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Diffstat (limited to 'ssh2userauth-server.c')
-rw-r--r--ssh2userauth-server.c377
1 files changed, 0 insertions, 377 deletions
diff --git a/ssh2userauth-server.c b/ssh2userauth-server.c
deleted file mode 100644
index cacddee6..00000000
--- a/ssh2userauth-server.c
+++ /dev/null
@@ -1,377 +0,0 @@
-/*
- * Packet protocol layer for the server side of the SSH-2 userauth
- * protocol (RFC 4252).
- */
-
-#include <assert.h>
-
-#include "putty.h"
-#include "ssh.h"
-#include "sshbpp.h"
-#include "sshppl.h"
-#include "sshcr.h"
-#include "sshserver.h"
-
-#ifndef NO_GSSAPI
-#include "sshgssc.h"
-#include "sshgss.h"
-#endif
-
-struct ssh2_userauth_server_state {
- int crState;
-
- PacketProtocolLayer *transport_layer, *successor_layer;
- ptrlen session_id;
-
- AuthPolicy *authpolicy;
- const SshServerConfig *ssc;
-
- ptrlen username, service, method;
- unsigned methods, this_method;
- bool partial_success;
-
- AuthKbdInt *aki;
-
- PacketProtocolLayer ppl;
-};
-
-static void ssh2_userauth_server_free(PacketProtocolLayer *);
-static void ssh2_userauth_server_process_queue(PacketProtocolLayer *);
-
-static const PacketProtocolLayerVtable ssh2_userauth_server_vtable = {
- .free = ssh2_userauth_server_free,
- .process_queue = ssh2_userauth_server_process_queue,
- .queued_data_size = ssh_ppl_default_queued_data_size,
- .name = "ssh-userauth",
- /* other methods are NULL */
-};
-
-static void free_auth_kbdint(AuthKbdInt *aki)
-{
- int i;
-
- if (!aki)
- return;
-
- sfree(aki->title);
- sfree(aki->instruction);
- for (i = 0; i < aki->nprompts; i++)
- sfree(aki->prompts[i].prompt);
- sfree(aki->prompts);
- sfree(aki);
-}
-
-PacketProtocolLayer *ssh2_userauth_server_new(
- PacketProtocolLayer *successor_layer, AuthPolicy *authpolicy,
- const SshServerConfig *ssc)
-{
- struct ssh2_userauth_server_state *s =
- snew(struct ssh2_userauth_server_state);
- memset(s, 0, sizeof(*s));
- s->ppl.vt = &ssh2_userauth_server_vtable;
-
- s->successor_layer = successor_layer;
- s->authpolicy = authpolicy;
- s->ssc = ssc;
-
- return &s->ppl;
-}
-
-void ssh2_userauth_server_set_transport_layer(PacketProtocolLayer *userauth,
- PacketProtocolLayer *transport)
-{
- struct ssh2_userauth_server_state *s =
- container_of(userauth, struct ssh2_userauth_server_state, ppl);
- s->transport_layer = transport;
-}
-
-static void ssh2_userauth_server_free(PacketProtocolLayer *ppl)
-{
- struct ssh2_userauth_server_state *s =
- container_of(ppl, struct ssh2_userauth_server_state, ppl);
-
- if (s->successor_layer)
- ssh_ppl_free(s->successor_layer);
-
- free_auth_kbdint(s->aki);
-
- sfree(s);
-}
-
-static PktIn *ssh2_userauth_server_pop(struct ssh2_userauth_server_state *s)
-{
- return pq_pop(s->ppl.in_pq);
-}
-
-static void ssh2_userauth_server_add_session_id(
- struct ssh2_userauth_server_state *s, strbuf *sigdata)
-{
- if (s->ppl.remote_bugs & BUG_SSH2_PK_SESSIONID) {
- put_datapl(sigdata, s->session_id);
- } else {
- put_stringpl(sigdata, s->session_id);
- }
-}
-
-static void ssh2_userauth_server_process_queue(PacketProtocolLayer *ppl)
-{
- struct ssh2_userauth_server_state *s =
- container_of(ppl, struct ssh2_userauth_server_state, ppl);
- PktIn *pktin;
- PktOut *pktout;
-
- crBegin(s->crState);
-
- s->session_id = ssh2_transport_get_session_id(s->transport_layer);
-
- if (s->ssc->banner.ptr) {
- pktout = ssh_bpp_new_pktout(s->ppl.bpp, SSH2_MSG_USERAUTH_BANNER);
- put_stringpl(pktout, s->ssc->banner);
- put_stringz(pktout, ""); /* language tag */
- pq_push(s->ppl.out_pq, pktout);
- }
-
- while (1) {
- crMaybeWaitUntilV((pktin = ssh2_userauth_server_pop(s)) != NULL);
- if (pktin->type != SSH2_MSG_USERAUTH_REQUEST) {
- ssh_proto_error(s->ppl.ssh, "Received unexpected packet when "
- "expecting USERAUTH_REQUEST, type %d (%s)",
- pktin->type,
- ssh2_pkt_type(s->ppl.bpp->pls->kctx,
- s->ppl.bpp->pls->actx, pktin->type));
- return;
- }
-
- s->username = get_string(pktin);
- s->service = get_string(pktin);
- s->method = get_string(pktin);
-
- if (!ptrlen_eq_string(s->service, s->successor_layer->vt->name)) {
- /*
- * Unconditionally reject authentication for any service
- * other than the one we're going to hand over to.
- */
- pktout = ssh_bpp_new_pktout(s->ppl.bpp, SSH2_MSG_USERAUTH_FAILURE);
- put_stringz(pktout, "");
- put_bool(pktout, false);
- pq_push(s->ppl.out_pq, pktout);
- continue;
- }
-
- s->methods = auth_methods(s->authpolicy);
- s->partial_success = false;
-
- if (ptrlen_eq_string(s->method, "none")) {
- s->this_method = AUTHMETHOD_NONE;
- if (!(s->methods & s->this_method))
- goto failure;
-
- if (!auth_none(s->authpolicy, s->username))
- goto failure;
- } else if (ptrlen_eq_string(s->method, "password")) {
- bool changing;
- ptrlen password, new_password, *new_password_ptr;
-
- s->this_method = AUTHMETHOD_PASSWORD;
- if (!(s->methods & s->this_method))
- goto failure;
-
- changing = get_bool(pktin);
- password = get_string(pktin);
-
- if (changing) {
- new_password = get_string(pktin);
- new_password_ptr = &new_password;
- } else {
- new_password_ptr = NULL;
- }
-
- int result = auth_password(s->authpolicy, s->username,
- password, new_password_ptr);
- if (result == 2) {
- pktout = ssh_bpp_new_pktout(
- s->ppl.bpp, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ);
- put_stringz(pktout, "Please change your password");
- put_stringz(pktout, ""); /* language tag */
- pq_push(s->ppl.out_pq, pktout);
- continue; /* skip USERAUTH_{SUCCESS,FAILURE} epilogue */
- } else if (result != 1) {
- goto failure;
- }
- } else if (ptrlen_eq_string(s->method, "publickey")) {
- bool has_signature, success, send_pk_ok, key_really_ok;
- ptrlen algorithm, blob, signature;
- const ssh_keyalg *keyalg;
- ssh_key *key;
- strbuf *sigdata;
-
- s->this_method = AUTHMETHOD_PUBLICKEY;
- if (!(s->methods & s->this_method))
- goto failure;
-
- has_signature = get_bool(pktin);
- algorithm = get_string(pktin);
- blob = get_string(pktin);
-
- key_really_ok = auth_publickey(s->authpolicy, s->username, blob);
- send_pk_ok = key_really_ok ||
- s->ssc->stunt_pretend_to_accept_any_pubkey;
-
- if (!has_signature) {
- if (!send_pk_ok)
- goto failure;
-
- pktout = ssh_bpp_new_pktout(
- s->ppl.bpp, SSH2_MSG_USERAUTH_PK_OK);
- put_stringpl(pktout, algorithm);
- put_stringpl(pktout, blob);
- pq_push(s->ppl.out_pq, pktout);
- continue; /* skip USERAUTH_{SUCCESS,FAILURE} epilogue */
- }
-
- if (!key_really_ok)
- goto failure;
-
- keyalg = find_pubkey_alg_len(algorithm);
- if (!keyalg)
- goto failure;
- key = ssh_key_new_pub(keyalg, blob);
- if (!key)
- goto failure;
-
- sigdata = strbuf_new();
- ssh2_userauth_server_add_session_id(s, sigdata);
- put_byte(sigdata, SSH2_MSG_USERAUTH_REQUEST);
- put_stringpl(sigdata, s->username);
- put_stringpl(sigdata, s->service);
- put_stringpl(sigdata, s->method);
- put_bool(sigdata, has_signature);
- put_stringpl(sigdata, algorithm);
- put_stringpl(sigdata, blob);
-
- signature = get_string(pktin);
- success = ssh_key_verify(key, signature,
- ptrlen_from_strbuf(sigdata));
- ssh_key_free(key);
- strbuf_free(sigdata);
-
- if (!success)
- goto failure;
- } else if (ptrlen_eq_string(s->method, "keyboard-interactive")) {
- int i, ok;
- unsigned n;
-
- s->this_method = AUTHMETHOD_KBDINT;
- if (!(s->methods & s->this_method))
- goto failure;
-
- do {
- s->aki = auth_kbdint_prompts(s->authpolicy, s->username);
- if (!s->aki)
- goto failure;
-
- pktout = ssh_bpp_new_pktout(
- s->ppl.bpp, SSH2_MSG_USERAUTH_INFO_REQUEST);
- put_stringz(pktout, s->aki->title);
- put_stringz(pktout, s->aki->instruction);
- put_stringz(pktout, ""); /* language tag */
- put_uint32(pktout, s->aki->nprompts);
- for (i = 0; i < s->aki->nprompts; i++) {
- put_stringz(pktout, s->aki->prompts[i].prompt);
- put_bool(pktout, s->aki->prompts[i].echo);
- }
- pq_push(s->ppl.out_pq, pktout);
-
- crMaybeWaitUntilV(
- (pktin = ssh2_userauth_server_pop(s)) != NULL);
- if (pktin->type != SSH2_MSG_USERAUTH_INFO_RESPONSE) {
- ssh_proto_error(
- s->ppl.ssh, "Received unexpected packet when "
- "expecting USERAUTH_INFO_RESPONSE, type %d (%s)",
- pktin->type,
- ssh2_pkt_type(s->ppl.bpp->pls->kctx,
- s->ppl.bpp->pls->actx, pktin->type));
- return;
- }
-
- n = get_uint32(pktin);
- if (n != s->aki->nprompts) {
- ssh_proto_error(
- s->ppl.ssh, "Received %u keyboard-interactive "
- "responses after sending %u prompts",
- n, s->aki->nprompts);
- return;
- }
-
- {
- ptrlen *responses = snewn(s->aki->nprompts, ptrlen);
- for (i = 0; i < s->aki->nprompts; i++)
- responses[i] = get_string(pktin);
- ok = auth_kbdint_responses(s->authpolicy, responses);
- sfree(responses);
- }
-
- free_auth_kbdint(s->aki);
- s->aki = NULL;
- } while (ok == 0);
-
- if (ok <= 0)
- goto failure;
- } else {
- goto failure;
- }
-
- /*
- * If we get here, we've successfully completed this
- * authentication step.
- */
- if (auth_successful(s->authpolicy, s->username, s->this_method)) {
- /*
- * ... and it was the last one, so we're completely done.
- */
- pktout = ssh_bpp_new_pktout(s->ppl.bpp, SSH2_MSG_USERAUTH_SUCCESS);
- pq_push(s->ppl.out_pq, pktout);
- break;
- } else {
- /*
- * ... but another is required, so fall through to
- * generation of USERAUTH_FAILURE, having first refreshed
- * the bit mask of available methods.
- */
- s->methods = auth_methods(s->authpolicy);
- }
- s->partial_success = true;
-
- failure:
- pktout = ssh_bpp_new_pktout(s->ppl.bpp, SSH2_MSG_USERAUTH_FAILURE);
- {
- strbuf *list = strbuf_new();
- if (s->methods & AUTHMETHOD_NONE)
- add_to_commasep(list, "none");
- if (s->methods & AUTHMETHOD_PASSWORD)
- add_to_commasep(list, "password");
- if (s->methods & AUTHMETHOD_PUBLICKEY)
- add_to_commasep(list, "publickey");
- if (s->methods & AUTHMETHOD_KBDINT)
- add_to_commasep(list, "keyboard-interactive");
- put_stringsb(pktout, list);
- }
- put_bool(pktout, s->partial_success);
- pq_push(s->ppl.out_pq, pktout);
- }
-
- /*
- * Finally, hand over to our successor layer, and return
- * immediately without reaching the crFinishV: ssh_ppl_replace
- * will have freed us, so crFinishV's zeroing-out of crState would
- * be a use-after-free bug.
- */
- {
- PacketProtocolLayer *successor = s->successor_layer;
- s->successor_layer = NULL; /* avoid freeing it ourself */
- ssh_ppl_replace(&s->ppl, successor);
- return; /* we've just freed s, so avoid even touching s->crState */
- }
-
- crFinishV;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-07 17:53:01 +0300