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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Google LLC.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <test_progs.h>
#include <linux/ring_buffer.h>
#include "ima.skel.h"
#define MAX_SAMPLES 4
static int _run_measured_process(const char *measured_dir, u32 *monitored_pid,
const char *cmd)
{
int child_pid, child_status;
child_pid = fork();
if (child_pid == 0) {
*monitored_pid = getpid();
execlp("./ima_setup.sh", "./ima_setup.sh", cmd, measured_dir,
NULL);
exit(errno);
} else if (child_pid > 0) {
waitpid(child_pid, &child_status, 0);
return WEXITSTATUS(child_status);
}
return -EINVAL;
}
static int run_measured_process(const char *measured_dir, u32 *monitored_pid)
{
return _run_measured_process(measured_dir, monitored_pid, "run");
}
static u64 ima_hash_from_bpf[MAX_SAMPLES];
static int ima_hash_from_bpf_idx;
static int process_sample(void *ctx, void *data, size_t len)
{
if (ima_hash_from_bpf_idx >= MAX_SAMPLES)
return -ENOSPC;
ima_hash_from_bpf[ima_hash_from_bpf_idx++] = *((u64 *)data);
return 0;
}
static void test_init(struct ima__bss *bss)
{
ima_hash_from_bpf_idx = 0;
bss->use_ima_file_hash = false;
bss->enable_bprm_creds_for_exec = false;
bss->enable_kernel_read_file = false;
bss->test_deny = false;
}
void test_test_ima(void)
{
char measured_dir_template[] = "/tmp/ima_measuredXXXXXX";
struct ring_buffer *ringbuf = NULL;
const char *measured_dir;
u64 bin_true_sample;
char cmd[256];
int err, duration = 0;
struct ima *skel = NULL;
skel = ima__open_and_load();
if (CHECK(!skel, "skel_load", "skeleton failed\n"))
goto close_prog;
ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf),
process_sample, NULL, NULL);
if (!ASSERT_OK_PTR(ringbuf, "ringbuf"))
goto close_prog;
err = ima__attach(skel);
if (CHECK(err, "attach", "attach failed: %d\n", err))
goto close_prog;
measured_dir = mkdtemp(measured_dir_template);
if (CHECK(measured_dir == NULL, "mkdtemp", "err %d\n", errno))
goto close_prog;
snprintf(cmd, sizeof(cmd), "./ima_setup.sh setup %s", measured_dir);
err = system(cmd);
if (CHECK(err, "failed to run command", "%s, errno = %d\n", cmd, errno))
goto close_clean;
/*
* Test #1
* - Goal: obtain a sample with the bpf_ima_inode_hash() helper
* - Expected result: 1 sample (/bin/true)
*/
test_init(skel->bss);
err = run_measured_process(measured_dir, &skel->bss->monitored_pid);
if (CHECK(err, "run_measured_process #1", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 1, "num_samples_or_err");
ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
/*
* Test #2
* - Goal: obtain samples with the bpf_ima_file_hash() helper
* - Expected result: 2 samples (./ima_setup.sh, /bin/true)
*/
test_init(skel->bss);
skel->bss->use_ima_file_hash = true;
err = run_measured_process(measured_dir, &skel->bss->monitored_pid);
if (CHECK(err, "run_measured_process #2", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 2, "num_samples_or_err");
ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[1], 0, "ima_hash");
bin_true_sample = ima_hash_from_bpf[1];
/*
* Test #3
* - Goal: confirm that bpf_ima_inode_hash() returns a non-fresh digest
* - Expected result: 2 samples (/bin/true: non-fresh, fresh)
*/
test_init(skel->bss);
err = _run_measured_process(measured_dir, &skel->bss->monitored_pid,
"modify-bin");
if (CHECK(err, "modify-bin #3", "err = %d\n", err))
goto close_clean;
skel->bss->enable_bprm_creds_for_exec = true;
err = run_measured_process(measured_dir, &skel->bss->monitored_pid);
if (CHECK(err, "run_measured_process #3", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 2, "num_samples_or_err");
ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[1], 0, "ima_hash");
ASSERT_EQ(ima_hash_from_bpf[0], bin_true_sample, "sample_equal_or_err");
/* IMA refreshed the digest. */
ASSERT_NEQ(ima_hash_from_bpf[1], bin_true_sample,
"sample_different_or_err");
/*
* Test #4
* - Goal: verify that bpf_ima_file_hash() returns a fresh digest
* - Expected result: 4 samples (./ima_setup.sh: fresh, fresh;
* /bin/true: fresh, fresh)
*/
test_init(skel->bss);
skel->bss->use_ima_file_hash = true;
skel->bss->enable_bprm_creds_for_exec = true;
err = run_measured_process(measured_dir, &skel->bss->monitored_pid);
if (CHECK(err, "run_measured_process #4", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 4, "num_samples_or_err");
ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[1], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[2], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[3], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[2], bin_true_sample,
"sample_different_or_err");
ASSERT_EQ(ima_hash_from_bpf[3], ima_hash_from_bpf[2],
"sample_equal_or_err");
skel->bss->use_ima_file_hash = false;
skel->bss->enable_bprm_creds_for_exec = false;
err = _run_measured_process(measured_dir, &skel->bss->monitored_pid,
"restore-bin");
if (CHECK(err, "restore-bin #3", "err = %d\n", err))
goto close_clean;
/*
* Test #5
* - Goal: obtain a sample from the kernel_read_file hook
* - Expected result: 2 samples (./ima_setup.sh, policy_test)
*/
test_init(skel->bss);
skel->bss->use_ima_file_hash = true;
skel->bss->enable_kernel_read_file = true;
err = _run_measured_process(measured_dir, &skel->bss->monitored_pid,
"load-policy");
if (CHECK(err, "run_measured_process #5", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 2, "num_samples_or_err");
ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
ASSERT_NEQ(ima_hash_from_bpf[1], 0, "ima_hash");
/*
* Test #6
* - Goal: ensure that the kernel_read_file hook denies an operation
* - Expected result: 0 samples
*/
test_init(skel->bss);
skel->bss->enable_kernel_read_file = true;
skel->bss->test_deny = true;
err = _run_measured_process(measured_dir, &skel->bss->monitored_pid,
"load-policy");
if (CHECK(!err, "run_measured_process #6", "err = %d\n", err))
goto close_clean;
err = ring_buffer__consume(ringbuf);
ASSERT_EQ(err, 0, "num_samples_or_err");
close_clean:
snprintf(cmd, sizeof(cmd), "./ima_setup.sh cleanup %s", measured_dir);
err = system(cmd);
CHECK(err, "failed to run command", "%s, errno = %d\n", cmd, errno);
close_prog:
ring_buffer__free(ringbuf);
ima__destroy(skel);
}
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