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- /* $OpenBSD: monitor.c,v 1.237 2023/08/16 16:14:11 djm Exp $ */
- /*
- * Copyright 2002 Niels Provos <provos@citi.umich.edu>
- * Copyright 2002 Markus Friedl <markus@openbsd.org>
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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"
-
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <sys/wait.h>
-
- #include <errno.h>
- #include <fcntl.h>
- #include <limits.h>
- #ifdef HAVE_PATHS_H
- #include <paths.h>
- #endif
- #include <pwd.h>
- #include <signal.h>
- #ifdef HAVE_STDINT_H
- # include <stdint.h>
- #endif
- #include <stdlib.h>
- #include <string.h>
- #include <stdarg.h>
- #include <stdio.h>
- #include <unistd.h>
- #ifdef HAVE_POLL_H
- #include <poll.h>
- #else
- # ifdef HAVE_SYS_POLL_H
- # include <sys/poll.h>
- # endif
- #endif
-
- #ifdef WITH_OPENSSL
- #include <openssl/dh.h>
- #endif
-
- #include "openbsd-compat/sys-tree.h"
- #include "openbsd-compat/sys-queue.h"
- #include "openbsd-compat/openssl-compat.h"
-
- #include "atomicio.h"
- #include "xmalloc.h"
- #include "ssh.h"
- #include "sshkey.h"
- #include "sshbuf.h"
- #include "hostfile.h"
- #include "auth.h"
- #include "cipher.h"
- #include "kex.h"
- #include "dh.h"
- #include "auth-pam.h"
- #include "packet.h"
- #include "auth-options.h"
- #include "sshpty.h"
- #include "channels.h"
- #include "session.h"
- #include "sshlogin.h"
- #include "canohost.h"
- #include "log.h"
- #include "misc.h"
- #include "servconf.h"
- #include "monitor.h"
- #ifdef GSSAPI
- #include "ssh-gss.h"
- #endif
- #include "monitor_wrap.h"
- #include "monitor_fdpass.h"
- #include "compat.h"
- #include "ssh2.h"
- #include "authfd.h"
- #include "match.h"
- #include "ssherr.h"
- #include "sk-api.h"
-
- #ifdef GSSAPI
- static Gssctxt *gsscontext = NULL;
- #endif
-
- /* Imports */
- extern ServerOptions options;
- extern u_int utmp_len;
- extern struct sshbuf *loginmsg;
- extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */
-
- /* State exported from the child */
- static struct sshbuf *child_state;
-
- /* Functions on the monitor that answer unprivileged requests */
-
- int mm_answer_moduli(struct ssh *, int, struct sshbuf *);
- int mm_answer_sign(struct ssh *, int, struct sshbuf *);
- int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *);
- int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *);
- int mm_answer_authserv(struct ssh *, int, struct sshbuf *);
- int mm_answer_authpassword(struct ssh *, int, struct sshbuf *);
- int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *);
- int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *);
- int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *);
- int mm_answer_keyverify(struct ssh *, int, struct sshbuf *);
- int mm_answer_pty(struct ssh *, int, struct sshbuf *);
- int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *);
- int mm_answer_term(struct ssh *, int, struct sshbuf *);
- int mm_answer_sesskey(struct ssh *, int, struct sshbuf *);
- int mm_answer_sessid(struct ssh *, int, struct sshbuf *);
-
- #ifdef USE_PAM
- int mm_answer_pam_start(struct ssh *, int, struct sshbuf *);
- int mm_answer_pam_account(struct ssh *, int, struct sshbuf *);
- int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *);
- int mm_answer_pam_query(struct ssh *, int, struct sshbuf *);
- int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *);
- int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *);
- #endif
-
- #ifdef GSSAPI
- int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *);
- int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
- int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
- int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
- #endif
-
- #ifdef SSH_AUDIT_EVENTS
- int mm_answer_audit_event(struct ssh *, int, struct sshbuf *);
- int mm_answer_audit_command(struct ssh *, int, struct sshbuf *);
- #endif
-
- static Authctxt *authctxt;
-
- /* local state for key verify */
- static u_char *key_blob = NULL;
- static size_t key_bloblen = 0;
- static u_int key_blobtype = MM_NOKEY;
- static struct sshauthopt *key_opts = NULL;
- static char *hostbased_cuser = NULL;
- static char *hostbased_chost = NULL;
- static char *auth_method = "unknown";
- static char *auth_submethod = NULL;
- static u_int session_id2_len = 0;
- static u_char *session_id2 = NULL;
- static pid_t monitor_child_pid;
-
- struct mon_table {
- enum monitor_reqtype type;
- int flags;
- int (*f)(struct ssh *, int, struct sshbuf *);
- };
-
- #define MON_ISAUTH 0x0004 /* Required for Authentication */
- #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */
- #define MON_ONCE 0x0010 /* Disable after calling */
- #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */
-
- #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE)
-
- #define MON_PERMIT 0x1000 /* Request is permitted */
-
- static int monitor_read(struct ssh *, struct monitor *, struct mon_table *,
- struct mon_table **);
- static int monitor_read_log(struct monitor *);
-
- struct mon_table mon_dispatch_proto20[] = {
- #ifdef WITH_OPENSSL
- {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
- #endif
- {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
- {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
- {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
- {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
- {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
- #ifdef USE_PAM
- {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
- {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
- {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx},
- {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query},
- {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond},
- {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
- #endif
- #ifdef SSH_AUDIT_EVENTS
- {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
- #endif
- #ifdef BSD_AUTH
- {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
- {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
- #endif
- {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
- {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
- #ifdef GSSAPI
- {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
- {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
- {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
- {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
- #endif
- {0, 0, NULL}
- };
-
- struct mon_table mon_dispatch_postauth20[] = {
- #ifdef WITH_OPENSSL
- {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
- #endif
- {MONITOR_REQ_SIGN, 0, mm_answer_sign},
- {MONITOR_REQ_PTY, 0, mm_answer_pty},
- {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
- {MONITOR_REQ_TERM, 0, mm_answer_term},
- #ifdef SSH_AUDIT_EVENTS
- {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
- {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
- #endif
- {0, 0, NULL}
- };
-
- struct mon_table *mon_dispatch;
-
- /* Specifies if a certain message is allowed at the moment */
- static void
- monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
- {
- while (ent->f != NULL) {
- if (ent->type == type) {
- ent->flags &= ~MON_PERMIT;
- ent->flags |= permit ? MON_PERMIT : 0;
- return;
- }
- ent++;
- }
- }
-
- static void
- monitor_permit_authentications(int permit)
- {
- struct mon_table *ent = mon_dispatch;
-
- while (ent->f != NULL) {
- if (ent->flags & MON_AUTH) {
- ent->flags &= ~MON_PERMIT;
- ent->flags |= permit ? MON_PERMIT : 0;
- }
- ent++;
- }
- }
-
- void
- monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor)
- {
- struct mon_table *ent;
- int authenticated = 0, partial = 0;
-
- debug3("preauth child monitor started");
-
- if (pmonitor->m_recvfd >= 0)
- close(pmonitor->m_recvfd);
- if (pmonitor->m_log_sendfd >= 0)
- close(pmonitor->m_log_sendfd);
- pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
-
- authctxt = (Authctxt *)ssh->authctxt;
- memset(authctxt, 0, sizeof(*authctxt));
- ssh->authctxt = authctxt;
-
- authctxt->loginmsg = loginmsg;
-
- mon_dispatch = mon_dispatch_proto20;
- /* Permit requests for moduli and signatures */
- monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
-
- /* The first few requests do not require asynchronous access */
- while (!authenticated) {
- partial = 0;
- auth_method = "unknown";
- auth_submethod = NULL;
- auth2_authctxt_reset_info(authctxt);
-
- authenticated = (monitor_read(ssh, pmonitor,
- mon_dispatch, &ent) == 1);
-
- /* Special handling for multiple required authentications */
- if (options.num_auth_methods != 0) {
- if (authenticated &&
- !auth2_update_methods_lists(authctxt,
- auth_method, auth_submethod)) {
- debug3_f("method %s: partial", auth_method);
- authenticated = 0;
- partial = 1;
- }
- }
-
- if (authenticated) {
- if (!(ent->flags & MON_AUTHDECIDE))
- fatal_f("unexpected authentication from %d",
- ent->type);
- if (authctxt->pw->pw_uid == 0 &&
- !auth_root_allowed(ssh, auth_method))
- authenticated = 0;
- #ifdef USE_PAM
- /* PAM needs to perform account checks after auth */
- if (options.use_pam && authenticated) {
- struct sshbuf *m;
-
- if ((m = sshbuf_new()) == NULL)
- fatal("%s: sshbuf_new failed",
- __func__);
- mm_request_receive_expect(pmonitor->m_sendfd,
- MONITOR_REQ_PAM_ACCOUNT, m);
- authenticated = mm_answer_pam_account(
- ssh, pmonitor->m_sendfd, m);
- sshbuf_free(m);
- }
- #endif
- }
- if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
- auth_log(ssh, authenticated, partial,
- auth_method, auth_submethod);
- if (!partial && !authenticated)
- authctxt->failures++;
- if (authenticated || partial) {
- auth2_update_session_info(authctxt,
- auth_method, auth_submethod);
- }
- }
- if (authctxt->failures > options.max_authtries) {
- /* Shouldn't happen */
- fatal_f("privsep child made too many authentication "
- "attempts");
- }
- }
-
- if (!authctxt->valid)
- fatal_f("authenticated invalid user");
- if (strcmp(auth_method, "unknown") == 0)
- fatal_f("authentication method name unknown");
-
- debug_f("user %s authenticated by privileged process", authctxt->user);
- ssh->authctxt = NULL;
- ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user);
-
- mm_get_keystate(ssh, pmonitor);
-
- /* Drain any buffered messages from the child */
- while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
- ;
-
- if (pmonitor->m_recvfd >= 0)
- close(pmonitor->m_recvfd);
- if (pmonitor->m_log_sendfd >= 0)
- close(pmonitor->m_log_sendfd);
- pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
- }
-
- static void
- monitor_set_child_handler(pid_t pid)
- {
- monitor_child_pid = pid;
- }
-
- static void
- monitor_child_handler(int sig)
- {
- kill(monitor_child_pid, sig);
- }
-
- void
- monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor)
- {
- close(pmonitor->m_recvfd);
- pmonitor->m_recvfd = -1;
-
- monitor_set_child_handler(pmonitor->m_pid);
- ssh_signal(SIGHUP, &monitor_child_handler);
- ssh_signal(SIGTERM, &monitor_child_handler);
- ssh_signal(SIGINT, &monitor_child_handler);
- #ifdef SIGXFSZ
- ssh_signal(SIGXFSZ, SIG_IGN);
- #endif
-
- mon_dispatch = mon_dispatch_postauth20;
-
- /* Permit requests for moduli and signatures */
- monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
-
- if (auth_opts->permit_pty_flag) {
- monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
- }
-
- for (;;)
- monitor_read(ssh, pmonitor, mon_dispatch, NULL);
- }
-
- static int
- monitor_read_log(struct monitor *pmonitor)
- {
- struct sshbuf *logmsg;
- u_int len, level, forced;
- char *msg;
- u_char *p;
- int r;
-
- if ((logmsg = sshbuf_new()) == NULL)
- fatal_f("sshbuf_new");
-
- /* Read length */
- if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0)
- fatal_fr(r, "reserve len");
- if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) {
- if (errno == EPIPE) {
- sshbuf_free(logmsg);
- debug_f("child log fd closed");
- close(pmonitor->m_log_recvfd);
- pmonitor->m_log_recvfd = -1;
- return -1;
- }
- fatal_f("log fd read: %s", strerror(errno));
- }
- if ((r = sshbuf_get_u32(logmsg, &len)) != 0)
- fatal_fr(r, "parse len");
- if (len <= 4 || len > 8192)
- fatal_f("invalid log message length %u", len);
-
- /* Read severity, message */
- sshbuf_reset(logmsg);
- if ((r = sshbuf_reserve(logmsg, len, &p)) != 0)
- fatal_fr(r, "reserve msg");
- if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len)
- fatal_f("log fd read: %s", strerror(errno));
- if ((r = sshbuf_get_u32(logmsg, &level)) != 0 ||
- (r = sshbuf_get_u32(logmsg, &forced)) != 0 ||
- (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0)
- fatal_fr(r, "parse");
-
- /* Log it */
- if (log_level_name(level) == NULL)
- fatal_f("invalid log level %u (corrupted message?)", level);
- sshlogdirect(level, forced, "%s [preauth]", msg);
-
- sshbuf_free(logmsg);
- free(msg);
-
- return 0;
- }
-
- static int
- monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent,
- struct mon_table **pent)
- {
- struct sshbuf *m;
- int r, ret;
- u_char type;
- struct pollfd pfd[2];
-
- for (;;) {
- memset(&pfd, 0, sizeof(pfd));
- pfd[0].fd = pmonitor->m_sendfd;
- pfd[0].events = POLLIN;
- pfd[1].fd = pmonitor->m_log_recvfd;
- pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
- if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
- if (errno == EINTR || errno == EAGAIN)
- continue;
- fatal_f("poll: %s", strerror(errno));
- }
- if (pfd[1].revents) {
- /*
- * Drain all log messages before processing next
- * monitor request.
- */
- monitor_read_log(pmonitor);
- continue;
- }
- if (pfd[0].revents)
- break; /* Continues below */
- }
-
- if ((m = sshbuf_new()) == NULL)
- fatal_f("sshbuf_new");
-
- mm_request_receive(pmonitor->m_sendfd, m);
- if ((r = sshbuf_get_u8(m, &type)) != 0)
- fatal_fr(r, "parse type");
-
- debug3_f("checking request %d", type);
-
- while (ent->f != NULL) {
- if (ent->type == type)
- break;
- ent++;
- }
-
- if (ent->f != NULL) {
- if (!(ent->flags & MON_PERMIT))
- fatal_f("unpermitted request %d", type);
- ret = (*ent->f)(ssh, pmonitor->m_sendfd, m);
- sshbuf_free(m);
-
- /* The child may use this request only once, disable it */
- if (ent->flags & MON_ONCE) {
- debug2_f("%d used once, disabling now", type);
- ent->flags &= ~MON_PERMIT;
- }
-
- if (pent != NULL)
- *pent = ent;
-
- return ret;
- }
-
- fatal_f("unsupported request: %d", type);
-
- /* NOTREACHED */
- return (-1);
- }
-
- /* allowed key state */
- static int
- monitor_allowed_key(const u_char *blob, u_int bloblen)
- {
- /* make sure key is allowed */
- if (key_blob == NULL || key_bloblen != bloblen ||
- timingsafe_bcmp(key_blob, blob, key_bloblen))
- return (0);
- return (1);
- }
-
- static void
- monitor_reset_key_state(void)
- {
- /* reset state */
- free(key_blob);
- free(hostbased_cuser);
- free(hostbased_chost);
- sshauthopt_free(key_opts);
- key_blob = NULL;
- key_bloblen = 0;
- key_blobtype = MM_NOKEY;
- key_opts = NULL;
- hostbased_cuser = NULL;
- hostbased_chost = NULL;
- }
-
- #ifdef WITH_OPENSSL
- int
- mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- DH *dh;
- const BIGNUM *dh_p, *dh_g;
- int r;
- u_int min, want, max;
-
- if ((r = sshbuf_get_u32(m, &min)) != 0 ||
- (r = sshbuf_get_u32(m, &want)) != 0 ||
- (r = sshbuf_get_u32(m, &max)) != 0)
- fatal_fr(r, "parse");
-
- debug3_f("got parameters: %d %d %d", min, want, max);
- /* We need to check here, too, in case the child got corrupted */
- if (max < min || want < min || max < want)
- fatal_f("bad parameters: %d %d %d", min, want, max);
-
- sshbuf_reset(m);
-
- dh = choose_dh(min, want, max);
- if (dh == NULL) {
- if ((r = sshbuf_put_u8(m, 0)) != 0)
- fatal_fr(r, "assemble empty");
- return (0);
- } else {
- /* Send first bignum */
- DH_get0_pqg(dh, &dh_p, NULL, &dh_g);
- if ((r = sshbuf_put_u8(m, 1)) != 0 ||
- (r = sshbuf_put_bignum2(m, dh_p)) != 0 ||
- (r = sshbuf_put_bignum2(m, dh_g)) != 0)
- fatal_fr(r, "assemble");
-
- DH_free(dh);
- }
- mm_request_send(sock, MONITOR_ANS_MODULI, m);
- return (0);
- }
- #endif
-
- int
- mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- extern int auth_sock; /* XXX move to state struct? */
- struct sshkey *key;
- struct sshbuf *sigbuf = NULL;
- u_char *p = NULL, *signature = NULL;
- char *alg = NULL;
- size_t datlen, siglen, alglen;
- int r, is_proof = 0;
- u_int keyid, compat;
- const char proof_req[] = "hostkeys-prove-00@openssh.com";
-
- debug3_f("entering");
-
- if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
- (r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
- (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 ||
- (r = sshbuf_get_u32(m, &compat)) != 0)
- fatal_fr(r, "parse");
- if (keyid > INT_MAX)
- fatal_f("invalid key ID");
-
- /*
- * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
- * SHA384 (48 bytes) and SHA512 (64 bytes).
- *
- * Otherwise, verify the signature request is for a hostkey
- * proof.
- *
- * XXX perform similar check for KEX signature requests too?
- * it's not trivial, since what is signed is the hash, rather
- * than the full kex structure...
- */
- if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
- /*
- * Construct expected hostkey proof and compare it to what
- * the client sent us.
- */
- if (session_id2_len == 0) /* hostkeys is never first */
- fatal_f("bad data length: %zu", datlen);
- if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
- fatal_f("no hostkey for index %d", keyid);
- if ((sigbuf = sshbuf_new()) == NULL)
- fatal_f("sshbuf_new");
- if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
- (r = sshbuf_put_string(sigbuf, session_id2,
- session_id2_len)) != 0 ||
- (r = sshkey_puts(key, sigbuf)) != 0)
- fatal_fr(r, "assemble private key proof");
- if (datlen != sshbuf_len(sigbuf) ||
- memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
- fatal_f("bad data length: %zu, hostkey proof len %zu",
- datlen, sshbuf_len(sigbuf));
- sshbuf_free(sigbuf);
- is_proof = 1;
- }
-
- /* save session id, it will be passed on the first call */
- if (session_id2_len == 0) {
- session_id2_len = datlen;
- session_id2 = xmalloc(session_id2_len);
- memcpy(session_id2, p, session_id2_len);
- }
-
- if ((key = get_hostkey_by_index(keyid)) != NULL) {
- if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
- options.sk_provider, NULL, compat)) != 0)
- fatal_fr(r, "sign");
- } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
- auth_sock > 0) {
- if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
- p, datlen, alg, compat)) != 0)
- fatal_fr(r, "agent sign");
- } else
- fatal_f("no hostkey from index %d", keyid);
-
- debug3_f("%s %s signature len=%zu", alg,
- is_proof ? "hostkey proof" : "KEX", siglen);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
- fatal_fr(r, "assemble");
-
- free(alg);
- free(p);
- free(signature);
-
- mm_request_send(sock, MONITOR_ANS_SIGN, m);
-
- /* Turn on permissions for getpwnam */
- monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
-
- return (0);
- }
-
- #define PUTPW(b, id) \
- do { \
- if ((r = sshbuf_put_string(b, \
- &pwent->id, sizeof(pwent->id))) != 0) \
- fatal_fr(r, "assemble %s", #id); \
- } while (0)
-
- /* Retrieves the password entry and also checks if the user is permitted */
- int
- mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- struct passwd *pwent;
- int r, allowed = 0;
- u_int i;
-
- debug3_f("entering");
-
- if (authctxt->attempt++ != 0)
- fatal_f("multiple attempts for getpwnam");
-
- if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0)
- fatal_fr(r, "parse");
-
- pwent = getpwnamallow(ssh, authctxt->user);
-
- setproctitle("%s [priv]", pwent ? authctxt->user : "unknown");
-
- sshbuf_reset(m);
-
- if (pwent == NULL) {
- if ((r = sshbuf_put_u8(m, 0)) != 0)
- fatal_fr(r, "assemble fakepw");
- authctxt->pw = fakepw();
- goto out;
- }
-
- allowed = 1;
- authctxt->pw = pwent;
- authctxt->valid = 1;
-
- /* XXX send fake class/dir/shell, etc. */
- if ((r = sshbuf_put_u8(m, 1)) != 0)
- fatal_fr(r, "assemble ok");
- PUTPW(m, pw_uid);
- PUTPW(m, pw_gid);
- #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
- PUTPW(m, pw_change);
- #endif
- #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
- PUTPW(m, pw_expire);
- #endif
- if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 ||
- (r = sshbuf_put_cstring(m, "*")) != 0 ||
- #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
- (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 ||
- #endif
- #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
- (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 ||
- #endif
- (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 ||
- (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0)
- fatal_fr(r, "assemble pw");
-
- out:
- ssh_packet_set_log_preamble(ssh, "%suser %s",
- authctxt->valid ? "authenticating" : "invalid ", authctxt->user);
- if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0)
- fatal_fr(r, "assemble options");
-
- #define M_CP_STROPT(x) do { \
- if (options.x != NULL && \
- (r = sshbuf_put_cstring(m, options.x)) != 0) \
- fatal_fr(r, "assemble %s", #x); \
- } while (0)
- #define M_CP_STRARRAYOPT(x, nx) do { \
- for (i = 0; i < options.nx; i++) { \
- if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \
- fatal_fr(r, "assemble %s", #x); \
- } \
- } while (0)
- /* See comment in servconf.h */
- COPY_MATCH_STRING_OPTS();
- #undef M_CP_STROPT
- #undef M_CP_STRARRAYOPT
-
- /* Create valid auth method lists */
- if (auth2_setup_methods_lists(authctxt) != 0) {
- /*
- * The monitor will continue long enough to let the child
- * run to its packet_disconnect(), but it must not allow any
- * authentication to succeed.
- */
- debug_f("no valid authentication method lists");
- }
-
- debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed);
- mm_request_send(sock, MONITOR_ANS_PWNAM, m);
-
- /* Allow service/style information on the auth context */
- monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
-
- #ifdef USE_PAM
- if (options.use_pam)
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
- #endif
-
- return (0);
- }
-
- int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- char *banner;
- int r;
-
- sshbuf_reset(m);
- banner = auth2_read_banner();
- if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0)
- fatal_fr(r, "assemble");
- mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
- free(banner);
-
- return (0);
- }
-
- int
- mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- int r;
-
- monitor_permit_authentications(1);
-
- if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 ||
- (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0)
- fatal_fr(r, "parse");
- debug3_f("service=%s, style=%s", authctxt->service, authctxt->style);
-
- if (strlen(authctxt->style) == 0) {
- free(authctxt->style);
- authctxt->style = NULL;
- }
-
- return (0);
- }
-
- /*
- * Check that the key type appears in the supplied pattern list, ignoring
- * mismatches in the signature algorithm. (Signature algorithm checks are
- * performed in the unprivileged authentication code).
- * Returns 1 on success, 0 otherwise.
- */
- static int
- key_base_type_match(const char *method, const struct sshkey *key,
- const char *list)
- {
- char *s, *l, *ol = xstrdup(list);
- int found = 0;
-
- l = ol;
- for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) {
- if (sshkey_type_from_name(s) == key->type) {
- found = 1;
- break;
- }
- }
- if (!found) {
- error("%s key type %s is not in permitted list %s", method,
- sshkey_ssh_name(key), list);
- }
-
- free(ol);
- return found;
- }
-
- int
- mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- static int call_count;
- char *passwd;
- int r, authenticated;
- size_t plen;
-
- if (!options.password_authentication)
- fatal_f("password authentication not enabled");
- if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0)
- fatal_fr(r, "parse");
- /* Only authenticate if the context is valid */
- authenticated = options.password_authentication &&
- auth_password(ssh, passwd);
- freezero(passwd, plen);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, authenticated)) != 0)
- fatal_fr(r, "assemble");
- #ifdef USE_PAM
- if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0)
- fatal_fr(r, "assemble PAM");
- #endif
-
- debug3("%s: sending result %d", __func__, authenticated);
- debug3_f("sending result %d", authenticated);
- mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
-
- call_count++;
- if (plen == 0 && call_count == 1)
- auth_method = "none";
- else
- auth_method = "password";
-
- /* Causes monitor loop to terminate if authenticated */
- return (authenticated);
- }
-
- #ifdef BSD_AUTH
- int
- mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- char *name, *infotxt;
- u_int numprompts, *echo_on, success;
- char **prompts;
- int r;
-
- if (!options.kbd_interactive_authentication)
- fatal_f("kbd-int authentication not enabled");
- success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
- &prompts, &echo_on) < 0 ? 0 : 1;
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, success)) != 0)
- fatal_fr(r, "assemble");
- if (success) {
- if ((r = sshbuf_put_cstring(m, prompts[0])) != 0)
- fatal_fr(r, "assemble prompt");
- }
-
- debug3_f("sending challenge success: %u", success);
- mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
-
- if (success) {
- free(name);
- free(infotxt);
- free(prompts);
- free(echo_on);
- }
-
- return (0);
- }
-
- int
- mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- char *response;
- int r, authok;
-
- if (!options.kbd_interactive_authentication)
- fatal_f("kbd-int authentication not enabled");
- if (authctxt->as == NULL)
- fatal_f("no bsd auth session");
-
- if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0)
- fatal_fr(r, "parse");
- authok = options.kbd_interactive_authentication &&
- auth_userresponse(authctxt->as, response, 0);
- authctxt->as = NULL;
- debug3_f("<%s> = <%d>", response, authok);
- free(response);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, authok)) != 0)
- fatal_fr(r, "assemble");
-
- debug3_f("sending authenticated: %d", authok);
- mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
-
- auth_method = "keyboard-interactive";
- auth_submethod = "bsdauth";
-
- return (authok != 0);
- }
- #endif
-
- #ifdef USE_PAM
- int
- mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- if (!options.use_pam)
- fatal("UsePAM not set, but ended up in %s anyway", __func__);
-
- start_pam(ssh);
-
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
- if (options.kbd_interactive_authentication)
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
-
- return (0);
- }
-
- int
- mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- u_int ret;
- int r;
-
- if (!options.use_pam)
- fatal("%s: PAM not enabled", __func__);
-
- ret = do_pam_account();
-
- if ((r = sshbuf_put_u32(m, ret)) != 0 ||
- (r = sshbuf_put_stringb(m, loginmsg)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
-
- mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
-
- return (ret);
- }
-
- static void *sshpam_ctxt, *sshpam_authok;
- extern KbdintDevice sshpam_device;
-
- int
- mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- u_int ok = 0;
- int r;
-
- debug3("%s", __func__);
- if (!options.kbd_interactive_authentication)
- fatal("%s: kbd-int authentication not enabled", __func__);
- if (sshpam_ctxt != NULL)
- fatal("%s: already called", __func__);
- sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
- sshpam_authok = NULL;
- sshbuf_reset(m);
- if (sshpam_ctxt != NULL) {
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1);
- ok = 1;
- }
- if ((r = sshbuf_put_u32(m, ok)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
- return (0);
- }
-
- int
- mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- char *name = NULL, *info = NULL, **prompts = NULL;
- u_int i, num = 0, *echo_on = 0;
- int r, ret;
-
- debug3("%s", __func__);
- sshpam_authok = NULL;
- if (sshpam_ctxt == NULL)
- fatal("%s: no context", __func__);
- ret = (sshpam_device.query)(sshpam_ctxt, &name, &info,
- &num, &prompts, &echo_on);
- if (ret == 0 && num == 0)
- sshpam_authok = sshpam_ctxt;
- if (num > 1 || name == NULL || info == NULL)
- fatal("sshpam_device.query failed");
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1);
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, ret)) != 0 ||
- (r = sshbuf_put_cstring(m, name)) != 0 ||
- (r = sshbuf_put_cstring(m, info)) != 0 ||
- (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 ||
- (r = sshbuf_put_u32(m, num)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- free(name);
- free(info);
- for (i = 0; i < num; ++i) {
- if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 ||
- (r = sshbuf_put_u32(m, echo_on[i])) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- free(prompts[i]);
- }
- free(prompts);
- free(echo_on);
- auth_method = "keyboard-interactive";
- auth_submethod = "pam";
- mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
- return (0);
- }
-
- int
- mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- char **resp;
- u_int i, num;
- int r, ret;
-
- debug3("%s", __func__);
- if (sshpam_ctxt == NULL)
- fatal("%s: no context", __func__);
- sshpam_authok = NULL;
- if ((r = sshbuf_get_u32(m, &num)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- if (num > PAM_MAX_NUM_MSG) {
- fatal_f("Too many PAM messages, got %u, expected <= %u",
- num, (unsigned)PAM_MAX_NUM_MSG);
- }
- if (num > 0) {
- resp = xcalloc(num, sizeof(char *));
- for (i = 0; i < num; ++i) {
- if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0)
- fatal("%s: buffer error: %s",
- __func__, ssh_err(r));
- }
- ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
- for (i = 0; i < num; ++i)
- free(resp[i]);
- free(resp);
- } else {
- ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
- }
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, ret)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
- auth_method = "keyboard-interactive";
- auth_submethod = "pam";
- if (ret == 0)
- sshpam_authok = sshpam_ctxt;
- return (0);
- }
-
- int
- mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
-
- debug3("%s", __func__);
- if (sshpam_ctxt == NULL)
- fatal("%s: no context", __func__);
- (sshpam_device.free_ctx)(sshpam_ctxt);
- sshpam_ctxt = sshpam_authok = NULL;
- sshbuf_reset(m);
- mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
- /* Allow another attempt */
- monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1);
- auth_method = "keyboard-interactive";
- auth_submethod = "pam";
- return r;
- }
- #endif
-
- int
- mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- struct sshkey *key = NULL;
- char *cuser, *chost;
- u_int pubkey_auth_attempt;
- u_int type = 0;
- int r, allowed = 0;
- struct sshauthopt *opts = NULL;
-
- debug3_f("entering");
- if ((r = sshbuf_get_u32(m, &type)) != 0 ||
- (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 ||
- (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 ||
- (r = sshkey_froms(m, &key)) != 0 ||
- (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0)
- fatal_fr(r, "parse");
-
- if (key != NULL && authctxt->valid) {
- switch (type) {
- case MM_USERKEY:
- auth_method = "publickey";
- if (!options.pubkey_authentication)
- break;
- if (auth2_key_already_used(authctxt, key))
- break;
- if (!key_base_type_match(auth_method, key,
- options.pubkey_accepted_algos))
- break;
- allowed = user_key_allowed(ssh, authctxt->pw, key,
- pubkey_auth_attempt, &opts);
- break;
- case MM_HOSTKEY:
- auth_method = "hostbased";
- if (!options.hostbased_authentication)
- break;
- if (auth2_key_already_used(authctxt, key))
- break;
- if (!key_base_type_match(auth_method, key,
- options.hostbased_accepted_algos))
- break;
- allowed = hostbased_key_allowed(ssh, authctxt->pw,
- cuser, chost, key);
- auth2_record_info(authctxt,
- "client user \"%.100s\", client host \"%.100s\"",
- cuser, chost);
- break;
- default:
- fatal_f("unknown key type %u", type);
- break;
- }
- }
-
- debug3_f("%s authentication%s: %s key is %s", auth_method,
- pubkey_auth_attempt ? "" : " test",
- (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key),
- allowed ? "allowed" : "not allowed");
-
- auth2_record_key(authctxt, 0, key);
-
- /* clear temporarily storage (used by verify) */
- monitor_reset_key_state();
-
- if (allowed) {
- /* Save temporarily for comparison in verify */
- if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0)
- fatal_fr(r, "sshkey_to_blob");
- key_blobtype = type;
- key_opts = opts;
- hostbased_cuser = cuser;
- hostbased_chost = chost;
- } else {
- /* Log failed attempt */
- auth_log(ssh, 0, 0, auth_method, NULL);
- free(cuser);
- free(chost);
- }
- sshkey_free(key);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, allowed)) != 0)
- fatal_fr(r, "assemble");
- if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0)
- fatal_fr(r, "sshauthopt_serialise");
- mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
-
- if (!allowed)
- sshauthopt_free(opts);
-
- return (0);
- }
-
- static int
- monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen)
- {
- struct sshbuf *b;
- struct sshkey *hostkey = NULL;
- const u_char *p;
- char *userstyle, *cp;
- size_t len;
- u_char type;
- int hostbound = 0, r, fail = 0;
-
- if ((b = sshbuf_from(data, datalen)) == NULL)
- fatal_f("sshbuf_from");
-
- if (ssh->compat & SSH_OLD_SESSIONID) {
- p = sshbuf_ptr(b);
- len = sshbuf_len(b);
- if ((session_id2 == NULL) ||
- (len < session_id2_len) ||
- (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
- fail++;
- if ((r = sshbuf_consume(b, session_id2_len)) != 0)
- fatal_fr(r, "consume");
- } else {
- if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
- fatal_fr(r, "parse sessionid");
- if ((session_id2 == NULL) ||
- (len != session_id2_len) ||
- (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
- fail++;
- }
- if ((r = sshbuf_get_u8(b, &type)) != 0)
- fatal_fr(r, "parse type");
- if (type != SSH2_MSG_USERAUTH_REQUEST)
- fail++;
- if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse userstyle");
- xasprintf(&userstyle, "%s%s%s", authctxt->user,
- authctxt->style ? ":" : "",
- authctxt->style ? authctxt->style : "");
- if (strcmp(userstyle, cp) != 0) {
- logit("wrong user name passed to monitor: "
- "expected %s != %.100s", userstyle, cp);
- fail++;
- }
- free(userstyle);
- free(cp);
- if ((r = sshbuf_skip_string(b)) != 0 || /* service */
- (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse method");
- if (strcmp("publickey", cp) != 0) {
- if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0)
- hostbound = 1;
- else
- fail++;
- }
- free(cp);
- if ((r = sshbuf_get_u8(b, &type)) != 0)
- fatal_fr(r, "parse pktype");
- if (type == 0)
- fail++;
- if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
- (r = sshbuf_skip_string(b)) != 0 || /* pkblob */
- (hostbound && (r = sshkey_froms(b, &hostkey)) != 0))
- fatal_fr(r, "parse pk");
- if (sshbuf_len(b) != 0)
- fail++;
- sshbuf_free(b);
- if (hostkey != NULL) {
- /*
- * Ensure this is actually one of our hostkeys; unfortunately
- * can't check ssh->kex->initial_hostkey directly at this point
- * as packet state has not yet been exported to monitor.
- */
- if (get_hostkey_index(hostkey, 1, ssh) == -1)
- fatal_f("hostbound hostkey does not match");
- sshkey_free(hostkey);
- }
- return (fail == 0);
- }
-
- static int
- monitor_valid_hostbasedblob(const u_char *data, u_int datalen,
- const char *cuser, const char *chost)
- {
- struct sshbuf *b;
- const u_char *p;
- char *cp, *userstyle;
- size_t len;
- int r, fail = 0;
- u_char type;
-
- if ((b = sshbuf_from(data, datalen)) == NULL)
- fatal_f("sshbuf_new");
- if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0)
- fatal_fr(r, "parse sessionid");
-
- if ((session_id2 == NULL) ||
- (len != session_id2_len) ||
- (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
- fail++;
-
- if ((r = sshbuf_get_u8(b, &type)) != 0)
- fatal_fr(r, "parse type");
- if (type != SSH2_MSG_USERAUTH_REQUEST)
- fail++;
- if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse userstyle");
- xasprintf(&userstyle, "%s%s%s", authctxt->user,
- authctxt->style ? ":" : "",
- authctxt->style ? authctxt->style : "");
- if (strcmp(userstyle, cp) != 0) {
- logit("wrong user name passed to monitor: "
- "expected %s != %.100s", userstyle, cp);
- fail++;
- }
- free(userstyle);
- free(cp);
- if ((r = sshbuf_skip_string(b)) != 0 || /* service */
- (r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse method");
- if (strcmp(cp, "hostbased") != 0)
- fail++;
- free(cp);
- if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */
- (r = sshbuf_skip_string(b)) != 0) /* pkblob */
- fatal_fr(r, "parse pk");
-
- /* verify client host, strip trailing dot if necessary */
- if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse host");
- if (((len = strlen(cp)) > 0) && cp[len - 1] == '.')
- cp[len - 1] = '\0';
- if (strcmp(cp, chost) != 0)
- fail++;
- free(cp);
-
- /* verify client user */
- if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0)
- fatal_fr(r, "parse ruser");
- if (strcmp(cp, cuser) != 0)
- fail++;
- free(cp);
-
- if (sshbuf_len(b) != 0)
- fail++;
- sshbuf_free(b);
- return (fail == 0);
- }
-
- int
- mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- struct sshkey *key;
- const u_char *signature, *data, *blob;
- char *sigalg = NULL, *fp = NULL;
- size_t signaturelen, datalen, bloblen;
- int r, ret, req_presence = 0, req_verify = 0, valid_data = 0;
- int encoded_ret;
- struct sshkey_sig_details *sig_details = NULL;
-
- if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 ||
- (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 ||
- (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 ||
- (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0)
- fatal_fr(r, "parse");
-
- if (hostbased_cuser == NULL || hostbased_chost == NULL ||
- !monitor_allowed_key(blob, bloblen))
- fatal_f("bad key, not previously allowed");
-
- /* Empty signature algorithm means NULL. */
- if (*sigalg == '\0') {
- free(sigalg);
- sigalg = NULL;
- }
-
- /* XXX use sshkey_froms here; need to change key_blob, etc. */
- if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0)
- fatal_fr(r, "parse key");
-
- switch (key_blobtype) {
- case MM_USERKEY:
- valid_data = monitor_valid_userblob(ssh, data, datalen);
- auth_method = "publickey";
- break;
- case MM_HOSTKEY:
- valid_data = monitor_valid_hostbasedblob(data, datalen,
- hostbased_cuser, hostbased_chost);
- auth_method = "hostbased";
- break;
- default:
- valid_data = 0;
- break;
- }
- if (!valid_data)
- fatal_f("bad %s signature data blob",
- key_blobtype == MM_USERKEY ? "userkey" :
- (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown"));
-
- if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
- SSH_FP_DEFAULT)) == NULL)
- fatal_f("sshkey_fingerprint failed");
-
- ret = sshkey_verify(key, signature, signaturelen, data, datalen,
- sigalg, ssh->compat, &sig_details);
- debug3_f("%s %s signature using %s %s%s%s", auth_method,
- sshkey_type(key), sigalg == NULL ? "default" : sigalg,
- (ret == 0) ? "verified" : "unverified",
- (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : "");
-
- if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) {
- req_presence = (options.pubkey_auth_options &
- PUBKEYAUTH_TOUCH_REQUIRED) ||
- !key_opts->no_require_user_presence;
- if (req_presence &&
- (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) {
- error("public key %s %s signature for %s%s from %.128s "
- "port %d rejected: user presence "
- "(authenticator touch) requirement not met ",
- sshkey_type(key), fp,
- authctxt->valid ? "" : "invalid user ",
- authctxt->user, ssh_remote_ipaddr(ssh),
- ssh_remote_port(ssh));
- ret = SSH_ERR_SIGNATURE_INVALID;
- }
- req_verify = (options.pubkey_auth_options &
- PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify;
- if (req_verify &&
- (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) {
- error("public key %s %s signature for %s%s from %.128s "
- "port %d rejected: user verification requirement "
- "not met ", sshkey_type(key), fp,
- authctxt->valid ? "" : "invalid user ",
- authctxt->user, ssh_remote_ipaddr(ssh),
- ssh_remote_port(ssh));
- ret = SSH_ERR_SIGNATURE_INVALID;
- }
- }
- auth2_record_key(authctxt, ret == 0, key);
-
- if (key_blobtype == MM_USERKEY)
- auth_activate_options(ssh, key_opts);
- monitor_reset_key_state();
-
- sshbuf_reset(m);
-
- /* encode ret != 0 as positive integer, since we're sending u32 */
- encoded_ret = (ret != 0);
- if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 ||
- (r = sshbuf_put_u8(m, sig_details != NULL)) != 0)
- fatal_fr(r, "assemble");
- if (sig_details != NULL) {
- if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 ||
- (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0)
- fatal_fr(r, "assemble sk");
- }
- sshkey_sig_details_free(sig_details);
- mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
-
- free(sigalg);
- free(fp);
- sshkey_free(key);
-
- return ret == 0;
- }
-
- static void
- mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw)
- {
- socklen_t fromlen;
- struct sockaddr_storage from;
-
- /*
- * Get IP address of client. If the connection is not a socket, let
- * the address be 0.0.0.0.
- */
- memset(&from, 0, sizeof(from));
- fromlen = sizeof(from);
- if (ssh_packet_connection_is_on_socket(ssh)) {
- if (getpeername(ssh_packet_get_connection_in(ssh),
- (struct sockaddr *)&from, &fromlen) == -1) {
- debug("getpeername: %.100s", strerror(errno));
- cleanup_exit(255);
- }
- }
- /* Record that there was a login on that tty from the remote host. */
- record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
- session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
- (struct sockaddr *)&from, fromlen);
- }
-
- static void
- mm_session_close(Session *s)
- {
- debug3_f("session %d pid %ld", s->self, (long)s->pid);
- if (s->ttyfd != -1) {
- debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd);
- session_pty_cleanup2(s);
- }
- session_unused(s->self);
- }
-
- int
- mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- extern struct monitor *pmonitor;
- Session *s;
- int r, res, fd0;
-
- debug3_f("entering");
-
- sshbuf_reset(m);
- s = session_new();
- if (s == NULL)
- goto error;
- s->authctxt = authctxt;
- s->pw = authctxt->pw;
- s->pid = pmonitor->m_pid;
- res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
- if (res == 0)
- goto error;
- pty_setowner(authctxt->pw, s->tty);
-
- if ((r = sshbuf_put_u32(m, 1)) != 0 ||
- (r = sshbuf_put_cstring(m, s->tty)) != 0)
- fatal_fr(r, "assemble");
-
- /* We need to trick ttyslot */
- if (dup2(s->ttyfd, 0) == -1)
- fatal_f("dup2");
-
- mm_record_login(ssh, s, authctxt->pw);
-
- /* Now we can close the file descriptor again */
- close(0);
-
- /* send messages generated by record_login */
- if ((r = sshbuf_put_stringb(m, loginmsg)) != 0)
- fatal_fr(r, "assemble loginmsg");
- sshbuf_reset(loginmsg);
-
- mm_request_send(sock, MONITOR_ANS_PTY, m);
-
- if (mm_send_fd(sock, s->ptyfd) == -1 ||
- mm_send_fd(sock, s->ttyfd) == -1)
- fatal_f("send fds failed");
-
- /* make sure nothing uses fd 0 */
- if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1)
- fatal_f("open(/dev/null): %s", strerror(errno));
- if (fd0 != 0)
- error_f("fd0 %d != 0", fd0);
-
- /* slave side of pty is not needed */
- close(s->ttyfd);
- s->ttyfd = s->ptyfd;
- /* no need to dup() because nobody closes ptyfd */
- s->ptymaster = s->ptyfd;
-
- debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd);
-
- return (0);
-
- error:
- if (s != NULL)
- mm_session_close(s);
- if ((r = sshbuf_put_u32(m, 0)) != 0)
- fatal_fr(r, "assemble 0");
- mm_request_send(sock, MONITOR_ANS_PTY, m);
- return (0);
- }
-
- int
- mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- Session *s;
- char *tty;
- int r;
-
- debug3_f("entering");
-
- if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0)
- fatal_fr(r, "parse tty");
- if ((s = session_by_tty(tty)) != NULL)
- mm_session_close(s);
- sshbuf_reset(m);
- free(tty);
- return (0);
- }
-
- int
- mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req)
- {
- extern struct monitor *pmonitor;
- int res, status;
-
- debug3_f("tearing down sessions");
-
- /* The child is terminating */
- session_destroy_all(ssh, &mm_session_close);
-
- #ifdef USE_PAM
- if (options.use_pam)
- sshpam_cleanup();
- #endif
-
- while (waitpid(pmonitor->m_pid, &status, 0) == -1)
- if (errno != EINTR)
- exit(1);
-
- res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
-
- /* Terminate process */
- exit(res);
- }
-
- #ifdef SSH_AUDIT_EVENTS
- /* Report that an audit event occurred */
- int
- mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m)
- {
- u_int n;
- ssh_audit_event_t event;
- int r;
-
- debug3("%s entering", __func__);
-
- if ((r = sshbuf_get_u32(m, &n)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- event = (ssh_audit_event_t)n;
- switch (event) {
- case SSH_AUTH_FAIL_PUBKEY:
- case SSH_AUTH_FAIL_HOSTBASED:
- case SSH_AUTH_FAIL_GSSAPI:
- case SSH_LOGIN_EXCEED_MAXTRIES:
- case SSH_LOGIN_ROOT_DENIED:
- case SSH_CONNECTION_CLOSE:
- case SSH_INVALID_USER:
- audit_event(ssh, event);
- break;
- default:
- fatal("Audit event type %d not permitted", event);
- }
-
- return (0);
- }
-
- int
- mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m)
- {
- char *cmd;
- int r;
-
- debug3("%s entering", __func__);
- if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0)
- fatal("%s: buffer error: %s", __func__, ssh_err(r));
- /* sanity check command, if so how? */
- audit_run_command(cmd);
- free(cmd);
- return (0);
- }
- #endif /* SSH_AUDIT_EVENTS */
-
- void
- monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor)
- {
- ssh_clear_newkeys(ssh, MODE_IN);
- ssh_clear_newkeys(ssh, MODE_OUT);
- sshbuf_free(child_state);
- child_state = NULL;
- }
-
- void
- monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor)
- {
- struct kex *kex;
- int r;
-
- debug3_f("packet_set_state");
- if ((r = ssh_packet_set_state(ssh, child_state)) != 0)
- fatal_fr(r, "packet_set_state");
- sshbuf_free(child_state);
- child_state = NULL;
- if ((kex = ssh->kex) == NULL)
- fatal_f("internal error: ssh->kex == NULL");
- if (session_id2_len != sshbuf_len(ssh->kex->session_id)) {
- fatal_f("incorrect session id length %zu (expected %u)",
- sshbuf_len(ssh->kex->session_id), session_id2_len);
- }
- if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2,
- session_id2_len) != 0)
- fatal_f("session ID mismatch");
- /* XXX set callbacks */
- #ifdef WITH_OPENSSL
- kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
- kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
- kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
- kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
- kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
- kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
- kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
- # ifdef OPENSSL_HAS_ECC
- kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
- # endif
- #endif /* WITH_OPENSSL */
- kex->kex[KEX_C25519_SHA256] = kex_gen_server;
- kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
- kex->load_host_public_key=&get_hostkey_public_by_type;
- kex->load_host_private_key=&get_hostkey_private_by_type;
- kex->host_key_index=&get_hostkey_index;
- kex->sign = sshd_hostkey_sign;
- }
-
- /* This function requires careful sanity checking */
-
- void
- mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor)
- {
- debug3_f("Waiting for new keys");
-
- if ((child_state = sshbuf_new()) == NULL)
- fatal_f("sshbuf_new failed");
- mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT,
- child_state);
- debug3_f("GOT new keys");
- }
-
-
- /* XXX */
-
- #define FD_CLOSEONEXEC(x) do { \
- if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
- fatal("fcntl(%d, F_SETFD)", x); \
- } while (0)
-
- static void
- monitor_openfds(struct monitor *mon, int do_logfds)
- {
- int pair[2];
- #ifdef SO_ZEROIZE
- int on = 1;
- #endif
-
- if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
- fatal_f("socketpair: %s", strerror(errno));
- #ifdef SO_ZEROIZE
- if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
- error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno));
- if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1)
- error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno));
- #endif
- FD_CLOSEONEXEC(pair[0]);
- FD_CLOSEONEXEC(pair[1]);
- mon->m_recvfd = pair[0];
- mon->m_sendfd = pair[1];
-
- if (do_logfds) {
- if (pipe(pair) == -1)
- fatal_f("pipe: %s", strerror(errno));
- FD_CLOSEONEXEC(pair[0]);
- FD_CLOSEONEXEC(pair[1]);
- mon->m_log_recvfd = pair[0];
- mon->m_log_sendfd = pair[1];
- } else
- mon->m_log_recvfd = mon->m_log_sendfd = -1;
- }
-
- #define MM_MEMSIZE 65536
-
- struct monitor *
- monitor_init(void)
- {
- struct monitor *mon;
-
- mon = xcalloc(1, sizeof(*mon));
- monitor_openfds(mon, 1);
-
- return mon;
- }
-
- void
- monitor_reinit(struct monitor *mon)
- {
- monitor_openfds(mon, 0);
- }
-
- #ifdef GSSAPI
- int
- mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- gss_OID_desc goid;
- OM_uint32 major;
- size_t len;
- u_char *p;
- int r;
-
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
-
- if ((r = sshbuf_get_string(m, &p, &len)) != 0)
- fatal_fr(r, "parse");
- goid.elements = p;
- goid.length = len;
-
- major = ssh_gssapi_server_ctx(&gsscontext, &goid);
-
- free(goid.elements);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, major)) != 0)
- fatal_fr(r, "assemble");
-
- mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
-
- /* Now we have a context, enable the step */
- monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
-
- return (0);
- }
-
- int
- mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- gss_buffer_desc in;
- gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
- OM_uint32 major, minor;
- OM_uint32 flags = 0; /* GSI needs this */
- int r;
-
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
-
- if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
- fatal_fr(r, "ssh_gssapi_get_buffer_desc");
- major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
- free(in.value);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, major)) != 0 ||
- (r = sshbuf_put_string(m, out.value, out.length)) != 0 ||
- (r = sshbuf_put_u32(m, flags)) != 0)
- fatal_fr(r, "assemble");
- mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
-
- gss_release_buffer(&minor, &out);
-
- if (major == GSS_S_COMPLETE) {
- monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
- monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
- monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
- }
- return (0);
- }
-
- int
- mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- gss_buffer_desc gssbuf, mic;
- OM_uint32 ret;
- int r;
-
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
-
- if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
- (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
- fatal_fr(r, "ssh_gssapi_get_buffer_desc");
-
- ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
-
- free(gssbuf.value);
- free(mic.value);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, ret)) != 0)
- fatal_fr(r, "assemble");
-
- mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
-
- if (!GSS_ERROR(ret))
- monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
-
- return (0);
- }
-
- int
- mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
- {
- int r, authenticated;
- const char *displayname;
-
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
-
- authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
-
- sshbuf_reset(m);
- if ((r = sshbuf_put_u32(m, authenticated)) != 0)
- fatal_fr(r, "assemble");
-
- debug3_f("sending result %d", authenticated);
- mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
-
- auth_method = "gssapi-with-mic";
-
- if ((displayname = ssh_gssapi_displayname()) != NULL)
- auth2_record_info(authctxt, "%s", displayname);
-
- /* Monitor loop will terminate if authenticated */
- return (authenticated);
- }
- #endif /* GSSAPI */
|