selinux/libsepol/fuzz/binpolicy-fuzzer.c
Christian Göttsche 00cfecf629 libsepol/fuzz: handle empty and non kernel policies
Do not check assertions for policies without any av rules.

Only output kernel policies in traditional and CIL format.

Perform hierarchy constraint checks.

Try to link, expand and output base module policies.

Also rework argument passing of verbose flags to improve debugging
usability.

Reported-by: oss-fuzz (issues 64515, 64531)
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
2023-12-06 13:32:50 -05:00

112 lines
2.4 KiB
C

#include <sepol/debug.h>
#include <sepol/kernel_to_cil.h>
#include <sepol/kernel_to_conf.h>
#include <sepol/policydb/expand.h>
#include <sepol/policydb/hierarchy.h>
#include <sepol/policydb/link.h>
#include <sepol/policydb/policydb.h>
extern int policydb_validate(sepol_handle_t *handle, const policydb_t *p);
extern int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
// set to 1 to enable more verbose libsepol logging
#define VERBOSE 0
static int write_binary_policy(policydb_t *p, FILE *outfp)
{
struct policy_file pf;
policy_file_init(&pf);
pf.type = PF_USE_STDIO;
pf.fp = outfp;
return policydb_write(p, &pf);
}
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
{
policydb_t policydb = {}, out = {};
sidtab_t sidtab = {};
struct policy_file pf;
FILE *devnull = NULL;
sepol_debug(VERBOSE);
policy_file_init(&pf);
pf.type = PF_USE_MEMORY;
pf.data = (char *) data;
pf.len = size;
if (policydb_init(&policydb))
goto exit;
if (policydb_read(&policydb, &pf, VERBOSE))
goto exit;
if (policydb_load_isids(&policydb, &sidtab))
goto exit;
if (policydb.policy_type == POLICY_KERN) {
(void) policydb_optimize(&policydb);
if (policydb_validate(NULL, &policydb) == -1)
abort();
}
if (policydb.global->branch_list)
(void) check_assertions(NULL, &policydb, policydb.global->branch_list->avrules);
(void) hierarchy_check_constraints(NULL, &policydb);
devnull = fopen("/dev/null", "we");
if (!devnull)
goto exit;
if (write_binary_policy(&policydb, devnull))
abort();
if (policydb.policy_type == POLICY_KERN) {
if (sepol_kernel_policydb_to_conf(devnull, &policydb))
abort();
if (sepol_kernel_policydb_to_cil(devnull, &policydb))
abort();
} else if (policydb.policy_type == POLICY_BASE) {
if (link_modules(NULL, &policydb, NULL, 0, VERBOSE))
goto exit;
if (policydb_init(&out))
goto exit;
if (expand_module(NULL, &policydb, &out, VERBOSE, /*check_assertions=*/0))
goto exit;
(void) check_assertions(NULL, &out, out.global->branch_list->avrules);
(void) hierarchy_check_constraints(NULL, &out);
if (write_binary_policy(&out, devnull))
abort();
if (sepol_kernel_policydb_to_conf(devnull, &out))
abort();
if (sepol_kernel_policydb_to_cil(devnull, &out))
abort();
}
exit:
if (devnull != NULL)
fclose(devnull);
policydb_destroy(&out);
policydb_destroy(&policydb);
sepol_sidtab_destroy(&sidtab);
/* Non-zero return values are reserved for future use. */
return 0;
}