#include <assert.h>

#include <setjmp.h>

#include <unistd.h>

#include <sys/mman.h>

#include <sepol/debug.h>

#include <sepol/kernel_to_cil.h>

#include <sepol/kernel_to_conf.h>

#include <sepol/module_to_cil.h>

#include <sepol/policydb/policydb.h>

#include <sepol/policydb/hierarchy.h>

#include <sepol/policydb/expand.h>

#include <sepol/policydb/link.h>

#include "module_compiler.h"

#include "queue.h"

extern int policydb_validate(sepol_handle_t *handle, const policydb_t *p);

extern int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);

extern int mlspol;

extern policydb_t *policydbp;

extern queue_t id_queue;

extern unsigned int policydb_errors;

extern int yynerrs;

extern FILE *yyin;

extern void init_parser(int pass, const char *input_name);

extern int yyparse(void);

extern void yyrestart(FILE *);

extern int yylex_destroy(void);

jmp_buf fuzzing_pre_parse_stack_state;

// Set to 1 for verbose libsepol logging

#define VERBOSE 0

static ssize_t full_write(int fd, const void *buf, size_t count)

{

  ssize_t written = 0;

  while (count > 0) {

    ssize_t ret = write(fd, buf, count);

    if (ret < 0) {

      if (errno == EINTR)

        continue;

      return ret;

    }

    if (ret == 0)

      break;

    written += ret;

    buf = (const unsigned char *)buf + (size_t)ret;

    count -= (size_t)ret;

  }

  return written;

}

static int read_source_policy(policydb_t *p, const uint8_t *data, size_t size)

{

  int fd, rc;

  ssize_t wr;

  fd = memfd_create("fuzz-input", MFD_CLOEXEC);

  if (fd < 0)

    return -1;

  wr = full_write(fd, data, size);

  if (wr < 0 || (size_t)wr != size) {

    close(fd);

    return -1;

  }

  fsync(fd);

  yynerrs = 0;

  yyin = fdopen(fd, "r");

  if (!yyin) {

    close(fd);

    return -1;

  }

  rewind(yyin);

  id_queue = queue_create();

  if (id_queue == NULL) {

    fclose(yyin);

    yylex_destroy();

    return -1;

  }

  policydbp = p;

  mlspol = p->mls;

  init_parser(1, "fuzz-input-1");

  if (setjmp(fuzzing_pre_parse_stack_state) != 0) {

    queue_destroy(id_queue);

    fclose(yyin);

    yylex_destroy();

    return -1;

  }

  rc = yyparse();

  // TODO: drop global variable policydb_errors if proven to be redundant

  assert(rc || !policydb_errors);

  if (rc || policydb_errors) {

    queue_destroy(id_queue);

    fclose(yyin);

    yylex_destroy();

    return -1;

  }

  rewind(yyin);

  init_parser(2, "fuzz-input-2");

  yyrestart(yyin);

  rc = yyparse();

  assert(rc || !policydb_errors);

  if (rc || policydb_errors) {

    queue_destroy(id_queue);

    fclose(yyin);

    yylex_destroy();

    return -1;

  }

  queue_destroy(id_queue);

  fclose(yyin);

  yylex_destroy();

  return 0;

}

static int write_binary_policy(FILE *outfp, policydb_t *p)

{

  struct policy_file pf;

  policy_file_init(&pf);

  pf.type = PF_USE_STDIO;

  pf.fp = outfp;

  return policydb_write(p, &pf);

}

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)

{

  policydb_t parsepolicydb = {};

  policydb_t kernpolicydb = {};

  policydb_t *finalpolicydb;

  sidtab_t sidtab = {};

  FILE *devnull = NULL;

  int mls, platform, policyvers;

  sepol_debug(VERBOSE);

  /*

   * Take the first byte whether to generate a SELinux or Xen policy,

   * the second byte whether to parse as MLS policy,

   * and the second byte as policy version.

   */

  if (size < 3)

    return 0;

  switch (data[0]) {

  case 'S':

    platform = SEPOL_TARGET_SELINUX;

    break;

  case 'X':

    platform = SEPOL_TARGET_XEN;

    break;

  default:

    return 0;

  }

  switch (data[1]) {

  case '0':

    mls = 0;

    break;

  case '1':

    mls = 1;

    break;

  default:

    return 0;

  }

  static_assert(0x7F - 'A' >= POLICYDB_VERSION_MAX, "Max policy version should be representable");

  policyvers = data[2] - 'A';

  if (policyvers < POLICYDB_VERSION_MIN || policyvers > POLICYDB_VERSION_MAX)

    return 0;

  data += 3;

  size -= 3;

  if (policydb_init(&parsepolicydb))

    goto exit;

  parsepolicydb.policy_type = POLICY_BASE;

  parsepolicydb.mls = mls;

  parsepolicydb.handle_unknown = DENY_UNKNOWN;

  parsepolicydb.policyvers = policyvers;

  policydb_set_target_platform(&parsepolicydb, platform);

  if (read_source_policy(&parsepolicydb, data, size))

    goto exit;

  if (parsepolicydb.policy_type == POLICY_BASE) {

    if (link_modules(NULL, &parsepolicydb, NULL, 0, VERBOSE))

      goto exit;

    if (policydb_init(&kernpolicydb))

      goto exit;

    if (expand_module(NULL, &parsepolicydb, &kernpolicydb, VERBOSE, /*check_assertions=*/0))

      goto exit;

    (void) check_assertions(NULL, &kernpolicydb, kernpolicydb.global->branch_list->avrules);

    (void) hierarchy_check_constraints(NULL, &kernpolicydb);

    kernpolicydb.policyvers = policyvers;

    assert(kernpolicydb.policy_type     == POLICY_KERN);

    assert(kernpolicydb.handle_unknown  == SEPOL_DENY_UNKNOWN);

    assert(kernpolicydb.mls             == mls);

    assert(kernpolicydb.target_platform == platform);

    finalpolicydb = &kernpolicydb;

  } else {

    assert(parsepolicydb.policy_type     == POLICY_MOD);

    assert(parsepolicydb.handle_unknown  == SEPOL_DENY_UNKNOWN);

    assert(parsepolicydb.mls             == mls);

    assert(parsepolicydb.target_platform == platform);

    finalpolicydb = &parsepolicydb;

  }

  if (policydb_load_isids(finalpolicydb, &sidtab))

    goto exit;

  if (finalpolicydb->policy_type == POLICY_KERN && policydb_optimize(finalpolicydb))

    goto exit;

  if (policydb_sort_ocontexts(finalpolicydb))

    goto exit;

  if (policydb_validate(NULL, finalpolicydb))

    /* never generate an invalid policy */

    abort();

  devnull = fopen("/dev/null", "we");

  if (devnull == NULL)

    goto exit;

  if (write_binary_policy(devnull, finalpolicydb))

    abort();

  if (finalpolicydb->policy_type == POLICY_KERN && sepol_kernel_policydb_to_conf(devnull, finalpolicydb))

    abort();

  if (finalpolicydb->policy_type == POLICY_KERN && sepol_kernel_policydb_to_cil(devnull, finalpolicydb))

    abort();

  if (finalpolicydb->policy_type == POLICY_MOD && sepol_module_policydb_to_cil(devnull, finalpolicydb, /*linked=*/0))

    abort();

exit:

  if (devnull != NULL)

    fclose(devnull);

  sepol_sidtab_destroy(&sidtab);

  policydb_destroy(&kernpolicydb);

  policydb_destroy(&parsepolicydb);

  id_queue = NULL;

  policydbp = NULL;

  module_compiler_reset();

  /* Non-zero return values are reserved for future use. */

  return 0;

}