// SPDX-License-Identifier: GPL-2.0
#include <kunit/test.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/init_syscalls.h>
#include <linux/stringify.h>
#include <linux/timekeeping.h>
#include "initramfs_internal.h"

struct initramfs_test_cpio {
        char *magic;
        unsigned int ino;
        unsigned int mode;
        unsigned int uid;
        unsigned int gid;
        unsigned int nlink;
        unsigned int mtime;
        unsigned int filesize;
        unsigned int devmajor;
        unsigned int devminor;
        unsigned int rdevmajor;
        unsigned int rdevminor;
        unsigned int namesize;
        unsigned int csum;
        char *fname;
        char *data;
};

static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, char *out)
{
        int i;
        size_t off = 0;

        for (i = 0; i < csz; i++) {
                char *pos = &out[off];
                struct initramfs_test_cpio *c = &cs[i];
                size_t thislen;

                /* +1 to account for nulterm */
                thislen = sprintf(pos, "%s"
                        "%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x"
                        "%s",
                        c->magic, c->ino, c->mode, c->uid, c->gid, c->nlink,
                        c->mtime, c->filesize, c->devmajor, c->devminor,
                        c->rdevmajor, c->rdevminor, c->namesize, c->csum,
                        c->fname) + 1;

                pr_debug("packing (%zu): %.*s\n", thislen, (int)thislen, pos);
                if (thislen != CPIO_HDRLEN + c->namesize)
                        pr_debug("padded to: %u\n", CPIO_HDRLEN + c->namesize);
                off += CPIO_HDRLEN + c->namesize;
                while (off & 3)
                        out[off++] = '\0';

                memcpy(&out[off], c->data, c->filesize);
                off += c->filesize;
                while (off & 3)
                        out[off++] = '\0';
        }

        return off;
}

static void __init initramfs_test_extract(struct kunit *test)
{
        char *err, *cpio_srcbuf;
        size_t len;
        struct timespec64 ts_before, ts_after;
        struct kstat st = {};
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .uid = 12,
                .gid = 34,
                .nlink = 1,
                .mtime = 56,
                .filesize = 0,
                .devmajor = 0,
                .devminor = 1,
                .rdevmajor = 0,
                .rdevminor = 0,
                .namesize = sizeof("initramfs_test_extract"),
                .csum = 0,
                .fname = "initramfs_test_extract",
        }, {
                .magic = "070701",
                .ino = 2,
                .mode = S_IFDIR | 0777,
                .nlink = 1,
                .mtime = 57,
                .devminor = 1,
                .namesize = sizeof("initramfs_test_extract_dir"),
                .fname = "initramfs_test_extract_dir",
        }, {
                .magic = "070701",
                .namesize = sizeof("TRAILER!!!"),
                .fname = "TRAILER!!!",
        } };

        /* +3 to cater for any 4-byte end-alignment */
        cpio_srcbuf = kzalloc(ARRAY_SIZE(c) * (CPIO_HDRLEN + PATH_MAX + 3),
                              GFP_KERNEL);
        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);

        ktime_get_real_ts64(&ts_before);
        err = unpack_to_rootfs(cpio_srcbuf, len);
        ktime_get_real_ts64(&ts_after);
        if (err) {
                KUNIT_FAIL(test, "unpack failed %s", err);
                goto out;
        }

        KUNIT_EXPECT_EQ(test, init_stat(c[0].fname, &st, 0), 0);
        KUNIT_EXPECT_TRUE(test, S_ISREG(st.mode));
        KUNIT_EXPECT_TRUE(test, uid_eq(st.uid, KUIDT_INIT(c[0].uid)));
        KUNIT_EXPECT_TRUE(test, gid_eq(st.gid, KGIDT_INIT(c[0].gid)));
        KUNIT_EXPECT_EQ(test, st.nlink, 1);
        if (IS_ENABLED(CONFIG_INITRAMFS_PRESERVE_MTIME)) {
                KUNIT_EXPECT_EQ(test, st.mtime.tv_sec, c[0].mtime);
        } else {
                KUNIT_EXPECT_GE(test, st.mtime.tv_sec, ts_before.tv_sec);
                KUNIT_EXPECT_LE(test, st.mtime.tv_sec, ts_after.tv_sec);
        }
        KUNIT_EXPECT_EQ(test, st.blocks, c[0].filesize);

        KUNIT_EXPECT_EQ(test, init_stat(c[1].fname, &st, 0), 0);
        KUNIT_EXPECT_TRUE(test, S_ISDIR(st.mode));
        if (IS_ENABLED(CONFIG_INITRAMFS_PRESERVE_MTIME)) {
                KUNIT_EXPECT_EQ(test, st.mtime.tv_sec, c[1].mtime);
        } else {
                KUNIT_EXPECT_GE(test, st.mtime.tv_sec, ts_before.tv_sec);
                KUNIT_EXPECT_LE(test, st.mtime.tv_sec, ts_after.tv_sec);
        }

        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
        KUNIT_EXPECT_EQ(test, init_rmdir(c[1].fname), 0);
out:
        kfree(cpio_srcbuf);
}

/*
 * Don't terminate filename. Previously, the cpio filename field was passed
 * directly to filp_open(collected, O_CREAT|..) without nulterm checks. See
 * https://lore.kernel.org/linux-fsdevel/20241030035509.20194-2-ddiss@suse.de
 */
static void __init initramfs_test_fname_overrun(struct kunit *test)
{
        char *err, *cpio_srcbuf;
        size_t len, suffix_off;
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .uid = 0,
                .gid = 0,
                .nlink = 1,
                .mtime = 1,
                .filesize = 0,
                .devmajor = 0,
                .devminor = 1,
                .rdevmajor = 0,
                .rdevminor = 0,
                .namesize = sizeof("initramfs_test_fname_overrun"),
                .csum = 0,
                .fname = "initramfs_test_fname_overrun",
        } };

        /*
         * poison cpio source buffer, so we can detect overrun. source
         * buffer is used by read_into() when hdr or fname
         * are already available (e.g. no compression).
         */
        cpio_srcbuf = kmalloc(CPIO_HDRLEN + PATH_MAX + 3, GFP_KERNEL);
        memset(cpio_srcbuf, 'B', CPIO_HDRLEN + PATH_MAX + 3);
        /* limit overrun to avoid crashes / filp_open() ENAMETOOLONG */
        cpio_srcbuf[CPIO_HDRLEN + strlen(c[0].fname) + 20] = '\0';

        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);
        /* overwrite trailing fname terminator and padding */
        suffix_off = len - 1;
        while (cpio_srcbuf[suffix_off] == '\0') {
                cpio_srcbuf[suffix_off] = 'P';
                suffix_off--;
        }

        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NOT_NULL(test, err);

        kfree(cpio_srcbuf);
}

static void __init initramfs_test_data(struct kunit *test)
{
        char *err, *cpio_srcbuf;
        size_t len;
        struct file *file;
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .uid = 0,
                .gid = 0,
                .nlink = 1,
                .mtime = 1,
                .filesize = sizeof("ASDF") - 1,
                .devmajor = 0,
                .devminor = 1,
                .rdevmajor = 0,
                .rdevminor = 0,
                .namesize = sizeof("initramfs_test_data"),
                .csum = 0,
                .fname = "initramfs_test_data",
                .data = "ASDF",
        } };

        /* +6 for max name and data 4-byte padding */
        cpio_srcbuf = kmalloc(CPIO_HDRLEN + c[0].namesize + c[0].filesize + 6,
                              GFP_KERNEL);

        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);

        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NULL(test, err);

        file = filp_open(c[0].fname, O_RDONLY, 0);
        if (IS_ERR(file)) {
                KUNIT_FAIL(test, "open failed");
                goto out;
        }

        /* read back file contents into @cpio_srcbuf and confirm match */
        len = kernel_read(file, cpio_srcbuf, c[0].filesize, NULL);
        KUNIT_EXPECT_EQ(test, len, c[0].filesize);
        KUNIT_EXPECT_MEMEQ(test, cpio_srcbuf, c[0].data, len);

        fput(file);
        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
out:
        kfree(cpio_srcbuf);
}

static void __init initramfs_test_csum(struct kunit *test)
{
        char *err, *cpio_srcbuf;
        size_t len;
        struct initramfs_test_cpio c[] = { {
                /* 070702 magic indicates a valid csum is present */
                .magic = "070702",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .nlink = 1,
                .filesize = sizeof("ASDF") - 1,
                .devminor = 1,
                .namesize = sizeof("initramfs_test_csum"),
                .csum = 'A' + 'S' + 'D' + 'F',
                .fname = "initramfs_test_csum",
                .data = "ASDF",
        }, {
                /* mix csum entry above with no-csum entry below */
                .magic = "070701",
                .ino = 2,
                .mode = S_IFREG | 0777,
                .nlink = 1,
                .filesize = sizeof("ASDF") - 1,
                .devminor = 1,
                .namesize = sizeof("initramfs_test_csum_not_here"),
                /* csum ignored */
                .csum = 5555,
                .fname = "initramfs_test_csum_not_here",
                .data = "ASDF",
        } };

        cpio_srcbuf = kmalloc(8192, GFP_KERNEL);

        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);

        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NULL(test, err);

        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
        KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), 0);

        /* mess up the csum and confirm that unpack fails */
        c[0].csum--;
        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);

        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NOT_NULL(test, err);

        /*
         * file (with content) is still retained in case of bad-csum abort.
         * Perhaps we should change this.
         */
        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
        KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), -ENOENT);
        kfree(cpio_srcbuf);
}

/*
 * hardlink hashtable may leak when the archive omits a trailer:
 * https://lore.kernel.org/r/20241107002044.16477-10-ddiss@suse.de/
 */
static void __init initramfs_test_hardlink(struct kunit *test)
{
        char *err, *cpio_srcbuf;
        size_t len;
        struct kstat st0, st1;
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .nlink = 2,
                .devminor = 1,
                .namesize = sizeof("initramfs_test_hardlink"),
                .fname = "initramfs_test_hardlink",
        }, {
                /* hardlink data is present in last archive entry */
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .nlink = 2,
                .filesize = sizeof("ASDF") - 1,
                .devminor = 1,
                .namesize = sizeof("initramfs_test_hardlink_link"),
                .fname = "initramfs_test_hardlink_link",
                .data = "ASDF",
        } };

        cpio_srcbuf = kmalloc(8192, GFP_KERNEL);

        len = fill_cpio(c, ARRAY_SIZE(c), cpio_srcbuf);

        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NULL(test, err);

        KUNIT_EXPECT_EQ(test, init_stat(c[0].fname, &st0, 0), 0);
        KUNIT_EXPECT_EQ(test, init_stat(c[1].fname, &st1, 0), 0);
        KUNIT_EXPECT_EQ(test, st0.ino, st1.ino);
        KUNIT_EXPECT_EQ(test, st0.nlink, 2);
        KUNIT_EXPECT_EQ(test, st1.nlink, 2);

        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
        KUNIT_EXPECT_EQ(test, init_unlink(c[1].fname), 0);

        kfree(cpio_srcbuf);
}

#define INITRAMFS_TEST_MANY_LIMIT 1000
#define INITRAMFS_TEST_MANY_PATH_MAX (sizeof("initramfs_test_many-") \
                        + sizeof(__stringify(INITRAMFS_TEST_MANY_LIMIT)))
static void __init initramfs_test_many(struct kunit *test)
{
        char *err, *cpio_srcbuf, *p;
        size_t len = INITRAMFS_TEST_MANY_LIMIT *
                     (CPIO_HDRLEN + INITRAMFS_TEST_MANY_PATH_MAX + 3);
        char thispath[INITRAMFS_TEST_MANY_PATH_MAX];
        int i;

        p = cpio_srcbuf = kmalloc(len, GFP_KERNEL);

        for (i = 0; i < INITRAMFS_TEST_MANY_LIMIT; i++) {
                struct initramfs_test_cpio c = {
                        .magic = "070701",
                        .ino = i,
                        .mode = S_IFREG | 0777,
                        .nlink = 1,
                        .devminor = 1,
                        .fname = thispath,
                };

                c.namesize = 1 + sprintf(thispath, "initramfs_test_many-%d", i);
                p += fill_cpio(&c, 1, p);
        }

        len = p - cpio_srcbuf;
        err = unpack_to_rootfs(cpio_srcbuf, len);
        KUNIT_EXPECT_NULL(test, err);

        for (i = 0; i < INITRAMFS_TEST_MANY_LIMIT; i++) {
                sprintf(thispath, "initramfs_test_many-%d", i);
                KUNIT_EXPECT_EQ(test, init_unlink(thispath), 0);
        }

        kfree(cpio_srcbuf);
}

/*
 * An initramfs filename is namesize in length, including the zero-terminator.
 * A filename can be zero-terminated prior to namesize, with the remainder used
 * as padding. This can be useful for e.g. alignment of file data segments with
 * a 4KB filesystem block, allowing for extent sharing (reflinks) between cpio
 * source and destination. This hack works with both GNU cpio and initramfs, as
 * long as PATH_MAX isn't exceeded.
 */
static void __init initramfs_test_fname_pad(struct kunit *test)
{
        char *err;
        size_t len;
        struct file *file;
        char fdata[] = "this file data is aligned at 4K in the archive";
        struct test_fname_pad {
                char padded_fname[4096 - CPIO_HDRLEN];
                char cpio_srcbuf[CPIO_HDRLEN + PATH_MAX + 3 + sizeof(fdata)];
        } *tbufs = kzalloc_obj(struct test_fname_pad);
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFREG | 0777,
                .uid = 0,
                .gid = 0,
                .nlink = 1,
                .mtime = 1,
                .filesize = sizeof(fdata),
                .devmajor = 0,
                .devminor = 1,
                .rdevmajor = 0,
                .rdevminor = 0,
                /* align file data at 4K archive offset via padded fname */
                .namesize = 4096 - CPIO_HDRLEN,
                .csum = 0,
                .fname = tbufs->padded_fname,
                .data = fdata,
        } };

        memcpy(tbufs->padded_fname, "padded_fname", sizeof("padded_fname"));
        len = fill_cpio(c, ARRAY_SIZE(c), tbufs->cpio_srcbuf);

        err = unpack_to_rootfs(tbufs->cpio_srcbuf, len);
        KUNIT_EXPECT_NULL(test, err);

        file = filp_open(c[0].fname, O_RDONLY, 0);
        if (IS_ERR(file)) {
                KUNIT_FAIL(test, "open failed");
                goto out;
        }

        /* read back file contents into @cpio_srcbuf and confirm match */
        len = kernel_read(file, tbufs->cpio_srcbuf, c[0].filesize, NULL);
        KUNIT_EXPECT_EQ(test, len, c[0].filesize);
        KUNIT_EXPECT_MEMEQ(test, tbufs->cpio_srcbuf, c[0].data, len);

        fput(file);
        KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0);
out:
        kfree(tbufs);
}

static void __init initramfs_test_fname_path_max(struct kunit *test)
{
        char *err;
        size_t len;
        struct kstat st0, st1;
        char fdata[] = "this file data will not be unpacked";
        struct test_fname_path_max {
                char fname_oversize[PATH_MAX + 1];
                char fname_ok[PATH_MAX];
                char cpio_src[(CPIO_HDRLEN + PATH_MAX + 3 + sizeof(fdata)) * 2];
        } *tbufs = kzalloc_obj(struct test_fname_path_max);
        struct initramfs_test_cpio c[] = { {
                .magic = "070701",
                .ino = 1,
                .mode = S_IFDIR | 0777,
                .nlink = 1,
                .namesize = sizeof(tbufs->fname_oversize),
                .fname = tbufs->fname_oversize,
                .filesize = sizeof(fdata),
                .data = fdata,
        }, {
                .magic = "070701",
                .ino = 2,
                .mode = S_IFDIR | 0777,
                .nlink = 1,
                .namesize = sizeof(tbufs->fname_ok),
                .fname = tbufs->fname_ok,
        } };

        memset(tbufs->fname_oversize, '/', sizeof(tbufs->fname_oversize) - 1);
        memset(tbufs->fname_ok, '/', sizeof(tbufs->fname_ok) - 1);
        memcpy(tbufs->fname_oversize, "fname_oversize",
               sizeof("fname_oversize") - 1);
        memcpy(tbufs->fname_ok, "fname_ok", sizeof("fname_ok") - 1);
        len = fill_cpio(c, ARRAY_SIZE(c), tbufs->cpio_src);

        /* unpack skips over fname_oversize instead of returning an error */
        err = unpack_to_rootfs(tbufs->cpio_src, len);
        KUNIT_EXPECT_NULL(test, err);

        KUNIT_EXPECT_EQ(test, init_stat("fname_oversize", &st0, 0), -ENOENT);
        KUNIT_EXPECT_EQ(test, init_stat("fname_ok", &st1, 0), 0);
        KUNIT_EXPECT_EQ(test, init_rmdir("fname_ok"), 0);

        kfree(tbufs);
}

/*
 * The kunit_case/_suite struct cannot be marked as __initdata as this will be
 * used in debugfs to retrieve results after test has run.
 */
static struct kunit_case __refdata initramfs_test_cases[] = {
        KUNIT_CASE(initramfs_test_extract),
        KUNIT_CASE(initramfs_test_fname_overrun),
        KUNIT_CASE(initramfs_test_data),
        KUNIT_CASE(initramfs_test_csum),
        KUNIT_CASE(initramfs_test_hardlink),
        KUNIT_CASE(initramfs_test_many),
        KUNIT_CASE(initramfs_test_fname_pad),
        KUNIT_CASE(initramfs_test_fname_path_max),
        {},
};

static struct kunit_suite initramfs_test_suite = {
        .name = "initramfs",
        .test_cases = initramfs_test_cases,
};
kunit_test_init_section_suites(&initramfs_test_suite);

MODULE_DESCRIPTION("Initramfs KUnit test suite");
MODULE_LICENSE("GPL v2");