PWN-Hunter/android_system_sepolicy
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checkfc: do not die on 0 length fc's

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Checkfc was treating 0 size fc files as a fatal error.
An empty fc file should be treated as "nothing to check"
so long as the -e option is passed.

We add this option, so we don't allow empty file_context
files to pass CTS checking.

Change-Id: Ibca6bd948a13389e10c605d613acc48c5504443e
Signed-off-by: William Roberts <william.c.roberts@intel.com>
This commit is contained in:
William Roberts 2016-01-14 17:06:37 -08:00
parent 5de7574a59
commit 922b4e9522
1 changed files with 27 additions and 5 deletions
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32
tools/checkfc.c
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@ -3,11 +3,14 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sepol/module.h>
#include <sepol/policydb/policydb.h>
#include <sepol/sepol.h>
#include <selinux/selinux.h>
#include <selinux/label.h>
#include <sys/stat.h>
#include <sys/types.h>
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 };
@ -182,10 +185,11 @@ static int validate(char **contextp)
}
static void usage(char *name) {
fprintf(stderr, "usage1: %s [-p|-s] sepolicy context_file\n\n"
fprintf(stderr, "usage1: %s [-p|-s] [-e] 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"
"unless the -p or -s option is used to indicate the property or service backend respectively.\n"
"If -e is specified, then the context_file is allowed to be empty.\n\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",
@ -244,8 +248,22 @@ static void do_compare_and_die_on_error(struct selinux_opt opts[], unsigned int
}
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)
const char *sepolicy_file, const char *context_file, bool allow_empty)
{
struct stat sb;
if (stat(context_file, &sb) < 0) {
perror("Error: could not get stat on file contexts file");
exit(1);
}
if (sb.st_size == 0) {
/* Nothing to check on empty file_contexts file if allowed*/
if (allow_empty) {
return;
}
/* else: We could throw the error here, but libselinux backend will catch it */
}
global_state.sepolicy.file = fopen(sepolicy_file, "r");
if (!global_state.sepolicy.file) {
perror("Error: could not open policy file");
@ -308,16 +326,20 @@ int main(int argc, char **argv)
// Default backend unless changed by input argument.
unsigned int backend = SELABEL_CTX_FILE;
bool allow_empty = false;
bool compare = false;
char c;
filemode mode = filemode_file_contexts;
while ((c = getopt(argc, argv, "cps")) != -1) {
while ((c = getopt(argc, argv, "cpse")) != -1) {
switch (c) {
case 'c':
compare = true;
break;
case 'e':
allow_empty = true;
break;
case 'p':
mode = filemode_property_contexts;
backend = SELABEL_CTX_ANDROID_PROP;
@ -351,7 +373,7 @@ int main(int argc, char **argv)
char *sepolicy_file = argv[index];
char *context_file = argv[index + 1];
do_fc_check_and_die_on_error(opts, backend, mode, sepolicy_file, context_file);
do_fc_check_and_die_on_error(opts, backend, mode, sepolicy_file, context_file, allow_empty);
}
exit(0);
}