1 files changed, 292 insertions, 0 deletions

diff --git a/gss-serv.c b/gss-serv.c
new file mode 100644
index 000000000..8fd1d63f0
--- /dev/null
+++ b/gss-serv.c
@@ -0,0 +1,292 @@
+/*      $OpenBSD: gss-serv.c,v 1.3 2003/08/31 13:31:57 markus Exp $     */
+
+/*
+ * Copyright (c) 2001-2003 Simon Wilkinson. 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"
+
+#ifdef GSSAPI
+
+#include "bufaux.h"
+#include "compat.h"
+#include "auth.h"
+#include "log.h"
+#include "channels.h"
+#include "session.h"
+#include "servconf.h"
+#include "monitor_wrap.h"
+#include "xmalloc.h"
+#include "getput.h"
+
+#include "ssh-gss.h"
+
+extern ServerOptions options;
+
+static ssh_gssapi_client gssapi_client =
+    { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
+    GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
+
+ssh_gssapi_mech gssapi_null_mech =
+    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
+
+#ifdef KRB5
+extern ssh_gssapi_mech gssapi_kerberos_mech;
+#endif
+
+ssh_gssapi_mech* supported_mechs[]= {
+#ifdef KRB5
+        &gssapi_kerberos_mech,
+#endif
+        &gssapi_null_mech,
+};
+
+/* Unpriviledged */
+void
+ssh_gssapi_supported_oids(gss_OID_set *oidset)
+{
+        int i = 0;
+        OM_uint32 min_status;
+        int present;
+        gss_OID_set supported;
+
+        gss_create_empty_oid_set(&min_status, oidset);
+        gss_indicate_mechs(&min_status, &supported);
+
+        while (supported_mechs[i]->name != NULL) {
+                if (GSS_ERROR(gss_test_oid_set_member(&min_status,
+                    &supported_mechs[i]->oid, supported, &present)))
+                        present = 0;
+                if (present)
+                        gss_add_oid_set_member(&min_status,
+                            &supported_mechs[i]->oid, oidset);
+                i++;
+        }
+}
+
+
+/* Wrapper around accept_sec_context
+ * Requires that the context contains:
+ *    oid
+ *    credentials       (from ssh_gssapi_acquire_cred)
+ */
+/* Priviledged */
+OM_uint32
+ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
+    gss_buffer_desc *send_tok, OM_uint32 *flags)
+{
+        OM_uint32 status;
+        gss_OID mech;
+
+        ctx->major = gss_accept_sec_context(&ctx->minor,
+            &ctx->context, ctx->creds, recv_tok,
+            GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
+            send_tok, flags, NULL, &ctx->client_creds);
+
+        if (GSS_ERROR(ctx->major))
+                ssh_gssapi_error(ctx);
+
+        if (ctx->client_creds)
+                debug("Received some client credentials");
+        else
+                debug("Got no client credentials");
+
+        status = ctx->major;
+
+        /* Now, if we're complete and we have the right flags, then
+         * we flag the user as also having been authenticated
+         */
+
+        if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
+            (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
+                if (ssh_gssapi_getclient(ctx, &gssapi_client))
+                        fatal("Couldn't convert client name");
+        }
+
+        return (status);
+}
+
+/*
+ * This parses an exported name, extracting the mechanism specific portion
+ * to use for ACL checking. It verifies that the name belongs the mechanism
+ * originally selected.
+ */
+static OM_uint32
+ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
+{
+        char *tok;
+        OM_uint32 offset;
+        OM_uint32 oidl;
+
+        tok=ename->value;
+
+        /*
+         * Check that ename is long enough for all of the fixed length
+         * header, and that the initial ID bytes are correct
+         */
+
+        if (ename->length<6 || memcmp(tok,"\x04\x01", 2)!=0)
+                return GSS_S_FAILURE;
+
+        /*
+         * Extract the OID, and check it. Here GSSAPI breaks with tradition
+         * and does use the OID type and length bytes. To confuse things
+         * there are two lengths - the first including these, and the
+         * second without.
+         */
+
+        oidl = GET_16BIT(tok+2); /* length including next two bytes */
+        oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
+
+        /*
+         * Check the BER encoding for correct type and length, that the
+         * string is long enough and that the OID matches that in our context
+         */
+        if (tok[4] != 0x06 || tok[5] != oidl ||
+            ename->length < oidl+6 ||
+           !ssh_gssapi_check_oid(ctx,tok+6,oidl))
+                return GSS_S_FAILURE;
+
+        offset = oidl+6;
+
+        if (ename->length < offset+4)
+                return GSS_S_FAILURE;
+
+        name->length = GET_32BIT(tok+offset);
+        offset += 4;
+
+        if (ename->length < offset+name->length)
+                return GSS_S_FAILURE;
+
+        name->value = xmalloc(name->length+1);
+        memcpy(name->value,tok+offset,name->length);
+        ((char *)name->value)[name->length] = 0;
+
+        return GSS_S_COMPLETE;
+}
+
+/* Extract the client details from a given context. This can only reliably
+ * be called once for a context */
+
+/* Priviledged (called from accept_secure_ctx) */
+OM_uint32
+ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
+{
+        int i = 0;
+
+        gss_buffer_desc ename;
+
+        client->mech = NULL;
+
+        while (supported_mechs[i]->name != NULL) {
+                if (supported_mechs[i]->oid.length == ctx->oid->length &&
+                    (memcmp(supported_mechs[i]->oid.elements,
+                    ctx->oid->elements, ctx->oid->length) == 0))
+                        client->mech = supported_mechs[i];
+                i++;
+        }
+
+        if (client->mech == NULL)
+                return GSS_S_FAILURE;
+
+        if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
+            &client->displayname, NULL))) {
+                ssh_gssapi_error(ctx);
+                return (ctx->major);
+        }
+
+        if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
+            &ename))) {
+                ssh_gssapi_error(ctx);
+                return (ctx->major);
+        }
+
+        if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
+            &client->exportedname))) {
+                return (ctx->major);
+        }
+
+        /* We can't copy this structure, so we just move the pointer to it */
+        client->creds = ctx->client_creds;
+        ctx->client_creds = GSS_C_NO_CREDENTIAL;
+        return (ctx->major);
+}
+
+/* As user - called through fatal cleanup hook */
+void
+ssh_gssapi_cleanup_creds(void *ignored)
+{
+        if (gssapi_client.store.filename != NULL) {
+                /* Unlink probably isn't sufficient */
+                debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
+                unlink(gssapi_client.store.filename);
+        }
+}
+
+/* As user */
+void
+ssh_gssapi_storecreds(void)
+{
+        if (gssapi_client.mech && gssapi_client.mech->storecreds) {
+                (*gssapi_client.mech->storecreds)(&gssapi_client);
+                if (options.gss_cleanup_creds)
+                        fatal_add_cleanup(ssh_gssapi_cleanup_creds, NULL);
+        } else
+                debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
+}
+
+/* This allows GSSAPI methods to do things to the childs environment based
+ * on the passed authentication process and credentials.
+ */
+/* As user */
+void
+ssh_gssapi_do_child(char ***envp, u_int *envsizep)
+{
+
+        if (gssapi_client.store.envvar != NULL &&
+            gssapi_client.store.envval != NULL) {
+
+                debug("Setting %s to %s", gssapi_client.store.envvar,
+                gssapi_client.store.envval);
+                child_set_env(envp, envsizep, gssapi_client.store.envvar,
+                     gssapi_client.store.envval);
+        }
+}
+
+/* Priviledged */
+int
+ssh_gssapi_userok(char *user)
+{
+        if (gssapi_client.exportedname.length == 0 ||
+            gssapi_client.exportedname.value == NULL) {
+                debug("No suitable client data");
+                return 0;
+        }
+        if (gssapi_client.mech && gssapi_client.mech->userok)
+                return ((*gssapi_client.mech->userok)(&gssapi_client, user));
+        else
+                debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
+        return (0);
+}
+
+#endif