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Merge "checkfc: add attribute test"

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This commit is contained in:
Jeffrey Vander Stoep 2015-12-16 03:35:56 +00:00 committed by Gerrit Code Review
commit d48773ab3e
3 changed files with 311 additions and 69 deletions
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4
Android.mk
View file

@ -351,7 +351,7 @@ $(service_contexts.tmp): $(all_svc_files) $(all_svcfiles_with_nl) $(built_nl)
$(LOCAL_BUILT_MODULE): PRIVATE_SEPOLICY := $(built_sepolicy)
$(LOCAL_BUILT_MODULE): $(service_contexts.tmp) $(built_sepolicy) $(HOST_OUT_EXECUTABLES)/checkfc $(ACP)
@mkdir -p $(dir $@)
$(hide) $(HOST_OUT_EXECUTABLES)/checkfc -p $(PRIVATE_SEPOLICY) $<
$(hide) $(HOST_OUT_EXECUTABLES)/checkfc -s $(PRIVATE_SEPOLICY) $<
$(hide) $(ACP) $< $@
built_svc := $(LOCAL_BUILT_MODULE)
@ -375,7 +375,7 @@ $(general_service_contexts.tmp): $(addprefix $(LOCAL_PATH)/, service_contexts)
$(LOCAL_BUILT_MODULE): PRIVATE_SEPOLICY := $(built_general_sepolicy)
$(LOCAL_BUILT_MODULE): $(general_service_contexts.tmp) $(built_general_sepolicy) $(HOST_OUT_EXECUTABLES)/checkfc $(ACP)
@mkdir -p $(dir $@)
$(hide) $(HOST_OUT_EXECUTABLES)/checkfc -p $(PRIVATE_SEPOLICY) $<
$(hide) $(HOST_OUT_EXECUTABLES)/checkfc -s $(PRIVATE_SEPOLICY) $<
$(hide) $(ACP) $< $@
general_service_contexts.tmp :=

10
attributes
View file

@ -3,6 +3,8 @@
#
# All types used for devices.
# On change, update CHECK_FC_ASSERT_ATTRS
# in tools/checkfc.c
attribute dev_type;
# All types used for processes.
@ -19,6 +21,8 @@ attribute domain;
attribute domain_deprecated;
# All types used for filesystems.
# On change, update CHECK_FC_ASSERT_ATTRS
# definition in tools/checkfc.c.
attribute fs_type;
# All types used for context= mounts.
@ -26,6 +30,8 @@ attribute contextmount_type;
# All types used for files that can exist on a labeled fs.
# Do not use for pseudo file types.
# On change, update CHECK_FC_ASSERT_ATTRS
# definition in tools/checkfc.c.
attribute file_type;
# All types used for domain entry points.
@ -53,6 +59,8 @@ attribute netif_type;
attribute port_type;
# All types used for property service
# On change, update CHECK_PC_ASSERT_ATTRS
# definition in tools/checkfc.c.
attribute property_type;
# All properties defined in core SELinux policy. Should not be
@ -69,6 +77,8 @@ attribute app_api_service;
attribute system_api_service;
# All types used for services managed by service_manager.
# On change, update CHECK_SC_ASSERT_ATTRS
# definition in tools/checkfc.c.
attribute service_manager_type;
# All domains that can override MLS restrictions.

366
tools/checkfc.c
View file

@ -1,35 +1,303 @@
#include <getopt.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <sepol/module.h>
#include <sepol/policydb/policydb.h>
#include <sepol/sepol.h>
#include <selinux/selinux.h>
#include <selinux/label.h>
static int nerr;
static const char * const CHECK_FC_ASSERT_ATTRS[] = { "fs_type", "dev_type", "file_type", NULL };
static const char * const CHECK_PC_ASSERT_ATTRS[] = { "property_type", NULL };
static const char * const CHECK_SC_ASSERT_ATTRS[] = { "service_manager_type", NULL };
typedef enum filemode filemode;
enum filemode {
filemode_file_contexts = 0,
filemode_property_contexts,
filemode_service_contexts
};
static struct {
/* policy */
struct {
union {
/* Union these so we don't have to cast */
sepol_policydb_t *sdb;
policydb_t *pdb;
};
sepol_policy_file_t *pf;
sepol_handle_t *handle;
FILE *file;
#define SEHANDLE_CNT 2
struct selabel_handle *sehnd[SEHANDLE_CNT];
} sepolicy;
/* assertions */
struct {
const char * const *attrs; /* for the original set to print on error */
ebitmap_t set; /* the ebitmap representation of the attrs */
} assert;
} global_state;
static const char * const *filemode_to_assert_attrs(filemode mode)
{
switch (mode) {
case filemode_file_contexts:
return CHECK_FC_ASSERT_ATTRS;
case filemode_property_contexts:
return CHECK_PC_ASSERT_ATTRS;
case filemode_service_contexts:
return CHECK_SC_ASSERT_ATTRS;
}
/* die on invalid parameters */
fprintf(stderr, "Error: Invalid mode of operation: %d\n", mode);
exit(1);
}
static int get_attr_bit(policydb_t *policydb, const char *attr_name)
{
struct type_datum *attr = hashtab_search(policydb->p_types.table, (char *)attr_name);
if (!attr) {
fprintf(stderr, "Error: \"%s\" is not defined in this policy.\n", attr_name);
return -1;
}
if (attr->flavor != TYPE_ATTRIB) {
fprintf(stderr, "Error: \"%s\" is not an attribute in this policy.\n", attr_name);
return -1;
}
return attr->s.value - 1;
}
static bool ebitmap_attribute_assertion_init(ebitmap_t *assertions, const char * const attributes[])
{
while (*attributes) {
int bit_pos = get_attr_bit(global_state.sepolicy.pdb, *attributes);
if (bit_pos < 0) {
/* get_attr_bit() logs error */
return false;
}
int err = ebitmap_set_bit(assertions, bit_pos, 1);
if (err) {
fprintf(stderr, "Error: setting bit on assertion ebitmap!\n");
return false;
}
attributes++;
}
return true;
}
static bool is_type_of_attribute_set(policydb_t *policydb, const char *type_name,
ebitmap_t *attr_set)
{
struct type_datum *type = hashtab_search(policydb->p_types.table, (char *)type_name);
if (!type) {
fprintf(stderr, "Error: \"%s\" is not defined in this policy.\n", type_name);
return false;
}
if (type->flavor != TYPE_TYPE) {
fprintf(stderr, "Error: \"%s\" is not a type in this policy.\n", type_name);
return false;
}
ebitmap_t dst;
ebitmap_init(&dst);
/* Take the intersection, if the set is empty, then its a failure */
int rc = ebitmap_and(&dst, attr_set, &policydb->type_attr_map[type->s.value - 1]);
if (rc) {
fprintf(stderr, "Error: Could not perform ebitmap_and: %d\n", rc);
exit(1);
}
bool res = (bool)ebitmap_length(&dst);
ebitmap_destroy(&dst);
return res;
}
static void dump_char_array(FILE *stream, const char * const *strings)
{
const char * const *p = strings;
fprintf(stream, "\"");
while (*p) {
const char *s = *p++;
const char *fmt = *p ? "%s, " : "%s\"";
fprintf(stream, fmt, s);
}
}
static int validate(char **contextp)
{
char *context = *contextp;
if (sepol_check_context(context) < 0) {
nerr++;
return -1;
}
return 0;
bool res;
char *context = *contextp;
sepol_context_t *ctx;
int rc = sepol_context_from_string(global_state.sepolicy.handle, context,
&ctx);
if (rc < 0) {
fprintf(stderr, "Error: Could not allocate context from string");
exit(1);
}
rc = sepol_context_check(global_state.sepolicy.handle,
global_state.sepolicy.sdb, ctx);
if (rc < 0) {
goto out;
}
const char *type_name = sepol_context_get_type(ctx);
uint32_t len = ebitmap_length(&global_state.assert.set);
if (len > 0) {
res = !is_type_of_attribute_set(global_state.sepolicy.pdb, type_name,
&global_state.assert.set);
if (res) {
fprintf(stderr, "Error: type \"%s\" is not of set: ", type_name);
dump_char_array(stderr, global_state.assert.attrs);
fprintf(stderr, "\n");
/* The calls above did not affect rc, so set error before going to out */
rc = -1;
goto out;
}
}
/* Success: Although it should be 0, we explicitly set rc to 0 for clarity */
rc = 0;
out:
sepol_context_free(ctx);
return rc;
}
static void usage(char *name) {
fprintf(stderr, "usage1: %s [-p] sepolicy context_file\n\n", name);
fprintf(stderr, "Parses a context file and checks for syntax errors.\n");
fprintf(stderr, "The context_file is assumed to be a file_contexts file\n");
fprintf(stderr, "unless the -p option is used to indicate the property backend.\n\n");
fprintf(stderr, "usage1: %s [-p|-s] sepolicy context_file\n\n"
"Parses a context file and checks for syntax errors.\n"
"The context_file is assumed to be a file_contexts file\n"
"unless the -p or -s option is used to indicate the property or service backend respectively.\n\n"
fprintf(stderr, "usage2: %s -c file_contexts1 file_contexts2\n\n", name);
fprintf(stderr, "Compares two file contexts files and reports one of subset, equal, superset, or incomparable.\n");
fprintf(stderr, "\n");
"usage2: %s -c file_contexts1 file_contexts2\n\n"
"Compares two file contexts files and reports one of subset, equal, superset, or incomparable.\n\n",
name, name);
exit(1);
}
static void cleanup(void) {
if (global_state.sepolicy.file) {
fclose(global_state.sepolicy.file);
}
if (global_state.sepolicy.sdb) {
sepol_policydb_free(global_state.sepolicy.sdb);
}
if (global_state.sepolicy.pf) {
sepol_policy_file_free(global_state.sepolicy.pf);
}
if (global_state.sepolicy.handle) {
sepol_handle_destroy(global_state.sepolicy.handle);
}
ebitmap_destroy(&global_state.assert.set);
int i;
for (i = 0; i < SEHANDLE_CNT; i++) {
struct selabel_handle *sehnd = global_state.sepolicy.sehnd[i];
if (sehnd) {
selabel_close(sehnd);
}
}
}
static void do_compare_and_die_on_error(struct selinux_opt opts[], unsigned int backend, char *paths[])
{
enum selabel_cmp_result result;
char *result_str[] = { "subset", "equal", "superset", "incomparable" };
int i;
opts[0].value = NULL; /* not validating against a policy when comparing */
for (i = 0; i < SEHANDLE_CNT; i++) {
opts[1].value = paths[i];
global_state.sepolicy.sehnd[i] = selabel_open(backend, opts, 2);
if (!global_state.sepolicy.sehnd[i]) {
fprintf(stderr, "Error: could not load context file from %s\n", paths[i]);
exit(1);
}
}
result = selabel_cmp(global_state.sepolicy.sehnd[0], global_state.sepolicy.sehnd[1]);
printf("%s\n", result_str[result]);
}
static void do_fc_check_and_die_on_error(struct selinux_opt opts[], unsigned int backend, filemode mode,
const char *sepolicy_file, const char *context_file)
{
global_state.sepolicy.file = fopen(sepolicy_file, "r");
if (!global_state.sepolicy.file) {
perror("Error: could not open policy file");
exit(1);
}
global_state.sepolicy.handle = sepol_handle_create();
if (!global_state.sepolicy.handle) {
fprintf(stderr, "Error: could not create policy handle: %s\n", strerror(errno));
exit(1);
}
if (sepol_policy_file_create(&global_state.sepolicy.pf) < 0) {
perror("Error: could not create policy handle");
exit(1);
}
sepol_policy_file_set_fp(global_state.sepolicy.pf, global_state.sepolicy.file);
sepol_policy_file_set_handle(global_state.sepolicy.pf, global_state.sepolicy.handle);
int rc = sepol_policydb_create(&global_state.sepolicy.sdb);
if (rc < 0) {
perror("Error: could not create policy db");
exit(1);
}
rc = sepol_policydb_read(global_state.sepolicy.sdb, global_state.sepolicy.pf);
if (rc < 0) {
perror("Error: could not read file into policy db");
exit(1);
}
global_state.assert.attrs = filemode_to_assert_attrs(mode);
bool ret = ebitmap_attribute_assertion_init(&global_state.assert.set, global_state.assert.attrs);
if (!ret) {
/* error messages logged by ebitmap_attribute_assertion_init() */
exit(1);
}
selinux_set_callback(SELINUX_CB_VALIDATE,
(union selinux_callback)&validate);
opts[1].value = context_file;
global_state.sepolicy.sehnd[0] = selabel_open(backend, opts, 2);
if (!global_state.sepolicy.sehnd[0]) {
fprintf(stderr, "Error: could not load context file from %s\n", context_file);
exit(1);
}
}
int main(int argc, char **argv)
{
struct selinux_opt opts[] = {
@ -40,17 +308,22 @@ int main(int argc, char **argv)
// Default backend unless changed by input argument.
unsigned int backend = SELABEL_CTX_FILE;
FILE *fp;
bool compare = false;
struct selabel_handle *sehnd[2];
char c;
while ((c = getopt(argc, argv, "cph")) != -1) {
filemode mode = filemode_file_contexts;
while ((c = getopt(argc, argv, "cps")) != -1) {
switch (c) {
case 'c':
compare = true;
break;
case 'p':
mode = filemode_property_contexts;
backend = SELABEL_CTX_ANDROID_PROP;
break;
case 's':
mode = filemode_service_contexts;
backend = SELABEL_CTX_ANDROID_PROP;
break;
case 'h':
@ -69,57 +342,16 @@ int main(int argc, char **argv)
usage(argv[0]);
}
atexit(cleanup);
if (compare) {
enum selabel_cmp_result result;
char *result_str[] = { "subset", "equal", "superset", "incomparable" };
int i;
do_compare_and_die_on_error(opts, backend, &(argv[index]));
} else {
/* remaining args are sepolicy file and context file */
char *sepolicy_file = argv[index];
char *context_file = argv[index + 1];
opts[0].value = NULL; /* not validating against a policy when comparing */
for (i = 0; i < 2; i++) {
opts[1].value = argv[index+i];
sehnd[i] = selabel_open(backend, opts, 2);
if (!sehnd[i]) {
fprintf(stderr, "Error loading context file from %s\n", argv[index+i]);
exit(1);
}
}
result = selabel_cmp(sehnd[0], sehnd[1]);
for (i = 0; i < 2; i++)
selabel_close(sehnd[i]);
printf("%s\n", result_str[result]);
exit(0);
do_fc_check_and_die_on_error(opts, backend, mode, sepolicy_file, context_file);
}
// remaining args are sepolicy file and context file
char *sepolicyFile = argv[index];
char *contextFile = argv[index + 1];
fp = fopen(sepolicyFile, "r");
if (!fp) {
perror(sepolicyFile);
exit(1);
}
if (sepol_set_policydb_from_file(fp) < 0) {
fprintf(stderr, "Error loading policy from %s\n", sepolicyFile);
exit(1);
}
selinux_set_callback(SELINUX_CB_VALIDATE,
(union selinux_callback)&validate);
opts[1].value = contextFile;
sehnd[0] = selabel_open(backend, opts, 2);
if (!sehnd[0]) {
fprintf(stderr, "Error loading context file from %s\n", contextFile);
exit(1);
}
if (nerr) {
fprintf(stderr, "Invalid context file found in %s\n", contextFile);
exit(1);
}
exit(0);
}