1 files changed, 240 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/test_ima.c b/tools/testing/selftests/bpf/prog_tests/test_ima.c
new file mode 100644
index 000000000000..810b14981c2e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_ima.c
@@ -0,0 +1,240 @@
+// 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, fresh_digest_idx = 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:
+	 *   1 sample (/bin/true: fresh) if commit 62622dab0a28 applied
+	 *   2 samples (/bin/true: non-fresh, fresh) if commit 62622dab0a28 is
+	 *     not applied
+	 *
+	 * If commit 62622dab0a28 ("ima: return IMA digest value only when
+	 * IMA_COLLECTED flag is set") is applied, bpf_ima_inode_hash() refuses
+	 * to give a non-fresh digest, hence the correct result is 1 instead of
+	 * 2.
+	 */
+	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_GE(err, 1, "num_samples_or_err");
+	if (err == 2) {
+		ASSERT_NEQ(ima_hash_from_bpf[0], 0, "ima_hash");
+		ASSERT_EQ(ima_hash_from_bpf[0], bin_true_sample,
+			  "sample_equal_or_err");
+		fresh_digest_idx = 1;
+	}
+
+	ASSERT_NEQ(ima_hash_from_bpf[fresh_digest_idx], 0, "ima_hash");
+	/* IMA refreshed the digest. */
+	ASSERT_NEQ(ima_hash_from_bpf[fresh_digest_idx], bin_true_sample,
+		   "sample_equal_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);
+}