-/* $OpenBSD: gss-genr.c,v 1.3 2003/11/21 11:57:03 djm Exp $ */
+/* $OpenBSD: gss-genr.c,v 1.20 2009/06/22 05:39:28 dtucker Exp $ */
/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
#ifdef GSSAPI
+#include <sys/types.h>
+#include <sys/param.h>
+
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
#include "xmalloc.h"
#include "buffer.h"
-#include "bufaux.h"
-#include "compat.h"
-#include <openssl/evp.h>
-#include "kex.h"
#include "log.h"
-#include "monitor_wrap.h"
#include "canohost.h"
#include "ssh2.h"
+#include "cipher.h"
+#include "key.h"
+#include "kex.h"
+#include <openssl/evp.h>
#include "ssh-gss.h"
char *encoded;
gss_OID oid;
} ssh_gss_kex_mapping;
-
-static ssh_gss_kex_mapping *gss_enc2oid;
-/* Return a list of the gss-group1-sha1-x mechanisms supported by this
- * program.
- *
- * On the client side, we don't need to worry about whether we 'know'
- * about the mechanism or not - we assume that any mechanism that we've been
- * linked against is suitable for inclusion.
+/*
+ * XXX - It would be nice to find a more elegant way of handling the
+ * XXX passing of the key exchange context to the userauth routines
+ */
+
+Gssctxt *gss_kex_context = NULL;
+
+static ssh_gss_kex_mapping *gss_enc2oid = NULL;
+
+int
+ssh_gssapi_oid_table_ok() {
+ return (gss_enc2oid != NULL);
+}
+
+/*
+ * Return a list of the gss-group1-sha1 mechanisms supported by this program
*
- * XXX - We might want to make this configurable in the future, so as to
- * XXX - allow the user control over which mechanisms to use.
+ * We test mechanisms to ensure that we can use them, to avoid starting
+ * a key exchange with a bad mechanism
*/
-
-char *
-ssh_gssapi_client_mechanisms(char *host) {
- gss_OID_set supported;
- OM_uint32 min_status;
- Buffer buf;
- int i = 0;
- char *mechs;
- char *encoded;
- int enclen;
- char digest[EVP_MAX_MD_SIZE];
- char deroid[2];
- const EVP_MD *evp_md = EVP_md5();
- EVP_MD_CTX md;
- int oidpos=0;
-
- if (datafellows & SSH_OLD_GSSAPI) return NULL;
-
- gss_indicate_mechs(&min_status,&supported);
- if (datafellows & SSH_BUG_GSSAPI_BER) {
- gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
- *((supported->count*2)+1));
- } else {
- gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
- *(supported->count+1));
+
+char *
+ssh_gssapi_client_mechanisms(const char *host, const char *client) {
+ gss_OID_set gss_supported;
+ OM_uint32 min_status;
+
+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
+ return NULL;
+
+ return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
+ host, client));
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+ const char *host, const char *client) {
+ Buffer buf;
+ size_t i;
+ int oidpos, enclen;
+ char *mechs, *encoded;
+ u_char digest[EVP_MAX_MD_SIZE];
+ char deroid[2];
+ const EVP_MD *evp_md = EVP_md5();
+ EVP_MD_CTX md;
+
+ if (gss_enc2oid != NULL) {
+ for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
+ xfree(gss_enc2oid[i].encoded);
+ xfree(gss_enc2oid);
}
-
+
+ gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
+ (gss_supported->count + 1));
+
buffer_init(&buf);
+ oidpos = 0;
+ for (i = 0; i < gss_supported->count; i++) {
+ if (gss_supported->elements[i].length < 128 &&
+ (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
- for (i=0;i<supported->count;i++) {
-
- gss_enc2oid[oidpos].encoded=NULL;
-
- if (supported->elements[i].length<128 &&
- ssh_gssapi_check_mechanism(&(supported->elements[i]),host)) {
-
- /* Earlier versions of this code interpreted the
- * spec incorrectly with regard to OID encoding. They
- * also mis-encoded the krb5 OID. The following
- * _temporary_ code interfaces with these broken
- * servers */
-
- if (datafellows & SSH_BUG_GSSAPI_BER) {
- char *bodge=NULL;
- gss_OID_desc krb5oid={9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"};
- gss_OID_desc gsioid={9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"};
-
- if (supported->elements[i].length==krb5oid.length &&
- memcmp(supported->elements[i].elements,
- krb5oid.elements, krb5oid.length)==0) {
- bodge="Se3H81ismmOC3OE+FwYCiQ==";
- }
-
- if (supported->elements[i].length==gsioid.length &&
- memcmp(supported->elements[i].elements,
- gsioid.elements, gsioid.length)==0) {
- bodge="N3+k7/4wGxHyuP8Yxi4RhA==";
- }
-
- if (bodge) {
- if (oidpos!=0) {
- buffer_put_char(&buf,',');
- }
-
- buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
- buffer_append(&buf, bodge, strlen(bodge));
-
- gss_enc2oid[oidpos].oid=&(supported->elements[i]);
- gss_enc2oid[oidpos].encoded=bodge;
-
- oidpos++;
- }
- }
-
- /* Add the required DER encoding octets and MD5 hash */
- deroid[0]=0x06; /* Object Identifier */
- deroid[1]=supported->elements[i].length;
+ deroid[0] = SSH_GSS_OIDTYPE;
+ deroid[1] = gss_supported->elements[i].length;
EVP_DigestInit(&md, evp_md);
- EVP_DigestUpdate(&md,deroid,2);
+ EVP_DigestUpdate(&md, deroid, 2);
EVP_DigestUpdate(&md,
- supported->elements[i].elements,
- supported->elements[i].length);
+ gss_supported->elements[i].elements,
+ gss_supported->elements[i].length);
EVP_DigestFinal(&md, digest, NULL);
-
- /* Base64 encode it */
- encoded=xmalloc(EVP_MD_size(evp_md)*2);
- enclen=__b64_ntop(digest, EVP_MD_size(evp_md),
- encoded,EVP_MD_size(evp_md)*2);
- if (oidpos!=0) {
- buffer_put_char(&buf,',');
- }
- buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
- buffer_append(&buf, encoded, enclen);
- debug("Mechanism encoded as %s",encoded);
+ encoded = xmalloc(EVP_MD_size(evp_md) * 2);
+ enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
+ encoded, EVP_MD_size(evp_md) * 2);
+
+ if (oidpos != 0)
+ buffer_put_char(&buf, ',');
- gss_enc2oid[oidpos].oid=&(supported->elements[i]);
- gss_enc2oid[oidpos].encoded=encoded;
+ buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
+ sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
+ buffer_append(&buf, encoded, enclen);
+ buffer_put_char(&buf, ',');
+ buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
+ sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
+ buffer_append(&buf, encoded, enclen);
+ buffer_put_char(&buf, ',');
+ buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
+ sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
+ buffer_append(&buf, encoded, enclen);
+
+ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
+ gss_enc2oid[oidpos].encoded = encoded;
oidpos++;
}
}
- gss_enc2oid[oidpos].oid=NULL;
- gss_enc2oid[oidpos].encoded=NULL;
-
- buffer_put_char(&buf,'\0');
-
- mechs=xmalloc(buffer_len(&buf));
- buffer_get(&buf,mechs,buffer_len(&buf));
+ gss_enc2oid[oidpos].oid = NULL;
+ gss_enc2oid[oidpos].encoded = NULL;
+
+ buffer_put_char(&buf, '\0');
+
+ mechs = xmalloc(buffer_len(&buf));
+ buffer_get(&buf, mechs, buffer_len(&buf));
buffer_free(&buf);
- if (strlen(mechs)==0)
- return(NULL);
- else
- return(mechs);
-}
-gss_OID
-ssh_gssapi_client_id_kex(Gssctxt *ctx, char *name) {
- int i=0;
-
- if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
- return(NULL);
+ if (strlen(mechs) == 0) {
+ xfree(mechs);
+ mechs = NULL;
}
- name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the ID string */
-
- while (gss_enc2oid[i].encoded!=NULL &&
- strcmp(name,gss_enc2oid[i].encoded)!=0) {
- i++;
- }
+ return (mechs);
+}
+
+gss_OID
+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
+ int i = 0;
- if (gss_enc2oid[i].oid!=NULL) {
- ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
+ switch (kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
+ break;
+ case KEX_GSS_GRP14_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
+ break;
+ case KEX_GSS_GEX_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
+ break;
+ default:
+ return GSS_C_NO_OID;
}
+ while (gss_enc2oid[i].encoded != NULL &&
+ strcmp(name, gss_enc2oid[i].encoded) != 0)
+ i++;
+
+ if (gss_enc2oid[i].oid != NULL && ctx != NULL)
+ ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
+
return gss_enc2oid[i].oid;
}
void
ssh_gssapi_error(Gssctxt *ctxt)
{
- debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
+ char *s;
+
+ s = ssh_gssapi_last_error(ctxt, NULL, NULL);
+ debug("%s", s);
+ xfree(s);
}
char *
-ssh_gssapi_last_error(Gssctxt *ctxt,
- OM_uint32 *major_status, OM_uint32 *minor_status)
+ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
+ OM_uint32 *minor_status)
{
OM_uint32 lmin;
gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
void
ssh_gssapi_build_ctx(Gssctxt **ctx)
{
- *ctx = xmalloc(sizeof (Gssctxt));
- (*ctx)->major = 0;
- (*ctx)->minor = 0;
+ *ctx = xcalloc(1, sizeof (Gssctxt));
(*ctx)->context = GSS_C_NO_CONTEXT;
(*ctx)->name = GSS_C_NO_NAME;
(*ctx)->oid = GSS_C_NO_OID;
}
ctx->major = gss_init_sec_context(&ctx->minor,
- GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
+ ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
0, NULL, recv_tok, NULL, send_tok, flags, NULL);
{
gss_buffer_desc gssbuf;
char *xhost;
+ char *val;
/* Make a copy of the host name, in case it was returned by a
* previous call to gethostbyname(). */
* this for us themselves */
resolve_localhost(&xhost);
- gssbuf.length = sizeof("host@") + strlen(xhost);
- gssbuf.value = xmalloc(gssbuf.length);
- snprintf(gssbuf.value, gssbuf.length, "host@%s", xhost);
+ xasprintf(&val, "host@%s", xhost);
+ gssbuf.value = val;
+ gssbuf.length = strlen(gssbuf.value);
if ((ctx->major = gss_import_name(&ctx->minor,
&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
return (ctx->major);
}
-/* Acquire credentials for a server running on the current host.
- * Requires that the context structure contains a valid OID
- */
-
-/* Returns a GSSAPI error code */
OM_uint32
-ssh_gssapi_acquire_cred(Gssctxt *ctx)
+ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
{
+ gss_buffer_desc gssbuf;
+ gss_name_t gssname;
OM_uint32 status;
- char lname[MAXHOSTNAMELEN];
gss_OID_set oidset;
+ gssbuf.value = (void *) name;
+ gssbuf.length = strlen(gssbuf.value);
+
gss_create_empty_oid_set(&status, &oidset);
gss_add_oid_set_member(&status, ctx->oid, &oidset);
- if (gethostname(lname, MAXHOSTNAMELEN))
- return (-1);
+ ctx->major = gss_import_name(&ctx->minor, &gssbuf,
+ GSS_C_NT_USER_NAME, &gssname);
+
+ if (!ctx->major)
+ ctx->major = gss_acquire_cred(&ctx->minor,
+ gssname, 0, oidset, GSS_C_INITIATE,
+ &ctx->client_creds, NULL, NULL);
- if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
- return (ctx->major);
+ gss_release_name(&status, &gssname);
+ gss_release_oid_set(&status, &oidset);
- if ((ctx->major = gss_acquire_cred(&ctx->minor,
- ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
+ if (ctx->major)
ssh_gssapi_error(ctx);
- gss_release_oid_set(&status, &oidset);
- return (ctx->major);
+ return(ctx->major);
}
OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
{
+ if (ctx == NULL)
+ return -1;
+
if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
GSS_C_QOP_DEFAULT, buffer, hash)))
ssh_gssapi_error(ctx);
return (ctx->major);
}
+/* Priviledged when used by server */
+OM_uint32
+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+{
+ if (ctx == NULL)
+ return -1;
+
+ ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+ gssbuf, gssmic, NULL);
+
+ return (ctx->major);
+}
+
void
ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
const char *context)
buffer_put_cstring(b, context);
}
-OM_uint32
-ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
- if (*ctx)
- ssh_gssapi_delete_ctx(ctx);
+int
+ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
+ const char *client)
+{
+ gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
+ OM_uint32 major, minor;
+ gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
+ Gssctxt *intctx = NULL;
+
+ if (ctx == NULL)
+ ctx = &intctx;
+
+ /* RFC 4462 says we MUST NOT do SPNEGO */
+ if (oid->length == spnego_oid.length &&
+ (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
+ return 0; /* false */
+
ssh_gssapi_build_ctx(ctx);
ssh_gssapi_set_oid(*ctx, oid);
- return (ssh_gssapi_acquire_cred(*ctx));
+ major = ssh_gssapi_import_name(*ctx, host);
+
+ if (!GSS_ERROR(major) && client)
+ major = ssh_gssapi_client_identity(*ctx, client);
+
+ if (!GSS_ERROR(major)) {
+ major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
+ NULL);
+ gss_release_buffer(&minor, &token);
+ if ((*ctx)->context != GSS_C_NO_CONTEXT)
+ gss_delete_sec_context(&minor, &(*ctx)->context,
+ GSS_C_NO_BUFFER);
+ }
+
+ if (GSS_ERROR(major) || intctx != NULL)
+ ssh_gssapi_delete_ctx(ctx);
+
+ return (!GSS_ERROR(major));
}
int
-ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
- Gssctxt * ctx = NULL;
- gss_buffer_desc token;
- OM_uint32 major,minor;
+ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
+ static gss_name_t saved_name = GSS_C_NO_NAME;
+ static OM_uint32 saved_lifetime = 0;
+ static gss_OID saved_mech = GSS_C_NO_OID;
+ static gss_name_t name;
+ static OM_uint32 last_call = 0;
+ OM_uint32 lifetime, now, major, minor;
+ int equal;
+
+ now = time(NULL);
+
+ if (ctxt) {
+ debug("Rekey has happened - updating saved versions");
+
+ if (saved_name != GSS_C_NO_NAME)
+ gss_release_name(&minor, &saved_name);
+
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &saved_name, &saved_lifetime, NULL, NULL);
+
+ if (!GSS_ERROR(major)) {
+ saved_mech = ctxt->oid;
+ saved_lifetime+= now;
+ } else {
+ /* Handle the error */
+ }
+ return 0;
+ }
+
+ if (now - last_call < 10)
+ return 0;
+
+ last_call = now;
+
+ if (saved_mech == GSS_C_NO_OID)
+ return 0;
- ssh_gssapi_build_ctx(&ctx);
- ssh_gssapi_set_oid(ctx,oid);
- ssh_gssapi_import_name(ctx,host);
- major=ssh_gssapi_init_ctx(ctx,0, GSS_C_NO_BUFFER, &token, NULL);
- gss_release_buffer(&minor,&token);
- ssh_gssapi_delete_ctx(&ctx);
- return(!GSS_ERROR(major));
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &name, &lifetime, NULL, NULL);
+ if (major == GSS_S_CREDENTIALS_EXPIRED)
+ return 0;
+ else if (GSS_ERROR(major))
+ return 0;
+
+ major = gss_compare_name(&minor, saved_name, name, &equal);
+ gss_release_name(&minor, &name);
+ if (GSS_ERROR(major))
+ return 0;
+
+ if (equal && (saved_lifetime < lifetime + now - 10))
+ return 1;
+
+ return 0;
}
#endif /* GSSAPI */
andersk / gssapi-openssh.git / blobdiff