/* $NetBSD: gssapi_link.c,v 1.3.4.1 2024/02/29 12:34:31 martin Exp $ */ /* * 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 /* IWYU pragma: keep */ #include #include /* IWYU pragma: keep */ #if HAVE_GSSAPI_GSSAPI_H #include #elif HAVE_GSSAPI_H #include #endif #if HAVE_GSSAPI_GSSAPI_KRB5_H #include #elif HAVE_GSSAPI_KRB5_H #include #endif #include #include #include #include #include #include #include #include #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); }