/src/selinux/libsepol/cil/src/cil_deny.c

Source
/*
 * This file is public domain software, i.e. not copyrighted.
 *
 * Warranty Exclusion
 * ------------------
 * You agree that this software is a non-commercially developed program
 * that may contain "bugs" (as that term is used in the industry) and
 * that it may not function as intended. The software is licensed
 * "as is". NSA makes no, and hereby expressly disclaims all, warranties,
 * express, implied, statutory, or otherwise with respect to the software,
 * including noninfringement and the implied warranties of merchantability
 * and fitness for a particular purpose.
 *
 * Limitation of Liability
 *-----------------------
 * In no event will NSA be liable for any damages, including loss of data,
 * lost profits, cost of cover, or other special, incidental, consequential,
 * direct or indirect damages arising from the software or the use thereof,
 * however caused and on any theory of liability. This limitation will apply
 * even if NSA has been advised of the possibility of such damage. You
 * acknowledge that this is a reasonable allocation of risk.
 *
 * Original author: James Carter
 */

#include <sepol/policydb/ebitmap.h>

#include "cil_internal.h"
#include "cil_find.h"
#include "cil_flavor.h"
#include "cil_list.h"
#include "cil_strpool.h"
#include "cil_log.h"
#include "cil_symtab.h"
#include "cil_build_ast.h"
#include "cil_copy_ast.h"
#include "cil_deny.h"

#define CIL_DENY_ATTR_PREFIX "deny_rule_attr"

/*
 * A deny rule is like a neverallow rule, except that permissions are
 * removed rather than an error reported.
 *
 * (allow S1 T1 P1)
 * (deny  S2 T2 P2)
 *
 * First, write the allow rule with all of the permissions not in the deny rule
 * P3 = P1 and not P2
 * (allow S1 T1 P3)
 *
 * Obviously, the rule is only written if P3 is not an empty list. This goes
 * for the rest of the rules as well--they are only written if the source and
 * target exist.
 *
 * The remaining rules will only involve the common permissions
 * P4 = P1 and P2
 *
 * Next, write the allow rule for any types in S1 that are not in S2
 * S3 = S1 and not S2
 * (allow S3 T1 P4)
 *
 * Finally, write any allow rules needed to cover the types in T1 that are
 * not in T2. Since, T1 and T2 might be "self", "notself", or "other", this
 * requires more complicated handling. Any rule with "self" will not match
 * a rule with either "notself" or "other".
 *
 * if (T1 is self and T2 is self) or (T1 is notself and T2 is notself) then
 *   Nothing more needs to be done.
 *
 * The rest of the rules will depend on the intersection of S1 and S2
 * which cannot be the empty set since the allow and deny rules match.
 * S4 = S1 and S2
 *
 * if T1 is notself or T1 is other or T2 is notself or T2 is other then
 *   if T1 is notself then
 *     if T2 is other then
 *       T = ALL and not S2
 *       (allow S4 T P4)
 *     else [T2 is not self, notself, or other]
 *       S5 = S4 and not T2
 *       S6 = S4 and T2
 *       TA = ALL and not T2
 *       TB = TA and not S4
 *       (allow S6 TA P4)
 *       (allow S5 TB P4)
 *       if cardinality(S5) > 1 then
 *         (allow S5 other P4)
 *   else if T1 is other then
 *     (allow S3 S4 P4)
 *     if T2 is notself then
 *       [Nothing else is needed]
 *     else if T2 is other then
 *       (allow S4 S3 P4)
 *     else [T2 is not self, notself, or other]
 *       S5 = S4 and not T2
 *       S6 = S4 and T2
 *       TC = S1 and not T2
 *       TD = S3 and not T2
 *       (allow S6 TC P4)
 *       (allow S5 TD P4)
 *       if cardinality(S5) > 1 then
 *         (allow S5 other P4)
 *   else [T1 is not self, notself, or other]
 *     S8 = S4 and T1
 *     (allow S8 self P4)
 *     if T2 is notself then
 *       [Nothing else is needed]
 *     else [T2 is other]
 *       T = T1 and not S2
 *       (allow S4 T P4)
 * else [Neither T1 nor T2 are notself or other]
 *   if T1 is self and T2 is not self then
 *     S5 = S4 and not T2
 *     (allow S5 self P4)
 *   else if T1 is not self and T2 is self then
 *     S7 = S4 and not T1
 *     S8 = S4 and T1
 *     T8 = T1 and not S4
 *     (allow S7 T1 P4)
 *     (allow S8 T8 P4)
 *     if cardinality(S8) > 1 then
 *       (allow S8 other P4)
 *   else [Neither T1 nor T2 is self]
 *     T3 = T1 and not T2
 *     (allow S4 T3 P4)
 */

static int cil_perm_match(const struct cil_perm *p1, const struct cil_list *pl2)
{
  struct cil_list_item *curr;

  cil_list_for_each(curr, pl2) {
    struct cil_perm *p = curr->data;
    if (p == p1) {
      return CIL_TRUE;
    }
  }
  return CIL_FALSE;
}

static int cil_class_perm_match(const struct cil_class *c1, const struct cil_perm *p1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  cil_list_for_each(curr, cpl2) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *cp = curr->data;
      if (FLAVOR(cp->class) == CIL_CLASS) {
        if (cp->class == c1) {
          if (cil_perm_match(p1, cp->perms)) {
            return CIL_TRUE;
          }
        }
      } else { /* MAP */
        struct cil_list_item *p;
        cil_list_for_each(p, cp->perms) {
          struct cil_perm *cmp = p->data;
          if (cil_class_perm_match(c1, p1, cmp->classperms)) {
            return CIL_TRUE;
          }
        }
      }
    } else { /* SET */
      struct cil_classperms_set *cp_set = curr->data;
      struct cil_classpermission *cp = cp_set->set;
      if (cil_class_perm_match(c1, p1, cp->classperms)) {
        return CIL_TRUE;
      }
    }
  }
  return CIL_FALSE;
}

static int cil_classperms_match_any(const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  cil_list_for_each(curr, cp1->perms) {
    struct cil_perm *perm = curr->data;
    if (cil_class_perm_match(cp1->class, perm, cpl2)) {
      return CIL_TRUE;
    }
  }
  return CIL_FALSE;
}

int cil_classperms_list_match_any(const struct cil_list *cpl1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  if (!cpl1 || !cpl2) {
    return (!cpl1 && !cpl2) ? CIL_TRUE : CIL_FALSE;
  }

  cil_list_for_each(curr, cpl1) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *cp = curr->data;
      if (FLAVOR(cp->class) == CIL_CLASS) {
        if (cil_classperms_match_any(cp, cpl2)) {
          return CIL_TRUE;
        }
      } else { /* MAP */
        struct cil_list_item *p;
        cil_list_for_each(p, cp->perms) {
          struct cil_perm *cmp = p->data;
          if (cil_classperms_list_match_any(cmp->classperms, cpl2)) {
            return CIL_TRUE;
          }
        }
      }
    } else { /* SET */
      struct cil_classperms_set *cp_set = curr->data;
      struct cil_classpermission *cp = cp_set->set;
      if (cil_classperms_list_match_any(cp->classperms, cpl2)) {
        return CIL_TRUE;
      }
    }
  }
  return CIL_FALSE;
}

static int cil_classperms_match_all(const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  cil_list_for_each(curr, cp1->perms) {
    struct cil_perm *perm = curr->data;
    if (!cil_class_perm_match(cp1->class, perm, cpl2)) {
      return CIL_FALSE;
    }
  }
  return CIL_TRUE;
}

int cil_classperms_list_match_all(const struct cil_list *cpl1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  if (!cpl1 || !cpl2) {
    return (!cpl1 && !cpl2) ? CIL_TRUE : CIL_FALSE;
  }

  cil_list_for_each(curr, cpl1) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *cp = curr->data;
      if (FLAVOR(cp->class) == CIL_CLASS) {
        if (!cil_classperms_match_all(cp, cpl2)) {
          return CIL_FALSE;
        }
      } else { /* MAP */
        struct cil_list_item *p;
        cil_list_for_each(p, cp->perms) {
          struct cil_perm *cmp = p->data;
          if (!cil_classperms_list_match_all(cmp->classperms, cpl2)) {
            return CIL_FALSE;
          }
        }
      }
    } else { /* SET */
      struct cil_classperms_set *cp_set = curr->data;
      struct cil_classpermission *cp = cp_set->set;
      if (!cil_classperms_list_match_all(cp->classperms, cpl2)) {
        return CIL_FALSE;
      }
    }
  }
  return CIL_TRUE;
}

static void cil_classperms_copy(struct cil_classperms **new, const struct cil_classperms *old)
{
  cil_classperms_init(new);
  (*new)->class_str = old->class_str;
  (*new)->class = old->class;
  cil_copy_list(old->perm_strs, &(*new)->perm_strs);
  cil_copy_list(old->perms, &(*new)->perms);
}

static void cil_classperms_set_copy(struct cil_classperms_set **new, const struct cil_classperms_set *old)
{
  cil_classperms_set_init(new);
  (*new)->set_str = old->set_str;
  (*new)->set = old->set;
}

void cil_classperms_list_copy(struct cil_list **new, const struct cil_list *old)
{
  struct cil_list_item *curr;

  if (!new) {
    return;
  }

  if (!old) {
    *new = NULL;
    return;
  }

  cil_list_init(new, CIL_LIST);

  cil_list_for_each(curr, old) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *new_cp;
      cil_classperms_copy(&new_cp, curr->data);
      cil_list_append(*new, CIL_CLASSPERMS, new_cp);
    } else { /* SET */
      struct cil_classperms_set *new_cps;
      cil_classperms_set_copy(&new_cps, curr->data);
      cil_list_append(*new, CIL_CLASSPERMS_SET, new_cps);
    }
  }

  if (cil_list_is_empty(*new)) {
    cil_list_destroy(new, CIL_FALSE);
  }
}

/* Append cp1 and cpl2 to result */
static void cil_classperms_and(struct cil_list **result, const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_classperms *new_cp = NULL;
  struct cil_list_item *curr;

  if (cil_classperms_match_all(cp1, cpl2)) {
    cil_classperms_copy(&new_cp, cp1);
    cil_list_append(*result, CIL_CLASSPERMS, new_cp);
    return;
  }

  cil_list_for_each(curr, cp1->perms) {
    struct cil_perm *perm = curr->data;
    if (cil_class_perm_match(cp1->class, perm, cpl2)) {
      if (new_cp == NULL) {
        cil_classperms_init(&new_cp);
        new_cp->class_str = cp1->class_str;
        new_cp->class = cp1->class;
        cil_list_init(&new_cp->perm_strs, CIL_PERM);
        cil_list_init(&new_cp->perms, CIL_PERM);
        cil_list_append(*result, CIL_CLASSPERMS, new_cp);
      }
      cil_list_append(new_cp->perm_strs, CIL_STRING, perm->datum.fqn);
      cil_list_append(new_cp->perms, CIL_DATUM, perm);
    }
  }
}

/* Append cp1 and cpl2 to result */
static void cil_classperms_map_and(struct cil_list **result, const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_classperms *new_cp = NULL;
  struct cil_list_item *p;

  cil_list_for_each(p, cp1->perms) {
    struct cil_perm *map_perm = p->data;
    if (cil_classperms_list_match_all(map_perm->classperms, cpl2)) {
      if (new_cp == NULL) {
        cil_classperms_init(&new_cp);
        new_cp->class_str = cp1->class_str;
        new_cp->class = cp1->class;
        cil_list_init(&new_cp->perm_strs, CIL_PERM);
        cil_list_init(&new_cp->perms, CIL_PERM);
        cil_list_append(*result, CIL_CLASSPERMS, new_cp);
      }
      cil_list_append(new_cp->perm_strs, CIL_STRING, map_perm->datum.fqn);
      cil_list_append(new_cp->perms, CIL_DATUM, map_perm);
    } else {
      struct cil_list *new_cpl = NULL;
      cil_classperms_list_and(&new_cpl, map_perm->classperms, cpl2);
      if (new_cpl) {
        struct cil_list_item *i;
        cil_list_for_each(i, new_cpl) {
          cil_list_append(*result, i->flavor, i->data);
        }
        cil_list_destroy(&new_cpl, CIL_FALSE);
      }
    }
  }
}

/* Append cps1 and cpl2 to result */
static void cil_classperms_set_and(struct cil_list **result, const struct cil_classperms_set *cps1, const struct cil_list *cpl2)
{
  struct cil_classpermission *cp = cps1->set;

  if (cil_classperms_list_match_all(cp->classperms, cpl2)) {
    struct cil_classperms_set *new_cps;
    cil_classperms_set_copy(&new_cps, cps1);
    cil_list_append(*result, CIL_CLASSPERMS_SET, new_cps);
  } else {
    struct cil_list *new_cpl;
    cil_classperms_list_and(&new_cpl, cp->classperms, cpl2);
    if (new_cpl) {
      struct cil_list_item *i;
      cil_list_for_each(i, new_cpl) {
        cil_list_append(*result, i->flavor, i->data);
      }
      cil_list_destroy(&new_cpl, CIL_FALSE);
    }
  }
}

/* result = cpl1 and cpl2 */
void cil_classperms_list_and(struct cil_list **result, const struct cil_list *cpl1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  if (!result) {
    return;
  }

  if (!cpl1 || !cpl2) {
    *result = NULL;
    return;
  }

  if (cil_classperms_list_match_all(cpl1, cpl2)) {
    cil_classperms_list_copy(result, cpl1);
    return;
  }

  cil_list_init(result, CIL_LIST);

  cil_list_for_each(curr, cpl1) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *cp = curr->data;
      if (FLAVOR(cp->class) == CIL_CLASS) {
        cil_classperms_and(result, cp, cpl2);
      } else { /* MAP */
        cil_classperms_map_and(result, cp, cpl2);
      }
    } else { /* SET */
      struct cil_classperms_set *cps = curr->data;
      cil_classperms_set_and(result, cps, cpl2);
    }
  }

  if (cil_list_is_empty(*result)) {
    cil_list_destroy(result, CIL_FALSE);
  }
}

/* Append cp1 and not cpl2 to result */
static void cil_classperms_andnot(struct cil_list **result, const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_classperms *new_cp = NULL;
  struct cil_list_item *curr;

  if (!cil_classperms_match_any(cp1, cpl2)) {
    cil_classperms_copy(&new_cp, cp1);
    cil_list_append(*result, CIL_CLASSPERMS, new_cp);
    return;
  }

  cil_list_for_each(curr, cp1->perms) {
    struct cil_perm *perm = curr->data;
    if (!cil_class_perm_match(cp1->class, perm, cpl2)) {
      if (new_cp == NULL) {
        cil_classperms_init(&new_cp);
        new_cp->class_str = cp1->class_str;
        new_cp->class = cp1->class;
        cil_list_init(&new_cp->perm_strs, CIL_PERM);
        cil_list_init(&new_cp->perms, CIL_PERM);
        cil_list_append(*result, CIL_CLASSPERMS, new_cp);
      }
      cil_list_append(new_cp->perm_strs, CIL_STRING, perm->datum.fqn);
      cil_list_append(new_cp->perms, CIL_DATUM, perm);
    }
  }
}

/* Append cp1 and not cpl2 to result */
static void cil_classperms_map_andnot(struct cil_list **result, const struct cil_classperms *cp1, const struct cil_list *cpl2)
{
  struct cil_classperms *new_cp = NULL;
  struct cil_list_item *p;

  cil_list_for_each(p, cp1->perms) {
    struct cil_perm *map_perm = p->data;
    if (!cil_classperms_list_match_any(map_perm->classperms, cpl2)) {
      if (new_cp == NULL) {
        cil_classperms_init(&new_cp);
        new_cp->class_str = cp1->class_str;
        new_cp->class = cp1->class;
        cil_list_init(&new_cp->perm_strs, CIL_PERM);
        cil_list_init(&new_cp->perms, CIL_PERM);
        cil_list_append(*result, CIL_CLASSPERMS, new_cp);
      }
      cil_list_append(new_cp->perm_strs, CIL_STRING, map_perm->datum.fqn);
      cil_list_append(new_cp->perms, CIL_DATUM, map_perm);
    } else {
      struct cil_list *new_cpl = NULL;
      cil_classperms_list_andnot(&new_cpl, map_perm->classperms, cpl2);
      if (new_cpl) {
        struct cil_list_item *i;
        cil_list_for_each(i, new_cpl) {
          cil_list_append(*result, i->flavor, i->data);
        }
        cil_list_destroy(&new_cpl, CIL_FALSE);
      }
    }
  }
}

/* Append cps1 and not cpl2 to result */
static void cil_classperms_set_andnot(struct cil_list **result, const struct cil_classperms_set *cps1, const struct cil_list *cpl2)
{
  struct cil_classpermission *cp = cps1->set;

  if (!cil_classperms_list_match_any(cp->classperms, cpl2)) {
    struct cil_classperms_set *new_cps;
    cil_classperms_set_copy(&new_cps, cps1);
    cil_list_append(*result, CIL_CLASSPERMS_SET, new_cps);
  } else {
    struct cil_list *new_cpl;
    cil_classperms_list_andnot(&new_cpl, cp->classperms, cpl2);
    if (new_cpl) {
      struct cil_list_item *i;
      cil_list_for_each(i, new_cpl) {
        cil_list_append(*result, i->flavor, i->data);
      }
      cil_list_destroy(&new_cpl, CIL_FALSE);
    }
  }
}

/* result = cpl1 and not cpl2 */
void cil_classperms_list_andnot(struct cil_list **result, const struct cil_list *cpl1, const struct cil_list *cpl2)
{
  struct cil_list_item *curr;

  if (!result) {
    return;
  }

  if (!cpl1) {
    *result = NULL;
    return;
  }

  if (!cpl2 || !cil_classperms_list_match_any(cpl1, cpl2)) {
    cil_classperms_list_copy(result, cpl1);
    return;
  }

  cil_list_init(result, CIL_LIST);

  cil_list_for_each(curr, cpl1) {
    if (curr->flavor == CIL_CLASSPERMS) {
      struct cil_classperms *cp = curr->data;
      if (FLAVOR(cp->class) == CIL_CLASS) {
        cil_classperms_andnot(result, cp, cpl2);
      } else { /* MAP */
        cil_classperms_map_andnot(result, cp, cpl2);
      }
    } else { /* SET */
      struct cil_classperms_set *cps = curr->data;
      cil_classperms_set_andnot(result, cps, cpl2);
    }
  }

  if (cil_list_is_empty(*result)) {
    cil_list_destroy(result, CIL_FALSE);
  }
}

static int cil_datum_cardinality(const struct cil_symtab_datum *d)
{
  if (!d) {
    return 0;
  }
  if (FLAVOR(d) != CIL_TYPEATTRIBUTE) {
    return 1;
  } else {
    struct cil_typeattribute *a = (struct cil_typeattribute *)d;
    return ebitmap_cardinality(a->types);
  }
}

/* result = ALL and not d2 */
static int cil_datum_not(ebitmap_t *result, const struct cil_symtab_datum *d, int max)
{
  int rc = SEPOL_OK;

  if (FLAVOR(d) != CIL_TYPEATTRIBUTE) {
    struct cil_type *t = (struct cil_type *)d;
    ebitmap_t e;

    ebitmap_init(&e);
    rc = ebitmap_set_bit(&e, t->value, 1);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(&e);
      goto exit;
    }

    ebitmap_init(result);
    rc = ebitmap_not(result, &e, max);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(&e);
      ebitmap_destroy(result);
      goto exit;
    }
    ebitmap_destroy(&e);
  } else {
    struct cil_typeattribute *a = (struct cil_typeattribute *)d;

    ebitmap_init(result);
    rc = ebitmap_not(result, a->types, max);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(result);
      goto exit;
    }
  }
exit:
  return rc;
}

/* result = d1 and d2 */
static int cil_datums_and(ebitmap_t *result, const struct cil_symtab_datum *d1, const struct cil_symtab_datum *d2)
{
  int rc = SEPOL_OK;
  enum cil_flavor f1 = FLAVOR(d1);
  enum cil_flavor f2 = FLAVOR(d2);

  if (f1 != CIL_TYPEATTRIBUTE && f2 != CIL_TYPEATTRIBUTE) {
    struct cil_type *t1 = (struct cil_type *)d1;
    struct cil_type *t2 = (struct cil_type *)d2;
    ebitmap_init(result);
    if (t1->value == t2->value) {
      rc = ebitmap_set_bit(result, t1->value, 1);
      if (rc != SEPOL_OK) {
        ebitmap_destroy(result);
        goto exit;
      }
    }
  } else if (f1 == CIL_TYPEATTRIBUTE && f2 != CIL_TYPEATTRIBUTE) {
    struct cil_typeattribute *a1 = (struct cil_typeattribute *)d1;
    struct cil_type *t2 = (struct cil_type *)d2;
    ebitmap_init(result);
    if (ebitmap_get_bit(a1->types, t2->value)) {
      rc = ebitmap_set_bit(result, t2->value, 1);
      if (rc != SEPOL_OK) {
        ebitmap_destroy(result);
        goto exit;
      }
    }
  } else if (f1 != CIL_TYPEATTRIBUTE && f2 == CIL_TYPEATTRIBUTE) {
    struct cil_type *t1 = (struct cil_type *)d1;
    struct cil_typeattribute *a2 = (struct cil_typeattribute *)d2;
    ebitmap_init(result);
    if (ebitmap_get_bit(a2->types, t1->value)) {
      rc = ebitmap_set_bit(result, t1->value, 1);
      if (rc != SEPOL_OK) {
        ebitmap_destroy(result);
        goto exit;
      }
    }
  } else {
    /* Both are attributes */
    struct cil_typeattribute *a1 = (struct cil_typeattribute *)d1;
    struct cil_typeattribute *a2 = (struct cil_typeattribute *)d2;
    rc = ebitmap_and(result, a1->types, a2->types);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(result);
      goto exit;
    }
  }
exit:
  return rc;
}

/* result = d1 and not d2 */
static int cil_datums_andnot(ebitmap_t *result, const struct cil_symtab_datum *d1, const struct cil_symtab_datum *d2)
{
  int rc = SEPOL_OK;
  enum cil_flavor f1 = FLAVOR(d1);
  enum cil_flavor f2 = FLAVOR(d2);

  if (f1 != CIL_TYPEATTRIBUTE && f2 != CIL_TYPEATTRIBUTE) {
    struct cil_type *t1 = (struct cil_type *)d1;
    struct cil_type *t2 = (struct cil_type *)d2;
    ebitmap_init(result);
    if (t1->value != t2->value) {
      rc = ebitmap_set_bit(result, t1->value, 1);
      if (rc != SEPOL_OK) {
        ebitmap_destroy(result);
        goto exit;
      }
    }
  } else if (f1 == CIL_TYPEATTRIBUTE && f2 != CIL_TYPEATTRIBUTE) {
    struct cil_typeattribute *a1 = (struct cil_typeattribute *)d1;
    struct cil_type *t2 = (struct cil_type *)d2;
    rc = ebitmap_cpy(result, a1->types);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    rc = ebitmap_set_bit(result, t2->value, 0);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(result);
      goto exit;
    }
  } else if (f1 != CIL_TYPEATTRIBUTE && f2 == CIL_TYPEATTRIBUTE) {
    struct cil_type *t1 = (struct cil_type *)d1;
    struct cil_typeattribute *a2 = (struct cil_typeattribute *)d2;
    ebitmap_init(result);
    if (!ebitmap_get_bit(a2->types, t1->value)) {
      rc = ebitmap_set_bit(result, t1->value, 1);
      if (rc != SEPOL_OK) {
        ebitmap_destroy(result);
        goto exit;
      }
    }
  } else {
    /* Both are attributes */
    struct cil_typeattribute *a1 = (struct cil_typeattribute *)d1;
    struct cil_typeattribute *a2 = (struct cil_typeattribute *)d2;
    rc = ebitmap_andnot(result, a1->types, a2->types, a1->types->highbit);
    if (rc != SEPOL_OK) {
      ebitmap_destroy(result);
      goto exit;
    }
  }
exit:
  return rc;
}

static size_t num_digits(unsigned n)
{
  size_t num = 1;
  while (n >= 10) {
    n /= 10;
    num++;
  }
  return num;
}

static char *cil_create_new_attribute_name(unsigned num)
{
  char *s1 = NULL;
  char *s2 = NULL;
  size_t len_num = num_digits(num);
  size_t len = strlen(CIL_DENY_ATTR_PREFIX) + 1 + len_num + 1;
  int rc;

  if (len >= CIL_MAX_NAME_LENGTH) {
    cil_log(CIL_ERR, "Name length greater than max name length of %d",
        CIL_MAX_NAME_LENGTH);
    goto exit;
  }

  s1 = cil_malloc(len);
  rc = snprintf(s1, len, "%s_%u", CIL_DENY_ATTR_PREFIX, num);
  if (rc < 0 || (size_t)rc >= len) {
    cil_log(CIL_ERR, "Error creating new attribute name");
    free(s1);
    goto exit;
  }

  s2 = cil_strpool_add(s1);
  free(s1);

exit:
  return s2;
}

static struct cil_list *cil_create_and_expr_list(enum cil_flavor f1, void *v1, enum cil_flavor f2, void *v2)
{
  struct cil_list *expr;

  cil_list_init(&expr, CIL_TYPE);
  cil_list_append(expr, CIL_OP, (void *)CIL_AND);
  cil_list_append(expr, f1, v1);
  cil_list_append(expr, f2, v2);

  return expr;
}

static struct cil_list *cil_create_andnot_expr_list(enum cil_flavor f1, void *v1, enum cil_flavor f2, void *v2)
{
  struct cil_list *expr, *sub_expr;

  cil_list_init(&expr, CIL_TYPE);
  cil_list_append(expr, CIL_OP, (void *)CIL_AND);
  cil_list_append(expr, f1, v1);
  cil_list_init(&sub_expr, CIL_TYPE);
  cil_list_append(sub_expr, CIL_OP, (void *)CIL_NOT);
  cil_list_append(sub_expr, f2, v2);
  cil_list_append(expr, CIL_LIST, sub_expr);

  return expr;
}

static struct cil_tree_node *cil_create_and_insert_node(struct cil_tree_node *prev, enum cil_flavor flavor, void *data)
{
  struct cil_tree_node *new;

  cil_tree_node_init(&new);
  new->parent = prev->parent;
  new->line = prev->line;
  new->hll_offset = prev->hll_offset;
  new->flavor = flavor;
  new->data = data;
  new->next = prev->next;
  prev->next = new;

  return new;
}

static int cil_create_and_insert_attribute_and_set(struct cil_db *db, struct cil_tree_node *prev, struct cil_list *str_expr, struct cil_list *datum_expr, ebitmap_t *types, struct cil_symtab_datum **d)
{
  struct cil_tree_node *attr_node = NULL;
  char *name;
  struct cil_typeattribute *attr = NULL;
  struct cil_tree_node *attrset_node = NULL;
  struct cil_typeattributeset *attrset = NULL;
  symtab_t *symtab = NULL;
  int rc = SEPOL_ERR;

  name = cil_create_new_attribute_name(db->num_types_and_attrs);
  if (!name) {
    goto exit;
  }

  cil_typeattributeset_init(&attrset);
  attrset->attr_str = name;
  attrset->str_expr = str_expr;
  attrset->datum_expr = datum_expr;

  cil_typeattribute_init(&attr);
  cil_list_init(&attr->expr_list, CIL_TYPE);
  cil_list_append(attr->expr_list, CIL_LIST, datum_expr);
  attr->types = types;
  attr->used = CIL_ATTR_AVRULE;
  attr->keep = (ebitmap_cardinality(types) < db->attrs_expand_size) ? CIL_FALSE : CIL_TRUE;

  attr_node = cil_create_and_insert_node(prev, CIL_TYPEATTRIBUTE, attr);
  attrset_node = cil_create_and_insert_node(attr_node, CIL_TYPEATTRIBUTESET, attrset);

  rc = cil_get_symtab(prev->parent, &symtab, CIL_SYM_TYPES);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  rc = cil_symtab_insert(symtab, name, &attr->datum, attr_node);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  db->num_types_and_attrs++;

  *d = &attr->datum;

  return SEPOL_OK;

exit:
  if (attr_node) {
    cil_destroy_typeattribute(attr_node->data); // This will not destroy datum_expr
    free(attr_node);
  }
  if (attrset_node) {
    prev->next = attrset_node->next;
    free(attrset_node);
  }
  return rc;
}

struct attr_symtab_map_data {
  struct cil_symtab_datum *d;
  ebitmap_t *types;
};

static int cil_check_attribute_in_symtab(__attribute__((unused))hashtab_key_t k, hashtab_datum_t d, void *args)
{
  struct attr_symtab_map_data *data = args;

  if (FLAVOR(d) == CIL_TYPEATTRIBUTE) {
    struct cil_typeattribute *attr = (struct cil_typeattribute *)d;
    if (ebitmap_cmp(data->types, attr->types)) {
      data->d = d;
    }
  }
  return SEPOL_OK;
}

static struct cil_symtab_datum *cil_check_for_previously_defined_attribute(struct cil_db *db, ebitmap_t *types, struct cil_symtab_datum *d)
{
  symtab_t *local_symtab, *root_symtab;
  struct attr_symtab_map_data data;
  int rc;

  data.d = NULL;
  data.types = types;

  local_symtab = d->symtab;
  root_symtab = &((struct cil_root *)db->ast->root->data)->symtab[CIL_SYM_TYPES];

  if (local_symtab != root_symtab) {
    rc = cil_symtab_map(local_symtab, cil_check_attribute_in_symtab, &data);
    if (rc != SEPOL_OK) {
      return NULL;
    }
  }

  if (!data.d) {
    rc = cil_symtab_map(root_symtab, cil_check_attribute_in_symtab, &data);
    if (rc != SEPOL_OK) {
      return NULL;
    }
  }

  return data.d;
}

static int cil_create_attribute_all_and_not_d(struct cil_db *db, struct cil_symtab_datum *d, struct cil_symtab_datum **d3)
{
  struct cil_list *str_expr;
  struct cil_list *datum_expr;
  ebitmap_t *types;
  int rc;

  *d3 = NULL;

  if (!d) {
    return SEPOL_ERR;
  }

  str_expr = cil_create_andnot_expr_list(CIL_OP, (void *)CIL_ALL, CIL_STRING, d->fqn);
  datum_expr = cil_create_andnot_expr_list(CIL_OP, (void *)CIL_ALL, CIL_DATUM, d);

  types = cil_malloc(sizeof(*types));
  rc = cil_datum_not(types, d, db->num_types);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  if (ebitmap_is_empty(types)) {
    rc = SEPOL_OK;
    goto exit;
  }

  if (ebitmap_cardinality(types) == 1) {
    unsigned i = ebitmap_highest_set_bit(types);
    *d3 = DATUM(db->val_to_type[i]);
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  *d3 = cil_check_for_previously_defined_attribute(db, types, d);
  if (*d3) {
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  rc = cil_create_and_insert_attribute_and_set(db, NODE(d), str_expr, datum_expr, types, d3);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  return SEPOL_OK;

exit:
  cil_list_destroy(&str_expr, CIL_FALSE);
  cil_list_destroy(&datum_expr, CIL_FALSE);
  free(types);
  return rc;
}

static int cil_create_attribute_d1_and_not_d2(struct cil_db *db, struct cil_symtab_datum *d1, struct cil_symtab_datum *d2, struct cil_symtab_datum **d3)
{
  struct cil_list *str_expr;
  struct cil_list *datum_expr;
  ebitmap_t *types;
  int rc;

  if (!d2) {
    *d3 = d1;
    return SEPOL_OK;
  }

  *d3 = NULL;

  if (!d1 || d1 == d2) {
    return SEPOL_OK;
  }

  str_expr = cil_create_andnot_expr_list(CIL_STRING, d1->fqn, CIL_STRING, d2->fqn);
  datum_expr = cil_create_andnot_expr_list(CIL_DATUM, d1, CIL_DATUM, d2);

  types = cil_malloc(sizeof(*types));
  rc = cil_datums_andnot(types, d1, d2);
  if (rc != SEPOL_OK) {
    goto exit;
  }
  if (ebitmap_is_empty(types)) {
    rc = SEPOL_OK;
    goto exit;
  }

  if (ebitmap_cardinality(types) == 1) {
    unsigned i = ebitmap_highest_set_bit(types);
    *d3 = DATUM(db->val_to_type[i]);
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  *d3 = cil_check_for_previously_defined_attribute(db, types, d1);
  if (*d3) {
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  rc = cil_create_and_insert_attribute_and_set(db, NODE(d1), str_expr, datum_expr, types, d3);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  return SEPOL_OK;

exit:
  cil_list_destroy(&str_expr, CIL_FALSE);
  cil_list_destroy(&datum_expr, CIL_FALSE);
  free(types);
  return rc;
}

static int cil_create_attribute_d1_and_d2(struct cil_db *db, struct cil_symtab_datum *d1, struct cil_symtab_datum *d2, struct cil_symtab_datum **d3)
{
  struct cil_list *str_expr;
  struct cil_list *datum_expr;
  ebitmap_t *types;
  int rc;

  if (d1 == d2) {
    *d3 = d1;
    return SEPOL_OK;
  }

  *d3 = NULL;

  if (!d1 || !d2) {
    return SEPOL_OK;
  }

  str_expr = cil_create_and_expr_list(CIL_STRING, d1->fqn, CIL_STRING, d2->fqn);
  datum_expr = cil_create_and_expr_list(CIL_DATUM, d1, CIL_DATUM, d2);

  types = cil_malloc(sizeof(*types));
  rc = cil_datums_and(types, d1, d2);
  if (rc != SEPOL_OK) {
    goto exit;
  }
  if (ebitmap_is_empty(types)) {
    rc = SEPOL_OK;
    goto exit;
  }

  if (ebitmap_cardinality(types) == 1) {
    unsigned i = ebitmap_highest_set_bit(types);
    *d3 = DATUM(db->val_to_type[i]);
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  *d3 = cil_check_for_previously_defined_attribute(db, types, d1);
  if (*d3) {
    ebitmap_destroy(types);
    rc = SEPOL_OK;
    goto exit;
  }

  rc = cil_create_and_insert_attribute_and_set(db, NODE(d1), str_expr, datum_expr, types, d3);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  return SEPOL_OK;

exit:
  cil_list_destroy(&str_expr, CIL_FALSE);
  cil_list_destroy(&datum_expr, CIL_FALSE);
  free(types);
  return rc;
}

static struct cil_avrule *cil_create_avrule(struct cil_symtab_datum *src, struct cil_symtab_datum *tgt, struct cil_list *classperms)
{
  struct cil_avrule *new;

  cil_avrule_init(&new);
  new->is_extended = CIL_FALSE;
  new->rule_kind = CIL_AVRULE_ALLOWED;
  new->src_str = src->name;
  new->src = src;
  new->tgt_str = tgt->name;
  new->tgt = tgt;
  new->perms.classperms = classperms;

  return new;
}

static struct cil_tree_node *cil_create_and_add_avrule(struct cil_tree_node *curr, struct cil_symtab_datum *src, struct cil_symtab_datum *tgt, struct cil_list *classperms)
{
  struct cil_avrule *new_avrule;
  struct cil_list *new_cp_list;

  if (!src || !tgt) {
    return curr;
  }

  cil_classperms_list_copy(&new_cp_list, classperms);
  new_avrule = cil_create_avrule(src, tgt, new_cp_list);
  return cil_create_and_insert_node(curr, CIL_AVRULE, new_avrule);
}

static int cil_remove_permissions_from_special_rule(struct cil_db *db, struct cil_tree_node *curr, struct cil_symtab_datum *s1, struct cil_symtab_datum *t1, struct cil_symtab_datum *s2, struct cil_symtab_datum *t2, struct cil_list *p4, struct cil_symtab_datum *s3, struct cil_symtab_datum *s4)
{
  int rc;

  if (t1 == DATUM(db->notselftype)) {
    if (t2 == DATUM(db->othertype)) {
      struct cil_symtab_datum *t;
      rc = cil_create_attribute_all_and_not_d(db, s2, &t);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      curr = cil_create_and_add_avrule(curr, s4, t, p4);
    } else {
      struct cil_symtab_datum *s5, *s6, *ta, *tb;
      rc = cil_create_attribute_d1_and_not_d2(db, s4, t2, &s5);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_d1_and_d2(db, s4, t2, &s6);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_all_and_not_d(db, t2, &ta);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_d1_and_not_d2(db, ta, s4, &tb);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      curr = cil_create_and_add_avrule(curr, s6, ta, p4);
      curr = cil_create_and_add_avrule(curr, s5, tb, p4);
      if (cil_datum_cardinality(s5) > 1) {
        curr = cil_create_and_add_avrule(curr, s5, DATUM(db->othertype), p4);
      }
    }
  } else if (t1 == DATUM(db->othertype)) {
    curr = cil_create_and_add_avrule(curr, s3, s4, p4);
    if (t2 == DATUM(db->notselftype)) {
      /* Nothing else is needed */
    } else if (t2 == DATUM(db->othertype)) {
      curr = cil_create_and_add_avrule(curr, s4, s3, p4);
    } else {
      struct cil_symtab_datum *s5, *s6, *tc, *td;
      rc = cil_create_attribute_d1_and_not_d2(db, s4, t2, &s5);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_d1_and_d2(db, s4, t2, &s6);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_d1_and_not_d2(db, s1, t2, &tc);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      rc = cil_create_attribute_d1_and_not_d2(db, s3, t2, &td);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      curr = cil_create_and_add_avrule(curr, s6, tc, p4);
      curr = cil_create_and_add_avrule(curr, s5, td, p4);
      if (cil_datum_cardinality(s5) > 1) {
        curr = cil_create_and_add_avrule(curr, s5, DATUM(db->othertype), p4);
      }
    }
  } else {
    struct cil_symtab_datum *s8;
    rc = cil_create_attribute_d1_and_d2(db, s4, t1, &s8);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    curr = cil_create_and_add_avrule(curr, s8, DATUM(db->selftype), p4);
    if (t2 == DATUM(db->notselftype)) {
      /* Nothing else is needed */
    } else { /* t2 == DATUM(db->othertype) */
      struct cil_symtab_datum *t;
      rc = cil_create_attribute_d1_and_not_d2(db, t1, s2, &t);
      if (rc != SEPOL_OK) {
        goto exit;
      }
      curr = cil_create_and_add_avrule(curr, s4, t, p4);
    }
  }
  return SEPOL_OK;

exit:
  return rc;
}

static int cil_remove_permissions_from_rule(struct cil_db *db, struct cil_tree_node *allow_node, const struct cil_tree_node *deny_node)
{
  struct cil_avrule *allow_rule = allow_node->data;
  struct cil_deny_rule *deny_rule = deny_node->data;
  struct cil_symtab_datum *s1 = allow_rule->src;
  struct cil_symtab_datum *t1 = allow_rule->tgt;
  struct cil_list *p1 = allow_rule->perms.classperms;
  struct cil_symtab_datum *s2 = deny_rule->src;
  struct cil_symtab_datum *t2 = deny_rule->tgt;
  struct cil_list *p2 = deny_rule->classperms;
  struct cil_list *p3 = NULL;
  struct cil_list *p4 = NULL;
  struct cil_symtab_datum *s3, *s4;
  struct cil_tree_node *curr = allow_node;
  int rc;

  cil_classperms_list_andnot(&p3, p1, p2);
  if (!cil_list_is_empty(p3)) {;
    curr = cil_create_and_add_avrule(curr, s1, t1, p3);
  }
  cil_destroy_classperms_list(&p3);
  p3 = NULL;

  cil_classperms_list_and(&p4, p1, p2);
  if (cil_list_is_empty(p4)) {
    cil_tree_log(allow_node, CIL_ERR, "Allow rule did not match deny rule: No matching class and permissions");
    cil_tree_log((struct cil_tree_node *)deny_node, CIL_ERR, "Deny rule");
    rc = SEPOL_ERR;
    goto exit;
  }

  rc = cil_create_attribute_d1_and_not_d2(db, s1, s2, &s3);
  if (rc != SEPOL_OK) {
    goto exit;
  }
  curr = cil_create_and_add_avrule(curr, s3, t1, p4);

  if ((t1 == DATUM(db->selftype) && t2 == DATUM(db->selftype)) ||
    (t1 == DATUM(db->notselftype) && t2 == DATUM(db->notselftype))) {
    /* Nothing more needs to be done */
    rc = SEPOL_OK;
    goto exit;
  }

  rc = cil_create_attribute_d1_and_d2(db, s1, s2, &s4);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  if (t1 == DATUM(db->notselftype) || t1 == DATUM(db->othertype) ||
    t2 == DATUM(db->notselftype) || t2 == DATUM(db->othertype)) {
    rc = cil_remove_permissions_from_special_rule(db, curr, s1, t1, s2, t2, p4, s3, s4);
    goto exit;
  }

  if (t1 == DATUM(db->selftype) && t2 != DATUM(db->selftype)) {
    struct cil_symtab_datum *s5;
    rc = cil_create_attribute_d1_and_not_d2(db, s4, t2, &s5);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    curr = cil_create_and_add_avrule(curr, s5, DATUM(db->selftype), p4);
  } else if (t1 != DATUM(db->selftype) && t2 == DATUM(db->selftype)) {
    struct cil_symtab_datum *s7, *s8, *t8;
    rc = cil_create_attribute_d1_and_not_d2(db, s4, t1, &s7);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    rc = cil_create_attribute_d1_and_d2(db, s4, t1, &s8);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    rc = cil_create_attribute_d1_and_not_d2(db, t1, s4, &t8);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    curr = cil_create_and_add_avrule(curr, s7, t1, p4);
    curr = cil_create_and_add_avrule(curr, s8, t8, p4);
    if (cil_datum_cardinality(s8) > 1) {
      curr = cil_create_and_add_avrule(curr, s8, DATUM(db->othertype), p4);
    }
  } else {
    struct cil_symtab_datum *t3;
    rc = cil_create_attribute_d1_and_not_d2(db, t1, t2, &t3);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    curr = cil_create_and_add_avrule(curr, s4, t3, p4);
  }

exit:
  if (p4) {
    cil_destroy_classperms_list(&p4);
  }
  return rc;
}

static int cil_find_matching_allow_rules(struct cil_list *matching, struct cil_tree_node *start, struct cil_tree_node *deny_node)
{
  struct cil_deny_rule *deny_rule = deny_node->data;
  struct cil_avrule target;

  target.rule_kind = CIL_AVRULE_ALLOWED;
  target.is_extended = CIL_FALSE;
  target.src = deny_rule->src;
  target.tgt = deny_rule->tgt;
  target.perms.classperms = deny_rule->classperms;

  return cil_find_matching_avrule_in_ast(start, CIL_AVRULE, &target, matching, CIL_FALSE);
}

static int cil_process_deny_rule(struct cil_db *db, struct cil_tree_node *start, struct cil_tree_node *deny_node)
{
  struct cil_list *matching;
  struct cil_list_item *item;
  int rc;

  cil_list_init(&matching, CIL_NODE);

  rc = cil_find_matching_allow_rules(matching, start, deny_node);
  if (rc != SEPOL_OK) {
    goto exit;
  }

  cil_list_for_each(item, matching) {
    struct cil_tree_node *allow_node = item->data;
    rc = cil_remove_permissions_from_rule(db, allow_node, deny_node);
    cil_tree_node_remove(allow_node);
    if (rc != SEPOL_OK) {
      goto exit;
    }

  }

exit:
  cil_list_destroy(&matching, CIL_FALSE);
  return rc;
}

static int cil_process_deny_rules(struct cil_db *db, struct cil_tree_node *start, struct cil_list *deny_rules)
{
  struct cil_list_item *item;
  int rc = SEPOL_OK;

  cil_list_for_each(item, deny_rules) {
    struct cil_tree_node *deny_node = item->data;
    rc = cil_process_deny_rule(db, start, deny_node);
    if (rc != SEPOL_OK) {
      goto exit;
    }
    cil_tree_node_remove(deny_node);
  }

exit:
  return rc;
}

static int __cil_find_deny_rules(struct cil_tree_node *node,  uint32_t *finished, void *extra_args)
{
  struct cil_list *deny_rules = extra_args;

  if (node->flavor == CIL_BLOCK) {
    struct cil_block *block = node->data;
    if (block->is_abstract == CIL_TRUE) {
      *finished = CIL_TREE_SKIP_HEAD;
    }
  } else if (node->flavor == CIL_MACRO) {
    *finished = CIL_TREE_SKIP_HEAD;
  } else if (node->flavor == CIL_DENY_RULE) {
    cil_list_append(deny_rules, CIL_DENY_RULE, node);
  }
  return SEPOL_OK;
}

int cil_process_deny_rules_in_ast(struct cil_db *db)
{
  struct cil_tree_node *start;
  struct cil_list *deny_rules;
  int rc = SEPOL_ERR;

  cil_list_init(&deny_rules, CIL_DENY_RULE);

  if (!db) {
    cil_log(CIL_ERR, "No CIL db provided to process deny rules\n");
    goto exit;
  }

  start = db->ast->root;
  rc = cil_tree_walk(start, __cil_find_deny_rules, NULL, NULL, deny_rules);
  if (rc != SEPOL_OK) {
    cil_log(CIL_ERR, "An error occurred while getting deny rules\n");
    goto exit;
  }

  rc = cil_process_deny_rules(db, start, deny_rules);
  if (rc != SEPOL_OK) {
    cil_log(CIL_ERR, "An error occurred while processing deny rules\n");
    goto exit;
  }

exit:
  cil_list_destroy(&deny_rules, CIL_FALSE);
  return rc;
}

Coverage Report

Created: 2026-01-17 06:07