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libsepol: cil: Add ability to redeclare types[attributes]

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Modify cil_gen_node() to check to see if the cil_db supports multiple
declarations, and if so, to check whether or not the
repeated symbol is eligible to share the existing, already-stored datum. The
only types considered so far are CIL_TYPE and CIL_TYPEATTRIBUTE, both of
which intall empty datums during AST building, so they automatically return
true.

Test: Build policy with multilpe type and attribute declarations, and
without. Policies are binary-identical.

Signed-off-by: Dan Cashman <dcashman@android.com>
Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
This commit is contained in:
Dan Cashman 2017-08-29 09:32:05 -07:00 committed by James Carter
parent 1346746d82
commit fafe4c212b
6 changed files with 57 additions and 8 deletions
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1
libsepol/cil/include/cil/cil.h
View file

@ -50,6 +50,7 @@ extern int cil_userprefixes_to_string(cil_db_t *db, char **out, size_t *size);
extern int cil_selinuxusers_to_string(cil_db_t *db, char **out, size_t *size);
extern int cil_filecons_to_string(cil_db_t *db, char **out, size_t *size);
extern void cil_set_disable_dontaudit(cil_db_t *db, int disable_dontaudit);
extern void cil_set_multiple_decls(cil_db_t *db, int multiple_decls);
extern void cil_set_disable_neverallow(cil_db_t *db, int disable_neverallow);
extern void cil_set_preserve_tunables(cil_db_t *db, int preserve_tunables);
extern int cil_set_handle_unknown(cil_db_t *db, int handle_unknown);

5
libsepol/cil/src/cil.c
View file

@ -1691,6 +1691,11 @@ void cil_set_mls(struct cil_db *db, int mls)
db->mls = mls;
}
void cil_set_multiple_decls(struct cil_db *db, int multiple_decls)
{
db->multiple_decls = multiple_decls;
}
void cil_set_target_platform(struct cil_db *db, int target_platform)
{
db->target_platform = target_platform;

48
libsepol/cil/src/cil_build_ast.c
View file

@ -82,10 +82,33 @@ exit:
return rc;
}
/*
* Determine whether or not multiple declarations of the same key can share a
* datum, given the new datum and the one already present in a given symtab.
*/
int cil_is_datum_multiple_decl(__attribute__((unused)) struct cil_symtab_datum *cur,
__attribute__((unused)) struct cil_symtab_datum *old,
enum cil_flavor f)
{
int rc = CIL_FALSE;
switch (f) {
case CIL_TYPE:
case CIL_TYPEATTRIBUTE:
/* type and typeattribute statements insert empty datums, ret true */
rc = CIL_TRUE;
break;
default:
break;
}
return rc;
}
int cil_gen_node(__attribute__((unused)) struct cil_db *db, struct cil_tree_node *ast_node, struct cil_symtab_datum *datum, hashtab_key_t key, enum cil_sym_index sflavor, enum cil_flavor nflavor)
{
int rc = SEPOL_ERR;
symtab_t *symtab = NULL;
struct cil_symtab_datum *prev;
rc = __cil_verify_name((const char*)key);
if (rc != SEPOL_OK) {
@ -103,15 +126,26 @@ int cil_gen_node(__attribute__((unused)) struct cil_db *db, struct cil_tree_node
if (symtab != NULL) {
rc = cil_symtab_insert(symtab, (hashtab_key_t)key, datum, ast_node);
if (rc == SEPOL_EEXIST) {
cil_log(CIL_ERR, "Re-declaration of %s %s\n",
cil_node_to_string(ast_node), key);
if (cil_symtab_get_datum(symtab, key, &datum) == SEPOL_OK) {
if (sflavor == CIL_SYM_BLOCKS) {
struct cil_tree_node *node = datum->nodes->head->data;
cil_tree_log(node, CIL_ERR, "Previous declaration");
if (!db->multiple_decls ||
cil_symtab_get_datum(symtab, (hashtab_key_t)key, &prev) != SEPOL_OK ||
!cil_is_datum_multiple_decl(datum, prev, nflavor)) {
/* multiple_decls not ok, ret error */
cil_log(CIL_ERR, "Re-declaration of %s %s\n",
cil_node_to_string(ast_node), key);
if (cil_symtab_get_datum(symtab, key, &datum) == SEPOL_OK) {
if (sflavor == CIL_SYM_BLOCKS) {
struct cil_tree_node *node = datum->nodes->head->data;
cil_tree_log(node, CIL_ERR, "Previous declaration");
}
}
goto exit;
}
goto exit;
/* multiple_decls is enabled and works for this datum type, add node */
cil_list_append(prev->nodes, CIL_NODE, ast_node);
ast_node->data = prev;
cil_symtab_datum_destroy(datum);
free(datum);
}
}

1
libsepol/cil/src/cil_internal.h
View file

@ -316,6 +316,7 @@ struct cil_db {
int preserve_tunables;
int handle_unknown;
int mls;
int multiple_decls;
int target_platform;
int policy_version;
};

1
libsepol/src/libsepol.map.in
View file

@ -49,6 +49,7 @@ LIBSEPOL_1.1 {
cil_set_mls;
cil_set_attrs_expand_generated;
cil_set_attrs_expand_size;
cil_set_multiple_decls;
cil_write_policy_conf;
sepol_ppfile_to_module_package;
sepol_module_package_to_cil;

9
secilc/secilc.c
View file

@ -63,6 +63,7 @@ static __attribute__((__noreturn__)) void usage(const char *prog)
printf(" statement if present in the policy\n");
printf(" -D, --disable-dontaudit do not add dontaudit rules to the binary policy\n");
printf(" -P, --preserve-tunables treat tunables as booleans\n");
printf(" -m, --multiple-decls allow some statements to be re-declared\n");
printf(" -N, --disable-neverallow do not check neverallow rules\n");
printf(" -G, --expand-generated Expand and remove auto-generated attributes\n");
printf(" -X, --expand-size <SIZE> Expand type attributes with fewer than <SIZE>\n");
@ -89,6 +90,7 @@ int main(int argc, char *argv[])
int target = SEPOL_TARGET_SELINUX;
int mls = -1;
int disable_dontaudit = 0;
int multiple_decls = 0;
int disable_neverallow = 0;
int preserve_tunables = 0;
int handle_unknown = -1;
@ -108,6 +110,7 @@ int main(int argc, char *argv[])
{"policyversion", required_argument, 0, 'c'},
{"handle-unknown", required_argument, 0, 'U'},
{"disable-dontaudit", no_argument, 0, 'D'},
{"multiple-decls", no_argument, 0, 'm'},
{"disable-neverallow", no_argument, 0, 'N'},
{"preserve-tunables", no_argument, 0, 'P'},
{"output", required_argument, 0, 'o'},
@ -119,7 +122,7 @@ int main(int argc, char *argv[])
int i;
while (1) {
opt_char = getopt_long(argc, argv, "o:f:U:hvt:M:PDNc:GX:", long_opts, &opt_index);
opt_char = getopt_long(argc, argv, "o:f:U:hvt:M:PDmNc:GX:", long_opts, &opt_index);
if (opt_char == -1) {
break;
}
@ -175,6 +178,9 @@ int main(int argc, char *argv[])
case 'D':
disable_dontaudit = 1;
break;
case 'm':
multiple_decls = 1;
break;
case 'N':
disable_neverallow = 1;
break;
@ -223,6 +229,7 @@ int main(int argc, char *argv[])
cil_db_init(&db);
cil_set_disable_dontaudit(db, disable_dontaudit);
cil_set_multiple_decls(db, multiple_decls);
cil_set_disable_neverallow(db, disable_neverallow);
cil_set_preserve_tunables(db, preserve_tunables);
if (handle_unknown != -1) {