heartbeat_test.c

/*
 * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*-
 * Unit test for TLS heartbeats.
 *
 * Acts as a regression test against the Heartbleed bug (CVE-2014-0160).
 *
 * Author:  Mike Bland (mbland@acm.org, http://mike-bland.com/)
 * Date:    2014-04-12
 * License: Creative Commons Attribution 4.0 International (CC By 4.0)
 *          http://creativecommons.org/licenses/by/4.0/deed.en_US
 *
 * OUTPUT
 * ------
 * The program returns zero on success. It will print a message with a count
 * of the number of failed tests and return nonzero if any tests fail.
 *
 * It will print the contents of the request and response buffers for each
 * failing test. In a "fixed" version, all the tests should pass and there
 * should be no output.
 *
 * In a "bleeding" version, you'll see:
 *
 *   test_dtls1_heartbleed failed:
 *     expected payload len: 0
 *     received: 1024
 *   sent 26 characters
 *     "HEARTBLEED                "
 *   received 1024 characters
 *     "HEARTBLEED                \xde\xad\xbe\xef..."
 *   ** test_dtls1_heartbleed failed **
 *
 * The contents of the returned buffer in the failing test will depend on the
 * contents of memory on your machine.
 *
 * MORE INFORMATION
 * ----------------
 * http://mike-bland.com/2014/04/12/heartbleed.html
 * http://mike-bland.com/tags/heartbleed.html
 */

#define OPENSSL_UNIT_TEST

#include "../ssl/ssl_locl.h"

#include "testutil.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if !defined(OPENSSL_NO_HEARTBEATS) && !defined(OPENSSL_NO_UNIT_TEST)

/* As per https://tools.ietf.org/html/rfc6520#section-4 */
# define MIN_PADDING_SIZE        16

/* Maximum number of payload characters to print as test output */
# define MAX_PRINTABLE_CHARACTERS        1024

typedef struct heartbeat_test_fixture {
    SSL_CTX *ctx;
    SSL *s;
    const char *test_case_name;
    int (*process_heartbeat) (SSL *s, unsigned char *p, unsigned int length);
    unsigned char *payload;
    int sent_payload_len;
    int expected_return_value;
    int return_payload_offset;
    int expected_payload_len;
    const char *expected_return_payload;
} HEARTBEAT_TEST_FIXTURE;

static HEARTBEAT_TEST_FIXTURE set_up(const char *const test_case_name,
                                     const SSL_METHOD *meth)
{
    HEARTBEAT_TEST_FIXTURE fixture;
    int setup_ok = 1;
    memset(&fixture, 0, sizeof(fixture));
    fixture.test_case_name = test_case_name;

    fixture.ctx = SSL_CTX_new(meth);
    if (!fixture.ctx) {
        fprintf(stderr, "Failed to allocate SSL_CTX for test: %s\n",
                test_case_name);
        setup_ok = 0;
        goto fail;
    }

    fixture.s = SSL_new(fixture.ctx);
    if (!fixture.s) {
        fprintf(stderr, "Failed to allocate SSL for test: %s\n",
                test_case_name);
        setup_ok = 0;
        goto fail;
    }

    if (!ssl_init_wbio_buffer(fixture.s)) {
        fprintf(stderr, "Failed to set up wbio buffer for test: %s\n",
                test_case_name);
        setup_ok = 0;
        goto fail;
    }

    if (!ssl3_setup_buffers(fixture.s)) {
        fprintf(stderr, "Failed to setup buffers for test: %s\n",
                test_case_name);
        setup_ok = 0;
        goto fail;
    }

    /*
     * Clear the memory for the return buffer, since this isn't automatically
     * zeroed in opt mode and will cause spurious test failures that will
     * change with each execution.
     */
    memset(fixture.s->rlayer.wbuf.buf, 0, fixture.s->rlayer.wbuf.len);

 fail:
    if (!setup_ok) {
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }
    return fixture;
}

static HEARTBEAT_TEST_FIXTURE set_up_dtls(const char *const test_case_name)
{
    HEARTBEAT_TEST_FIXTURE fixture = set_up(test_case_name,
                                            DTLS_server_method());
    fixture.process_heartbeat = dtls1_process_heartbeat;

    /*
     * As per dtls1_get_record(), skipping the following from the beginning
     * of the returned heartbeat message: type-1 byte; version-2 bytes;
     * sequence number-8 bytes; length-2 bytes And then skipping the 1-byte
     * type encoded by process_heartbeat for a total of 14 bytes, at which
     * point we can grab the length and the payload we seek.
     */
    fixture.return_payload_offset = 14;
    return fixture;
}

/* Needed by ssl3_write_bytes() */
static int dummy_handshake(SSL *s)
{
    return 1;
}

static void tear_down(HEARTBEAT_TEST_FIXTURE fixture)
{
    ERR_print_errors_fp(stderr);
    SSL_free(fixture.s);
    SSL_CTX_free(fixture.ctx);
}

static void print_payload(const char *const prefix,
                          const unsigned char *payload, const int n)
{
    const int end = n < MAX_PRINTABLE_CHARACTERS ? n
        : MAX_PRINTABLE_CHARACTERS;
    int i = 0;

    printf("%s %d character%s", prefix, n, n == 1 ? "" : "s");
    if (end != n)
        printf(" (first %d shown)", end);
    printf("\n  \"");

    for (; i != end; ++i) {
        const unsigned char c = payload[i];
        if (isprint(c))
            fputc(c, stdout);
        else
            printf("\\x%02x", c);
    }
    printf("\"\n");
}

static int execute_heartbeat(HEARTBEAT_TEST_FIXTURE fixture)
{
    int result = 0;
    SSL *s = fixture.s;
    unsigned char *payload = fixture.payload;
    unsigned char sent_buf[MAX_PRINTABLE_CHARACTERS + 1];
    int return_value;
    unsigned const char *p;
    int actual_payload_len;

    s->rlayer.rrec.data = payload;
    s->rlayer.rrec.length = strlen((const char *)payload);
    *payload++ = TLS1_HB_REQUEST;
    s2n(fixture.sent_payload_len, payload);

    /*
     * Make a local copy of the request, since it gets overwritten at some
     * point
     */
    memcpy(sent_buf, payload, sizeof(sent_buf));

    return_value = fixture.process_heartbeat(s, s->rlayer.rrec.data,
        s->rlayer.rrec.length);

    if (return_value != fixture.expected_return_value) {
        printf("%s failed: expected return value %d, received %d\n",
               fixture.test_case_name, fixture.expected_return_value,
               return_value);
        result = 1;
    }

    /*
     * If there is any byte alignment, it will be stored in wbuf.offset.
     */
    p = &(s->rlayer.
          wbuf.buf[fixture.return_payload_offset + s->rlayer.wbuf.offset]);
    actual_payload_len = 0;
    n2s(p, actual_payload_len);

    if (actual_payload_len != fixture.expected_payload_len) {
        printf("%s failed:\n  expected payload len: %d\n  received: %d\n",
               fixture.test_case_name, fixture.expected_payload_len,
               actual_payload_len);
        print_payload("sent", sent_buf, strlen((const char *)sent_buf));
        print_payload("received", p, actual_payload_len);
        result = 1;
    } else {
        char *actual_payload =
            OPENSSL_strndup((const char *)p, actual_payload_len);
        if (strcmp(actual_payload, fixture.expected_return_payload) != 0) {
            printf
                ("%s failed:\n  expected payload: \"%s\"\n  received: \"%s\"\n",
                 fixture.test_case_name, fixture.expected_return_payload,
                 actual_payload);
            result = 1;
        }
        OPENSSL_free(actual_payload);
    }

    if (result != 0) {
        printf("** %s failed **\n--------\n", fixture.test_case_name);
    }
    return result;
}

static int honest_payload_size(unsigned char payload_buf[])
{
    /* Omit three-byte pad at the beginning for type and payload length */
    return strlen((const char *)&payload_buf[3]) - MIN_PADDING_SIZE;
}

# define SETUP_HEARTBEAT_TEST_FIXTURE(type)\
  SETUP_TEST_FIXTURE(HEARTBEAT_TEST_FIXTURE, set_up_##type)

# define EXECUTE_HEARTBEAT_TEST()\
  EXECUTE_TEST(execute_heartbeat, tear_down)

static int test_dtls1_not_bleeding()
{
    SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
    /* Three-byte pad at the beginning for type and payload length */
    unsigned char payload_buf[MAX_PRINTABLE_CHARACTERS + 4] =
        "   Not bleeding, sixteen spaces of padding" "                ";
    const int payload_buf_len = honest_payload_size(payload_buf);

    fixture.payload = &payload_buf[0];
    fixture.sent_payload_len = payload_buf_len;
    fixture.expected_return_value = 0;
    fixture.expected_payload_len = payload_buf_len;
    fixture.expected_return_payload =
        "Not bleeding, sixteen spaces of padding";
    EXECUTE_HEARTBEAT_TEST();
}

static int test_dtls1_not_bleeding_empty_payload()
{
    int payload_buf_len;

    SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
    /*
     * Three-byte pad at the beginning for type and payload length, plus a
     * NUL at the end
     */
    unsigned char payload_buf[4 + MAX_PRINTABLE_CHARACTERS];
    memset(payload_buf, ' ', MIN_PADDING_SIZE + 3);
    payload_buf[MIN_PADDING_SIZE + 3] = '\0';
    payload_buf_len = honest_payload_size(payload_buf);

    fixture.payload = &payload_buf[0];
    fixture.sent_payload_len = payload_buf_len;
    fixture.expected_return_value = 0;
    fixture.expected_payload_len = payload_buf_len;
    fixture.expected_return_payload = "";
    EXECUTE_HEARTBEAT_TEST();
}

static int test_dtls1_heartbleed()
{
    SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
    /* Three-byte pad at the beginning for type and payload length */
    unsigned char payload_buf[4 + MAX_PRINTABLE_CHARACTERS] =
        "   HEARTBLEED                ";

    fixture.payload = &payload_buf[0];
    fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
    fixture.expected_return_value = 0;
    fixture.expected_payload_len = 0;
    fixture.expected_return_payload = "";
    EXECUTE_HEARTBEAT_TEST();
}

static int test_dtls1_heartbleed_empty_payload()
{
    SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
    /*
     * Excluding the NUL at the end, one byte short of type + payload length
     * + minimum padding
     */
    unsigned char payload_buf[MAX_PRINTABLE_CHARACTERS + 4];
    memset(payload_buf, ' ', MIN_PADDING_SIZE + 2);
    payload_buf[MIN_PADDING_SIZE + 2] = '\0';

    fixture.payload = &payload_buf[0];
    fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
    fixture.expected_return_value = 0;
    fixture.expected_payload_len = 0;
    fixture.expected_return_payload = "";
    EXECUTE_HEARTBEAT_TEST();
}

static int test_dtls1_heartbleed_excessive_plaintext_length()
{
    SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
    /*
     * Excluding the NUL at the end, one byte in excess of maximum allowed
     * heartbeat message length
     */
    unsigned char payload_buf[SSL3_RT_MAX_PLAIN_LENGTH + 2];
    memset(payload_buf, ' ', sizeof(payload_buf));
    payload_buf[sizeof(payload_buf) - 1] = '\0';

    fixture.payload = &payload_buf[0];
    fixture.sent_payload_len = honest_payload_size(payload_buf);
    fixture.expected_return_value = 0;
    fixture.expected_payload_len = 0;
    fixture.expected_return_payload = "";
    EXECUTE_HEARTBEAT_TEST();
}

# undef EXECUTE_HEARTBEAT_TEST
# undef SETUP_HEARTBEAT_TEST_FIXTURE

int main(int argc, char *argv[])
{
    int result = 0;

    ADD_TEST(test_dtls1_not_bleeding);
    ADD_TEST(test_dtls1_not_bleeding_empty_payload);
    ADD_TEST(test_dtls1_heartbleed);
    ADD_TEST(test_dtls1_heartbleed_empty_payload);
    ADD_TEST(test_dtls1_heartbleed_excessive_plaintext_length);

    result = run_tests(argv[0]);
    ERR_print_errors_fp(stderr);
    return result;
}

#else                           /* OPENSSL_NO_HEARTBEATS */

int main(int argc, char *argv[])
{
    return EXIT_SUCCESS;
}
#endif                          /* OPENSSL_NO_HEARTBEATS */