/* $OpenBSD: monitor_wrap.c,v 1.84 2015/02/16 22:13:32 djm Exp $ */ /* * Copyright 2002 Niels Provos * Copyright 2002 Markus Friedl * 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 #include #include #include #include #include #include #include #include #ifdef WITH_OPENSSL #include #include #endif #include "xmalloc.h" #include "ssh.h" #ifdef WITH_OPENSSL #include "dh.h" #endif #include "buffer.h" #include "key.h" #include "cipher.h" #include "kex.h" #include "hostfile.h" #include "auth.h" #include "auth-options.h" #include "packet.h" #include "mac.h" #include "log.h" #include #include "monitor.h" #ifdef GSSAPI #include "ssh-gss.h" #endif #include "monitor_wrap.h" #include "atomicio.h" #include "monitor_fdpass.h" #include "misc.h" #include "uuencode.h" #include "channels.h" #include "session.h" #include "servconf.h" #include "roaming.h" #include "ssherr.h" /* Imports */ extern int compat20; extern z_stream incoming_stream; extern z_stream outgoing_stream; extern struct monitor *pmonitor; extern Buffer loginmsg; extern ServerOptions options; void mm_log_handler(LogLevel level, const char *msg, void *ctx) { Buffer log_msg; struct monitor *mon = (struct monitor *)ctx; if (mon->m_log_sendfd == -1) fatal("%s: no log channel", __func__); buffer_init(&log_msg); /* * Placeholder for packet length. Will be filled in with the actual * packet length once the packet has been constucted. This saves * fragile math. */ buffer_put_int(&log_msg, 0); buffer_put_int(&log_msg, level); buffer_put_cstring(&log_msg, msg); put_u32(buffer_ptr(&log_msg), buffer_len(&log_msg) - 4); if (atomicio(vwrite, mon->m_log_sendfd, buffer_ptr(&log_msg), buffer_len(&log_msg)) != buffer_len(&log_msg)) fatal("%s: write: %s", __func__, strerror(errno)); buffer_free(&log_msg); } int mm_is_monitor(void) { /* * m_pid is only set in the privileged part, and * points to the unprivileged child. */ return (pmonitor && pmonitor->m_pid > 0); } void mm_request_send(int sock, enum monitor_reqtype type, Buffer *m) { u_int mlen = buffer_len(m); u_char buf[5]; debug3("%s entering: type %d", __func__, type); put_u32(buf, mlen + 1); buf[4] = (u_char) type; /* 1st byte of payload is mesg-type */ if (atomicio(vwrite, sock, buf, sizeof(buf)) != sizeof(buf)) fatal("%s: write: %s", __func__, strerror(errno)); if (atomicio(vwrite, sock, buffer_ptr(m), mlen) != mlen) fatal("%s: write: %s", __func__, strerror(errno)); } void mm_request_receive(int sock, Buffer *m) { u_char buf[4]; u_int msg_len; debug3("%s entering", __func__); if (atomicio(read, sock, buf, sizeof(buf)) != sizeof(buf)) { if (errno == EPIPE) cleanup_exit(255); fatal("%s: read: %s", __func__, strerror(errno)); } msg_len = get_u32(buf); if (msg_len > 256 * 1024) fatal("%s: read: bad msg_len %d", __func__, msg_len); buffer_clear(m); buffer_append_space(m, msg_len); if (atomicio(read, sock, buffer_ptr(m), msg_len) != msg_len) fatal("%s: read: %s", __func__, strerror(errno)); } void mm_request_receive_expect(int sock, enum monitor_reqtype type, Buffer *m) { u_char rtype; debug3("%s entering: type %d", __func__, type); mm_request_receive(sock, m); rtype = buffer_get_char(m); if (rtype != type) fatal("%s: read: rtype %d != type %d", __func__, rtype, type); } #ifdef WITH_OPENSSL DH * mm_choose_dh(int min, int nbits, int max) { BIGNUM *p, *g; int success = 0; Buffer m; buffer_init(&m); buffer_put_int(&m, min); buffer_put_int(&m, nbits); buffer_put_int(&m, max); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_MODULI, &m); debug3("%s: waiting for MONITOR_ANS_MODULI", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_MODULI, &m); success = buffer_get_char(&m); if (success == 0) fatal("%s: MONITOR_ANS_MODULI failed", __func__); if ((p = BN_new()) == NULL) fatal("%s: BN_new failed", __func__); if ((g = BN_new()) == NULL) fatal("%s: BN_new failed", __func__); buffer_get_bignum2(&m, p); buffer_get_bignum2(&m, g); debug3("%s: remaining %d", __func__, buffer_len(&m)); buffer_free(&m); return (dh_new_group(g, p)); } #endif int mm_key_sign(Key *key, u_char **sigp, u_int *lenp, const u_char *data, u_int datalen) { struct kex *kex = *pmonitor->m_pkex; Buffer m; debug3("%s entering", __func__); buffer_init(&m); buffer_put_int(&m, kex->host_key_index(key, 0, active_state)); buffer_put_string(&m, data, datalen); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SIGN, &m); debug3("%s: waiting for MONITOR_ANS_SIGN", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SIGN, &m); *sigp = buffer_get_string(&m, lenp); buffer_free(&m); return (0); } struct passwd * mm_getpwnamallow(const char *username) { Buffer m; struct passwd *pw; u_int len, i; ServerOptions *newopts; debug3("%s entering", __func__); buffer_init(&m); buffer_put_cstring(&m, username); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PWNAM, &m); debug3("%s: waiting for MONITOR_ANS_PWNAM", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PWNAM, &m); if (buffer_get_char(&m) == 0) { pw = NULL; goto out; } pw = buffer_get_string(&m, &len); if (len != sizeof(struct passwd)) fatal("%s: struct passwd size mismatch", __func__); pw->pw_name = buffer_get_string(&m, NULL); pw->pw_passwd = buffer_get_string(&m, NULL); pw->pw_gecos = buffer_get_string(&m, NULL); pw->pw_class = buffer_get_string(&m, NULL); pw->pw_dir = buffer_get_string(&m, NULL); pw->pw_shell = buffer_get_string(&m, NULL); out: /* copy options block as a Match directive may have changed some */ newopts = buffer_get_string(&m, &len); if (len != sizeof(*newopts)) fatal("%s: option block size mismatch", __func__); #define M_CP_STROPT(x) do { \ if (newopts->x != NULL) \ newopts->x = buffer_get_string(&m, NULL); \ } while (0) #define M_CP_STRARRAYOPT(x, nx) do { \ for (i = 0; i < newopts->nx; i++) \ newopts->x[i] = buffer_get_string(&m, NULL); \ } while (0) /* See comment in servconf.h */ COPY_MATCH_STRING_OPTS(); #undef M_CP_STROPT #undef M_CP_STRARRAYOPT copy_set_server_options(&options, newopts, 1); free(newopts); buffer_free(&m); return (pw); } char * mm_auth2_read_banner(void) { Buffer m; char *banner; debug3("%s entering", __func__); buffer_init(&m); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTH2_READ_BANNER, &m); buffer_clear(&m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUTH2_READ_BANNER, &m); banner = buffer_get_string(&m, NULL); buffer_free(&m); /* treat empty banner as missing banner */ if (strlen(banner) == 0) { free(banner); banner = NULL; } return (banner); } /* Inform the privileged process about service and style */ void mm_inform_authserv(char *service, char *style) { Buffer m; debug3("%s entering", __func__); buffer_init(&m); buffer_put_cstring(&m, service); buffer_put_cstring(&m, style ? style : ""); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, &m); buffer_free(&m); } /* Do the password authentication */ int mm_auth_password(Authctxt *authctxt, char *password) { Buffer m; int authenticated = 0; debug3("%s entering", __func__); buffer_init(&m); buffer_put_cstring(&m, password); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHPASSWORD, &m); debug3("%s: waiting for MONITOR_ANS_AUTHPASSWORD", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUTHPASSWORD, &m); authenticated = buffer_get_int(&m); buffer_free(&m); debug3("%s: user %sauthenticated", __func__, authenticated ? "" : "not "); return (authenticated); } int mm_user_key_allowed(struct passwd *pw, Key *key) { return (mm_key_allowed(MM_USERKEY, NULL, NULL, key)); } int mm_hostbased_key_allowed(struct passwd *pw, char *user, char *host, Key *key) { return (mm_key_allowed(MM_HOSTKEY, user, host, key)); } int mm_auth_rhosts_rsa_key_allowed(struct passwd *pw, char *user, char *host, Key *key) { int ret; key->type = KEY_RSA; /* XXX hack for key_to_blob */ ret = mm_key_allowed(MM_RSAHOSTKEY, user, host, key); key->type = KEY_RSA1; return (ret); } int mm_key_allowed(enum mm_keytype type, char *user, char *host, Key *key) { Buffer m; u_char *blob; u_int len; int allowed = 0, have_forced = 0; debug3("%s entering", __func__); /* Convert the key to a blob and the pass it over */ if (!key_to_blob(key, &blob, &len)) return (0); buffer_init(&m); buffer_put_int(&m, type); buffer_put_cstring(&m, user ? user : ""); buffer_put_cstring(&m, host ? host : ""); buffer_put_string(&m, blob, len); free(blob); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYALLOWED, &m); debug3("%s: waiting for MONITOR_ANS_KEYALLOWED", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_KEYALLOWED, &m); allowed = buffer_get_int(&m); /* fake forced command */ auth_clear_options(); have_forced = buffer_get_int(&m); forced_command = have_forced ? xstrdup("true") : NULL; buffer_free(&m); return (allowed); } /* * This key verify needs to send the key type along, because the * privileged parent makes the decision if the key is allowed * for authentication. */ int mm_key_verify(Key *key, u_char *sig, u_int siglen, u_char *data, u_int datalen) { Buffer m; u_char *blob; u_int len; int verified = 0; debug3("%s entering", __func__); /* Convert the key to a blob and the pass it over */ if (!key_to_blob(key, &blob, &len)) return (0); buffer_init(&m); buffer_put_string(&m, blob, len); buffer_put_string(&m, sig, siglen); buffer_put_string(&m, data, datalen); free(blob); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, &m); debug3("%s: waiting for MONITOR_ANS_KEYVERIFY", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_KEYVERIFY, &m); verified = buffer_get_int(&m); buffer_free(&m); return (verified); } void mm_send_keystate(struct monitor *monitor) { struct ssh *ssh = active_state; /* XXX */ struct sshbuf *m; int r; if ((m = sshbuf_new()) == NULL) fatal("%s: sshbuf_new failed", __func__); if ((r = ssh_packet_get_state(ssh, m)) != 0) fatal("%s: get_state failed: %s", __func__, ssh_err(r)); mm_request_send(monitor->m_recvfd, MONITOR_REQ_KEYEXPORT, m); debug3("%s: Finished sending state", __func__); sshbuf_free(m); } int mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen) { Buffer m; char *p, *msg; int success = 0, tmp1 = -1, tmp2 = -1; /* Kludge: ensure there are fds free to receive the pty/tty */ if ((tmp1 = dup(pmonitor->m_recvfd)) == -1 || (tmp2 = dup(pmonitor->m_recvfd)) == -1) { error("%s: cannot allocate fds for pty", __func__); if (tmp1 > 0) close(tmp1); if (tmp2 > 0) close(tmp2); return 0; } close(tmp1); close(tmp2); buffer_init(&m); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTY, &m); debug3("%s: waiting for MONITOR_ANS_PTY", __func__); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PTY, &m); success = buffer_get_int(&m); if (success == 0) { debug3("%s: pty alloc failed", __func__); buffer_free(&m); return (0); } p = buffer_get_string(&m, NULL); msg = buffer_get_string(&m, NULL); buffer_free(&m); strlcpy(namebuf, p, namebuflen); /* Possible truncation */ free(p); buffer_append(&loginmsg, msg, strlen(msg)); free(msg); if ((*ptyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1 || (*ttyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1) fatal("%s: receive fds failed", __func__); /* Success */ return (1); } void mm_session_pty_cleanup2(Session *s) { Buffer m; if (s->ttyfd == -1) return; buffer_init(&m); buffer_put_cstring(&m, s->tty); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTYCLEANUP, &m); buffer_free(&m); /* closed dup'ed master */ if (s->ptymaster != -1 && close(s->ptymaster) < 0) error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno)); /* unlink pty from session */ s->ttyfd = -1; } /* Request process termination */ void mm_terminate(void) { Buffer m; buffer_init(&m); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_TERM, &m); buffer_free(&m); } #ifdef WITH_SSH1 int mm_ssh1_session_key(BIGNUM *num) { int rsafail; Buffer m; buffer_init(&m); buffer_put_bignum2(&m, num); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SESSKEY, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SESSKEY, &m); rsafail = buffer_get_int(&m); buffer_get_bignum2(&m, num); buffer_free(&m); return (rsafail); } #endif static void mm_chall_setup(char **name, char **infotxt, u_int *numprompts, char ***prompts, u_int **echo_on) { *name = xstrdup(""); *infotxt = xstrdup(""); *numprompts = 1; *prompts = xcalloc(*numprompts, sizeof(char *)); *echo_on = xcalloc(*numprompts, sizeof(u_int)); (*echo_on)[0] = 0; } int mm_bsdauth_query(void *ctx, char **name, char **infotxt, u_int *numprompts, char ***prompts, u_int **echo_on) { Buffer m; u_int success; char *challenge; debug3("%s: entering", __func__); buffer_init(&m); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHQUERY, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_BSDAUTHQUERY, &m); success = buffer_get_int(&m); if (success == 0) { debug3("%s: no challenge", __func__); buffer_free(&m); return (-1); } /* Get the challenge, and format the response */ challenge = buffer_get_string(&m, NULL); buffer_free(&m); mm_chall_setup(name, infotxt, numprompts, prompts, echo_on); (*prompts)[0] = challenge; debug3("%s: received challenge: %s", __func__, challenge); return (0); } int mm_bsdauth_respond(void *ctx, u_int numresponses, char **responses) { Buffer m; int authok; debug3("%s: entering", __func__); if (numresponses != 1) return (-1); buffer_init(&m); buffer_put_cstring(&m, responses[0]); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHRESPOND, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_BSDAUTHRESPOND, &m); authok = buffer_get_int(&m); buffer_free(&m); return ((authok == 0) ? -1 : 0); } void mm_ssh1_session_id(u_char session_id[16]) { Buffer m; int i; debug3("%s entering", __func__); buffer_init(&m); for (i = 0; i < 16; i++) buffer_put_char(&m, session_id[i]); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SESSID, &m); buffer_free(&m); } #ifdef WITH_SSH1 int mm_auth_rsa_key_allowed(struct passwd *pw, BIGNUM *client_n, Key **rkey) { Buffer m; Key *key; u_char *blob; u_int blen; int allowed = 0, have_forced = 0; debug3("%s entering", __func__); buffer_init(&m); buffer_put_bignum2(&m, client_n); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSAKEYALLOWED, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSAKEYALLOWED, &m); allowed = buffer_get_int(&m); /* fake forced command */ auth_clear_options(); have_forced = buffer_get_int(&m); forced_command = have_forced ? xstrdup("true") : NULL; if (allowed && rkey != NULL) { blob = buffer_get_string(&m, &blen); if ((key = key_from_blob(blob, blen)) == NULL) fatal("%s: key_from_blob failed", __func__); *rkey = key; free(blob); } buffer_free(&m); return (allowed); } BIGNUM * mm_auth_rsa_generate_challenge(Key *key) { Buffer m; BIGNUM *challenge; u_char *blob; u_int blen; debug3("%s entering", __func__); if ((challenge = BN_new()) == NULL) fatal("%s: BN_new failed", __func__); key->type = KEY_RSA; /* XXX cheat for key_to_blob */ if (key_to_blob(key, &blob, &blen) == 0) fatal("%s: key_to_blob failed", __func__); key->type = KEY_RSA1; buffer_init(&m); buffer_put_string(&m, blob, blen); free(blob); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSACHALLENGE, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSACHALLENGE, &m); buffer_get_bignum2(&m, challenge); buffer_free(&m); return (challenge); } int mm_auth_rsa_verify_response(Key *key, BIGNUM *p, u_char response[16]) { Buffer m; u_char *blob; u_int blen; int success = 0; debug3("%s entering", __func__); key->type = KEY_RSA; /* XXX cheat for key_to_blob */ if (key_to_blob(key, &blob, &blen) == 0) fatal("%s: key_to_blob failed", __func__); key->type = KEY_RSA1; buffer_init(&m); buffer_put_string(&m, blob, blen); buffer_put_string(&m, response, 16); free(blob); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSARESPONSE, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSARESPONSE, &m); success = buffer_get_int(&m); buffer_free(&m); return (success); } #endif #ifdef GSSAPI OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID goid) { Buffer m; OM_uint32 major; /* Client doesn't get to see the context */ *ctx = NULL; buffer_init(&m); buffer_put_string(&m, goid->elements, goid->length); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSETUP, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSETUP, &m); major = buffer_get_int(&m); buffer_free(&m); return (major); } OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *in, gss_buffer_desc *out, OM_uint32 *flags) { Buffer m; OM_uint32 major; u_int len; buffer_init(&m); buffer_put_string(&m, in->value, in->length); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSTEP, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSTEP, &m); major = buffer_get_int(&m); out->value = buffer_get_string(&m, &len); out->length = len; if (flags) *flags = buffer_get_int(&m); buffer_free(&m); return (major); } OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic) { Buffer m; OM_uint32 major; buffer_init(&m); buffer_put_string(&m, gssbuf->value, gssbuf->length); buffer_put_string(&m, gssmic->value, gssmic->length); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSCHECKMIC, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSCHECKMIC, &m); major = buffer_get_int(&m); buffer_free(&m); return(major); } int mm_ssh_gssapi_userok(char *user) { Buffer m; int authenticated = 0; buffer_init(&m); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, &m); mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUSEROK, &m); authenticated = buffer_get_int(&m); buffer_free(&m); debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not "); return (authenticated); } #endif /* GSSAPI */