1 files changed, 169 insertions, 1 deletions

diff --git a/gss-genr.c b/gss-genr.c
index e9190575d..822a08212 100644
--- a/gss-genr.c
+++ b/gss-genr.c
@@ -39,12 +39,160 @@
 #include "buffer.h"
 #include "log.h"
 #include "ssh2.h"
+#include "cipher.h"
+#include "key.h"
+#include "kex.h"
+#include <openssl/evp.h>
 
 #include "ssh-gss.h"
 
 extern u_char *session_id2;
 extern u_int session_id2_len;
 
+typedef struct {
+        char *encoded;
+        gss_OID oid;
+} ssh_gss_kex_mapping;
+
+/*
+ * 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
+ *
+ * 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(const char *host) {
+        gss_OID_set gss_supported;
+        OM_uint32 min_status;
+
+        gss_indicate_mechs(&min_status, &gss_supported);
+
+        return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
+            host));
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+    const char *data) {
+        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]), data)) {
+
+                        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,
+                            gss_supported->elements[i].elements,
+                            gss_supported->elements[i].length);
+                        EVP_DigestFinal(&md, digest, NULL);
+
+                        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_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));
+        buffer_free(&buf);
+
+        if (strlen(mechs) == 0) {
+                xfree(mechs);
+                mechs = NULL;
+        }
+        
+        return (mechs);
+}
+
+gss_OID
+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
+        int i = 0;
+        
+        switch (kex_type) {
+        case KEX_GSS_GRP1_SHA1:
+                name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
+                break;
+        case KEX_GSS_GRP14_SHA1:
+                name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
+                break;
+        case KEX_GSS_GEX_SHA1:
+                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;
+}
+
 /* 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)
@@ -229,6 +377,9 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
 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);
@@ -236,6 +387,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
         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)
@@ -254,6 +418,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
         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 && 
@@ -272,7 +440,7 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
                             GSS_C_NO_BUFFER);
         }
 
-        if (GSS_ERROR(major)) 
+        if (GSS_ERROR(major) || intctx != NULL) 
                 ssh_gssapi_delete_ctx(ctx);
 
         return (!GSS_ERROR(major));