/* $OpenBSD: callbackfailures.c,v 1.3 2024/08/23 12:56:26 anton Exp $ */
/*
 * Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
 * Copyright (c) 2020-2021 Bob Beck <beck@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <err.h>
#include <string.h>

#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>

#include "x509_verify.h"

#define MODE_MODERN_VFY         0
#define MODE_MODERN_VFY_DIR     1
#define MODE_LEGACY_VFY         2
#define MODE_VERIFY             3

static int verbose = 1;

static int expected_depth;
static int expected_error;
static int seen_depth;
static int seen_error;

static int
passwd_cb(char *buf, int size, int rwflag, void *u)
{
        memset(buf, 0, size);
        return (0);
}

static int
certs_from_file(const char *filename, STACK_OF(X509) **certs, int clear)
{
        STACK_OF(X509_INFO) *xis = NULL;
        STACK_OF(X509) *xs = NULL;
        BIO *bio = NULL;
        X509 *x;
        int i;

        if (clear) {
                if ((xs = sk_X509_new_null()) == NULL)
                        errx(1, "failed to create X509 stack");
        } else
                xs = *certs;
        if ((bio = BIO_new_file(filename, "r")) == NULL) {
                ERR_print_errors_fp(stderr);
                errx(1, "failed to create bio");
        }
        if ((xis = PEM_X509_INFO_read_bio(bio, NULL, passwd_cb, NULL)) == NULL)
                errx(1, "failed to read PEM");

        for (i = 0; i < sk_X509_INFO_num(xis); i++) {
                if ((x = sk_X509_INFO_value(xis, i)->x509) == NULL)
                        continue;
                if (!sk_X509_push(xs, x))
                        errx(1, "failed to push X509");
                X509_up_ref(x);
        }

        *certs = xs;
        xs = NULL;

        sk_X509_INFO_pop_free(xis, X509_INFO_free);
        sk_X509_pop_free(xs, X509_free);
        BIO_free(bio);

        return 1;
}

static int
verify_cert_cb(int ok, X509_STORE_CTX *xsc)
{
        X509 *current_cert;
        int verify_err;

        current_cert = X509_STORE_CTX_get_current_cert(xsc);
        if (current_cert != NULL) {
                X509_NAME_print_ex_fp(stderr,
                    X509_get_subject_name(current_cert), 0,
                    XN_FLAG_ONELINE);
                fprintf(stderr, "\n");
        }

        verify_err = X509_STORE_CTX_get_error(xsc);
        if (verify_err != X509_V_OK) {
                seen_depth = X509_STORE_CTX_get_error_depth(xsc);
                seen_error = verify_err;
                fprintf(stderr, "verify error at depth %d: %s\n",
                    X509_STORE_CTX_get_error_depth(xsc),
                    X509_verify_cert_error_string(verify_err));
        }

        fprintf(stderr, "chain of length %d\n", sk_X509_num (X509_STORE_CTX_get0_chain (xsc)));

        return ok;
}

static void
verify_cert(const char *roots_dir, const char *roots_file,
    const char *bundle_file, const char*bundle_file2, int *chains, int mode)
{
        STACK_OF(X509) *roots = NULL, *bundle = NULL;
        X509_STORE_CTX *xsc = NULL;
        X509_STORE *store = NULL;
        int verify_err, use_dir;
        X509 *leaf = NULL;

        *chains = 0;
        use_dir = (mode == MODE_MODERN_VFY_DIR);

        if (!use_dir && !certs_from_file(roots_file, &roots, 1))
                errx(1, "failed to load roots from '%s'", roots_file);
        if (!certs_from_file(bundle_file, &bundle, 1))
                errx(1, "failed to load bundle from '%s'", bundle_file);
        if (!certs_from_file(bundle_file, &bundle, 0))
                errx(1, "failed to load bundle from '%s'", bundle_file2);
        if (sk_X509_num(bundle) < 1)
                errx(1, "not enough certs in bundle");
        leaf = sk_X509_shift(bundle);

        if ((xsc = X509_STORE_CTX_new()) == NULL)
                errx(1, "X509_STORE_CTX");
        if (use_dir && (store = X509_STORE_new()) == NULL)
                errx(1, "X509_STORE");
        if (!X509_STORE_CTX_init(xsc, store, leaf, bundle)) {
                ERR_print_errors_fp(stderr);
                errx(1, "failed to init store context");
        }

        if (use_dir) {
                if (!X509_STORE_load_locations(store, NULL, roots_dir))
                        errx(1, "failed to set by_dir directory of %s", roots_dir);
        }
        if (mode == MODE_LEGACY_VFY)
                X509_STORE_CTX_set_flags(xsc, X509_V_FLAG_LEGACY_VERIFY);
        else
                X509_VERIFY_PARAM_clear_flags(X509_STORE_CTX_get0_param(xsc),
                    X509_V_FLAG_LEGACY_VERIFY);

        if (verbose)
                X509_STORE_CTX_set_verify_cb(xsc, verify_cert_cb);
        if (!use_dir)
                X509_STORE_CTX_set0_trusted_stack(xsc, roots);

        if (X509_verify_cert(xsc) == 1) {
                *chains = 1; /* XXX */
                goto done;
        }

        verify_err = X509_STORE_CTX_get_error(xsc);
        if (verify_err == 0)
                errx(1, "Error unset on failure!");

        fprintf(stderr, "failed to verify at %d: %s\n",
            X509_STORE_CTX_get_error_depth(xsc),
            X509_verify_cert_error_string(verify_err));

 done:
        sk_X509_pop_free(roots, X509_free);
        sk_X509_pop_free(bundle, X509_free);
        X509_STORE_free(store);
        X509_STORE_CTX_free(xsc);
        X509_free(leaf);
}

struct verify_cert_test {
        const char *id;
        int want_chains;
        int failing;
        int depth;
        int error;
};

struct verify_cert_test verify_cert_tests[] = {
        {
                .id = "1a",
                .want_chains = 0,
                .depth = 0,
                .error = X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY,
        },
        {
                .id = "2a",
                .want_chains = 0,
                .depth = 1,
                .error = X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY,
        },
        {
                .id = "2c",
                .want_chains = 0,
                .depth = 2,
                .error = X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN,
        },
};

#define N_VERIFY_CERT_TESTS \
    (sizeof(verify_cert_tests) / sizeof(*verify_cert_tests))

static int
verify_cert_test(const char *certs_path, int mode)
{
        char *roots_file, *bundle_file, *bundle_file2, *roots_dir;
        struct verify_cert_test *vct;
        int failed = 0;
        int chains;
        size_t i;

        for (i = 0; i < N_VERIFY_CERT_TESTS; i++) {
                vct = &verify_cert_tests[i];

                if (asprintf(&roots_file, "/etc/ssl/cert.pem") == -1)
                        errx(1, "asprintf");
                if (asprintf(&bundle_file, "%s/%s/bundle.pem", certs_path,
                    vct->id) == -1)
                        errx(1, "asprintf");
                if (asprintf(&bundle_file2, "%s/%s/roots.pem", certs_path,
                    vct->id) == -1)
                        errx(1, "asprintf");
                if (asprintf(&roots_dir, "./%s/roots", vct->id) == -1)
                        errx(1, "asprintf");

                fprintf(stderr, "== Test %zu (%s)\n", i, vct->id);
                fprintf(stderr, "== depth %d\n", vct->depth);
                fprintf(stderr, "== error %d\n", vct->error);
                expected_depth = vct->depth;
                expected_error = vct->error;
                verify_cert(roots_dir, roots_file, bundle_file, bundle_file2, &chains, mode);
                if (chains == 0 && vct->want_chains == 0) {
                        if (seen_error != expected_error) {
                                fprintf(stderr, "FAIL: expected error %d, got %d\n",
                                    seen_error, expected_error);
                                failed |= 1;
                        }
                        if (seen_depth != expected_depth) {
                                fprintf(stderr, "FAIL: expected depth %d, got %d\n",
                                    seen_depth, expected_depth);
                                failed |= 1;
                        }
                }

                if ((mode == MODE_VERIFY && chains == vct->want_chains) ||
                    (chains == 0 && vct->want_chains == 0) ||
                    (chains == 1 && vct->want_chains > 0)) {
                        fprintf(stderr, "INFO: Succeeded with %d chains%s\n",
                            chains, vct->failing ? " (legacy failure)" : "");
                        if (mode == MODE_LEGACY_VFY && vct->failing)
                                failed |= 1;
                } else {
                        fprintf(stderr, "FAIL: Failed with %d chains%s\n",
                            chains, vct->failing ? " (legacy failure)" : "");
                        if (!vct->failing)
                                failed |= 1;
                }
                fprintf(stderr, "\n");

                free(roots_file);
                free(bundle_file);
                free(bundle_file2);
                free(roots_dir);
        }

        return failed;
}

int
main(int argc, char **argv)
{
        int failed = 0;

        if (argc != 2) {
                fprintf(stderr, "usage: %s <certs_path>\n", argv[0]);
                exit(1);
        }

        fprintf(stderr, "\n\nTesting legacy x509_vfy\n");
        failed |= verify_cert_test(argv[1], MODE_LEGACY_VFY);
        fprintf(stderr, "\n\nTesting modern x509_vfy\n");
        failed |= verify_cert_test(argv[1], MODE_MODERN_VFY);

        return (failed);
}