssh_err(r));
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goto out;
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}
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if (opts->force_command != NULL) {
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error("Certificate has multiple "
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"force-command options");
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free(command);
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goto out;
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}
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opts->force_command = command;
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found = 1;
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}
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if (strcmp(name, "source-address") == 0) {
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if ((r = sshbuf_get_cstring(data, &allowed,
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NULL)) != 0) {
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error("Unable to parse \"%s\" "
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"section: %s", name, ssh_err(r));
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goto out;
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}
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if (opts->required_from_host_cert != NULL) {
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error("Certificate has multiple "
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"source-address options");
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free(allowed);
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goto out;
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}
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/* Check syntax */
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if (addr_match_cidr_list(NULL, allowed) == -1) {
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error("Certificate source-address "
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"contents invalid");
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goto out;
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}
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opts->required_from_host_cert = allowed;
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found = 1;
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}
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}
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if (!found) {
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if (crit) {
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error("Certificate critical option \"%s\" "
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"is not supported", name);
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goto out;
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} else {
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logit("Certificate extension \"%s\" "
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"is not supported", name);
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}
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} else if (sshbuf_len(data) != 0) {
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error("Certificate option \"%s\" corrupt "
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"(extra data)", name);
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goto out;
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}
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free(name);
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name = NULL;
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}
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/* successfully parsed all options */
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ret = 0;
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out:
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free(name);
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sshbuf_free(data);
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sshbuf_free(c);
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return ret;
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}
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struct sshauthopt *
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sshauthopt_new(void)
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{
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struct sshauthopt *ret;
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if ((ret = calloc(1, sizeof(*ret))) == NULL)
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return NULL;
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ret->force_tun_device = -1;
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return ret;
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}
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void
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sshauthopt_free(struct sshauthopt *opts)
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{
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size_t i;
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if (opts == NULL)
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return;
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free(opts->cert_principals);
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free(opts->force_command);
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free(opts->required_from_host_cert);
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free(opts->required_from_host_keys);
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for (i = 0; i < opts->nenv; i++)
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free(opts->env[i]);
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free(opts->env);
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for (i = 0; i < opts->npermitopen; i++)
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free(opts->permitopen[i]);
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free(opts->permitopen);
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explicit_bzero(opts, sizeof(*opts));
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free(opts);
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}
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struct sshauthopt *
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sshauthopt_new_with_keys_defaults(void)
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{
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struct sshauthopt *ret = NULL;
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if ((ret = sshauthopt_new()) == NULL)
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return NULL;
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/* Defaults for authorized_keys flags */
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ret->permit_port_forwarding_flag = 1;
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ret->permit_agent_forwarding_flag = 1;
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ret->permit_x11_forwarding_flag = 1;
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ret->permit_pty_flag = 1;
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ret->permit_user_rc = 1;
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return ret;
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}
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struct sshauthopt *
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sshauthopt_parse(const char *opts, const char **errstrp)
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{
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char **oarray, *opt, *cp, *tmp, *host;
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int r;
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struct sshauthopt *ret = NULL;
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const char *errstr = "unknown error";
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if (errstrp != NULL)
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*errstrp = NULL;
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if ((ret = sshauthopt_new_with_keys_defaults()) == NULL)
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goto alloc_fail;
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||||
|
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if (opts == NULL)
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||||
return ret;
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|
||||
while (*opts && *opts != ' ' && *opts != '\t') {
|
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/* flag options */
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if ((r = opt_flag("restrict", 0, &opts)) != -1) {
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ret->restricted = 1;
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ret->permit_port_forwarding_flag = 0;
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ret->permit_agent_forwarding_flag = 0;
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ret->permit_x11_forwarding_flag = 0;
|
||||
ret->permit_pty_flag = 0;
|
||||
ret->permit_user_rc = 0;
|
||||
} else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) {
|
||||
ret->cert_authority = r;
|
||||
} else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) {
|
||||
ret->permit_port_forwarding_flag = r == 1;
|
||||
} else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) {
|
||||
ret->permit_agent_forwarding_flag = r == 1;
|
||||
} else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) {
|
||||
ret->permit_x11_forwarding_flag = r == 1;
|
||||
} else if ((r = opt_flag("pty", 1, &opts)) != -1) {
|
||||
ret->permit_pty_flag = r == 1;
|
||||
} else if ((r = opt_flag("user-rc", 1, &opts)) != -1) {
|
||||
ret->permit_user_rc = r == 1;
|
||||
} else if (opt_match(&opts, "command")) {
|
||||
if (ret->force_command != NULL) {
|
||||
errstr = "multiple \"command\" clauses";
|
||||
goto fail;
|
||||
}
|
||||
ret->force_command = opt_dequote(&opts, &errstr);
|
||||
if (ret->force_command == NULL)
|
||||
goto fail;
|
||||
} else if (opt_match(&opts, "principals")) {
|
||||
if (ret->cert_principals != NULL) {
|
||||
errstr = "multiple \"principals\" clauses";
|
||||
goto fail;
|
||||
}
|
||||
ret->cert_principals = opt_dequote(&opts, &errstr);
|
||||
if (ret->cert_principals == NULL)
|
||||
goto fail;
|
||||
} else if (opt_match(&opts, "from")) {
|
||||
if (ret->required_from_host_keys != NULL) {
|
||||
errstr = "multiple \"from\" clauses";
|
||||
goto fail;
|
||||
}
|
||||
ret->required_from_host_keys = opt_dequote(&opts,
|
||||
&errstr);
|
||||
if (ret->required_from_host_keys == NULL)
|
||||
goto fail;
|
||||
} else if (opt_match(&opts, "environment")) {
|
||||
if (ret->nenv > INT_MAX) {
|
||||
errstr = "too many environment strings";
|
||||
goto fail;
|
||||
}
|
||||
if ((opt = opt_dequote(&opts, &errstr)) == NULL)
|
||||
goto fail;
|
||||
/* env name must be alphanumeric and followed by '=' */
|
||||
if ((tmp = strchr(opt, '=')) == NULL) {
|
||||
free(opt);
|
||||
errstr = "invalid environment string";
|
||||
goto fail;
|
||||
}
|
||||
for (cp = opt; cp < tmp; cp++) {
|
||||
if (!isalnum((u_char)*cp)) {
|
||||
free(opt);
|
||||
errstr = "invalid environment string";
|
||||
goto fail;
|
||||
}
|
||||
}
|
||||
/* Append it. */
|
||||
oarray = ret->env;
|
||||
if ((ret->env = recallocarray(ret->env, ret->nenv,
|
||||
ret->nenv + 1, sizeof(*ret->env))) == NULL) {
|
||||
free(opt);
|
||||
ret->env = oarray; /* put it back for cleanup */
|
||||
goto alloc_fail;
|
||||
}
|
||||
ret->env[ret->nenv++] = opt;
|
||||
} else if (opt_match(&opts, "permitopen")) {
|
||||
if (ret->npermitopen > INT_MAX) {
|
||||
errstr = "too many permitopens";
|
||||
goto fail;
|
||||
}
|
||||
if ((opt = opt_dequote(&opts, &errstr)) == NULL)
|
||||
goto fail;
|
||||
if ((tmp = strdup(opt)) == NULL) {
|
||||
free(opt);
|
||||
goto alloc_fail;
|
||||
}
|
||||
cp = tmp;
|
||||
/* validate syntax of permitopen before recording it. */
|
||||
host = hpdelim(&cp);
|
||||
if (host == NULL || strlen(host) >= NI_MAXHOST) {
|
||||
free(tmp);
|
||||
free(opt);
|
||||
errstr = "invalid permitopen hostname";
|
||||
goto fail;
|
||||
}
|
||||
/*
|
||||
* don't want to use permitopen_port to avoid
|
||||
* dependency on channels.[ch] here.
|
||||
*/
|
||||
if (cp == NULL ||
|
||||
(strcmp(cp, "*") != 0 && a2port(cp) <= 0)) {
|
||||
free(tmp);
|
||||
free(opt);
|
||||
errstr = "invalid permitopen port";
|
||||
goto fail;
|
||||
}
|
||||
/* XXX - add streamlocal support */
|
||||
free(tmp);
|
||||
/* Record it */
|
||||
oarray = ret->permitopen;
|
||||
if ((ret->permitopen = recallocarray(ret->permitopen,
|
||||
ret->npermitopen, ret->npermitopen + 1,
|
||||
sizeof(*ret->permitopen))) == NULL) {
|
||||
free(opt);
|
||||
ret->permitopen = oarray;
|
||||
goto alloc_fail;
|
||||
}
|
||||
ret->permitopen[ret->npermitopen++] = opt;
|
||||
} else if (opt_match(&opts, "tunnel")) {
|
||||
if ((opt = opt_dequote(&opts, &errstr)) == NULL)
|
||||
goto fail;
|
||||
ret->force_tun_device = a2tun(opt, NULL);
|
||||
free(opt);
|
||||
if (ret->force_tun_device == SSH_TUNID_ERR) {
|
||||
errstr = "invalid tun device";
|
||||
goto fail;
|
||||
}
|
||||
}
|
||||
/*
|
||||
* Skip the comma, and move to the next option
|
||||
* (or break out if there are no more).
|
||||
*/
|
||||
if (*opts == '\0' || *opts == ' ' || *opts == '\t')
|
||||
break; /* End of options. */
|
||||
/* Anything other than a comma is an unknown option */
|
||||
if (*opts != ',') {
|
||||
errstr = "unknown key option";
|
||||
goto fail;
|
||||
}
|
||||
opts++;
|
||||
if (*opts == '\0') {
|
||||
errstr = "unexpected end-of-options";
|
||||
goto fail;
|
||||
}
|
||||
}
|
||||
|
||||
/* success */
|
||||
if (errstrp != NULL)
|
||||
*errstrp = NULL;
|
||||
return ret;
|
||||
|
||||
alloc_fail:
|
||||
errstr = "memory allocation failed";
|
||||
fail:
|
||||
sshauthopt_free(ret);
|
||||
if (errstrp != NULL)
|
||||
*errstrp = errstr;
|
||||
return NULL;
|
||||
}
|
||||
|
||||
struct sshauthopt *
|
||||
sshauthopt_from_cert(struct sshkey *k)
|
||||
{
|
||||
struct sshauthopt *ret;
|
||||
|
||||
if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL ||
|
||||
k->cert->type != SSH2_CERT_TYPE_USER)
|
||||
return NULL;
|
||||
|
||||
if ((ret = sshauthopt_new()) == NULL)
|
||||
return NULL;
|
||||
|
||||
/* Handle options and critical extensions separately */
|
||||
if (cert_option_list(ret, k->cert->critical,
|
||||
OPTIONS_CRITICAL, 1) == -1) {
|
||||
sshauthopt_free(ret);
|
||||
return NULL;
|
||||
}
|
||||
if (cert_option_list(ret, k->cert->extensions,
|
||||
OPTIONS_EXTENSIONS, 0) == -1) {
|
||||
sshauthopt_free(ret);
|
||||
return NULL;
|
||||
}
|
||||
/* success */
|
||||
return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* Merges "additional" options to "primary" and returns the result.
|
||||
* NB. Some options from primary have primacy.
|
||||
*/
|
||||
struct sshauthopt *
|
||||
sshauthopt_merge(const struct sshauthopt *primary,
|
||||
const struct sshauthopt *additional, const char **errstrp)
|
||||
{
|
||||
struct sshauthopt *ret;
|
||||
const char *errstr = "internal error";
|
||||
const char *tmp;
|
||||
|
||||
if (errstrp != NULL)
|
||||
*errstrp = NULL;
|
||||
|
||||
if ((ret = sshauthopt_new()) == NULL)
|
||||
goto alloc_fail;
|
||||
|
||||
/* cert_authority and cert_principals are cleared in result */
|
||||
|
||||
/* Prefer access lists from primary. */
|
||||
/* XXX err is both set and mismatch? */
|
||||
tmp = primary->required_from_host_cert;
|
||||
if (tmp == NULL)
|
||||
tmp = additional->required_from_host_cert;
|
||||
if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL)
|
||||
goto alloc_fail;
|
||||
tmp = primary->required_from_host_keys;
|
||||
if (tmp == NULL)
|
||||
tmp = additional->required_from_host_keys;
|
||||
if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL)
|
||||
goto alloc_fail;
|
||||
|
||||
/* force_tun_device, permitopen and environment prefer the primary. */
|
||||
ret->force_tun_device = primary->force_tun_device;
|
||||
if (ret->force_tun_device == -1)
|
||||
ret->force_tun_device = additional->force_tun_device;
|
||||
if (primary->nenv > 0) {
|
||||
if (dup_strings(&ret->env, &ret->nenv,
|
||||
primary->env, primary->nenv) != 0)
|
||||
goto alloc_fail;
|
||||
} else if (additional->nenv) {
|
||||
if (dup_strings(&ret->env, &ret->nenv,
|
||||
additional->env, additional->nenv) != 0)
|
||||
goto alloc_fail;
|
||||
}
|
||||
if (primary->npermitopen > 0) {
|
||||
if (dup_strings(&ret->permitopen, &ret->npermitopen,
|
||||
primary->permitopen, primary->npermitopen) != 0)
|
||||
goto alloc_fail;
|
||||
} else if (additional->npermitopen > 0) {
|
||||
if (dup_strings(&ret->permitopen, &ret->npermitopen,
|
||||
additional->permitopen, additional->npermitopen) != 0)
|
||||
goto alloc_fail;
|
||||
}
|
||||
|
||||
/* Flags are logical-AND (i.e. must be set in both for permission) */
|
||||
#define OPTFLAG(x) ret->x = (primary->x == 1) && (additional->x == 1)
|
||||
OPTFLAG(permit_port_forwarding_flag);
|
||||
OPTFLAG(permit_agent_forwarding_flag);
|
||||
OPTFLAG(permit_x11_forwarding_flag);
|
||||
OPTFLAG(permit_pty_flag);
|
||||
OPTFLAG(permit_user_rc);
|
||||
#undef OPTFLAG
|
||||
|
||||
/*
|
||||
* When both multiple forced-command are specified, only
|
||||
* proceed if they are identical, otherwise fail.
|
||||
*/
|
||||
if (primary->force_command != NULL &&
|
||||
additional->force_command != NULL) {
|
||||
if (strcmp(primary->force_command,
|
||||
additional->force_command) == 0) {
|
||||
/* ok */
|
||||
ret->force_command = strdup(primary->force_command);
|
||||
if (ret->force_command == NULL)
|
||||
goto alloc_fail;
|
||||
} else {
|
||||
errstr = "forced command options do not match";
|
||||
goto fail;
|
||||
}
|
||||
} else if (primary->force_command != NULL) {
|
||||
if ((ret->force_command = strdup(
|
||||
primary->force_command)) == NULL)
|
||||
goto alloc_fail;
|
||||
} else if (additional->force_command != NULL) {
|
||||
if ((ret->force_command = strdup(
|
||||
additional->force_command)) == NULL)
|
||||
goto alloc_fail;
|
||||
}
|
||||
/* success */
|
||||
if (errstrp != NULL)
|
||||
*errstrp = NULL;
|
||||
return ret;
|
||||
|
||||
alloc_fail:
|
||||
errstr = "memory allocation failed";
|
||||
fail:
|
||||
if (errstrp != NULL)
|
||||
*errstrp = errstr;
|
||||
sshauthopt_free(ret);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/*
|
||||
* Copy options
|
||||
*/
|
||||
struct sshauthopt *
|
||||
sshauthopt_copy(const struct sshauthopt *orig)
|
||||
{
|
||||
struct sshauthopt *ret;
|
||||
|
||||
if ((ret = sshauthopt_new()) == NULL)
|
||||
return NULL;
|
||||
|
||||
#define OPTSCALAR(x) ret->x = orig->x
|
||||
OPTSCALAR(permit_port_forwarding_flag);
|
||||
OPTSCALAR(permit_agent_forwarding_flag);
|
||||
OPTSCALAR(permit_x11_forwarding_flag);
|
||||
OPTSCALAR(permit_pty_flag);
|
||||
OPTSCALAR(permit_user_rc);
|
||||
OPTSCALAR(restricted);
|
||||
OPTSCALAR(cert_authority);
|
||||
OPTSCALAR(force_tun_device);
|
||||
#undef OPTSCALAR
|
||||
#define OPTSTRING(x) \
|
||||
do { \
|
||||
if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \
|
||||
sshauthopt_free(ret); \
|
||||
return NULL; \
|
||||
} \
|
||||
} while (0)
|
||||
OPTSTRING(cert_principals);
|
||||
OPTSTRING(force_command);
|
||||
OPTSTRING(required_from_host_cert);
|
||||
OPTSTRING(required_from_host_keys);
|
||||
#undef OPTSTRING
|
||||
|
||||
if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 ||
|
||||
dup_strings(&ret->permitopen, &ret->npermitopen,
|
||||
orig->permitopen, orig->npermitopen) != 0) {
|
||||
sshauthopt_free(ret);
|
||||
return NULL;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int
|
||||
serialise_array(struct sshbuf *m, char **a, size_t n)
|
||||
{
|
||||
struct sshbuf *b;
|
||||
size_t i;
|
||||
int r;
|
||||
|
||||
if (n > INT_MAX)
|
||||
return SSH_ERR_INTERNAL_ERROR;
|
||||
|
||||
if ((b = sshbuf_new()) == NULL) {
|
||||
return SSH_ERR_ALLOC_FAIL;
|
||||
}
|
||||
for (i = 0; i < n; i++) {
|
||||
if ((r = sshbuf_put_cstring(b, a[i])) != 0) {
|
||||
sshbuf_free(b);
|
||||
return r;
|
||||
}
|
||||
}
|
||||
if ((r = sshbuf_put_u32(m, n)) != 0 ||
|
||||
(r = sshbuf_put_stringb(m, b)) != 0) {
|
||||
sshbuf_free(b);
|
||||
return r;
|
||||
}
|
||||
/* success */
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
deserialise_array(struct sshbuf *m, char ***ap, size_t *np)
|
||||
{
|
||||
char **a = NULL;
|
||||
size_t i, n = 0;
|
||||
struct sshbuf *b = NULL;
|
||||
u_int tmp;
|
||||
int r = SSH_ERR_INTERNAL_ERROR;
|
||||
|
||||
if ((r = sshbuf_get_u32(m, &tmp)) != 0 ||
|
||||
(r = sshbuf_froms(m, &b)) != 0)
|
||||
goto out;
|
||||
if (tmp > INT_MAX) {
|
||||
r = SSH_ERR_INVALID_FORMAT;
|
||||
goto out;
|
||||
}
|
||||
n = tmp;
|
||||
if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) {
|
||||
r = SSH_ERR_ALLOC_FAIL;
|
||||
goto out;
|
||||
}
|
||||
for (i = 0; i < n; i++) {
|
||||
if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0)
|
||||
goto out;
|
||||
}
|
||||
/* success */
|
||||
r = 0;
|
||||
*ap = a;
|
||||
a = NULL;
|
||||
*np = n;
|
||||
n = 0;
|
||||
out:
|
||||
for (i = 0; i < n; i++)
|
||||
free(a[i]);
|
||||
free(a);
|
||||
sshbuf_free(b);
|
||||
return r;
|
||||
}
|
||||
|
||||
static int
|
||||
serialise_nullable_string(struct sshbuf *m, const char *s)
|
||||
{
|
||||
int r;
|
||||
|
||||
if ((r = sshbuf_put_u8(m, s == NULL)) != 0 ||
|
||||
(r = sshbuf_put_cstring(m, s)) != 0)
|
||||
return r;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
deserialise_nullable_string(struct sshbuf *m, char **sp)
|
||||
{
|
||||
int r;
|
||||
u_char flag;
|
||||
|
||||
*sp = NULL;
|
||||
if ((r = sshbuf_get_u8(m, &flag)) != 0 ||
|
||||
(r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0)
|
||||
return r;
|
||||
return 0;
|
||||
}
|
||||
|
||||
int
|
||||
sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m,
|
||||
int untrusted)
|
||||
{
|
||||
int r = SSH_ERR_INTERNAL_ERROR;
|
||||
|
||||
/* Flag options */
|
||||
if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->restricted)) != 0 ||
|
||||
(r = sshbuf_put_u8(m, opts->cert_authority)) != 0)
|
||||
return r;
|
||||
|
||||
/* tunnel number can be negative to indicate "unset" */
|
||||
if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 ||
|
||||
(r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ?
|
||||
0 : (u_int)opts->force_tun_device)) != 0)
|
||||
return r;
|
||||
|
||||
/* String options; these may be NULL */
|
||||
if ((r = serialise_nullable_string(m,
|
||||
untrusted ? "yes" : opts->cert_principals)) != 0 ||
|
||||
(r = serialise_nullable_string(m,
|
||||
untrusted ? "true" : opts->force_command)) != 0 ||
|
||||
(r = serialise_nullable_string(m,
|
||||
untrusted ? NULL : opts->required_from_host_cert)) != 0 ||
|
||||
(r = serialise_nullable_string(m,
|
||||
untrusted ? NULL : opts->required_from_host_keys)) != 0)
|
||||
return r;
|
||||
|
||||
/* Array options */
|
||||
if ((r = serialise_array(m, opts->env,
|
||||
untrusted ? 0 : opts->nenv)) != 0 ||
|
||||
(r = serialise_array(m, opts->permitopen,
|
||||
untrusted ? 0 : opts->npermitopen)) != 0)
|
||||
return r;
|
||||
|
||||
/* success */
|
||||
return 0;
|
||||
}
|
||||
|
||||
int
|
||||
sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp)
|
||||
{
|
||||
struct sshauthopt *opts = NULL;
|
||||
int r = SSH_ERR_INTERNAL_ERROR;
|
||||
u_char f;
|
||||
u_int tmp;
|
||||
|
||||
if ((opts = calloc(1, sizeof(*opts))) == NULL)
|
||||
return SSH_ERR_ALLOC_FAIL;
|
||||
|
||||
#define OPT_FLAG(x) \
|
||||
do { \
|
||||
if ((r = sshbuf_get_u8(m, &f)) != 0) \
|
||||
goto out; \
|
||||
opts->x = f; \
|
||||
} while (0)
|
||||
OPT_FLAG(permit_port_forwarding_flag);
|
||||
OPT_FLAG(permit_agent_forwarding_flag);
|
||||
OPT_FLAG(permit_x11_forwarding_flag);
|
||||
OPT_FLAG(permit_pty_flag);
|
||||
OPT_FLAG(permit_user_rc);
|
||||
OPT_FLAG(restricted);
|
||||
OPT_FLAG(cert_authority);
|
||||
#undef OPT_FLAG
|
||||
|
||||
/* tunnel number can be negative to indicate "unset" */
|
||||
if ((r = sshbuf_get_u8(m, &f)) != 0 ||
|
||||
(r = sshbuf_get_u32(m, &tmp)) != 0)
|
||||
goto out;
|
||||
opts->force_tun_device = f ? -1 : (int)tmp;
|
||||
|
||||
/* String options may be NULL */
|
||||
if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 ||
|
||||
(r = deserialise_nullable_string(m, &opts->force_command)) != 0 ||
|
||||
(r = deserialise_nullable_string(m,
|
||||
&opts->required_from_host_cert)) != 0 ||
|
||||
(r = deserialise_nullable_string(m,
|
||||
&opts->required_from_host_keys)) != 0)
|
||||
goto out;
|
||||
|
||||
/* Array options */
|
||||
if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 ||
|
||||
(r = deserialise_array(m,
|
||||
&opts->permitopen, &opts->npermitopen)) != 0)
|
||||
goto out;
|
||||
|
||||
/* success */
|
||||
r = 0;
|
||||
*optsp = opts;
|
||||
opts = NULL;
|
||||
out:
|
||||
sshauthopt_free(opts);
|
||||
return r;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
/* $OpenBSD: auth-options.h,v 1.23 2017/05/31 10:54:00 markus Exp $ */
|
||||
/* $OpenBSD: auth-options.h,v 1.24 2018/03/03 03:06:02 djm Exp $ */
|
||||
|
||||
/*
|
||||
* Author: Tatu Ylonen <ylo@cs.hut.fi>
|
||||
|
|
@ -15,6 +15,9 @@
|
|||
#ifndef AUTH_OPTIONS_H
|
||||
#define AUTH_OPTIONS_H
|
||||
|
||||
struct passwd;
|
||||
struct sshkey;
|
||||
|
||||
/* Linked list of custom environment strings */
|
||||
struct envstring {
|
||||
struct envstring *next;
|
||||
|
|
@ -37,4 +40,69 @@ int auth_parse_options(struct passwd *, char *, const char *, u_long);
|
|||
void auth_clear_options(void);
|
||||
int auth_cert_options(struct sshkey *, struct passwd *, const char **);
|
||||
|
||||
/* authorized_keys options handling */
|
||||
|
||||
/*
|
||||
* sshauthopt represents key options parsed from authorized_keys or
|
||||
* from certificate extensions/options.
|
||||
*/
|
||||
struct sshauthopt {
|
||||
/* Feature flags */
|
||||
int permit_port_forwarding_flag;
|
||||
int permit_agent_forwarding_flag;
|
||||
int permit_x11_forwarding_flag;
|
||||
int permit_pty_flag;
|
||||
int permit_user_rc;
|
||||
|
||||
/* "restrict" keyword was invoked */
|
||||
int restricted;
|
||||
|
||||
/* Certificate-related options */
|
||||
int cert_authority;
|
||||
char *cert_principals;
|
||||
|
||||
int force_tun_device;
|
||||
char *force_command;
|
||||
|
||||
/* Custom environment */
|
||||
size_t nenv;
|
||||
char **env;
|
||||
|
||||
/* Permitted port forwardings */
|
||||
size_t npermitopen;
|
||||
char **permitopen;
|
||||
|
||||
/*
|
||||
* Permitted host/addresses (comma-separated)
|
||||
* Caller must check source address matches both lists (if present).
|
||||
*/
|
||||
char *required_from_host_cert;
|
||||
char *required_from_host_keys;
|
||||
};
|
||||
|
||||
struct sshauthopt *sshauthopt_new(void);
|
||||
struct sshauthopt *sshauthopt_new_with_keys_defaults(void);
|
||||
void sshauthopt_free(struct sshauthopt *opts);
|
||||
struct sshauthopt *sshauthopt_copy(const struct sshauthopt *orig);
|
||||
int sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, int);
|
||||
int sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **opts);
|
||||
|
||||
/*
|
||||
* Parse authorized_keys options. Returns an options structure on success
|
||||
* or NULL on failure. Will set errstr on failure.
|
||||
*/
|
||||
struct sshauthopt *sshauthopt_parse(const char *s, const char **errstr);
|
||||
|
||||
/*
|
||||
* Parse certification options to a struct sshauthopt.
|
||||
* Returns options on success or NULL on failure.
|
||||
*/
|
||||
struct sshauthopt *sshauthopt_from_cert(struct sshkey *k);
|
||||
|
||||
/*
|
||||
* Merge key options.
|
||||
*/
|
||||
struct sshauthopt *sshauthopt_merge(const struct sshauthopt *primary,
|
||||
const struct sshauthopt *additional, const char **errstrp);
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Reference in New Issue