#include "fuzz.h"

#include "session.h"

#include "fuzz-wrapfd.h"

#include "debug.h"

#include "runopts.h"

#include "algo.h"

#include "bignum.h"

static const struct dropbear_kex *ecdh[3]; /* 256, 384, 521 */

static struct key_context* keep_newkeys = NULL;

/* number of generated parameters. An arbitrary limit, but will delay startup */

#define NUM_PARAMS 80

static struct kex_ecdh_param *ecdh_params[NUM_PARAMS];

static void setup() __attribute__((constructor));

// Perform initial setup here to avoid hitting timeouts on first run

static void setup() {

  fuzz_common_setup();

  fuzz_svr_setup();

  /* ses gets zeroed by fuzz_set_input */

  keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));

  ecdh[0] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp256");

  ecdh[1] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp384");

  ecdh[2] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp521");

  assert(ecdh[0]);

  assert(ecdh[1]);

  assert(ecdh[2]);

  keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256;

  ses.newkeys = keep_newkeys;

  /* Pre-generate parameters */

  int i;

  for (i = 0; i < NUM_PARAMS; i++) {

    ses.newkeys->algo_kex = ecdh[i % 3];

    ecdh_params[i] = gen_kexecdh_param();

  }

}

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {

  if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {

    return 0;

  }

  m_malloc_set_epoch(1);

  if (setjmp(fuzz.jmp) == 0) {

    /* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply() 

    with DROPBEAR_KEX_ECDH */

    ses.newkeys = keep_newkeys;

    /* random choice of ecdh 256, 384, 521 */

    unsigned char b = buf_getbyte(fuzz.input);

    ses.newkeys->algo_kex = ecdh[b % 3];

    /* Choose from the collection of ecdh params */

    unsigned int e = buf_getint(fuzz.input);

    struct kex_ecdh_param *ecdh_param = ecdh_params[e % NUM_PARAMS];

    buffer * ecdh_qc = buf_getstringbuf(fuzz.input);

    ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS);

    kexecdh_comb_key(ecdh_param, ecdh_qc, svr_opts.hostkey);

    mp_clear(ses.dh_K);

    m_free(ses.dh_K);

    buf_free(ecdh_qc);

    buf_free(ses.hash);

    buf_free(ses.session_id);

    /* kexhashbuf is freed in kexdh_comb_key */

    m_malloc_free_epoch(1, 0);

  } else {

    m_malloc_free_epoch(1, 1);

    TRACE(("dropbear_exit longjmped"))

    /* dropbear_exit jumped here */

  }

  return 0;

}