#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <sepol/policydb/policydb.h>

#include <sepol/policydb/services.h>

#include "context_internal.h"

#include "debug.h"

#include "context.h"

#include "handle.h"

#include "mls.h"

#include "private.h"

/* ----- Compatibility ---- */

int policydb_context_isvalid(const policydb_t *p, const context_struct_t *c)

{

  return context_is_valid(p, c);

}

int sepol_check_context(const char *context)

{

  return sepol_context_to_sid(context, strlen(context) + 1, NULL);

}

/* ---- End compatibility --- */

/*

 * Return 1 if the fields in the security context

 * structure `c' are valid.  Return 0 otherwise.

 */

int context_is_valid(const policydb_t *p, const context_struct_t *c)

{

  role_datum_t *role;

  user_datum_t *usrdatum;

  ebitmap_t types, roles;

  ebitmap_init(&types);

  ebitmap_init(&roles);

  if (!c->role || c->role > p->p_roles.nprim)

    return 0;

  if (!c->user || c->user > p->p_users.nprim)

    return 0;

  if (!c->type || c->type > p->p_types.nprim)

    return 0;

  if (c->role != OBJECT_R_VAL) {

    /*

     * Role must be authorized for the type.

     */

    role = p->role_val_to_struct[c->role - 1];

    if (!role || !ebitmap_get_bit(&role->cache, c->type - 1))

      /* role may not be associated with type */

      return 0;

    /*

     * User must be authorized for the role.

     */

    usrdatum = p->user_val_to_struct[c->user - 1];

    if (!usrdatum)

      return 0;

    if (!ebitmap_get_bit(&usrdatum->cache, c->role - 1))

      /* user may not be associated with role */

      return 0;

  }

  if (!mls_context_isvalid(p, c))

    return 0;

  return 1;

}

/*

 * Write the security context string representation of

 * the context structure `context' into a dynamically

 * allocated string of the correct size.  Set `*scontext'

 * to point to this string and set `*scontext_len' to

 * the length of the string.

 */

int context_to_string(sepol_handle_t *handle, const policydb_t *policydb,

          const context_struct_t *context, char **result,

          size_t *result_len)

{

  char *scontext = NULL;

  size_t scontext_len = 0;

  char *ptr;

  /* Compute the size of the context. */

  scontext_len +=

    strlen(policydb->p_user_val_to_name[context->user - 1]) + 1;

  scontext_len +=

    strlen(policydb->p_role_val_to_name[context->role - 1]) + 1;

  scontext_len += strlen(policydb->p_type_val_to_name[context->type - 1]);

  scontext_len += mls_compute_context_len(policydb, context);

  /* We must null terminate the string */

  scontext_len += 1;

  /* Allocate space for the context; caller must free this space. */

  scontext = malloc(scontext_len);

  if (!scontext)

    goto omem;

  scontext[scontext_len - 1] = '\0';

  /*

   * Copy the user name, role name and type name into the context.

   */

  ptr = scontext;

  sprintf(ptr, "%s:%s:%s",

    policydb->p_user_val_to_name[context->user - 1],

    policydb->p_role_val_to_name[context->role - 1],

    policydb->p_type_val_to_name[context->type - 1]);

  ptr += strlen(policydb->p_user_val_to_name[context->user - 1]) + 1 +

         strlen(policydb->p_role_val_to_name[context->role - 1]) + 1 +

         strlen(policydb->p_type_val_to_name[context->type - 1]);

  mls_sid_to_context(policydb, context, &ptr);

  *result = scontext;

  *result_len = scontext_len;

  return STATUS_SUCCESS;

omem:

  ERR(handle, "out of memory, could not convert "

        "context to string");

  free(scontext);

  return STATUS_ERR;

}

/*

 * Create a context structure from the given record

 */

int context_from_record(sepol_handle_t *handle, const policydb_t *policydb,

      context_struct_t **cptr, const sepol_context_t *record)

{

  context_struct_t *scontext = NULL;

  user_datum_t *usrdatum;

  role_datum_t *roldatum;

  type_datum_t *typdatum;

  /* Hashtab keys are not constant - suppress warnings */

  char *user = strdup(sepol_context_get_user(record));

  char *role = strdup(sepol_context_get_role(record));

  char *type = strdup(sepol_context_get_type(record));

  const char *mls = sepol_context_get_mls(record);

  scontext = (context_struct_t *)malloc(sizeof(context_struct_t));

  if (!user || !role || !type || !scontext) {

    ERR(handle, "out of memory");

    goto err;

  }

  context_init(scontext);

  /* User */

  usrdatum = (user_datum_t *)hashtab_search(policydb->p_users.table,

              (hashtab_key_t)user);

  if (!usrdatum) {

    ERR(handle, "user %s is not defined", user);

    goto err_destroy;

  }

  scontext->user = usrdatum->s.value;

  /* Role */

  roldatum = (role_datum_t *)hashtab_search(policydb->p_roles.table,

              (hashtab_key_t)role);

  if (!roldatum) {

    ERR(handle, "role %s is not defined", role);

    goto err_destroy;

  }

  scontext->role = roldatum->s.value;

  /* Type */

  typdatum = (type_datum_t *)hashtab_search(policydb->p_types.table,

              (hashtab_key_t)type);

  if (!typdatum || typdatum->flavor == TYPE_ATTRIB) {

    ERR(handle, "type %s is not defined", type);

    goto err_destroy;

  }

  scontext->type = typdatum->s.value;

  /* MLS */

  if (mls && !policydb->mls) {

    ERR(handle, "MLS is disabled, but MLS context \"%s\" found",

        mls);

    goto err_destroy;

  } else if (!mls && policydb->mls) {

    ERR(handle, "MLS is enabled, but no MLS context found");

    goto err_destroy;

  }

  if (mls && (mls_from_string(handle, policydb, mls, scontext) < 0))

    goto err_destroy;

  /* Validity check */

  if (!context_is_valid(policydb, scontext)) {

    if (mls) {

      ERR(handle, "invalid security context: \"%s:%s:%s:%s\"",

          user, role, type, mls);

    } else {

      ERR(handle, "invalid security context: \"%s:%s:%s\"",

          user, role, type);

    }

    goto err_destroy;

  }

  *cptr = scontext;

  free(user);

  free(type);

  free(role);

  return STATUS_SUCCESS;

err_destroy:

  errno = EINVAL;

  context_destroy(scontext);

err:

  free(scontext);

  free(user);

  free(type);

  free(role);

  ERR(handle, "could not create context structure");

  return STATUS_ERR;

}

/*

 * Create a record from the given context structure

 */

int context_to_record(sepol_handle_t *handle, const policydb_t *policydb,

          const context_struct_t *context, sepol_context_t **record)

{

  sepol_context_t *tmp_record = NULL;

  char *mls = NULL;

  if (sepol_context_create(handle, &tmp_record) < 0)

    goto err;

  if (sepol_context_set_user(

        handle, tmp_record,

        policydb->p_user_val_to_name[context->user - 1]) < 0)

    goto err;

  if (sepol_context_set_role(

        handle, tmp_record,

        policydb->p_role_val_to_name[context->role - 1]) < 0)

    goto err;

  if (sepol_context_set_type(

        handle, tmp_record,

        policydb->p_type_val_to_name[context->type - 1]) < 0)

    goto err;

  if (policydb->mls) {

    if (mls_to_string(handle, policydb, context, &mls) < 0)

      goto err;

    if (sepol_context_set_mls(handle, tmp_record, mls) < 0)

      goto err;

  }

  free(mls);

  *record = tmp_record;

  return STATUS_SUCCESS;

err:

  ERR(handle, "could not create context record");

  sepol_context_free(tmp_record);

  free(mls);

  return STATUS_ERR;

}

/*

 * Create a context structure from the provided string.

 */

int context_from_string(sepol_handle_t *handle, const policydb_t *policydb,

      context_struct_t **cptr, const char *con_str,

      size_t con_str_len)

{

  char *con_cpy = NULL;

  sepol_context_t *ctx_record = NULL;

  if (zero_or_saturated(con_str_len)) {

    ERR(handle, "Invalid context length");

    goto err;

  }

  /* sepol_context_from_string expects a NULL-terminated string */

  con_cpy = malloc(con_str_len + 1);

  if (!con_cpy) {

    ERR(handle, "out of memory");

    goto err;

  }

  memcpy(con_cpy, con_str, con_str_len);

  con_cpy[con_str_len] = '\0';

  if (sepol_context_from_string(handle, con_cpy, &ctx_record) < 0)

    goto err;

  /* Now create from the data structure */

  if (context_from_record(handle, policydb, cptr, ctx_record) < 0)

    goto err;

  free(con_cpy);

  sepol_context_free(ctx_record);

  return STATUS_SUCCESS;

err:

  ERR(handle, "could not create context structure");

  free(con_cpy);

  sepol_context_free(ctx_record);

  return STATUS_ERR;

}

int sepol_context_check(sepol_handle_t *handle,

      const sepol_policydb_t *policydb,

      const sepol_context_t *context)

{

  context_struct_t *con = NULL;

  int ret = context_from_record(handle, &policydb->p, &con, context);

  context_destroy(con);

  free(con);

  return ret;

}