1 files changed, 364 insertions, 0 deletions
diff --git a/lib/dns/gssapi_link.c b/lib/dns/gssapi_link.c
new file mode 100644
index 0000000..a3fbb6e
--- /dev/null
+++ b/lib/dns/gssapi_link.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <inttypes.h> /* IWYU pragma: keep */
+#include <stdbool.h>
+#include <time.h> /* IWYU pragma: keep */
+
+#if HAVE_GSSAPI_GSSAPI_H
+#include <gssapi/gssapi.h>
+#elif HAVE_GSSAPI_H
+#include <gssapi.h>
+#endif
+
+#if HAVE_GSSAPI_GSSAPI_KRB5_H
+#include <gssapi/gssapi_krb5.h>
+#elif HAVE_GSSAPI_KRB5_H
+#include <gssapi_krb5.h>
+#endif
+
+#include <isc/base64.h>
+#include <isc/buffer.h>
+#include <isc/mem.h>
+#include <isc/print.h>
+#include <isc/result.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include <dst/gssapi.h>
+
+#include "dst_internal.h"
+#include "dst_parse.h"
+
+#define INITIAL_BUFFER_SIZE 1024
+#define BUFFER_EXTRA	    1024
+
+#define REGION_TO_GBUFFER(r, gb)          \
+	do {                              \
+		(gb).length = (r).length; \
+		(gb).value = (r).base;    \
+	} while (0)
+
+#define GBUFFER_TO_REGION(gb, r)                        \
+	do {                                            \
+		(r).length = (unsigned int)(gb).length; \
+		(r).base = (gb).value;                  \
+	} while (0)
+
+struct dst_gssapi_signverifyctx {
+	isc_buffer_t *buffer;
+};
+
+/*%
+ * Allocate a temporary "context" for use in gathering data for signing
+ * or verifying.
+ */
+static isc_result_t
+gssapi_create_signverify_ctx(dst_key_t *key, dst_context_t *dctx) {
+	dst_gssapi_signverifyctx_t *ctx;
+
+	UNUSED(key);
+
+	ctx = isc_mem_get(dctx->mctx, sizeof(dst_gssapi_signverifyctx_t));
+	ctx->buffer = NULL;
+	isc_buffer_allocate(dctx->mctx, &ctx->buffer, INITIAL_BUFFER_SIZE);
+
+	dctx->ctxdata.gssctx = ctx;
+
+	return (ISC_R_SUCCESS);
+}
+
+/*%
+ * Destroy the temporary sign/verify context.
+ */
+static void
+gssapi_destroy_signverify_ctx(dst_context_t *dctx) {
+	dst_gssapi_signverifyctx_t *ctx = dctx->ctxdata.gssctx;
+
+	if (ctx != NULL) {
+		if (ctx->buffer != NULL) {
+			isc_buffer_free(&ctx->buffer);
+		}
+		isc_mem_put(dctx->mctx, ctx,
+			    sizeof(dst_gssapi_signverifyctx_t));
+		dctx->ctxdata.gssctx = NULL;
+	}
+}
+
+/*%
+ * Add data to our running buffer of data we will be signing or verifying.
+ * This code will see if the new data will fit in our existing buffer, and
+ * copy it in if it will.  If not, it will attempt to allocate a larger
+ * buffer and copy old+new into it, and free the old buffer.
+ */
+static isc_result_t
+gssapi_adddata(dst_context_t *dctx, const isc_region_t *data) {
+	dst_gssapi_signverifyctx_t *ctx = dctx->ctxdata.gssctx;
+	isc_buffer_t *newbuffer = NULL;
+	isc_region_t r;
+	unsigned int length;
+	isc_result_t result;
+
+	result = isc_buffer_copyregion(ctx->buffer, data);
+	if (result == ISC_R_SUCCESS) {
+		return (ISC_R_SUCCESS);
+	}
+
+	length = isc_buffer_length(ctx->buffer) + data->length + BUFFER_EXTRA;
+
+	isc_buffer_allocate(dctx->mctx, &newbuffer, length);
+
+	isc_buffer_usedregion(ctx->buffer, &r);
+	(void)isc_buffer_copyregion(newbuffer, &r);
+	(void)isc_buffer_copyregion(newbuffer, data);
+
+	isc_buffer_free(&ctx->buffer);
+	ctx->buffer = newbuffer;
+
+	return (ISC_R_SUCCESS);
+}
+
+/*%
+ * Sign.
+ */
+static isc_result_t
+gssapi_sign(dst_context_t *dctx, isc_buffer_t *sig) {
+	dst_gssapi_signverifyctx_t *ctx = dctx->ctxdata.gssctx;
+	isc_region_t message;
+	gss_buffer_desc gmessage, gsig;
+	OM_uint32 minor, gret;
+	gss_ctx_id_t gssctx = dctx->key->keydata.gssctx;
+	char buf[1024];
+
+	/*
+	 * Convert the data we wish to sign into a structure gssapi can
+	 * understand.
+	 */
+	isc_buffer_usedregion(ctx->buffer, &message);
+	REGION_TO_GBUFFER(message, gmessage);
+
+	/*
+	 * Generate the signature.
+	 */
+	gret = gss_get_mic(&minor, gssctx, GSS_C_QOP_DEFAULT, &gmessage, &gsig);
+
+	/*
+	 * If it did not complete, we log the result and return a generic
+	 * failure code.
+	 */
+	if (gret != GSS_S_COMPLETE) {
+		gss_log(3, "GSS sign error: %s",
+			gss_error_tostring(gret, minor, buf, sizeof(buf)));
+		return (ISC_R_FAILURE);
+	}
+
+	/*
+	 * If it will not fit in our allocated buffer, return that we need
+	 * more space.
+	 */
+	if (gsig.length > isc_buffer_availablelength(sig)) {
+		gss_release_buffer(&minor, &gsig);
+		return (ISC_R_NOSPACE);
+	}
+
+	/*
+	 * Copy the output into our buffer space, and release the gssapi
+	 * allocated space.
+	 */
+	isc_buffer_putmem(sig, gsig.value, (unsigned int)gsig.length);
+	if (gsig.length != 0U) {
+		gss_release_buffer(&minor, &gsig);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*%
+ * Verify.
+ */
+static isc_result_t
+gssapi_verify(dst_context_t *dctx, const isc_region_t *sig) {
+	dst_gssapi_signverifyctx_t *ctx = dctx->ctxdata.gssctx;
+	isc_region_t message;
+	gss_buffer_desc gmessage, gsig;
+	OM_uint32 minor, gret;
+	gss_ctx_id_t gssctx = dctx->key->keydata.gssctx;
+	char err[1024];
+
+	/*
+	 * Convert the data we wish to sign into a structure gssapi can
+	 * understand.
+	 */
+	isc_buffer_usedregion(ctx->buffer, &message);
+	REGION_TO_GBUFFER(message, gmessage);
+	REGION_TO_GBUFFER(*sig, gsig);
+
+	/*
+	 * Verify the data.
+	 */
+	gret = gss_verify_mic(&minor, gssctx, &gmessage, &gsig, NULL);
+
+	/*
+	 * Convert return codes into something useful to us.
+	 */
+	if (gret != GSS_S_COMPLETE) {
+		gss_log(3, "GSS verify error: %s",
+			gss_error_tostring(gret, minor, err, sizeof(err)));
+		if (gret == GSS_S_DEFECTIVE_TOKEN || gret == GSS_S_BAD_SIG ||
+		    gret == GSS_S_DUPLICATE_TOKEN || gret == GSS_S_OLD_TOKEN ||
+		    gret == GSS_S_UNSEQ_TOKEN || gret == GSS_S_GAP_TOKEN ||
+		    gret == GSS_S_CONTEXT_EXPIRED || gret == GSS_S_NO_CONTEXT ||
+		    gret == GSS_S_FAILURE)
+		{
+			return (DST_R_VERIFYFAILURE);
+		} else {
+			return (ISC_R_FAILURE);
+		}
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static bool
+gssapi_compare(const dst_key_t *key1, const dst_key_t *key2) {
+	gss_ctx_id_t gsskey1 = key1->keydata.gssctx;
+	gss_ctx_id_t gsskey2 = key2->keydata.gssctx;
+
+	/* No idea */
+	return (gsskey1 == gsskey2);
+}
+
+static isc_result_t
+gssapi_generate(dst_key_t *key, int unused, void (*callback)(int)) {
+	UNUSED(key);
+	UNUSED(unused);
+	UNUSED(callback);
+
+	/* No idea */
+	return (ISC_R_FAILURE);
+}
+
+static bool
+gssapi_isprivate(const dst_key_t *key) {
+	UNUSED(key);
+	return (true);
+}
+
+static void
+gssapi_destroy(dst_key_t *key) {
+	REQUIRE(key != NULL);
+	dst_gssapi_deletectx(key->mctx, &key->keydata.gssctx);
+	key->keydata.gssctx = NULL;
+}
+
+static isc_result_t
+gssapi_restore(dst_key_t *key, const char *keystr) {
+	OM_uint32 major, minor;
+	unsigned int len;
+	isc_buffer_t *b = NULL;
+	isc_region_t r;
+	gss_buffer_desc gssbuffer;
+	isc_result_t result;
+
+	len = strlen(keystr);
+	if ((len % 4) != 0U) {
+		return (ISC_R_BADBASE64);
+	}
+
+	len = (len / 4) * 3;
+
+	isc_buffer_allocate(key->mctx, &b, len);
+
+	result = isc_base64_decodestring(keystr, b);
+	if (result != ISC_R_SUCCESS) {
+		isc_buffer_free(&b);
+		return (result);
+	}
+
+	isc_buffer_remainingregion(b, &r);
+	REGION_TO_GBUFFER(r, gssbuffer);
+	major = gss_import_sec_context(&minor, &gssbuffer,
+				       (gss_ctx_id_t *)&key->keydata.gssctx);
+	if (major != GSS_S_COMPLETE) {
+		isc_buffer_free(&b);
+		return (ISC_R_FAILURE);
+	}
+
+	isc_buffer_free(&b);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+gssapi_dump(dst_key_t *key, isc_mem_t *mctx, char **buffer, int *length) {
+	OM_uint32 major, minor;
+	gss_buffer_desc gssbuffer;
+	size_t len;
+	char *buf;
+	isc_buffer_t b;
+	isc_region_t r;
+	isc_result_t result;
+
+	major = gss_export_sec_context(
+		&minor, (gss_ctx_id_t *)&key->keydata.gssctx, &gssbuffer);
+	if (major != GSS_S_COMPLETE) {
+		fprintf(stderr, "gss_export_sec_context -> %u, %u\n", major,
+			minor);
+		return (ISC_R_FAILURE);
+	}
+	if (gssbuffer.length == 0U) {
+		return (ISC_R_FAILURE);
+	}
+	len = ((gssbuffer.length + 2) / 3) * 4;
+	buf = isc_mem_get(mctx, len);
+	isc_buffer_init(&b, buf, (unsigned int)len);
+	GBUFFER_TO_REGION(gssbuffer, r);
+	result = isc_base64_totext(&r, 0, "", &b);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	gss_release_buffer(&minor, &gssbuffer);
+	*buffer = buf;
+	*length = (int)len;
+	return (ISC_R_SUCCESS);
+}
+
+static dst_func_t gssapi_functions = {
+	gssapi_create_signverify_ctx,
+	NULL, /*%< createctx2 */
+	gssapi_destroy_signverify_ctx,
+	gssapi_adddata,
+	gssapi_sign,
+	gssapi_verify,
+	NULL, /*%< verify2 */
+	NULL, /*%< computesecret */
+	gssapi_compare,
+	NULL, /*%< paramcompare */
+	gssapi_generate,
+	gssapi_isprivate,
+	gssapi_destroy,
+	NULL, /*%< todns */
+	NULL, /*%< fromdns */
+	NULL, /*%< tofile */
+	NULL, /*%< parse */
+	NULL, /*%< cleanup */
+	NULL, /*%< fromlabel */
+	gssapi_dump,
+	gssapi_restore,
+};
+
+isc_result_t
+dst__gssapi_init(dst_func_t **funcp) {
+	REQUIRE(funcp != NULL);
+	if (*funcp == NULL) {
+		*funcp = &gssapi_functions;
+	}
+	return (ISC_R_SUCCESS);
+}