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