// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Christian Brauner <brauner@kernel.org> */

/*
 * Test BPF LSM block device integrity hooks with dm-verity.
 *
 * Creates a dm-verity device over loopback, which triggers
 * security_bdev_setintegrity() during verity_preresume().
 * Verifies that the BPF program correctly tracks the integrity
 * metadata in its hashmap.
 */

#define _GNU_SOURCE
#include <test_progs.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "lsm_bdev.skel.h"

/* Must match the definition in progs/lsm_bdev.c. */
struct verity_info {
        __u8  has_roothash;
        __u8  sig_valid;
        __u32 setintegrity_cnt;
};

#define DATA_SIZE_MB    8
#define HASH_SIZE_MB    1
#define DM_NAME         "bpf_test_verity"
#define DM_DEV_PATH     "/dev/mapper/" DM_NAME

/* Run a command and optionally capture the first line of stdout. */
static int run_cmd(const char *cmd, char *out, size_t out_sz)
{
        FILE *fp;
        int ret;

        fp = popen(cmd, "r");
        if (!fp)
                return -1;

        if (out && out_sz > 0) {
                if (!fgets(out, out_sz, fp))
                        out[0] = '\0';
                /* strip trailing newline */
                out[strcspn(out, "\n")] = '\0';
        }

        ret = pclose(fp);
        return WIFEXITED(ret) ? WEXITSTATUS(ret) : -1;
}

static bool has_prerequisites(void)
{
        if (getuid() != 0) {
                printf("SKIP: must be root\n");
                return false;
        }

        if (run_cmd("modprobe loop 2>/dev/null", NULL, 0) &&
            run_cmd("ls /dev/loop-control 2>/dev/null", NULL, 0)) {
                printf("SKIP: no loop device support\n");
                return false;
        }

        if (run_cmd("modprobe dm-verity 2>/dev/null", NULL, 0) &&
            run_cmd("dmsetup targets 2>/dev/null | grep -q verity", NULL, 0)) {
                printf("SKIP: dm-verity module not available\n");
                return false;
        }

        if (run_cmd("which veritysetup >/dev/null 2>&1", NULL, 0)) {
                printf("SKIP: veritysetup not found\n");
                return false;
        }

        return true;
}

void test_lsm_bdev(void)
{
        char data_img[] = "/tmp/bpf_verity_data_XXXXXX";
        char hash_img[] = "/tmp/bpf_verity_hash_XXXXXX";
        char data_loop[64] = {};
        char hash_loop[64] = {};
        char roothash[256] = {};
        char cmd[512];
        int data_fd = -1, hash_fd = -1;
        struct lsm_bdev *skel = NULL;
        struct verity_info val;
        struct stat st;
        __u32 dev_key;
        int err;

        if (!has_prerequisites()) {
                test__skip();
                return;
        }

        /* Clean up any stale device from a previous crashed run. */
        snprintf(cmd, sizeof(cmd), "dmsetup remove %s 2>/dev/null", DM_NAME);
        run_cmd(cmd, NULL, 0);

        /* Create temporary image files. */
        data_fd = mkstemp(data_img);
        if (!ASSERT_OK_FD(data_fd, "mkstemp data"))
                return;

        hash_fd = mkstemp(hash_img);
        if (!ASSERT_OK_FD(hash_fd, "mkstemp hash"))
                goto cleanup;

        if (!ASSERT_OK(ftruncate(data_fd, DATA_SIZE_MB * 1024 * 1024),
                       "truncate data"))
                goto cleanup;

        if (!ASSERT_OK(ftruncate(hash_fd, HASH_SIZE_MB * 1024 * 1024),
                       "truncate hash"))
                goto cleanup;

        close(data_fd);
        data_fd = -1;
        close(hash_fd);
        hash_fd = -1;

        /* Set up loop devices. */
        snprintf(cmd, sizeof(cmd),
                 "losetup --find --show %s 2>/dev/null", data_img);
        if (!ASSERT_OK(run_cmd(cmd, data_loop, sizeof(data_loop)),
                       "losetup data"))
                goto teardown;

        snprintf(cmd, sizeof(cmd),
                 "losetup --find --show %s 2>/dev/null", hash_img);
        if (!ASSERT_OK(run_cmd(cmd, hash_loop, sizeof(hash_loop)),
                       "losetup hash"))
                goto teardown;

        /* Format the dm-verity device and capture the root hash. */
        snprintf(cmd, sizeof(cmd),
                 "veritysetup format %s %s 2>/dev/null | "
                 "grep -i 'root hash' | awk '{print $NF}'",
                 data_loop, hash_loop);
        if (!ASSERT_OK(run_cmd(cmd, roothash, sizeof(roothash)),
                       "veritysetup format"))
                goto teardown;

        if (!ASSERT_GT((int)strlen(roothash), 0, "roothash not empty"))
                goto teardown;

        /* Load and attach BPF program before activating dm-verity. */
        skel = lsm_bdev__open_and_load();
        if (!ASSERT_OK_PTR(skel, "skel open_and_load"))
                goto teardown;

        err = lsm_bdev__attach(skel);
        if (!ASSERT_OK(err, "skel attach"))
                goto teardown;

        /* Activate dm-verity — triggers verity_preresume() hooks. */
        snprintf(cmd, sizeof(cmd),
                 "veritysetup open %s %s %s %s 2>/dev/null",
                 data_loop, DM_NAME, hash_loop, roothash);
        if (!ASSERT_OK(run_cmd(cmd, NULL, 0), "veritysetup open"))
                goto teardown;

        /* Get the dm device's dev_t. */
        if (!ASSERT_OK(stat(DM_DEV_PATH, &st), "stat dm dev"))
                goto remove_dm;

        dev_key = (__u32)st.st_rdev;

        /* Look up the device in the BPF map and verify. */
        err = bpf_map__lookup_elem(skel->maps.verity_devices,
                                   &dev_key, sizeof(dev_key),
                                   &val, sizeof(val), 0);
        if (!ASSERT_OK(err, "map lookup"))
                goto remove_dm;

        ASSERT_EQ(val.has_roothash, 1, "has_roothash");
        ASSERT_EQ(val.sig_valid, 0, "sig_valid (unsigned)");
        /*
         * verity_preresume() always calls security_bdev_setintegrity()
         * for the roothash. The signature-validity call only happens
         * when CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG is enabled.
         */
        ASSERT_GE(val.setintegrity_cnt, 1, "setintegrity_cnt min");
        ASSERT_LE(val.setintegrity_cnt, 2, "setintegrity_cnt max");

        /* Verify that the alloc hook fired at least once. */
        ASSERT_GT(skel->bss->alloc_count, 0, "alloc_count");

remove_dm:
        snprintf(cmd, sizeof(cmd), "dmsetup remove %s 2>/dev/null", DM_NAME);
        run_cmd(cmd, NULL, 0);

teardown:
        if (data_loop[0]) {
                snprintf(cmd, sizeof(cmd), "losetup -d %s 2>/dev/null",
                         data_loop);
                run_cmd(cmd, NULL, 0);
        }
        if (hash_loop[0]) {
                snprintf(cmd, sizeof(cmd), "losetup -d %s 2>/dev/null",
                         hash_loop);
                run_cmd(cmd, NULL, 0);
        }

cleanup:
        lsm_bdev__destroy(skel);
        if (data_fd >= 0)
                close(data_fd);
        if (hash_fd >= 0)
                close(hash_fd);
        unlink(data_img);
        unlink(hash_img);
}