X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/d9cd35756202e3fa03a289a2f346f72e965ae28d..HEAD:/auth2-chall.c diff --git a/auth2-chall.c b/auth2-chall.c index 5af60e42..e6dbffe2 100644 --- a/auth2-chall.c +++ b/auth2-chall.c @@ -1,5 +1,7 @@ +/* $OpenBSD: auth2-chall.c,v 1.34 2008/12/09 04:32:22 djm Exp $ */ /* * Copyright (c) 2001 Markus Friedl. All rights reserved. + * Copyright (c) 2001 Per Allansson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -21,92 +23,352 @@ * (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: auth2-chall.c,v 1.4 2001/03/28 22:43:31 markus Exp $"); +#include + +#include +#include +#include + +#include "xmalloc.h" #include "ssh2.h" +#include "key.h" +#include "hostfile.h" #include "auth.h" +#include "buffer.h" #include "packet.h" -#include "xmalloc.h" #include "dispatch.h" #include "log.h" +#include "servconf.h" + +/* import */ +extern ServerOptions options; + +static int auth2_challenge_start(Authctxt *); +static int send_userauth_info_request(Authctxt *); +static void input_userauth_info_response(int, u_int32_t, void *); + +#ifdef BSD_AUTH +extern KbdintDevice bsdauth_device; +#else +#ifdef USE_PAM +extern KbdintDevice sshpam_device; +#endif +#ifdef SKEY +extern KbdintDevice skey_device; +#endif +#endif + +KbdintDevice *devices[] = { +#ifdef BSD_AUTH + &bsdauth_device, +#else +#ifdef USE_PAM + &sshpam_device, +#endif +#ifdef SKEY + &skey_device, +#endif +#endif + NULL +}; + +typedef struct KbdintAuthctxt KbdintAuthctxt; +struct KbdintAuthctxt +{ + char *devices; + void *ctxt; + KbdintDevice *device; + u_int nreq; +}; + +#ifdef USE_PAM +void +remove_kbdint_device(const char *devname) +{ + int i, j; + + for (i = 0; devices[i] != NULL; i++) + if (strcmp(devices[i]->name, devname) == 0) { + for (j = i; devices[j] != NULL; j++) + devices[j] = devices[j+1]; + i--; + } +} +#endif + +static KbdintAuthctxt * +kbdint_alloc(const char *devs) +{ + KbdintAuthctxt *kbdintctxt; + Buffer b; + int i; -void send_userauth_into_request(Authctxt *authctxt, char *challenge, int echo); -void input_userauth_info_response(int type, int plen, void *ctxt); +#ifdef USE_PAM + if (!options.use_pam) + remove_kbdint_device("pam"); +#endif + + kbdintctxt = xmalloc(sizeof(KbdintAuthctxt)); + if (strcmp(devs, "") == 0) { + buffer_init(&b); + for (i = 0; devices[i]; i++) { + if (buffer_len(&b) > 0) + buffer_append(&b, ",", 1); + buffer_append(&b, devices[i]->name, + strlen(devices[i]->name)); + } + buffer_append(&b, "\0", 1); + kbdintctxt->devices = xstrdup(buffer_ptr(&b)); + buffer_free(&b); + } else { + kbdintctxt->devices = xstrdup(devs); + } + debug("kbdint_alloc: devices '%s'", kbdintctxt->devices); + kbdintctxt->ctxt = NULL; + kbdintctxt->device = NULL; + kbdintctxt->nreq = 0; + + return kbdintctxt; +} +static void +kbdint_reset_device(KbdintAuthctxt *kbdintctxt) +{ + if (kbdintctxt->ctxt) { + kbdintctxt->device->free_ctx(kbdintctxt->ctxt); + kbdintctxt->ctxt = NULL; + } + kbdintctxt->device = NULL; +} +static void +kbdint_free(KbdintAuthctxt *kbdintctxt) +{ + if (kbdintctxt->device) + kbdint_reset_device(kbdintctxt); + if (kbdintctxt->devices) { + xfree(kbdintctxt->devices); + kbdintctxt->devices = NULL; + } + xfree(kbdintctxt); +} +/* get next device */ +static int +kbdint_next_device(KbdintAuthctxt *kbdintctxt) +{ + size_t len; + char *t; + int i; + + if (kbdintctxt->device) + kbdint_reset_device(kbdintctxt); + do { + len = kbdintctxt->devices ? + strcspn(kbdintctxt->devices, ",") : 0; + + if (len == 0) + break; + for (i = 0; devices[i]; i++) + if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0) + kbdintctxt->device = devices[i]; + t = kbdintctxt->devices; + kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL; + xfree(t); + debug2("kbdint_next_device: devices %s", kbdintctxt->devices ? + kbdintctxt->devices : ""); + } while (kbdintctxt->devices && !kbdintctxt->device); + + return kbdintctxt->device ? 1 : 0; +} /* - * try challenge-reponse, return -1 (= postponed) if we have to + * try challenge-response, set authctxt->postponed if we have to * wait for the response. */ int auth2_challenge(Authctxt *authctxt, char *devs) { - char *challenge; + debug("auth2_challenge: user=%s devs=%s", + authctxt->user ? authctxt->user : "", + devs ? devs : ""); + + if (authctxt->user == NULL || !devs) + return 0; + if (authctxt->kbdintctxt == NULL) + authctxt->kbdintctxt = kbdint_alloc(devs); + return auth2_challenge_start(authctxt); +} + +/* unregister kbd-int callbacks and context */ +void +auth2_challenge_stop(Authctxt *authctxt) +{ + /* unregister callback */ + dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL); + if (authctxt->kbdintctxt != NULL) { + kbdint_free(authctxt->kbdintctxt); + authctxt->kbdintctxt = NULL; + } +} + +/* side effect: sets authctxt->postponed if a reply was sent*/ +static int +auth2_challenge_start(Authctxt *authctxt) +{ + KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt; + + debug2("auth2_challenge_start: devices %s", + kbdintctxt->devices ? kbdintctxt->devices : ""); - if (!authctxt->valid || authctxt->user == NULL) + if (kbdint_next_device(kbdintctxt) == 0) { + auth2_challenge_stop(authctxt); return 0; - if ((challenge = get_challenge(authctxt, devs)) == NULL) + } + debug("auth2_challenge_start: trying authentication method '%s'", + kbdintctxt->device->name); + + if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) { + auth2_challenge_stop(authctxt); return 0; - send_userauth_into_request(authctxt, challenge, 0); + } + if (send_userauth_info_request(authctxt) == 0) { + auth2_challenge_stop(authctxt); + return 0; + } dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &input_userauth_info_response); + authctxt->postponed = 1; return 0; } -void -send_userauth_into_request(Authctxt *authctxt, char *challenge, int echo) +static int +send_userauth_info_request(Authctxt *authctxt) { - int nprompts = 1; + KbdintAuthctxt *kbdintctxt; + char *name, *instr, **prompts; + u_int i, *echo_on; + + kbdintctxt = authctxt->kbdintctxt; + if (kbdintctxt->device->query(kbdintctxt->ctxt, + &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on)) + return 0; packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST); - /* name, instruction and language are unused */ - packet_put_cstring(""); - packet_put_cstring(""); - packet_put_cstring(""); - packet_put_int(nprompts); - packet_put_cstring(challenge); - packet_put_char(echo); + packet_put_cstring(name); + packet_put_cstring(instr); + packet_put_cstring(""); /* language not used */ + packet_put_int(kbdintctxt->nreq); + for (i = 0; i < kbdintctxt->nreq; i++) { + packet_put_cstring(prompts[i]); + packet_put_char(echo_on[i]); + } packet_send(); packet_write_wait(); + + for (i = 0; i < kbdintctxt->nreq; i++) + xfree(prompts[i]); + xfree(prompts); + xfree(echo_on); + xfree(name); + xfree(instr); + return 1; } -void -input_userauth_info_response(int type, int plen, void *ctxt) +static void +input_userauth_info_response(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; - int authenticated = 0; - u_int nresp, rlen; - char *response, *method = "challenge-reponse"; + KbdintAuthctxt *kbdintctxt; + int authenticated = 0, res; + u_int i, nresp; + char **response = NULL, *method; if (authctxt == NULL) fatal("input_userauth_info_response: no authctxt"); + kbdintctxt = authctxt->kbdintctxt; + if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL) + fatal("input_userauth_info_response: no kbdintctxt"); + if (kbdintctxt->device == NULL) + fatal("input_userauth_info_response: no device"); authctxt->postponed = 0; /* reset */ nresp = packet_get_int(); - if (nresp == 1) { - response = packet_get_string(&rlen); - packet_done(); - if (strlen(response) == 0) { - /* - * if we received an empty response, resend challenge - * with echo enabled - */ - char *challenge = get_challenge(authctxt, NULL); - if (challenge != NULL) { - send_userauth_into_request(authctxt, - challenge, 1); - authctxt->postponed = 1; - } - } else if (authctxt->valid) { - authenticated = verify_response(authctxt, response); - memset(response, 'r', rlen); - } + if (nresp != kbdintctxt->nreq) + fatal("input_userauth_info_response: wrong number of replies"); + if (nresp > 100) + fatal("input_userauth_info_response: too many replies"); + if (nresp > 0) { + response = xcalloc(nresp, sizeof(char *)); + for (i = 0; i < nresp; i++) + response[i] = packet_get_string(NULL); + } + packet_check_eom(); + + res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response); + + for (i = 0; i < nresp; i++) { + memset(response[i], 'r', strlen(response[i])); + xfree(response[i]); + } + if (response) xfree(response); + + switch (res) { + case 0: + /* Success! */ + authenticated = authctxt->valid ? 1 : 0; + break; + case 1: + /* Authentication needs further interaction */ + if (send_userauth_info_request(authctxt) == 1) + authctxt->postponed = 1; + break; + default: + /* Failure! */ + break; } - /* unregister callback */ - if (!authctxt->postponed) - dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL); + xasprintf(&method, "keyboard-interactive/%s", kbdintctxt->device->name); + + if (!authctxt->postponed) { + if (authenticated) { + auth2_challenge_stop(authctxt); + } else { + /* start next device */ + /* may set authctxt->postponed */ + auth2_challenge_start(authctxt); + } + } userauth_finish(authctxt, authenticated, method); + xfree(method); +} + +void +privsep_challenge_enable(void) +{ +#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY) + int n = 0; +#endif +#ifdef BSD_AUTH + extern KbdintDevice mm_bsdauth_device; +#endif +#ifdef USE_PAM + extern KbdintDevice mm_sshpam_device; +#endif +#ifdef SKEY + extern KbdintDevice mm_skey_device; +#endif + +#ifdef BSD_AUTH + devices[n++] = &mm_bsdauth_device; +#else +#ifdef USE_PAM + devices[n++] = &mm_sshpam_device; +#endif +#ifdef SKEY + devices[n++] = &mm_skey_device; +#endif +#endif }