diff options
Diffstat (limited to 'crypto/openssh/monitor.c')
| -rw-r--r-- | crypto/openssh/monitor.c | 1498 |
1 files changed, 1498 insertions, 0 deletions
diff --git a/crypto/openssh/monitor.c b/crypto/openssh/monitor.c new file mode 100644 index 000000000000..4957be9cd07a --- /dev/null +++ b/crypto/openssh/monitor.c @@ -0,0 +1,1498 @@ +/* + * 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" +RCSID("$OpenBSD: monitor.c,v 1.16 2002/06/21 05:50:51 djm Exp $"); + +#include <openssl/dh.h> + +#ifdef SKEY +#include <skey.h> +#endif + +#include "ssh.h" +#include "auth.h" +#include "kex.h" +#include "dh.h" +#include "zlib.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 "servconf.h" +#include "monitor.h" +#include "monitor_mm.h" +#include "monitor_wrap.h" +#include "monitor_fdpass.h" +#include "xmalloc.h" +#include "misc.h" +#include "buffer.h" +#include "bufaux.h" +#include "compat.h" +#include "ssh2.h" +#include "mpaux.h" + +/* Imports */ +extern ServerOptions options; +extern u_int utmp_len; +extern Newkeys *current_keys[]; +extern z_stream incoming_stream; +extern z_stream outgoing_stream; +extern u_char session_id[]; +extern Buffer input, output; +extern Buffer auth_debug; +extern int auth_debug_init; + +/* State exported from the child */ + +struct { + z_stream incoming; + z_stream outgoing; + u_char *keyin; + u_int keyinlen; + u_char *keyout; + u_int keyoutlen; + u_char *ivin; + u_int ivinlen; + u_char *ivout; + u_int ivoutlen; + u_char *ssh1key; + u_int ssh1keylen; + int ssh1cipher; + int ssh1protoflags; + u_char *input; + u_int ilen; + u_char *output; + u_int olen; +} child_state; + +/* Functions on the montior 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 *); + +static Authctxt *authctxt; +static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ + +/* local state for key verify */ +static u_char *key_blob = NULL; +static u_int key_bloblen = 0; +static int key_blobtype = MM_NOKEY; +static u_char *hostbased_cuser = NULL; +static u_char *hostbased_chost = NULL; +static char *auth_method = "unknown"; +static int session_id2_len = 0; +static u_char *session_id2 = NULL; + +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_AUTH (MON_ISAUTH|MON_AUTHDECIDE) + +#define MON_PERMIT 0x1000 /* Request is permitted */ + +struct mon_table mon_dispatch_proto20[] = { + {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, + {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 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}, + {0, 0, NULL} +}; + +struct mon_table mon_dispatch_postauth20[] = { + {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, + {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}, + {0, 0, NULL} +}; + +struct mon_table mon_dispatch_proto15[] = { + {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, + {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey}, + {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid}, + {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, + {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH, mm_answer_rsa_keyallowed}, + {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, + {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge}, + {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response}, +#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 + {0, 0, NULL} +}; + +struct mon_table mon_dispatch_postauth15[] = { + {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty}, + {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup}, + {MONITOR_REQ_TERM, 0, mm_answer_term}, + {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++; + } +} + +Authctxt * +monitor_child_preauth(struct monitor *pmonitor) +{ + struct mon_table *ent; + int authenticated = 0; + + debug3("preauth child monitor started"); + + if (compat20) { + 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); + } else { + mon_dispatch = mon_dispatch_proto15; + + monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); + } + + authctxt = authctxt_new(); + + /* The first few requests do not require asynchronous access */ + while (!authenticated) { + authenticated = monitor_read(pmonitor, mon_dispatch, &ent); + 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; + } + + if (ent->flags & MON_AUTHDECIDE) { + auth_log(authctxt, authenticated, auth_method, + compat20 ? " ssh2" : ""); + if (!authenticated) + authctxt->failures++; + } + } + + if (!authctxt->valid) + fatal("%s: authenticated invalid user", __func__); + + debug("%s: %s has been authenticated by privileged process", + __func__, authctxt->user); + + mm_get_keystate(pmonitor); + + return (authctxt); +} + +void +monitor_child_postauth(struct monitor *pmonitor) +{ + if (compat20) { + 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); + + } else { + mon_dispatch = mon_dispatch_postauth15; + 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); + } +} + +int +monitor_read(struct monitor *pmonitor, struct mon_table *ent, + struct mon_table **pent) +{ + Buffer m; + int ret; + u_char type; + + 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 || + memcmp(key_blob, blob, key_bloblen)) + return (0); + return (1); +} + +static void +monitor_reset_key_state(void) +{ + /* reset state */ + if (key_blob != NULL) + xfree(key_blob); + if (hostbased_cuser != NULL) + xfree(hostbased_cuser); + if (hostbased_chost != NULL) + xfree(hostbased_chost); + key_blob = NULL; + key_bloblen = 0; + key_blobtype = MM_NOKEY; + hostbased_cuser = NULL; + hostbased_chost = NULL; +} + +int +mm_answer_moduli(int socket, 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(socket, MONITOR_ANS_MODULI, m); + return (0); +} + +int +mm_answer_sign(int socket, Buffer *m) +{ + Key *key; + u_char *p; + u_char *signature; + u_int siglen, datlen; + int keyid; + + debug3("%s", __func__); + + keyid = buffer_get_int(m); + p = buffer_get_string(m, &datlen); + + if (datlen != 20) + fatal("%s: data length incorrect: %d", __func__, datlen); + + /* 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) + fatal("%s: no hostkey from index %d", __func__, keyid); + if (key_sign(key, &signature, &siglen, p, datlen) < 0) + fatal("%s: key_sign failed", __func__); + + debug3("%s: signature %p(%d)", __func__, signature, siglen); + + buffer_clear(m); + buffer_put_string(m, signature, siglen); + + xfree(p); + xfree(signature); + + mm_request_send(socket, 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 socket, Buffer *m) +{ + char *login; + struct passwd *pwent; + int allowed = 0; + + debug3("%s", __func__); + + if (authctxt->attempt++ != 0) + fatal("%s: multiple attempts for getpwnam", __func__); + + login = buffer_get_string(m, NULL); + + pwent = getpwnamallow(login); + + authctxt->user = xstrdup(login); + setproctitle("%s [priv]", pwent ? login : "unknown"); + xfree(login); + + buffer_clear(m); + + if (pwent == NULL) { + buffer_put_char(m, 0); + 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, "*"); + buffer_put_cstring(m, pwent->pw_gecos); + buffer_put_cstring(m, pwent->pw_class); + buffer_put_cstring(m, pwent->pw_dir); + buffer_put_cstring(m, pwent->pw_shell); + + out: + debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); + mm_request_send(socket, MONITOR_ANS_PWNAM, m); + + /* For SSHv1 allow authentication now */ + if (!compat20) + monitor_permit_authentications(1); + else { + /* 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); + } + + + return (0); +} + +int mm_answer_auth2_read_banner(int socket, Buffer *m) +{ + char *banner; + + buffer_clear(m); + banner = auth2_read_banner(); + buffer_put_cstring(m, banner != NULL ? banner : ""); + mm_request_send(socket, MONITOR_ANS_AUTH2_READ_BANNER, m); + + if (banner != NULL) + free(banner); + + return (0); +} + +int +mm_answer_authserv(int socket, 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) { + xfree(authctxt->style); + authctxt->style = NULL; + } + + return (0); +} + +int +mm_answer_authpassword(int socket, Buffer *m) +{ + static int call_count; + char *passwd; + int authenticated, plen; + + passwd = buffer_get_string(m, &plen); + /* Only authenticate if the context is valid */ + authenticated = options.password_authentication && + authctxt->valid && auth_password(authctxt, passwd); + memset(passwd, 0, strlen(passwd)); + xfree(passwd); + + buffer_clear(m); + buffer_put_int(m, authenticated); + + debug3("%s: sending result %d", __func__, authenticated); + mm_request_send(socket, 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 socket, Buffer *m) +{ + char *name, *infotxt; + u_int numprompts; + u_int *echo_on; + char **prompts; + int res; + + res = bsdauth_query(authctxt, &name, &infotxt, &numprompts, + &prompts, &echo_on); + + buffer_clear(m); + buffer_put_int(m, res); + if (res != -1) + buffer_put_cstring(m, prompts[0]); + + debug3("%s: sending challenge res: %d", __func__, res); + mm_request_send(socket, MONITOR_ANS_BSDAUTHQUERY, m); + + if (res != -1) { + xfree(name); + xfree(infotxt); + xfree(prompts); + xfree(echo_on); + } + + return (0); +} + +int +mm_answer_bsdauthrespond(int socket, Buffer *m) +{ + char *response; + int authok; + + if (authctxt->as == 0) + 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); + xfree(response); + + buffer_clear(m); + buffer_put_int(m, authok); + + debug3("%s: sending authenticated: %d", __func__, authok); + mm_request_send(socket, MONITOR_ANS_BSDAUTHRESPOND, m); + + auth_method = "bsdauth"; + + return (authok != 0); +} +#endif + +#ifdef SKEY +int +mm_answer_skeyquery(int socket, Buffer *m) +{ + struct skey skey; + char challenge[1024]; + int res; + + res = skeychallenge(&skey, authctxt->user, challenge); + + buffer_clear(m); + buffer_put_int(m, res); + if (res != -1) + buffer_put_cstring(m, challenge); + + debug3("%s: sending challenge res: %d", __func__, res); + mm_request_send(socket, MONITOR_ANS_SKEYQUERY, m); + + return (0); +} + +int +mm_answer_skeyrespond(int socket, 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); + + xfree(response); + + buffer_clear(m); + buffer_put_int(m, authok); + + debug3("%s: sending authenticated: %d", __func__, authok); + mm_request_send(socket, MONITOR_ANS_SKEYRESPOND, m); + + auth_method = "skey"; + + return (authok != 0); +} +#endif + +static void +mm_append_debug(Buffer *m) +{ + if (auth_debug_init && buffer_len(&auth_debug)) { + debug3("%s: Appending debug messages for child", __func__); + buffer_append(m, buffer_ptr(&auth_debug), + buffer_len(&auth_debug)); + buffer_clear(&auth_debug); + } +} + +int +mm_answer_keyallowed(int socket, Buffer *m) +{ + Key *key; + u_char *cuser, *chost, *blob; + u_int bloblen; + 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); + + key = key_from_blob(blob, bloblen); + + if ((compat20 && type == MM_RSAHOSTKEY) || + (!compat20 && type != MM_RSAHOSTKEY)) + fatal("%s: key type and protocol mismatch", __func__); + + debug3("%s: key_from_blob: %p", __func__, key); + + if (key != NULL && authctxt->pw != NULL) { + switch(type) { + case MM_USERKEY: + allowed = options.pubkey_authentication && + user_key_allowed(authctxt->pw, key); + break; + case MM_HOSTKEY: + allowed = options.hostbased_authentication && + hostbased_key_allowed(authctxt->pw, + cuser, chost, key); + break; + case MM_RSAHOSTKEY: + key->type = KEY_RSA1; /* XXX */ + allowed = options.rhosts_rsa_authentication && + auth_rhosts_rsa_key_allowed(authctxt->pw, + cuser, chost, key); + break; + default: + fatal("%s: unknown key type %d", __func__, type); + break; + } + 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; + } + + debug3("%s: key %p is %s", + __func__, key, allowed ? "allowed" : "disallowed"); + + buffer_clear(m); + buffer_put_int(m, allowed); + + mm_append_debug(m); + + mm_request_send(socket, MONITOR_ANS_KEYALLOWED, m); + + if (type == MM_RSAHOSTKEY) + monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); + + return (0); +} + +static int +monitor_valid_userblob(u_char *data, u_int datalen) +{ + Buffer b; + u_char *p; + 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) || + (memcmp(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) || + (memcmp(p, session_id2, session_id2_len) != 0)) + fail++; + xfree(p); + } + if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) + fail++; + p = buffer_get_string(&b, NULL); + if (strcmp(authctxt->user, p) != 0) { + log("wrong user name passed to monitor: expected %s != %.100s", + authctxt->user, p); + fail++; + } + xfree(p); + buffer_skip_string(&b); + if (datafellows & SSH_BUG_PKAUTH) { + if (!buffer_get_char(&b)) + fail++; + } else { + p = buffer_get_string(&b, NULL); + if (strcmp("publickey", p) != 0) + fail++; + xfree(p); + 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, u_char *cuser, + u_char *chost) +{ + Buffer b; + u_char *p; + 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) || + (memcmp(p, session_id2, session_id2_len) != 0)) + fail++; + xfree(p); + + if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) + fail++; + p = buffer_get_string(&b, NULL); + if (strcmp(authctxt->user, p) != 0) { + log("wrong user name passed to monitor: expected %s != %.100s", + authctxt->user, p); + fail++; + } + xfree(p); + buffer_skip_string(&b); /* service */ + p = buffer_get_string(&b, NULL); + if (strcmp(p, "hostbased") != 0) + fail++; + xfree(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++; + xfree(p); + + /* verify client user */ + p = buffer_get_string(&b, NULL); + if (strcmp(p, cuser) != 0) + fail++; + xfree(p); + + if (buffer_len(&b) != 0) + fail++; + buffer_free(&b); + return (fail == 0); +} + +int +mm_answer_keyverify(int socket, 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 ? "verified" : "unverified"); + + key_free(key); + xfree(blob); + xfree(signature); + xfree(data); + + monitor_reset_key_state(); + + buffer_clear(m); + buffer_put_int(m, verified); + mm_request_send(socket, MONITOR_ANS_KEYVERIFY, m); + + auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; + + return (verified); +} + +static void +mm_record_login(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)); + if (packet_connection_is_on_socket()) { + fromlen = sizeof(from); + if (getpeername(packet_get_connection_in(), + (struct sockaddr *) & from, &fromlen) < 0) { + debug("getpeername: %.100s", strerror(errno)); + fatal_cleanup(); + } + } + /* 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, + get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping), + (struct sockaddr *)&from); +} + +static void +mm_session_close(Session *s) +{ + debug3("%s: session %d pid %d", __func__, s->self, s->pid); + if (s->ttyfd != -1) { + debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); + fatal_remove_cleanup(session_pty_cleanup2, (void *)s); + session_pty_cleanup2(s); + } + s->used = 0; +} + +int +mm_answer_pty(int socket, 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; + fatal_add_cleanup(session_pty_cleanup2, (void *)s); + pty_setowner(authctxt->pw, s->tty); + + buffer_put_int(m, 1); + buffer_put_cstring(m, s->tty); + mm_request_send(socket, MONITOR_ANS_PTY, m); + + mm_send_fd(socket, s->ptyfd); + mm_send_fd(socket, s->ttyfd); + + /* 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); + + /* 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(socket, MONITOR_ANS_PTY, m); + return (0); +} + +int +mm_answer_pty_cleanup(int socket, 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); + xfree(tty); + return (0); +} + +int +mm_answer_sesskey(int socket, Buffer *m) +{ + BIGNUM *p; + int rsafail; + + /* Turn off permissions */ + monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); + + if ((p = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + + buffer_get_bignum2(m, p); + + rsafail = ssh1_session_key(p); + + buffer_clear(m); + buffer_put_int(m, rsafail); + buffer_put_bignum2(m, p); + + BN_clear_free(p); + + mm_request_send(socket, MONITOR_ANS_SESSKEY, m); + + /* Turn on permissions for sessid passing */ + monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); + + return (0); +} + +int +mm_answer_sessid(int socket, Buffer *m) +{ + int i; + + debug3("%s entering", __func__); + + if (buffer_len(m) != 16) + fatal("%s: bad ssh1 session id", __func__); + for (i = 0; i < 16; i++) + session_id[i] = buffer_get_char(m); + + /* Turn on permissions for getpwnam */ + monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); + + return (0); +} + +int +mm_answer_rsa_keyallowed(int socket, Buffer *m) +{ + BIGNUM *client_n; + Key *key = NULL; + u_char *blob = NULL; + u_int blen = 0; + int allowed = 0; + + debug3("%s entering", __func__); + + if (options.rsa_authentication && authctxt->valid) { + if ((client_n = BN_new()) == NULL) + fatal("%s: BN_new", __func__); + buffer_get_bignum2(m, client_n); + allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); + BN_clear_free(client_n); + } + buffer_clear(m); + buffer_put_int(m, allowed); + + /* clear temporarily storage (used by generate challenge) */ + monitor_reset_key_state(); + + if (allowed && key != NULL) { + key->type = KEY_RSA; /* cheat for key_to_blob */ + if (key_to_blob(key, &blob, &blen) == 0) + fatal("%s: key_to_blob failed", __func__); + buffer_put_string(m, blob, blen); + + /* Save temporarily for comparison in verify */ + key_blob = blob; + key_bloblen = blen; + key_blobtype = MM_RSAUSERKEY; + key_free(key); + } + + mm_append_debug(m); + + mm_request_send(socket, MONITOR_ANS_RSAKEYALLOWED, m); + + monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); + monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); + return (0); +} + +int +mm_answer_rsa_challenge(int socket, Buffer *m) +{ + Key *key = NULL; + u_char *blob; + u_int blen; + + debug3("%s entering", __func__); + + if (!authctxt->valid) + fatal("%s: authctxt not valid", __func__); + blob = buffer_get_string(m, &blen); + if (!monitor_allowed_key(blob, blen)) + fatal("%s: bad key, not previously allowed", __func__); + if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) + fatal("%s: key type mismatch", __func__); + if ((key = key_from_blob(blob, blen)) == NULL) + fatal("%s: received bad key", __func__); + + if (ssh1_challenge) + BN_clear_free(ssh1_challenge); + ssh1_challenge = auth_rsa_generate_challenge(key); + + buffer_clear(m); + buffer_put_bignum2(m, ssh1_challenge); + + debug3("%s sending reply", __func__); + mm_request_send(socket, MONITOR_ANS_RSACHALLENGE, m); + + monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); + return (0); +} + +int +mm_answer_rsa_response(int socket, Buffer *m) +{ + Key *key = NULL; + u_char *blob, *response; + u_int blen, len; + int success; + + debug3("%s entering", __func__); + + if (!authctxt->valid) + fatal("%s: authctxt not valid", __func__); + if (ssh1_challenge == NULL) + fatal("%s: no ssh1_challenge", __func__); + + blob = buffer_get_string(m, &blen); + if (!monitor_allowed_key(blob, blen)) + fatal("%s: bad key, not previously allowed", __func__); + if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) + fatal("%s: key type mismatch: %d", __func__, key_blobtype); + if ((key = key_from_blob(blob, blen)) == NULL) + fatal("%s: received bad key", __func__); + response = buffer_get_string(m, &len); + if (len != 16) + fatal("%s: received bad response to challenge", __func__); + success = auth_rsa_verify_response(key, ssh1_challenge, response); + + key_free(key); + xfree(response); + + auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; + + /* reset state */ + BN_clear_free(ssh1_challenge); + ssh1_challenge = NULL; + monitor_reset_key_state(); + + buffer_clear(m); + buffer_put_int(m, success); + mm_request_send(socket, MONITOR_ANS_RSARESPONSE, m); + + return (success); +} + +int +mm_answer_term(int socket, 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); + + while (waitpid(pmonitor->m_pid, &status, 0) == -1) + if (errno != EINTR) + exit(1); + + res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; + + /* Terminate process */ + exit (res); +} + +void +monitor_apply_keystate(struct monitor *pmonitor) +{ + if (compat20) { + set_newkeys(MODE_IN); + set_newkeys(MODE_OUT); + } else { + packet_set_protocol_flags(child_state.ssh1protoflags); + packet_set_encryption_key(child_state.ssh1key, + child_state.ssh1keylen, child_state.ssh1cipher); + xfree(child_state.ssh1key); + } + + /* for rc4 and other stateful ciphers */ + packet_set_keycontext(MODE_OUT, child_state.keyout); + xfree(child_state.keyout); + packet_set_keycontext(MODE_IN, child_state.keyin); + xfree(child_state.keyin); + + if (!compat20) { + packet_set_iv(MODE_OUT, child_state.ivout); + xfree(child_state.ivout); + packet_set_iv(MODE_IN, child_state.ivin); + xfree(child_state.ivin); + } + + memcpy(&incoming_stream, &child_state.incoming, + sizeof(incoming_stream)); + memcpy(&outgoing_stream, &child_state.outgoing, + sizeof(outgoing_stream)); + + /* Update with new address */ + if (options.compression) + mm_init_compression(pmonitor->m_zlib); + + /* Network I/O buffers */ + /* XXX inefficient for large buffers, need: buffer_init_from_string */ + buffer_clear(&input); + buffer_append(&input, child_state.input, child_state.ilen); + memset(child_state.input, 0, child_state.ilen); + xfree(child_state.input); + + buffer_clear(&output); + buffer_append(&output, child_state.output, child_state.olen); + memset(child_state.output, 0, child_state.olen); + xfree(child_state.output); +} + +static Kex * +mm_get_kex(Buffer *m) +{ + Kex *kex; + void *blob; + u_int bloblen; + + kex = xmalloc(sizeof(*kex)); + memset(kex, 0, sizeof(*kex)); + kex->session_id = buffer_get_string(m, &kex->session_id_len); + if ((session_id2 == NULL) || + (kex->session_id_len != session_id2_len) || + (memcmp(kex->session_id, session_id2, session_id2_len) != 0)) + fatal("mm_get_get: internal error: bad session id"); + kex->we_need = buffer_get_int(m); + kex->server = 1; + kex->hostkey_type = buffer_get_int(m); + kex->kex_type = buffer_get_int(m); + blob = buffer_get_string(m, &bloblen); + buffer_init(&kex->my); + buffer_append(&kex->my, blob, bloblen); + xfree(blob); + blob = buffer_get_string(m, &bloblen); + buffer_init(&kex->peer); + buffer_append(&kex->peer, blob, bloblen); + xfree(blob); + kex->done = 1; + kex->flags = buffer_get_int(m); + kex->client_version_string = buffer_get_string(m, NULL); + kex->server_version_string = buffer_get_string(m, NULL); + kex->load_host_key=&get_hostkey_by_type; + kex->host_key_index=&get_hostkey_index; + + return (kex); +} + +/* This function requries careful sanity checking */ + +void +mm_get_keystate(struct monitor *pmonitor) +{ + Buffer m; + u_char *blob, *p; + u_int bloblen, plen; + + debug3("%s: Waiting for new keys", __func__); + + buffer_init(&m); + mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m); + if (!compat20) { + child_state.ssh1protoflags = buffer_get_int(&m); + child_state.ssh1cipher = buffer_get_int(&m); + child_state.ssh1key = buffer_get_string(&m, + &child_state.ssh1keylen); + child_state.ivout = buffer_get_string(&m, + &child_state.ivoutlen); + child_state.ivin = buffer_get_string(&m, &child_state.ivinlen); + goto skip; + } else { + /* Get the Kex for rekeying */ + *pmonitor->m_pkex = mm_get_kex(&m); + } + + blob = buffer_get_string(&m, &bloblen); + current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen); + xfree(blob); + + debug3("%s: Waiting for second key", __func__); + blob = buffer_get_string(&m, &bloblen); + current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen); + xfree(blob); + + /* Now get sequence numbers for the packets */ + packet_set_seqnr(MODE_OUT, buffer_get_int(&m)); + packet_set_seqnr(MODE_IN, buffer_get_int(&m)); + + skip: + /* Get the key context */ + child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen); + child_state.keyin = buffer_get_string(&m, &child_state.keyinlen); + + debug3("%s: Getting compression state", __func__); + /* Get compression state */ + p = buffer_get_string(&m, &plen); + if (plen != sizeof(child_state.outgoing)) + fatal("%s: bad request size", __func__); + memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing)); + xfree(p); + + p = buffer_get_string(&m, &plen); + if (plen != sizeof(child_state.incoming)) + fatal("%s: bad request size", __func__); + memcpy(&child_state.incoming, p, sizeof(child_state.incoming)); + xfree(p); + + /* Network I/O buffers */ + debug3("%s: Getting Network I/O buffers", __func__); + child_state.input = buffer_get_string(&m, &child_state.ilen); + child_state.output = buffer_get_string(&m, &child_state.olen); + + buffer_free(&m); +} + + +/* Allocation functions for zlib */ +void * +mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) +{ + void *address; + + address = mm_malloc(mm, size * ncount); + + return (address); +} + +void +mm_zfree(struct mm_master *mm, void *address) +{ + mm_free(mm, address); +} + +void +mm_init_compression(struct mm_master *mm) +{ + outgoing_stream.zalloc = (alloc_func)mm_zalloc; + outgoing_stream.zfree = (free_func)mm_zfree; + outgoing_stream.opaque = mm; + + incoming_stream.zalloc = (alloc_func)mm_zalloc; + incoming_stream.zfree = (free_func)mm_zfree; + incoming_stream.opaque = mm; +} + +/* XXX */ + +#define FD_CLOSEONEXEC(x) do { \ + if (fcntl(x, F_SETFD, 1) == -1) \ + fatal("fcntl(%d, F_SETFD)", x); \ +} while (0) + +static void +monitor_socketpair(int *pair) +{ + if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) + fatal("%s: socketpair", __func__); + FD_CLOSEONEXEC(pair[0]); + FD_CLOSEONEXEC(pair[1]); +} + +#define MM_MEMSIZE 65536 + +struct monitor * +monitor_init(void) +{ + struct monitor *mon; + int pair[2]; + + mon = xmalloc(sizeof(*mon)); + + monitor_socketpair(pair); + + mon->m_recvfd = pair[0]; + mon->m_sendfd = pair[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 */ + mm_init_compression(mon->m_zlib); + } + + return mon; +} + +void +monitor_reinit(struct monitor *mon) +{ + int pair[2]; + + monitor_socketpair(pair); + + mon->m_recvfd = pair[0]; + mon->m_sendfd = pair[1]; +} |