| /* $OpenBSD: monitor.c,v 1.163 2016/08/19 03:18:06 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 "openbsd-compat/sys-tree.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 SKEY |
| #include <skey.h> |
| #endif |
| |
| #ifdef WITH_OPENSSL |
| #include <openssl/dh.h> |
| #endif |
| |
| #include "openbsd-compat/sys-queue.h" |
| #include "atomicio.h" |
| #include "xmalloc.h" |
| #include "ssh.h" |
| #include "key.h" |
| #include "buffer.h" |
| #include "hostfile.h" |
| #include "auth.h" |
| #include "cipher.h" |
| #include "kex.h" |
| #include "dh.h" |
| #include "auth-pam.h" |
| #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ |
| #undef TARGET_OS_MAC |
| #include "zlib.h" |
| #define TARGET_OS_MAC 1 |
| #else |
| #include "zlib.h" |
| #endif |
| #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" |
| #include "monitor_mm.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" |
| |
| #ifdef GSSAPI |
| static Gssctxt *gsscontext = NULL; |
| #endif |
| |
| /* Imports */ |
| extern ServerOptions options; |
| extern u_int utmp_len; |
| extern u_char session_id[]; |
| extern Buffer auth_debug; |
| extern int auth_debug_init; |
| extern Buffer loginmsg; |
| |
| /* State exported from the child */ |
| static struct sshbuf *child_state; |
| |
| /* Functions on the monitor that answer unprivileged requests */ |
| |
| int mm_answer_moduli(int, Buffer *); |
| int mm_answer_sign(int, Buffer *); |
| int mm_answer_pwnamallow(int, Buffer *); |
| int mm_answer_auth2_read_banner(int, Buffer *); |
| int mm_answer_authserv(int, Buffer *); |
| int mm_answer_authpassword(int, Buffer *); |
| int mm_answer_bsdauthquery(int, Buffer *); |
| int mm_answer_bsdauthrespond(int, Buffer *); |
| int mm_answer_skeyquery(int, Buffer *); |
| int mm_answer_skeyrespond(int, Buffer *); |
| int mm_answer_keyallowed(int, Buffer *); |
| int mm_answer_keyverify(int, Buffer *); |
| int mm_answer_pty(int, Buffer *); |
| int mm_answer_pty_cleanup(int, Buffer *); |
| int mm_answer_term(int, Buffer *); |
| int mm_answer_rsa_keyallowed(int, Buffer *); |
| int mm_answer_rsa_challenge(int, Buffer *); |
| int mm_answer_rsa_response(int, Buffer *); |
| int mm_answer_sesskey(int, Buffer *); |
| int mm_answer_sessid(int, Buffer *); |
| |
| #ifdef USE_PAM |
| int mm_answer_pam_start(int, Buffer *); |
| int mm_answer_pam_account(int, Buffer *); |
| int mm_answer_pam_init_ctx(int, Buffer *); |
| int mm_answer_pam_query(int, Buffer *); |
| int mm_answer_pam_respond(int, Buffer *); |
| int mm_answer_pam_free_ctx(int, Buffer *); |
| #endif |
| |
| #ifdef GSSAPI |
| int mm_answer_gss_setup_ctx(int, Buffer *); |
| int mm_answer_gss_accept_ctx(int, Buffer *); |
| int mm_answer_gss_userok(int, Buffer *); |
| int mm_answer_gss_checkmic(int, Buffer *); |
| #endif |
| |
| #ifdef SSH_AUDIT_EVENTS |
| int mm_answer_audit_event(int, Buffer *); |
| int mm_answer_audit_command(int, Buffer *); |
| #endif |
| |
| static int monitor_read_log(struct monitor *); |
| |
| static Authctxt *authctxt; |
| |
| /* local state for key verify */ |
| static u_char *key_blob = NULL; |
| static u_int key_bloblen = 0; |
| static int key_blobtype = MM_NOKEY; |
| 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)(int, Buffer *); |
| }; |
| |
| #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 */ |
| |
| 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_ISAUTH, mm_answer_pam_init_ctx}, |
| {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, |
| {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, 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 |
| #ifdef SKEY |
| {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, |
| {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, |
| #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, MON_ISAUTH, mm_answer_gss_accept_ctx}, |
| {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, |
| {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, 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(Authctxt *_authctxt, struct monitor *pmonitor) |
| { |
| struct mon_table *ent; |
| int authenticated = 0, partial = 0; |
| |
| debug3("preauth child monitor started"); |
| |
| close(pmonitor->m_recvfd); |
| close(pmonitor->m_log_sendfd); |
| pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; |
| |
| authctxt = _authctxt; |
| memset(authctxt, 0, sizeof(*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; |
| authenticated = (monitor_read(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("%s: method %s: partial", __func__, |
| auth_method); |
| authenticated = 0; |
| partial = 1; |
| } |
| } |
| |
| if (authenticated) { |
| if (!(ent->flags & MON_AUTHDECIDE)) |
| fatal("%s: unexpected authentication from %d", |
| __func__, ent->type); |
| if (authctxt->pw->pw_uid == 0 && |
| !auth_root_allowed(auth_method)) |
| authenticated = 0; |
| #ifdef USE_PAM |
| /* PAM needs to perform account checks after auth */ |
| if (options.use_pam && authenticated) { |
| Buffer m; |
| |
| buffer_init(&m); |
| mm_request_receive_expect(pmonitor->m_sendfd, |
| MONITOR_REQ_PAM_ACCOUNT, &m); |
| authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); |
| buffer_free(&m); |
| } |
| #endif |
| } |
| if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { |
| auth_log(authctxt, authenticated, partial, |
| auth_method, auth_submethod); |
| if (!partial && !authenticated) |
| authctxt->failures++; |
| } |
| } |
| |
| if (!authctxt->valid) |
| fatal("%s: authenticated invalid user", __func__); |
| if (strcmp(auth_method, "unknown") == 0) |
| fatal("%s: authentication method name unknown", __func__); |
| |
| debug("%s: %s has been authenticated by privileged process", |
| __func__, authctxt->user); |
| |
| mm_get_keystate(pmonitor); |
| |
| /* Drain any buffered messages from the child */ |
| while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) |
| ; |
| |
| close(pmonitor->m_sendfd); |
| close(pmonitor->m_log_recvfd); |
| 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 monitor *pmonitor) |
| { |
| close(pmonitor->m_recvfd); |
| pmonitor->m_recvfd = -1; |
| |
| monitor_set_child_handler(pmonitor->m_pid); |
| signal(SIGHUP, &monitor_child_handler); |
| signal(SIGTERM, &monitor_child_handler); |
| signal(SIGINT, &monitor_child_handler); |
| #ifdef SIGXFSZ |
| 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 (!no_pty_flag) { |
| monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); |
| monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); |
| } |
| |
| for (;;) |
| monitor_read(pmonitor, mon_dispatch, NULL); |
| } |
| |
| void |
| monitor_sync(struct monitor *pmonitor) |
| { |
| if (options.compression) { |
| /* The member allocation is not visible, so sync it */ |
| mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback); |
| } |
| } |
| |
| /* Allocation functions for zlib */ |
| static void * |
| mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) |
| { |
| if (size == 0 || ncount == 0 || ncount > SIZE_MAX / size) |
| fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); |
| |
| return mm_malloc(mm, size * ncount); |
| } |
| |
| static void |
| mm_zfree(struct mm_master *mm, void *address) |
| { |
| mm_free(mm, address); |
| } |
| |
| static int |
| monitor_read_log(struct monitor *pmonitor) |
| { |
| Buffer logmsg; |
| u_int len, level; |
| char *msg; |
| |
| buffer_init(&logmsg); |
| |
| /* Read length */ |
| buffer_append_space(&logmsg, 4); |
| if (atomicio(read, pmonitor->m_log_recvfd, |
| buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { |
| if (errno == EPIPE) { |
| buffer_free(&logmsg); |
| debug("%s: child log fd closed", __func__); |
| close(pmonitor->m_log_recvfd); |
| pmonitor->m_log_recvfd = -1; |
| return -1; |
| } |
| fatal("%s: log fd read: %s", __func__, strerror(errno)); |
| } |
| len = buffer_get_int(&logmsg); |
| if (len <= 4 || len > 8192) |
| fatal("%s: invalid log message length %u", __func__, len); |
| |
| /* Read severity, message */ |
| buffer_clear(&logmsg); |
| buffer_append_space(&logmsg, len); |
| if (atomicio(read, pmonitor->m_log_recvfd, |
| buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) |
| fatal("%s: log fd read: %s", __func__, strerror(errno)); |
| |
| /* Log it */ |
| level = buffer_get_int(&logmsg); |
| msg = buffer_get_string(&logmsg, NULL); |
| if (log_level_name(level) == NULL) |
| fatal("%s: invalid log level %u (corrupted message?)", |
| __func__, level); |
| do_log2(level, "%s [preauth]", msg); |
| |
| buffer_free(&logmsg); |
| free(msg); |
| |
| return 0; |
| } |
| |
| int |
| monitor_read(struct monitor *pmonitor, struct mon_table *ent, |
| struct mon_table **pent) |
| { |
| Buffer m; |
| int 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("%s: poll: %s", __func__, 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 */ |
| } |
| |
| buffer_init(&m); |
| |
| mm_request_receive(pmonitor->m_sendfd, &m); |
| type = buffer_get_char(&m); |
| |
| debug3("%s: checking request %d", __func__, type); |
| |
| while (ent->f != NULL) { |
| if (ent->type == type) |
| break; |
| ent++; |
| } |
| |
| if (ent->f != NULL) { |
| if (!(ent->flags & MON_PERMIT)) |
| fatal("%s: unpermitted request %d", __func__, |
| type); |
| ret = (*ent->f)(pmonitor->m_sendfd, &m); |
| buffer_free(&m); |
| |
| /* The child may use this request only once, disable it */ |
| if (ent->flags & MON_ONCE) { |
| debug2("%s: %d used once, disabling now", __func__, |
| type); |
| ent->flags &= ~MON_PERMIT; |
| } |
| |
| if (pent != NULL) |
| *pent = ent; |
| |
| return ret; |
| } |
| |
| fatal("%s: unsupported request: %d", __func__, type); |
| |
| /* NOTREACHED */ |
| return (-1); |
| } |
| |
| /* allowed key state */ |
| static int |
| monitor_allowed_key(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); |
| key_blob = NULL; |
| key_bloblen = 0; |
| key_blobtype = MM_NOKEY; |
| hostbased_cuser = NULL; |
| hostbased_chost = NULL; |
| } |
| |
| #ifdef WITH_OPENSSL |
| int |
| mm_answer_moduli(int sock, Buffer *m) |
| { |
| DH *dh; |
| int min, want, max; |
| |
| min = buffer_get_int(m); |
| want = buffer_get_int(m); |
| max = buffer_get_int(m); |
| |
| debug3("%s: got parameters: %d %d %d", |
| __func__, min, want, max); |
| /* We need to check here, too, in case the child got corrupted */ |
| if (max < min || want < min || max < want) |
| fatal("%s: bad parameters: %d %d %d", |
| __func__, min, want, max); |
| |
| buffer_clear(m); |
| |
| dh = choose_dh(min, want, max); |
| if (dh == NULL) { |
| buffer_put_char(m, 0); |
| return (0); |
| } else { |
| /* Send first bignum */ |
| buffer_put_char(m, 1); |
| buffer_put_bignum2(m, dh->p); |
| buffer_put_bignum2(m, dh->g); |
| |
| DH_free(dh); |
| } |
| mm_request_send(sock, MONITOR_ANS_MODULI, m); |
| return (0); |
| } |
| #endif |
| |
| int |
| mm_answer_sign(int sock, Buffer *m) |
| { |
| struct ssh *ssh = active_state; /* XXX */ |
| 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; |
| const char proof_req[] = "hostkeys-prove-00@openssh.com"; |
| |
| debug3("%s", __func__); |
| |
| if ((r = sshbuf_get_u32(m, &keyid)) != 0 || |
| (r = sshbuf_get_string(m, &p, &datlen)) != 0 || |
| (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| if (keyid > INT_MAX) |
| fatal("%s: invalid key ID", __func__); |
| |
| /* |
| * 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("%s: bad data length: %zu", __func__, datlen); |
| if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) |
| fatal("%s: no hostkey for index %d", __func__, keyid); |
| if ((sigbuf = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new", __func__); |
| 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("%s: couldn't prepare private key " |
| "proof buffer: %s", __func__, ssh_err(r)); |
| if (datlen != sshbuf_len(sigbuf) || |
| memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) |
| fatal("%s: bad data length: %zu, hostkey proof len %zu", |
| __func__, 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, |
| datafellows)) != 0) |
| fatal("%s: sshkey_sign failed: %s", |
| __func__, ssh_err(r)); |
| } 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, datafellows)) != 0) { |
| fatal("%s: ssh_agent_sign failed: %s", |
| __func__, ssh_err(r)); |
| } |
| } else |
| fatal("%s: no hostkey from index %d", __func__, keyid); |
| |
| debug3("%s: %s signature %p(%zu)", __func__, |
| is_proof ? "KEX" : "hostkey proof", signature, siglen); |
| |
| sshbuf_reset(m); |
| if ((r = sshbuf_put_string(m, signature, siglen)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| |
| 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); |
| } |
| |
| /* Retrieves the password entry and also checks if the user is permitted */ |
| |
| int |
| mm_answer_pwnamallow(int sock, Buffer *m) |
| { |
| char *username; |
| struct passwd *pwent; |
| int allowed = 0; |
| u_int i; |
| |
| debug3("%s", __func__); |
| |
| if (authctxt->attempt++ != 0) |
| fatal("%s: multiple attempts for getpwnam", __func__); |
| |
| username = buffer_get_string(m, NULL); |
| |
| pwent = getpwnamallow(username); |
| |
| authctxt->user = xstrdup(username); |
| setproctitle("%s [priv]", pwent ? username : "unknown"); |
| free(username); |
| |
| buffer_clear(m); |
| |
| if (pwent == NULL) { |
| buffer_put_char(m, 0); |
| authctxt->pw = fakepw(); |
| goto out; |
| } |
| |
| allowed = 1; |
| authctxt->pw = pwent; |
| authctxt->valid = 1; |
| |
| buffer_put_char(m, 1); |
| buffer_put_string(m, pwent, sizeof(struct passwd)); |
| buffer_put_cstring(m, pwent->pw_name); |
| buffer_put_cstring(m, "*"); |
| #ifdef HAVE_STRUCT_PASSWD_PW_GECOS |
| buffer_put_cstring(m, pwent->pw_gecos); |
| #endif |
| #ifdef HAVE_STRUCT_PASSWD_PW_CLASS |
| buffer_put_cstring(m, pwent->pw_class); |
| #endif |
| buffer_put_cstring(m, pwent->pw_dir); |
| buffer_put_cstring(m, pwent->pw_shell); |
| |
| out: |
| buffer_put_string(m, &options, sizeof(options)); |
| |
| #define M_CP_STROPT(x) do { \ |
| if (options.x != NULL) \ |
| buffer_put_cstring(m, options.x); \ |
| } while (0) |
| #define M_CP_STRARRAYOPT(x, nx) do { \ |
| for (i = 0; i < options.nx; i++) \ |
| buffer_put_cstring(m, options.x[i]); \ |
| } 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 it's packet_disconnect(), but it must not allow any |
| * authentication to succeed. |
| */ |
| debug("%s: no valid authentication method lists", __func__); |
| } |
| |
| debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, 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(int sock, Buffer *m) |
| { |
| char *banner; |
| |
| buffer_clear(m); |
| banner = auth2_read_banner(); |
| buffer_put_cstring(m, banner != NULL ? banner : ""); |
| mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); |
| free(banner); |
| |
| return (0); |
| } |
| |
| int |
| mm_answer_authserv(int sock, Buffer *m) |
| { |
| monitor_permit_authentications(1); |
| |
| authctxt->service = buffer_get_string(m, NULL); |
| authctxt->style = buffer_get_string(m, NULL); |
| debug3("%s: service=%s, style=%s", |
| __func__, authctxt->service, authctxt->style); |
| |
| if (strlen(authctxt->style) == 0) { |
| free(authctxt->style); |
| authctxt->style = NULL; |
| } |
| |
| return (0); |
| } |
| |
| int |
| mm_answer_authpassword(int sock, Buffer *m) |
| { |
| static int call_count; |
| char *passwd; |
| int authenticated; |
| u_int plen; |
| |
| passwd = buffer_get_string(m, &plen); |
| /* Only authenticate if the context is valid */ |
| authenticated = options.password_authentication && |
| auth_password(authctxt, passwd); |
| explicit_bzero(passwd, strlen(passwd)); |
| free(passwd); |
| |
| buffer_clear(m); |
| buffer_put_int(m, authenticated); |
| #ifdef USE_PAM |
| buffer_put_int(m, sshpam_get_maxtries_reached()); |
| #endif |
| |
| debug3("%s: sending result %d", __func__, 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(int sock, Buffer *m) |
| { |
| char *name, *infotxt; |
| u_int numprompts; |
| u_int *echo_on; |
| char **prompts; |
| u_int success; |
| |
| success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, |
| &prompts, &echo_on) < 0 ? 0 : 1; |
| |
| buffer_clear(m); |
| buffer_put_int(m, success); |
| if (success) |
| buffer_put_cstring(m, prompts[0]); |
| |
| debug3("%s: sending challenge success: %u", __func__, 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(int sock, Buffer *m) |
| { |
| char *response; |
| int authok; |
| |
| if (authctxt->as == NULL) |
| fatal("%s: no bsd auth session", __func__); |
| |
| response = buffer_get_string(m, NULL); |
| authok = options.challenge_response_authentication && |
| auth_userresponse(authctxt->as, response, 0); |
| authctxt->as = NULL; |
| debug3("%s: <%s> = <%d>", __func__, response, authok); |
| free(response); |
| |
| buffer_clear(m); |
| buffer_put_int(m, authok); |
| |
| debug3("%s: sending authenticated: %d", __func__, authok); |
| mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); |
| |
| auth_method = "keyboard-interactive"; |
| auth_submethod = "bsdauth"; |
| |
| return (authok != 0); |
| } |
| #endif |
| |
| #ifdef SKEY |
| int |
| mm_answer_skeyquery(int sock, Buffer *m) |
| { |
| struct skey skey; |
| char challenge[1024]; |
| u_int success; |
| |
| success = _compat_skeychallenge(&skey, authctxt->user, challenge, |
| sizeof(challenge)) < 0 ? 0 : 1; |
| |
| buffer_clear(m); |
| buffer_put_int(m, success); |
| if (success) |
| buffer_put_cstring(m, challenge); |
| |
| debug3("%s: sending challenge success: %u", __func__, success); |
| mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); |
| |
| return (0); |
| } |
| |
| int |
| mm_answer_skeyrespond(int sock, Buffer *m) |
| { |
| char *response; |
| int authok; |
| |
| response = buffer_get_string(m, NULL); |
| |
| authok = (options.challenge_response_authentication && |
| authctxt->valid && |
| skey_haskey(authctxt->pw->pw_name) == 0 && |
| skey_passcheck(authctxt->pw->pw_name, response) != -1); |
| |
| free(response); |
| |
| buffer_clear(m); |
| buffer_put_int(m, authok); |
| |
| debug3("%s: sending authenticated: %d", __func__, authok); |
| mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); |
| |
| auth_method = "keyboard-interactive"; |
| auth_submethod = "skey"; |
| |
| return (authok != 0); |
| } |
| #endif |
| |
| #ifdef USE_PAM |
| int |
| mm_answer_pam_start(int sock, Buffer *m) |
| { |
| if (!options.use_pam) |
| fatal("UsePAM not set, but ended up in %s anyway", __func__); |
| |
| start_pam(authctxt); |
| |
| monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); |
| |
| return (0); |
| } |
| |
| int |
| mm_answer_pam_account(int sock, Buffer *m) |
| { |
| u_int ret; |
| |
| if (!options.use_pam) |
| fatal("UsePAM not set, but ended up in %s anyway", __func__); |
| |
| ret = do_pam_account(); |
| |
| buffer_put_int(m, ret); |
| buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); |
| |
| 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(int sock, Buffer *m) |
| { |
| debug3("%s", __func__); |
| sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); |
| sshpam_authok = NULL; |
| buffer_clear(m); |
| if (sshpam_ctxt != NULL) { |
| monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); |
| buffer_put_int(m, 1); |
| } else { |
| buffer_put_int(m, 0); |
| } |
| mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); |
| return (0); |
| } |
| |
| int |
| mm_answer_pam_query(int sock, Buffer *m) |
| { |
| char *name = NULL, *info = NULL, **prompts = NULL; |
| u_int i, num = 0, *echo_on = 0; |
| int ret; |
| |
| debug3("%s", __func__); |
| sshpam_authok = NULL; |
| 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) |
| ret = -1; |
| buffer_clear(m); |
| buffer_put_int(m, ret); |
| buffer_put_cstring(m, name); |
| free(name); |
| buffer_put_cstring(m, info); |
| free(info); |
| buffer_put_int(m, sshpam_get_maxtries_reached()); |
| buffer_put_int(m, num); |
| for (i = 0; i < num; ++i) { |
| buffer_put_cstring(m, prompts[i]); |
| free(prompts[i]); |
| buffer_put_int(m, echo_on[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(int sock, Buffer *m) |
| { |
| char **resp; |
| u_int i, num; |
| int ret; |
| |
| debug3("%s", __func__); |
| sshpam_authok = NULL; |
| num = buffer_get_int(m); |
| if (num > 0) { |
| resp = xcalloc(num, sizeof(char *)); |
| for (i = 0; i < num; ++i) |
| resp[i] = buffer_get_string(m, NULL); |
| 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); |
| } |
| buffer_clear(m); |
| buffer_put_int(m, ret); |
| 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(int sock, Buffer *m) |
| { |
| int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; |
| |
| debug3("%s", __func__); |
| (sshpam_device.free_ctx)(sshpam_ctxt); |
| sshpam_ctxt = sshpam_authok = NULL; |
| buffer_clear(m); |
| mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); |
| auth_method = "keyboard-interactive"; |
| auth_submethod = "pam"; |
| return r; |
| } |
| #endif |
| |
| int |
| mm_answer_keyallowed(int sock, Buffer *m) |
| { |
| Key *key; |
| char *cuser, *chost; |
| u_char *blob; |
| u_int bloblen, pubkey_auth_attempt; |
| enum mm_keytype type = 0; |
| int allowed = 0; |
| |
| debug3("%s entering", __func__); |
| |
| type = buffer_get_int(m); |
| cuser = buffer_get_string(m, NULL); |
| chost = buffer_get_string(m, NULL); |
| blob = buffer_get_string(m, &bloblen); |
| pubkey_auth_attempt = buffer_get_int(m); |
| |
| key = key_from_blob(blob, bloblen); |
| |
| debug3("%s: key_from_blob: %p", __func__, key); |
| |
| if (key != NULL && authctxt->valid) { |
| /* These should not make it past the privsep child */ |
| if (key_type_plain(key->type) == KEY_RSA && |
| (datafellows & SSH_BUG_RSASIGMD5) != 0) |
| fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); |
| |
| switch (type) { |
| case MM_USERKEY: |
| allowed = options.pubkey_authentication && |
| !auth2_userkey_already_used(authctxt, key) && |
| match_pattern_list(sshkey_ssh_name(key), |
| options.pubkey_key_types, 0) == 1 && |
| user_key_allowed(authctxt->pw, key, |
| pubkey_auth_attempt); |
| pubkey_auth_info(authctxt, key, NULL); |
| auth_method = "publickey"; |
| if (options.pubkey_authentication && |
| (!pubkey_auth_attempt || allowed != 1)) |
| auth_clear_options(); |
| break; |
| case MM_HOSTKEY: |
| allowed = options.hostbased_authentication && |
| match_pattern_list(sshkey_ssh_name(key), |
| options.hostbased_key_types, 0) == 1 && |
| hostbased_key_allowed(authctxt->pw, |
| cuser, chost, key); |
| pubkey_auth_info(authctxt, key, |
| "client user \"%.100s\", client host \"%.100s\"", |
| cuser, chost); |
| auth_method = "hostbased"; |
| break; |
| default: |
| fatal("%s: unknown key type %d", __func__, type); |
| break; |
| } |
| } |
| |
| debug3("%s: key %p is %s", |
| __func__, key, allowed ? "allowed" : "not allowed"); |
| |
| if (key != NULL) |
| key_free(key); |
| |
| /* clear temporarily storage (used by verify) */ |
| monitor_reset_key_state(); |
| |
| if (allowed) { |
| /* Save temporarily for comparison in verify */ |
| key_blob = blob; |
| key_bloblen = bloblen; |
| key_blobtype = type; |
| hostbased_cuser = cuser; |
| hostbased_chost = chost; |
| } else { |
| /* Log failed attempt */ |
| auth_log(authctxt, 0, 0, auth_method, NULL); |
| free(blob); |
| free(cuser); |
| free(chost); |
| } |
| |
| buffer_clear(m); |
| buffer_put_int(m, allowed); |
| buffer_put_int(m, forced_command != NULL); |
| |
| mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); |
| |
| return (0); |
| } |
| |
| static int |
| monitor_valid_userblob(u_char *data, u_int datalen) |
| { |
| Buffer b; |
| u_char *p; |
| char *userstyle, *cp; |
| u_int len; |
| int fail = 0; |
| |
| buffer_init(&b); |
| buffer_append(&b, data, datalen); |
| |
| if (datafellows & SSH_OLD_SESSIONID) { |
| p = buffer_ptr(&b); |
| len = buffer_len(&b); |
| if ((session_id2 == NULL) || |
| (len < session_id2_len) || |
| (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) |
| fail++; |
| buffer_consume(&b, session_id2_len); |
| } else { |
| p = buffer_get_string(&b, &len); |
| if ((session_id2 == NULL) || |
| (len != session_id2_len) || |
| (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) |
| fail++; |
| free(p); |
| } |
| if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) |
| fail++; |
| cp = buffer_get_cstring(&b, NULL); |
| 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); |
| buffer_skip_string(&b); |
| if (datafellows & SSH_BUG_PKAUTH) { |
| if (!buffer_get_char(&b)) |
| fail++; |
| } else { |
| cp = buffer_get_cstring(&b, NULL); |
| if (strcmp("publickey", cp) != 0) |
| fail++; |
| free(cp); |
| if (!buffer_get_char(&b)) |
| fail++; |
| buffer_skip_string(&b); |
| } |
| buffer_skip_string(&b); |
| if (buffer_len(&b) != 0) |
| fail++; |
| buffer_free(&b); |
| return (fail == 0); |
| } |
| |
| static int |
| monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, |
| char *chost) |
| { |
| Buffer b; |
| char *p, *userstyle; |
| u_int len; |
| int fail = 0; |
| |
| buffer_init(&b); |
| buffer_append(&b, data, datalen); |
| |
| p = buffer_get_string(&b, &len); |
| if ((session_id2 == NULL) || |
| (len != session_id2_len) || |
| (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) |
| fail++; |
| free(p); |
| |
| if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) |
| fail++; |
| p = buffer_get_cstring(&b, NULL); |
| xasprintf(&userstyle, "%s%s%s", authctxt->user, |
| authctxt->style ? ":" : "", |
| authctxt->style ? authctxt->style : ""); |
| if (strcmp(userstyle, p) != 0) { |
| logit("wrong user name passed to monitor: expected %s != %.100s", |
| userstyle, p); |
| fail++; |
| } |
| free(userstyle); |
| free(p); |
| buffer_skip_string(&b); /* service */ |
| p = buffer_get_cstring(&b, NULL); |
| if (strcmp(p, "hostbased") != 0) |
| fail++; |
| free(p); |
| buffer_skip_string(&b); /* pkalg */ |
| buffer_skip_string(&b); /* pkblob */ |
| |
| /* verify client host, strip trailing dot if necessary */ |
| p = buffer_get_string(&b, NULL); |
| if (((len = strlen(p)) > 0) && p[len - 1] == '.') |
| p[len - 1] = '\0'; |
| if (strcmp(p, chost) != 0) |
| fail++; |
| free(p); |
| |
| /* verify client user */ |
| p = buffer_get_string(&b, NULL); |
| if (strcmp(p, cuser) != 0) |
| fail++; |
| free(p); |
| |
| if (buffer_len(&b) != 0) |
| fail++; |
| buffer_free(&b); |
| return (fail == 0); |
| } |
| |
| int |
| mm_answer_keyverify(int sock, Buffer *m) |
| { |
| Key *key; |
| u_char *signature, *data, *blob; |
| u_int signaturelen, datalen, bloblen; |
| int verified = 0; |
| int valid_data = 0; |
| |
| blob = buffer_get_string(m, &bloblen); |
| signature = buffer_get_string(m, &signaturelen); |
| data = buffer_get_string(m, &datalen); |
| |
| if (hostbased_cuser == NULL || hostbased_chost == NULL || |
| !monitor_allowed_key(blob, bloblen)) |
| fatal("%s: bad key, not previously allowed", __func__); |
| |
| key = key_from_blob(blob, bloblen); |
| if (key == NULL) |
| fatal("%s: bad public key blob", __func__); |
| |
| switch (key_blobtype) { |
| case MM_USERKEY: |
| valid_data = monitor_valid_userblob(data, datalen); |
| break; |
| case MM_HOSTKEY: |
| valid_data = monitor_valid_hostbasedblob(data, datalen, |
| hostbased_cuser, hostbased_chost); |
| break; |
| default: |
| valid_data = 0; |
| break; |
| } |
| if (!valid_data) |
| fatal("%s: bad signature data blob", __func__); |
| |
| verified = key_verify(key, signature, signaturelen, data, datalen); |
| debug3("%s: key %p signature %s", |
| __func__, key, (verified == 1) ? "verified" : "unverified"); |
| |
| /* If auth was successful then record key to ensure it isn't reused */ |
| if (verified == 1 && key_blobtype == MM_USERKEY) |
| auth2_record_userkey(authctxt, key); |
| else |
| key_free(key); |
| |
| free(blob); |
| free(signature); |
| free(data); |
| |
| auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; |
| |
| monitor_reset_key_state(); |
| |
| buffer_clear(m); |
| buffer_put_int(m, verified); |
| mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); |
| |
| return (verified == 1); |
| } |
| |
| static void |
| mm_record_login(Session *s, struct passwd *pw) |
| { |
| struct ssh *ssh = active_state; /* XXX */ |
| 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 (packet_connection_is_on_socket()) { |
| if (getpeername(packet_get_connection_in(), |
| (struct sockaddr *)&from, &fromlen) < 0) { |
| 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("%s: session %d pid %ld", __func__, s->self, (long)s->pid); |
| if (s->ttyfd != -1) { |
| debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); |
| session_pty_cleanup2(s); |
| } |
| session_unused(s->self); |
| } |
| |
| int |
| mm_answer_pty(int sock, Buffer *m) |
| { |
| extern struct monitor *pmonitor; |
| Session *s; |
| int res, fd0; |
| |
| debug3("%s entering", __func__); |
| |
| buffer_clear(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); |
| |
| buffer_put_int(m, 1); |
| buffer_put_cstring(m, s->tty); |
| |
| /* We need to trick ttyslot */ |
| if (dup2(s->ttyfd, 0) == -1) |
| fatal("%s: dup2", __func__); |
| |
| mm_record_login(s, authctxt->pw); |
| |
| /* Now we can close the file descriptor again */ |
| close(0); |
| |
| /* send messages generated by record_login */ |
| buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); |
| buffer_clear(&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("%s: send fds failed", __func__); |
| |
| /* make sure nothing uses fd 0 */ |
| if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) |
| fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); |
| if (fd0 != 0) |
| error("%s: fd0 %d != 0", __func__, fd0); |
| |
| /* slave is not needed */ |
| close(s->ttyfd); |
| s->ttyfd = s->ptyfd; |
| /* no need to dup() because nobody closes ptyfd */ |
| s->ptymaster = s->ptyfd; |
| |
| debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); |
| |
| return (0); |
| |
| error: |
| if (s != NULL) |
| mm_session_close(s); |
| buffer_put_int(m, 0); |
| mm_request_send(sock, MONITOR_ANS_PTY, m); |
| return (0); |
| } |
| |
| int |
| mm_answer_pty_cleanup(int sock, Buffer *m) |
| { |
| Session *s; |
| char *tty; |
| |
| debug3("%s entering", __func__); |
| |
| tty = buffer_get_string(m, NULL); |
| if ((s = session_by_tty(tty)) != NULL) |
| mm_session_close(s); |
| buffer_clear(m); |
| free(tty); |
| return (0); |
| } |
| |
| int |
| mm_answer_term(int sock, Buffer *req) |
| { |
| extern struct monitor *pmonitor; |
| int res, status; |
| |
| debug3("%s: tearing down sessions", __func__); |
| |
| /* The child is terminating */ |
| session_destroy_all(&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(int socket, Buffer *m) |
| { |
| ssh_audit_event_t event; |
| |
| debug3("%s entering", __func__); |
| |
| event = buffer_get_int(m); |
| 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(event); |
| break; |
| default: |
| fatal("Audit event type %d not permitted", event); |
| } |
| |
| return (0); |
| } |
| |
| int |
| mm_answer_audit_command(int socket, Buffer *m) |
| { |
| u_int len; |
| char *cmd; |
| |
| debug3("%s entering", __func__); |
| cmd = buffer_get_string(m, &len); |
| /* sanity check command, if so how? */ |
| audit_run_command(cmd); |
| free(cmd); |
| return (0); |
| } |
| #endif /* SSH_AUDIT_EVENTS */ |
| |
| void |
| monitor_apply_keystate(struct monitor *pmonitor) |
| { |
| struct ssh *ssh = active_state; /* XXX */ |
| struct kex *kex; |
| int r; |
| |
| debug3("%s: packet_set_state", __func__); |
| if ((r = ssh_packet_set_state(ssh, child_state)) != 0) |
| fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); |
| sshbuf_free(child_state); |
| child_state = NULL; |
| |
| if ((kex = ssh->kex) != NULL) { |
| /* XXX set callbacks */ |
| #ifdef WITH_OPENSSL |
| kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
| kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
| kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; |
| kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; |
| kex->kex[KEX_DH_GRP18_SHA512] = kexdh_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] = kexecdh_server; |
| # endif |
| #endif /* WITH_OPENSSL */ |
| kex->kex[KEX_C25519_SHA256] = kexc25519_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; |
| } |
| |
| /* Update with new address */ |
| if (options.compression) { |
| ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib, |
| (ssh_packet_comp_alloc_func *)mm_zalloc, |
| (ssh_packet_comp_free_func *)mm_zfree); |
| } |
| } |
| |
| /* This function requries careful sanity checking */ |
| |
| void |
| mm_get_keystate(struct monitor *pmonitor) |
| { |
| debug3("%s: Waiting for new keys", __func__); |
| |
| if ((child_state = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, |
| child_state); |
| debug3("%s: GOT new keys", __func__); |
| } |
| |
| |
| /* 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]; |
| |
| if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) |
| fatal("%s: socketpair: %s", __func__, strerror(errno)); |
| 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("%s: pipe: %s", __func__, 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 ssh *ssh = active_state; /* XXX */ |
| struct monitor *mon; |
| |
| mon = xcalloc(1, sizeof(*mon)); |
| |
| monitor_openfds(mon, 1); |
| |
| /* Used to share zlib space across processes */ |
| if (options.compression) { |
| mon->m_zback = mm_create(NULL, MM_MEMSIZE); |
| mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); |
| |
| /* Compression needs to share state across borders */ |
| ssh_packet_set_compress_hooks(ssh, mon->m_zlib, |
| (ssh_packet_comp_alloc_func *)mm_zalloc, |
| (ssh_packet_comp_free_func *)mm_zfree); |
| } |
| |
| return mon; |
| } |
| |
| void |
| monitor_reinit(struct monitor *mon) |
| { |
| monitor_openfds(mon, 0); |
| } |
| |
| #ifdef GSSAPI |
| int |
| mm_answer_gss_setup_ctx(int sock, Buffer *m) |
| { |
| gss_OID_desc goid; |
| OM_uint32 major; |
| u_int len; |
| |
| goid.elements = buffer_get_string(m, &len); |
| goid.length = len; |
| |
| major = ssh_gssapi_server_ctx(&gsscontext, &goid); |
| |
| free(goid.elements); |
| |
| buffer_clear(m); |
| buffer_put_int(m, major); |
| |
| 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(int sock, Buffer *m) |
| { |
| gss_buffer_desc in; |
| gss_buffer_desc out = GSS_C_EMPTY_BUFFER; |
| OM_uint32 major, minor; |
| OM_uint32 flags = 0; /* GSI needs this */ |
| u_int len; |
| |
| in.value = buffer_get_string(m, &len); |
| in.length = len; |
| major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); |
| free(in.value); |
| |
| buffer_clear(m); |
| buffer_put_int(m, major); |
| buffer_put_string(m, out.value, out.length); |
| buffer_put_int(m, flags); |
| 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(int sock, Buffer *m) |
| { |
| gss_buffer_desc gssbuf, mic; |
| OM_uint32 ret; |
| u_int len; |
| |
| gssbuf.value = buffer_get_string(m, &len); |
| gssbuf.length = len; |
| mic.value = buffer_get_string(m, &len); |
| mic.length = len; |
| |
| ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); |
| |
| free(gssbuf.value); |
| free(mic.value); |
| |
| buffer_clear(m); |
| buffer_put_int(m, ret); |
| |
| 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(int sock, Buffer *m) |
| { |
| int authenticated; |
| |
| authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); |
| |
| buffer_clear(m); |
| buffer_put_int(m, authenticated); |
| |
| debug3("%s: sending result %d", __func__, authenticated); |
| mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); |
| |
| auth_method = "gssapi-with-mic"; |
| |
| /* Monitor loop will terminate if authenticated */ |
| return (authenticated); |
| } |
| #endif /* GSSAPI */ |
| |