root/fs/ext4/hash-test.c
// SPDX-License-Identifier: GPL-2.0
/*
 * KUnit tests for ext4 directory hash computation.
 */

#include <kunit/test.h>
#include <kunit/resource.h>
#include <linux/fs.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/unicode.h>
#include "ext4.h"

static void ext4_hash_init_fake_dir(struct inode *dir, struct super_block *sb)
{
        memset(sb, 0, sizeof(*sb));
        memset(dir, 0, sizeof(*dir));
        dir->i_sb = sb;
        strscpy(sb->s_id, "kunit-ext4", sizeof(sb->s_id));
}

static void ext4_hash_init_fake_dir_with_sbi(struct inode *dir,
                                             struct super_block *sb,
                                             struct ext4_sb_info *sbi)
{
        ext4_hash_init_fake_dir(dir, sb);
        memset(sbi, 0, sizeof(*sbi));
        sb->s_fs_info = sbi;
        sbi->s_sb = sb;
}

#ifdef CONFIG_FS_ENCRYPTION
static const struct fscrypt_operations ext4_hash_test_cryptops = {
        .inode_info_offs =
                (int)offsetof(struct ext4_inode_info, i_crypt_info) -
                (int)offsetof(struct ext4_inode_info, vfs_inode),
};
#endif

static void ext4_hash_init_fake_ext4_dir(struct ext4_inode_info *ei,
                                         struct super_block *sb,
                                         struct ext4_sb_info *sbi)
{
        struct inode *dir = &ei->vfs_inode;

        memset(sb, 0, sizeof(*sb));
        memset(ei, 0, sizeof(*ei));
        memset(sbi, 0, sizeof(*sbi));

        strscpy(sb->s_id, "kunit-ext4", sizeof(sb->s_id));
        sb->s_fs_info = sbi;
        sbi->s_sb = sb;

        dir->i_sb = sb;
        dir->i_mode = S_IFDIR;

#ifdef CONFIG_FS_ENCRYPTION
        fscrypt_set_ops(sb, &ext4_hash_test_cryptops);
#endif
}

struct ext4_dirhash_test_case {
        const char *name;
        u32 hash_version;
        const char *input;
        int len;
        u32 seed[4];
        bool use_seed;
        u32 expected_hash;
        u32 expected_minor_hash;
};

static const struct ext4_dirhash_test_case ext4_dirhash_test_cases[] = {
        {
                .name = "legacy_abc",
                .hash_version = DX_HASH_LEGACY,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0x75afd992,
                .expected_minor_hash = 0x00000000,
        },
        {
                .name = "legacy_unsigned_abc",
                .hash_version = DX_HASH_LEGACY_UNSIGNED,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0x75afd992,
                .expected_minor_hash = 0x00000000,
        },
        {
                .name = "half_md4_abc",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0xd196a868,
                .expected_minor_hash = 0xc420eb28,
        },
        {
                .name = "half_md4_unsigned_abc",
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0xd196a868,
                .expected_minor_hash = 0xc420eb28,
        },
        {
                .name = "tea_abc",
                .hash_version = DX_HASH_TEA,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0xb1435ec4,
                .expected_minor_hash = 0x3f7eaa0e,
        },
        {
                .name = "tea_unsigned_abc",
                .hash_version = DX_HASH_TEA_UNSIGNED,
                .input = "abc",
                .len = 3,
                .use_seed = false,
                .expected_hash = 0xb1435ec4,
                .expected_minor_hash = 0x3f7eaa0e,
        },
        {
                .name = "empty_half_md4",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "",
                .len = 0,
                .use_seed = false,
                .expected_hash = 0xefcdab88,
                .expected_minor_hash = 0x98badcfe,
        },
        {
                .name = "half_md4_31bytes",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "1234567890123456789012345678901",
                .len = 31,
                .use_seed = false,
                .expected_hash = 0xc4db1f78,
                .expected_minor_hash = 0xea23921b,
        },
        {
                .name = "half_md4_32bytes",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "12345678901234567890123456789012",
                .len = 32,
                .use_seed = false,
                .expected_hash = 0xfa6cc63e,
                .expected_minor_hash = 0x2f77bd1c,
        },
        {
                .name = "half_md4_33bytes",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "123456789012345678901234567890123",
                .len = 33,
                .use_seed = false,
                .expected_hash = 0xdc0c2dec,
                .expected_minor_hash = 0x5ca23365,
        },
        {
                .name = "half_md4_unsigned_31bytes",
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
                .input = "1234567890123456789012345678901",
                .len = 31,
                .use_seed = false,
                .expected_hash = 0xc4db1f78,
                .expected_minor_hash = 0xea23921b,
        },
        {
                .name = "half_md4_unsigned_32bytes",
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
                .input = "12345678901234567890123456789012",
                .len = 32,
                .use_seed = false,
                .expected_hash = 0xfa6cc63e,
                .expected_minor_hash = 0x2f77bd1c,
        },
        {
                .name = "half_md4_unsigned_33bytes",
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
                .input = "123456789012345678901234567890123",
                .len = 33,
                .use_seed = false,
                .expected_hash = 0xdc0c2dec,
                .expected_minor_hash = 0x5ca23365,
        },
        {
                .name = "tea_15bytes",
                .hash_version = DX_HASH_TEA,
                .input = "123456789abcdef",
                .len = 15,
                .use_seed = false,
                .expected_hash = 0xa562903a,
                .expected_minor_hash = 0x6174a00f,
        },
        {
                .name = "tea_16bytes",
                .hash_version = DX_HASH_TEA,
                .input = "1234567890abcdef",
                .len = 16,
                .use_seed = false,
                .expected_hash = 0x8449f258,
                .expected_minor_hash = 0x49a16d46,
        },
        {
                .name = "tea_17bytes",
                .hash_version = DX_HASH_TEA,
                .input = "123456789abcdefgh",
                .len = 17,
                .use_seed = false,
                .expected_hash = 0xf32ec10c,
                .expected_minor_hash = 0x58ceae61,
        },
        {
                .name = "half_md4_seeded",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "same-name",
                .len = 9,
                .seed = { 0x11111111, 0x22222222, 0x33333333, 0x44444444 },
                .use_seed = true,
                .expected_hash = 0x8aebf604,
                .expected_minor_hash = 0x66ce48fe,
        },
        {
                .name = "half_md4_non_ascii_signed",
                .hash_version = DX_HASH_HALF_MD4,
                .input = "\x80\x81\x82\x83\x84",
                .len = 5,
                .use_seed = false,
                .expected_hash = 0x8bab0498,
                .expected_minor_hash = 0xc326632d,
        },
        {
                .name = "half_md4_non_ascii_unsigned",
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
                .input = "\x80\x81\x82\x83\x84",
                .len = 5,
                .use_seed = false,
                .expected_hash = 0xbc48596e,
                .expected_minor_hash = 0xde0fad41,
        },
        {
                .name = "tea_non_ascii_signed",
                .hash_version = DX_HASH_TEA,
                .input = "\x80\x81\x82\x83\x84",
                .len = 5,
                .use_seed = false,
                .expected_hash = 0x21e3a154,
                .expected_minor_hash = 0x90112c3d,
        },
        {
                .name = "tea_non_ascii_unsigned",
                .hash_version = DX_HASH_TEA_UNSIGNED,
                .input = "\x80\x81\x82\x83\x84",
                .len = 5,
                .use_seed = false,
                .expected_hash = 0x9b648616,
                .expected_minor_hash = 0x011dd507,
        },
};

static void test_ext4fs_dirhash_vectors(struct kunit *test)
{
        struct super_block *sb;
        struct inode *dir;
        int i;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        dir = kunit_kzalloc(test, sizeof(*dir), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, dir);

        ext4_hash_init_fake_dir(dir, sb);

        for (i = 0; i < ARRAY_SIZE(ext4_dirhash_test_cases); i++) {
                const struct ext4_dirhash_test_case *tc =
                        &ext4_dirhash_test_cases[i];
                struct dx_hash_info hinfo;
                int ret;

                memset(&hinfo, 0, sizeof(hinfo));
                hinfo.hash_version = tc->hash_version;
                hinfo.seed = tc->use_seed ? (u32 *)tc->seed : NULL;

                ret = ext4fs_dirhash(dir, tc->input, tc->len, &hinfo);

                KUNIT_ASSERT_EQ_MSG(test, ret, 0, "case=%s", tc->name);
                KUNIT_EXPECT_EQ_MSG(test, hinfo.hash, tc->expected_hash,
                                    "case=%s", tc->name);
                KUNIT_EXPECT_EQ_MSG(test, hinfo.minor_hash,
                                    tc->expected_minor_hash,
                                    "case=%s", tc->name);
        }
}

static void test_ext4fs_dirhash_seed_changes_result(struct kunit *test)
{
        struct super_block *sb;
        struct inode *dir;
        u32 seed[4] = { 0x11111111, 0x22222222, 0x33333333, 0x44444444 };
        struct dx_hash_info plain = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        struct dx_hash_info seeded = {
                .hash_version = DX_HASH_HALF_MD4,
                .seed = seed,
        };
        int ret_plain, ret_seeded;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        dir = kunit_kzalloc(test, sizeof(*dir), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, dir);

        ext4_hash_init_fake_dir(dir, sb);

        ret_plain = ext4fs_dirhash(dir, "same-name", 9, &plain);
        ret_seeded = ext4fs_dirhash(dir, "same-name", 9, &seeded);

        KUNIT_ASSERT_EQ(test, ret_plain, 0);
        KUNIT_ASSERT_EQ(test, ret_seeded, 0);

        KUNIT_EXPECT_TRUE(test,
                          plain.hash != seeded.hash ||
                          plain.minor_hash != seeded.minor_hash);
}

static void test_ext4fs_dirhash_invalid_version_returns_einval(struct kunit *test)
{
        struct super_block *sb;
        struct inode *dir;
        struct ext4_sb_info *sbi;
        struct dx_hash_info hinfo = {
                .hash = 0xdeadbeef,
                .minor_hash = 0xcafebabe,
                .hash_version = DX_HASH_LAST + 1,
        };
        int ret;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        dir = kunit_kzalloc(test, sizeof(*dir), GFP_KERNEL);
        sbi = kunit_kzalloc(test, sizeof(*sbi), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, dir);
        KUNIT_ASSERT_NOT_NULL(test, sbi);

        ext4_hash_init_fake_dir_with_sbi(dir, sb, sbi);

        ret = ext4fs_dirhash(dir, "abc", 3, &hinfo);

        KUNIT_EXPECT_EQ(test, ret, -EINVAL);
        KUNIT_EXPECT_EQ(test, hinfo.hash, 0);
        KUNIT_EXPECT_EQ(test, hinfo.minor_hash, 0);
}

static void test_ext4fs_dirhash_siphash_without_key_returns_einval(struct kunit *test)
{
        struct super_block *sb;
        struct ext4_inode_info *ei;
        struct inode *dir;
        struct ext4_sb_info *sbi;
        struct dx_hash_info hinfo = {
                .hash_version = DX_HASH_SIPHASH,
        };
        int ret;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        ei = kunit_kzalloc(test, sizeof(*ei), GFP_KERNEL);
        sbi = kunit_kzalloc(test, sizeof(*sbi), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, ei);
        KUNIT_ASSERT_NOT_NULL(test, sbi);

        ext4_hash_init_fake_ext4_dir(ei, sb, sbi);
        dir = &ei->vfs_inode;

        ret = ext4fs_dirhash(dir, "name", strlen("name"), &hinfo);

        KUNIT_EXPECT_EQ(test, ret, -EINVAL);
}

static void test_ext4fs_dirhash_signed_unsigned_differ_on_nonascii(struct kunit *test)
{
        struct super_block *sb;
        struct inode *dir;
        static const char input[] = "\x80\xff\x81\xfe\101bc";
        struct dx_hash_info legacy_signed = {
                .hash_version = DX_HASH_LEGACY,
        };
        struct dx_hash_info legacy_unsigned = {
                .hash_version = DX_HASH_LEGACY_UNSIGNED,
        };
        struct dx_hash_info md4_signed = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        struct dx_hash_info md4_unsigned = {
                .hash_version = DX_HASH_HALF_MD4_UNSIGNED,
        };
        struct dx_hash_info tea_signed = {
                .hash_version = DX_HASH_TEA,
        };
        struct dx_hash_info tea_unsigned = {
                .hash_version = DX_HASH_TEA_UNSIGNED,
        };
        int ret;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        dir = kunit_kzalloc(test, sizeof(*dir), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, dir);

        ext4_hash_init_fake_dir(dir, sb);

        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &legacy_signed);
        KUNIT_ASSERT_EQ(test, ret, 0);
        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &legacy_unsigned);
        KUNIT_ASSERT_EQ(test, ret, 0);
        KUNIT_EXPECT_NE(test, legacy_signed.hash, legacy_unsigned.hash);

        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &md4_signed);
        KUNIT_ASSERT_EQ(test, ret, 0);
        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &md4_unsigned);
        KUNIT_ASSERT_EQ(test, ret, 0);
        KUNIT_EXPECT_TRUE(test,
                          md4_signed.hash != md4_unsigned.hash ||
                          md4_signed.minor_hash != md4_unsigned.minor_hash);

        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &tea_signed);
        KUNIT_ASSERT_EQ(test, ret, 0);
        ret = ext4fs_dirhash(dir, input, sizeof(input) - 1, &tea_unsigned);
        KUNIT_ASSERT_EQ(test, ret, 0);
        KUNIT_EXPECT_TRUE(test,
                          tea_signed.hash != tea_unsigned.hash ||
                          tea_signed.minor_hash != tea_unsigned.minor_hash);
}

#if IS_ENABLED(CONFIG_UNICODE)
KUNIT_DEFINE_ACTION_WRAPPER(utf8_unload_action, utf8_unload,
                            struct unicode_map *);
static void test_ext4fs_dirhash_casefolded_names_hash_consistently(struct kunit *test)
{
        struct super_block *sb;
        struct ext4_inode_info *ei;
        struct ext4_sb_info *sbi;
        struct unicode_map *um;
        struct dx_hash_info h1 = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        struct dx_hash_info h2 = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        int ret, ret1, ret2;

        sb = kunit_kzalloc(test, sizeof(*sb), GFP_KERNEL);
        ei = kunit_kzalloc(test, sizeof(*ei), GFP_KERNEL);
        sbi = kunit_kzalloc(test, sizeof(*sbi), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb);
        KUNIT_ASSERT_NOT_NULL(test, ei);
        KUNIT_ASSERT_NOT_NULL(test, sbi);

        um = utf8_load(UTF8_LATEST);
        if (IS_ERR(um)) {
                kunit_skip(test, "utf8_load(UTF8_LATEST) failed: %pe",
                           um);
                return;
        }

        ret = kunit_add_action_or_reset(test, utf8_unload_action, um);
        KUNIT_ASSERT_EQ(test, ret, 0);

        ext4_hash_init_fake_ext4_dir(ei, sb, sbi);
        sb->s_encoding = um;
        ei->vfs_inode.i_flags |= S_CASEFOLD;

        KUNIT_ASSERT_TRUE(test, IS_CASEFOLDED(&ei->vfs_inode));

        ret1 = ext4fs_dirhash(&ei->vfs_inode, "Alpha", 5, &h1);
        ret2 = ext4fs_dirhash(&ei->vfs_inode, "aLPHa", 5, &h2);

        KUNIT_ASSERT_EQ(test, ret1, 0);
        KUNIT_ASSERT_EQ(test, ret2, 0);
        KUNIT_EXPECT_EQ(test, h1.hash, h2.hash);
        KUNIT_EXPECT_EQ(test, h1.minor_hash, h2.minor_hash);
}

static void test_ext4fs_dirhash_casefold_fallback(struct kunit *test)
{
        struct super_block *sb_cf, *sb_plain;
        struct ext4_inode_info *ei;
        struct ext4_sb_info *sbi;
        struct inode *plain_dir;
        struct unicode_map *um;
        static const char invalid_utf8[] = "\xc3\x28";
        struct dx_hash_info folded_dir = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        struct dx_hash_info plain = {
                .hash_version = DX_HASH_HALF_MD4,
        };
        int ret, ret_cf, ret_plain;

        sb_cf = kunit_kzalloc(test, sizeof(*sb_cf), GFP_KERNEL);
        sb_plain = kunit_kzalloc(test, sizeof(*sb_plain), GFP_KERNEL);
        ei = kunit_kzalloc(test, sizeof(*ei), GFP_KERNEL);
        sbi = kunit_kzalloc(test, sizeof(*sbi), GFP_KERNEL);
        plain_dir = kunit_kzalloc(test, sizeof(*plain_dir), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, sb_cf);
        KUNIT_ASSERT_NOT_NULL(test, sb_plain);
        KUNIT_ASSERT_NOT_NULL(test, ei);
        KUNIT_ASSERT_NOT_NULL(test, sbi);
        KUNIT_ASSERT_NOT_NULL(test, plain_dir);

        um = utf8_load(UTF8_LATEST);
        if (IS_ERR(um)) {
                kunit_skip(test, "utf8_load(UTF8_LATEST) failed: %pe",
                           um);
                return;
        }

        ret = kunit_add_action_or_reset(test, utf8_unload_action, um);
        KUNIT_ASSERT_EQ(test, ret, 0);

        ext4_hash_init_fake_ext4_dir(ei, sb_cf, sbi);
        sb_cf->s_encoding = um;
        ei->vfs_inode.i_flags |= S_CASEFOLD;

        KUNIT_ASSERT_TRUE(test, IS_CASEFOLDED(&ei->vfs_inode));

        ext4_hash_init_fake_dir(plain_dir, sb_plain);

        ret_cf = ext4fs_dirhash(&ei->vfs_inode, invalid_utf8,
                                sizeof(invalid_utf8) - 1, &folded_dir);
        ret_plain = ext4fs_dirhash(plain_dir, invalid_utf8,
                                   sizeof(invalid_utf8) - 1, &plain);

        KUNIT_ASSERT_EQ(test, ret_cf, 0);
        KUNIT_ASSERT_EQ(test, ret_plain, 0);
        KUNIT_EXPECT_EQ(test, folded_dir.hash, plain.hash);
        KUNIT_EXPECT_EQ(test, folded_dir.minor_hash, plain.minor_hash);
}
#endif

static struct kunit_case ext4_hash_test_cases[] = {
        KUNIT_CASE(test_ext4fs_dirhash_vectors),
        KUNIT_CASE(test_ext4fs_dirhash_seed_changes_result),
        KUNIT_CASE(test_ext4fs_dirhash_invalid_version_returns_einval),
        KUNIT_CASE(test_ext4fs_dirhash_siphash_without_key_returns_einval),
        KUNIT_CASE(test_ext4fs_dirhash_signed_unsigned_differ_on_nonascii),
#if IS_ENABLED(CONFIG_UNICODE)
        KUNIT_CASE(test_ext4fs_dirhash_casefolded_names_hash_consistently),
        KUNIT_CASE(test_ext4fs_dirhash_casefold_fallback),
#endif
        {}
};

static struct kunit_suite ext4_hash_test_suite = {
        .name = "ext4_hash",
        .test_cases = ext4_hash_test_cases,
};

kunit_test_suites(&ext4_hash_test_suite);

MODULE_LICENSE("GPL");