/*
- * Copyright (c) 2001,2002 Simon Wilkinson. All rights reserved. *
+ * 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:
#include "log.h"
#include "compat.h"
#include "monitor_wrap.h"
+#include "canohost.h"
#include <netdb.h>
#include "ssh-gss.h"
-/* Assorted globals for tracking the clients identity once they've
- * authenticated */
-
-gss_buffer_desc gssapi_client_name = {0,NULL}; /* Name of our client */
-gss_cred_id_t gssapi_client_creds = GSS_C_NO_CREDENTIAL; /* Their credentials */
-enum ssh_gss_id gssapi_client_type = GSS_LAST_ENTRY;
-
-unsigned char ssh1_key_digest[16]; /* used for ssh1 gssapi */
-
-/* The mechanism name used in the list below is defined in the internet
- * draft as the Base 64 encoding of the MD5 hash of the ASN.1 DER encoding
- * of the underlying GSSAPI mechanism's OID.
- *
- * Also from the draft, before considering adding SPNEGO, bear in mind that
- * "mechanisms ... MUST NOT use SPNEGO as the underlying GSSAPI mechanism"
- */
-
-/* These must be in the same order as ssh_gss_id, in ssh-gss.h */
-
-ssh_gssapi_mech supported_mechs[]= {
-#ifdef KRB5
- /* Official OID - 1.2.850.113554.1.2.2 */
- {"Se3H81ismmOC3OE+FwYCiQ==","Kerberos",
- {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}},
-#endif
-#ifdef GSI
- /* gssapi_ssleay 1.3.6.1.4.1.3536.1.1 */
- {"N3+k7/4wGxHyuP8Yxi4RhA==",
- "GSI",
- {9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"}
- },
-#endif /* GSI */
- {NULL,NULL,{0,0}}
-};
-
-char gssprefix[]=KEX_GSS_SHA1;
+typedef struct {
+ 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.
*
- * We only support the mechanisms that we've indicated in the list above,
- * but we check that they're supported by the GSSAPI mechanism on the
- * machine. We also check, before including them in the list, that
- * we have the necesary information in order to carry out the key exchange
- * (that is, that the user has credentials, the server's creds are accessible,
- * etc)
+ * 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.
*
- * The way that this is done is fairly nasty, as we do a lot of work that
- * is then thrown away. This should possibly be implemented with a cache
- * that stores the results (in an expanded Gssctxt structure), which are
- * then used by the first calls if that key exchange mechanism is chosen.
+ * XXX - We might want to make this configurable in the future, so as to
+ * XXX - allow the user control over which mechanisms to use.
*/
char *
-ssh_gssapi_mechanisms(int server,char *host) {
+ssh_gssapi_client_mechanisms(char *host) {
gss_OID_set supported;
- OM_uint32 maj_status, min_status;
+ OM_uint32 min_status;
Buffer buf;
int i = 0;
- int present;
- char * mechs;
- Gssctxt * ctx = NULL;
-
+ 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);
+ 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));
+ }
- buffer_init(&buf);
-
- do {
- if ((maj_status=gss_test_oid_set_member(&min_status,
- &supported_mechs[i].oid,
- supported,
- &present))) {
- present=0;
+ buffer_init(&buf);
+
+
+ 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;
+
+ EVP_DigestInit(&md, evp_md);
+ EVP_DigestUpdate(&md,deroid,2);
+ EVP_DigestUpdate(&md,
+ supported->elements[i].elements,
+ 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);
+
+ gss_enc2oid[oidpos].oid=&(supported->elements[i]);
+ gss_enc2oid[oidpos].encoded=encoded;
+ oidpos++;
}
- if (present) {
- if ((server &&
- !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
- &supported_mechs[i].oid))))
- || (!server &&
- !GSS_ERROR(ssh_gssapi_client_ctx(&ctx,
- &supported_mechs[i].oid,
- host)))) {
- /* Append gss_group1_sha1_x to our list */
- buffer_append(&buf, gssprefix,
- strlen(gssprefix));
- buffer_append(&buf,
- supported_mechs[i].enc_name,
- strlen(supported_mechs[i].enc_name));
- }
- }
- } while (supported_mechs[++i].name != NULL);
+ }
+ gss_enc2oid[oidpos].oid=NULL;
+ gss_enc2oid[oidpos].encoded=NULL;
buffer_put_char(&buf,'\0');
buffer_get(&buf,mechs,buffer_len(&buf));
buffer_free(&buf);
if (strlen(mechs)==0)
- return(NULL);
+ return(NULL);
else
- return(mechs);
+ return(mechs);
}
-void ssh_gssapi_supported_oids(gss_OID_set *oidset) {
- enum ssh_gss_id i =0;
- OM_uint32 maj_status,min_status;
- int present;
- gss_OID_set supported;
+gss_OID
+ssh_gssapi_client_id_kex(Gssctxt *ctx, char *name) {
+ int i=0;
- gss_create_empty_oid_set(&min_status,oidset);
- 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++;
+ if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
+ return(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++;
+ }
+
+ if (gss_enc2oid[i].oid!=NULL) {
+ ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
}
-}
+ return gss_enc2oid[i].oid;
+}
+
+/* Check that the OID in a data stream matches that in the context */
+int ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len) {
+
+ return (ctx!=NULL && ctx->oid != GSS_C_NO_OID &&
+ ctx->oid->length == len &&
+ memcmp(ctx->oid->elements,data,len)==0);
+}
+
/* Set the contexts OID from a data stream */
void ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len) {
if (ctx->oid != GSS_C_NO_OID) {
ssh_gssapi_set_oid_data(ctx,oid->elements,oid->length);
}
-/* Find out which GSS type (out of the list we define in ssh-gss.h) a
- * particular connection is using
- */
-enum ssh_gss_id ssh_gssapi_get_ctype(Gssctxt *ctxt) {
- enum ssh_gss_id 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 i;
- i++;
- }
- return(GSS_LAST_ENTRY);
-}
-
-/* Set the GSS context's OID to the oid indicated by the given key exchange
- * name. */
-gss_OID ssh_gssapi_id_kex(Gssctxt *ctx, char *name) {
- enum ssh_gss_id i=0;
-
- if (strncmp(name, gssprefix, strlen(gssprefix)-1) !=0) {
- return(NULL);
- }
-
- name+=strlen(gssprefix); /* Move to the start of the MIME string */
-
- while (supported_mechs[i].name!=NULL &&
- 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);
+/* All this effort to report an error ... */
- return &supported_mechs[i].oid;
+void
+ssh_gssapi_error(Gssctxt *ctxt) {
+
+ debug(ssh_gssapi_last_error(ctxt,NULL,NULL));
}
-
-/* All this effort to report an error ... */
-static void
-ssh_gssapi_error_ex(OM_uint32 major_status,OM_uint32 minor_status,
- int send_packet) {
- OM_uint32 lmaj, lmin;
+char *
+ssh_gssapi_last_error(Gssctxt *ctxt,
+ OM_uint32 *major_status, OM_uint32 *minor_status) {
+ OM_uint32 lmin;
gss_buffer_desc msg;
OM_uint32 ctx;
+ Buffer b;
+ char *ret;
+ buffer_init(&b);
+
+ if (major_status!=NULL) *major_status=ctxt->major;
+ if (minor_status!=NULL) *minor_status=ctxt->minor;
+
ctx = 0;
/* The GSSAPI error */
do {
- lmaj = gss_display_status(&lmin, major_status,
- GSS_C_GSS_CODE,
- GSS_C_NULL_OID,
- &ctx, &msg);
- if (lmaj == GSS_S_COMPLETE) {
- debug((char *)msg.value);
- if (send_packet) packet_send_debug((char *)msg.value);
- (void) gss_release_buffer(&lmin, &msg);
- }
- } while (ctx!=0);
+ gss_display_status(&lmin, ctxt->major,
+ GSS_C_GSS_CODE, ctxt->oid,
+ &ctx, &msg);
+
+ buffer_append(&b,msg.value,msg.length);
+ buffer_put_char(&b,'\n');
+
+ gss_release_buffer(&lmin, &msg);
+ } while (ctx!=0);
/* The mechanism specific error */
do {
- lmaj = gss_display_status(&lmin, minor_status,
- GSS_C_MECH_CODE,
- GSS_C_NULL_OID,
- &ctx, &msg);
- if (lmaj == GSS_S_COMPLETE) {
- debug((char *)msg.value);
- if (send_packet) packet_send_debug((char *)msg.value);
- (void) gss_release_buffer(&lmin, &msg);
- }
+ gss_display_status(&lmin, ctxt->minor,
+ GSS_C_MECH_CODE, ctxt->oid,
+ &ctx, &msg);
+
+ buffer_append(&b,msg.value,msg.length);
+ buffer_put_char(&b,'\n');
+
+ gss_release_buffer(&lmin, &msg);
} while (ctx!=0);
+
+ buffer_put_char(&b,'\0');
+ ret=xmalloc(buffer_len(&b));
+ buffer_get(&b,ret,buffer_len(&b));
+ buffer_free(&b);
+ return(ret);
}
-void
-ssh_gssapi_error(OM_uint32 major_status,OM_uint32 minor_status) {
- ssh_gssapi_error_ex(major_status, minor_status, 0);
-}
-
-void
-ssh_gssapi_send_error(OM_uint32 major_status,OM_uint32 minor_status) {
- ssh_gssapi_error_ex(major_status, minor_status, 1);
-}
-
-
-
-
/* Initialise our GSSAPI context. We use this opaque structure to contain all
* of the data which both the client and server need to persist across
* {accept,init}_sec_context calls, so that when we do it from the userauth
ssh_gssapi_build_ctx(Gssctxt **ctx)
{
*ctx=xmalloc(sizeof (Gssctxt));
+ (*ctx)->major=0;
+ (*ctx)->minor=0;
(*ctx)->context=GSS_C_NO_CONTEXT;
(*ctx)->name=GSS_C_NO_NAME;
(*ctx)->oid=GSS_C_NO_OID;
void
ssh_gssapi_delete_ctx(Gssctxt **ctx)
{
+#if !defined(MECHGLUE)
OM_uint32 ms;
+#endif
/* Return if there's no context */
if ((*ctx)==NULL)
return;
+#if !defined(MECHGLUE) /* mechglue has some memory management issues */
if ((*ctx)->context != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&ms,&(*ctx)->context,GSS_C_NO_BUFFER);
if ((*ctx)->name != GSS_C_NO_NAME)
gss_release_name(&ms,&(*ctx)->client);
if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
gss_release_cred(&ms,&(*ctx)->client_creds);
+#endif
xfree(*ctx);
*ctx=NULL;
ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
gss_buffer_desc* send_tok, OM_uint32 *flags)
{
- OM_uint32 maj_status, min_status;
int deleg_flag = 0;
if (deleg_creds) {
debug("Delegating credentials");
}
- maj_status=gss_init_sec_context(&min_status,
+ ctx->major=gss_init_sec_context(&ctx->minor,
GSS_C_NO_CREDENTIAL, /* def. cred */
&ctx->context,
ctx->name,
send_tok,
flags,
NULL);
- ctx->status=maj_status;
- if (GSS_ERROR(maj_status)) {
- ssh_gssapi_error(maj_status,min_status);
+ if (GSS_ERROR(ctx->major)) {
+ ssh_gssapi_error(ctx);
}
- return(maj_status);
-}
-
-/* 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 maj_status, min_status;
- gss_OID mech;
-
- maj_status=gss_accept_sec_context(&min_status,
- &ctx->context,
- ctx->creds,
- recv_tok,
- GSS_C_NO_CHANNEL_BINDINGS,
- &ctx->client,
- &mech,
- send_tok,
- flags,
- NULL,
- &ctx->client_creds);
- if (GSS_ERROR(maj_status)) {
- ssh_gssapi_send_error(maj_status,min_status);
- }
-
- 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) */
-
- ctx->status=maj_status;
-
- /* 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))) &&
- (maj_status == GSS_S_COMPLETE)) {
- if (ssh_gssapi_getclient(ctx,&gssapi_client_type,
- &gssapi_client_name,
- &gssapi_client_creds))
- fatal("Couldn't convert client name");
- }
-
- return(maj_status);
+ return(ctx->major);
}
/* Create a service name for the given host */
OM_uint32
ssh_gssapi_import_name(Gssctxt *ctx, const char *host) {
gss_buffer_desc gssbuf;
- OM_uint32 maj_status, min_status;
- struct hostent *hostinfo = NULL;
char *xhost;
/* Make a copy of the host name, in case it was returned by a
/* Make sure we have the FQDN. Some GSSAPI implementations don't do
* this for us themselves */
+ resolve_localhost(&xhost);
- hostinfo = gethostbyname(xhost);
-
- if ((hostinfo == NULL) || (hostinfo->h_name == NULL)) {
- debug("Unable to get FQDN for \"%s\"", xhost);
- } else {
- xfree(xhost);
- xhost = xstrdup(hostinfo->h_name);
- }
-
gssbuf.length = sizeof("host@")+strlen(xhost);
gssbuf.value = xmalloc(gssbuf.length);
return(-1);
}
snprintf(gssbuf.value,gssbuf.length,"host@%s",xhost);
- if ((maj_status=gss_import_name(&min_status,
+ if ((ctx->major=gss_import_name(&ctx->minor,
&gssbuf,
GSS_C_NT_HOSTBASED_SERVICE,
&ctx->name))) {
- ssh_gssapi_error(maj_status,min_status);
+ ssh_gssapi_error(ctx);
}
xfree(xhost);
xfree(gssbuf.value);
- return(maj_status);
+ return(ctx->major);
}
/* Acquire credentials for a server running on the current host.
/* Returns a GSSAPI error code */
OM_uint32
ssh_gssapi_acquire_cred(Gssctxt *ctx) {
- OM_uint32 maj_status, min_status;
+ OM_uint32 status;
char lname[MAXHOSTNAMELEN];
gss_OID_set oidset;
- gss_create_empty_oid_set(&min_status,&oidset);
- gss_add_oid_set_member(&min_status,ctx->oid,&oidset);
+ gss_create_empty_oid_set(&status,&oidset);
+ gss_add_oid_set_member(&status,ctx->oid,&oidset);
if (gethostname(lname, MAXHOSTNAMELEN)) {
return(-1);
}
- if ((maj_status=ssh_gssapi_import_name(ctx,lname))) {
- return(maj_status);
+ if (GSS_ERROR(ssh_gssapi_import_name(ctx,lname))) {
+ return(ctx->major);
}
- if ((maj_status=gss_acquire_cred(&min_status,
+
+ if ((ctx->major=gss_acquire_cred(&ctx->minor,
ctx->name,
0,
oidset,
&ctx->creds,
NULL,
NULL))) {
- ssh_gssapi_error(maj_status,min_status);
+ ssh_gssapi_error(ctx);
}
- gss_release_oid_set(&min_status, &oidset);
- return(maj_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, enum ssh_gss_id *type,
- gss_buffer_desc *name, gss_cred_id_t *creds) {
-
- OM_uint32 maj_status,min_status;
-
- *type=ssh_gssapi_get_ctype(ctx);
- if ((maj_status=gss_display_name(&min_status,ctx->client,name,NULL))) {
- ssh_gssapi_error(maj_status,min_status);
- }
-
- /* 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(maj_status);
+ gss_release_oid_set(&status, &oidset);
+ return(ctx->major);
}
OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *buffer, gss_buffer_desc *hash) {
- OM_uint32 maj_status,min_status;
/* ssh1 needs to exchange the hash of the keys */
/* will us this hash to return it */
if (!compat20) {
- if ((maj_status=gss_wrap(&min_status,ctx->context,
- 0,
- GSS_C_QOP_DEFAULT,
- buffer,
- NULL,
- hash)))
- ssh_gssapi_error(maj_status,min_status);
+ if ((ctx->major=gss_wrap(&ctx->minor,ctx->context,
+ 0,
+ GSS_C_QOP_DEFAULT,
+ buffer,
+ NULL,
+ hash)))
+ ssh_gssapi_error(ctx);
}
else
- if ((maj_status=gss_get_mic(&min_status,ctx->context,
+ if ((ctx->major=gss_get_mic(&ctx->minor,ctx->context,
GSS_C_QOP_DEFAULT, buffer, hash))) {
- ssh_gssapi_error(maj_status,min_status);
+ ssh_gssapi_error(ctx);
}
- return(maj_status);
+ return(ctx->major);
}
OM_uint32
return(ssh_gssapi_acquire_cred(*ctx));
}
-OM_uint32
-ssh_gssapi_client_ctx(Gssctxt **ctx,gss_OID oid, char *host) {
+int
+ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
+ Gssctxt * ctx = NULL;
gss_buffer_desc token;
OM_uint32 major,minor;
- if (*ctx) ssh_gssapi_delete_ctx(ctx);
- 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);
+ 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);
- return(major);
+ ssh_gssapi_delete_ctx(&ctx);
+ return(!GSS_ERROR(major));
}
-
+
#endif /* GSSAPI */