X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/23987cb804fd95e78ffefe5fb614b621e8395a62..2fff96d8cea95213d66e7ba65e36cae6adcf403a:/openssh/gss-serv.c

diff --git a/openssh/gss-serv.c b/openssh/gss-serv.c
index b94472e..2c26762 100644
--- a/openssh/gss-serv.c
+++ b/openssh/gss-serv.c
@@ -1,3 +1,5 @@
+/*	$OpenBSD: gss-serv.c,v 1.5 2003/11/17 11:06:07 markus Exp $	*/
+
 /*
  * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
  *
@@ -26,24 +28,19 @@
 
 #ifdef GSSAPI
 
-#include "ssh.h"
-#include "ssh2.h"
-#include "xmalloc.h"
 #include "buffer.h"
 #include "bufaux.h"
-#include "packet.h"
 #include "compat.h"
 #include <openssl/evp.h>
-#include "cipher.h"
 #include "kex.h"
 #include "auth.h"
 #include "log.h"
 #include "channels.h"
 #include "session.h"
-#include "dispatch.h"
 #include "servconf.h"
-#include "compat.h"
 #include "monitor_wrap.h"
+#include "xmalloc.h"
+#include "getput.h"
 
 #include "ssh-gss.h"
 
@@ -52,10 +49,11 @@ extern u_char *session_id2;
 extern int session_id2_len;
 
 static ssh_gssapi_client gssapi_client =
-	{ {0,NULL}, GSS_C_NO_CREDENTIAL, NULL, {NULL,NULL,NULL}};
+    { 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};
+ssh_gssapi_mech gssapi_null_mech =
+    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
 
 #ifdef KRB5
 extern ssh_gssapi_mech gssapi_kerberos_mech;
@@ -68,16 +66,268 @@ extern ssh_gssapi_mech gssapi_gsi_mech_old;
 
 ssh_gssapi_mech* supported_mechs[]= {
 #ifdef KRB5
-  &gssapi_kerberos_mech,
-  &gssapi_kerberos_mech_old, /* Support for legacy clients */
+	&gssapi_kerberos_mech,
+	&gssapi_kerberos_mech_old, /* Support for legacy clients */
 #endif
 #ifdef GSI
-  &gssapi_gsi_mech,
-  &gssapi_gsi_mech_old,	/* Support for legacy clients */
+	&gssapi_gsi_mech,
+	&gssapi_gsi_mech_old,	/* Support for legacy clients */
 #endif
-  &gssapi_null_mech,
+	&gssapi_null_mech,
 };
 
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+static int limited = 0;
+#endif
+
+/* 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);
+	/* Ask priviledged process what mechanisms it supports. */
+	PRIVSEP(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");
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+		if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
+			limited=1;
+#endif
+	}
+
+	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;
+
+#ifdef GSI /* GSI gss_export_name() is broken. */
+	if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
+	    (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
+		    gssapi_gsi_mech.oid.length) == 0)) {
+	    name->length = ename->length;
+	    name->value = xmalloc(ename->length+1);
+	    memcpy(name->value, ename->value, ename->length);
+	    return GSS_S_COMPLETE;
+	}
+#endif
+
+	/*
+	 * 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 on fatal/exit */
+void
+ssh_gssapi_cleanup_creds(void)
+{
+	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);
+	} 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;
+	}
+#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
+	if (limited) {
+		debug("limited proxy not acceptable for remote login");
+		return 0;
+	}
+#endif
+	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);
+}
+
 /* Return a list of the gss-group1-sha1-x mechanisms supported by this
  * program.
  *
@@ -93,7 +343,8 @@ ssh_gssapi_mech* supported_mechs[]= {
  * that stores the results (in an expanded Gssctxt structure), which are
  * then used by the first calls if that key exchange mechanism is chosen.
  */
- 
+
+/* Unpriviledged */ 
 char * 
 ssh_gssapi_server_mechanisms() {
 	gss_OID_set 	supported;
@@ -156,54 +407,11 @@ ssh_gssapi_server_mechanisms() {
 	   return(mechs);
 }
 
-void ssh_gssapi_supported_oids(gss_OID_set *oidset) {
-	int i =0;
-	OM_uint32 maj_status,min_status;
-	int present;
-	gss_OID_set supported;
-	
-	gss_create_empty_oid_set(&min_status,oidset);
-	PRIVSEP(gss_indicate_mechs(&min_status, &supported));
-
-	while (supported_mechs[i]->name!=NULL) {
-		if ((maj_status=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++;
-	}
-}	
-
-/* Find out which GSS type (out of the list we define in ssh-gss.h) a
- * particular connection is using 
- */
-ssh_gssapi_mech *
-ssh_gssapi_get_ctype(Gssctxt *ctxt) {
-	int i=0;
-	
-	while(supported_mechs[i]->name!=NULL) {
-	    if (supported_mechs[i]->oid.length == ctxt->oid->length &&
-	      	(memcmp(supported_mechs[i]->oid.elements,
-			ctxt->oid->elements,ctxt->oid->length)==0)) {
-		return supported_mechs[i];
-	    }
-	    i++;
-	}
-	return NULL;
-}
-
-/* Set the GSS context's OID to the oid indicated by the given key exchange
- * name. */
+/* Return the OID that corresponds to the given context name */
  
+/* Unpriviledged */
 gss_OID 
-ssh_gssapi_id_kex(Gssctxt *ctx, char *name) {
+ssh_gssapi_server_id_kex(char *name) {
   int i=0;
   
   if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
@@ -213,162 +421,26 @@ ssh_gssapi_id_kex(Gssctxt *ctx, char *name) {
   name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
   
   while (supported_mechs[i]->name!=NULL &&
-  	strcmp(name,supported_mechs[i]->enc_name)!=0) {
+  	 strcmp(name,supported_mechs[i]->enc_name)!=0) {
   	i++;
   }
 
   if (supported_mechs[i]->name==NULL)
      return (NULL);
 
-  if (ctx) ssh_gssapi_set_oid(ctx,&supported_mechs[i]->oid);
-
   debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
 	KEX_GSS_SHA1, supported_mechs[i]->enc_name);
 
   return &supported_mechs[i]->oid;
 }
 
-/* Wrapper arround accept_sec_context
- * Requires that the context contains:
- *    oid		
- *    credentials	(from ssh_gssapi_acquire_cred)
- */
-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, /* read-only pointer */
-					  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");
-	}
-
-	/* FIXME: We should check that the me
-	* the one that we asked for (in ctx->oid) */
-
-	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.mech,
-	  			         &gssapi_client.name,
-	  			         &gssapi_client.creds))
-	  		fatal("Couldn't convert client name");
-	}
-
-	/* Make sure that the getclient call hasn't stamped on this */
-	return(status);
-}
-
-/* Extract the client details from a given context. This can only reliably
- * be called once for a context */
-
-OM_uint32 
-ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_mech **type,
-		     gss_buffer_desc *name, gss_cred_id_t *creds) {
-
-	*type=ssh_gssapi_get_ctype(ctx);
-	if ((ctx->major=gss_display_name(&ctx->minor,ctx->client,name,NULL))) {
-		ssh_gssapi_error(ctx);
-		return(ctx->major);
-	}
-	
-	/* This is icky. There appears to be no way to copy this structure,
-	* rather than the pointer to it, so we simply copy the pointer and
-	* mark the originator as empty so we don't destroy it. 
-	*/
-	*creds=ctx->client_creds;
-	ctx->client_creds=GSS_C_NO_CREDENTIAL;
-	return(ctx->major);
-}
-
-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);
-	}
-}
-
-void 
-ssh_gssapi_storecreds()
-{
-	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.
- *
- * Question: If we didn't use userauth_external for some reason, should we
- * still delegate credentials?
- */
-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);
-	}
-}
-
-int
-ssh_gssapi_userok(char *user)
-{
-	if (gssapi_client.name.length==0 || 
-	    gssapi_client.name.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);
-}
-
+/* Priviledged */
 int
 ssh_gssapi_localname(char **user)
 {
     	*user = NULL;
-	if (gssapi_client.name.length==0 || 
-	    gssapi_client.name.value==NULL) {
+	if (gssapi_client.displayname.length==0 || 
+	    gssapi_client.displayname.value==NULL) {
 		debug("No suitable client data");
 		return(0);;
 	}
@@ -379,4 +451,15 @@ ssh_gssapi_localname(char **user)
 	}
 	return(0);
 }
+
+/* Priviledged */
+OM_uint32
+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+{
+	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+	    gssbuf, gssmic, NULL);
+
+	return (ctx->major);
+}
+
 #endif