parse_54.c

Go to the documentation of this file.

// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: 2021 Heersin <teablearcher@gmail.com>
 
#include "luac_specs_54.h"
 
static void lua_load_block(RzBuffer *buffer, void *dest, size_t size, ut64 offset, ut64 data_size) {
    if (offset + size > data_size) {
        RZ_LOG_ERROR("Truncated load block at 0x%llx\n", offset);
        return;
    }
    rz_buf_read_at(buffer, offset, dest, size);
}
 
static ut64 lua_load_integer(RzBuffer *buffer, ut64 offset) {
    ut64 x = 0;
    rz_buf_read_le64_at(buffer, offset, &x);
    return x;
}
 
static double lua_load_number(RzBuffer *buffer, ut64 offset) {
    double x = 0;
    rz_buf_read_le64_at(buffer, offset, (ut64 *)&x);
    return x;
}
 
// return an offset to skip string, return 1 if no string (0x80)
// TODO : clean type related issues
static ut64 lua_parse_szint(RzBuffer *buffer, int *size, ut64 offset, ut64 data_size) {
    int x = 0;
    int b;
    int i = 0;
    ut32 limit = (~(ut32)0);
    limit >>= 7;
 
    // 1 byte at least
    if (offset + 1 > data_size) {
        RZ_LOG_ERROR("Truncated integer size at 0x%llx\n", offset);
        return 0;
    }
 
    do {
        ut8 tmp;
        if (!rz_buf_read8_at(buffer, offset + i, &tmp)) {
            return 0;
        }
 
        b = tmp;
 
        i += 1;
        if (x >= limit) {
            RZ_LOG_ERROR("integer overflow while decoding integer size\n");
            return 0;
        }
        x = (x << 7) | (b & 0x7f);
    } while (((b & 0x80) == 0) && (i + offset < data_size));
 
    *size = x;
    return i;
}
 
static ut64 lua_parse_string(RzBuffer *buffer, ut8 **dest, int *str_len, ut64 offset, ut64 data_size) {
    ut64 size_offset;
    ut64 total_offset;
    int ret_buf_size;
    int string_len;
    ut8 *ret;
 
    size_offset = lua_parse_szint(buffer, &ret_buf_size, offset, data_size);
    lua_check_error_offset(size_offset);
 
    /* no string */
    if (ret_buf_size == 0) {
        ret = NULL;
        string_len = 0;
    } else {
        /* skip size byte */
        string_len = ret_buf_size - 1;
        if ((ret = RZ_NEWS(ut8, ret_buf_size)) == NULL) {
            string_len = 0;
        } else {
            rz_buf_read_at(buffer, offset + size_offset, ret, string_len);
            ret[string_len] = 0x00;
        }
    }
 
    /* set to outside vars */
    if (dest && str_len) {
        *dest = ret;
        *str_len = string_len;
    } else {
        RZ_LOG_ERROR("cannot store string\n");
    }
 
    total_offset = size_offset + string_len;
    return total_offset;
}
 
static ut64 lua_parse_name(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    return lua_parse_string(buffer, &proto->proto_name, &proto->name_size, offset, data_size);
}
 
static ut64 lua_parse_line_defined(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    ut64 size_offset;
    ut64 delta_offset;
    int line_defined;
    int last_line_defined;
 
    size_offset = lua_parse_szint(buffer, &line_defined, offset, data_size);
    lua_check_error_offset(size_offset);
 
    delta_offset = lua_parse_szint(buffer, &last_line_defined, offset + size_offset, data_size);
    lua_check_error_offset(delta_offset);
 
    size_offset += delta_offset;
 
    /* Set Proto Member */
    proto->line_defined = line_defined;
    proto->lastline_defined = last_line_defined;
 
    return size_offset;
}
 
static ut64 lua_parse_code(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    ut64 size_offset;
    ut64 total_size;
    int code_size;
 
    size_offset = lua_parse_szint(buffer, &code_size, offset, data_size);
    lua_check_error_offset(size_offset);
    total_size = code_size * 4 + size_offset;
 
    if (total_size + offset > data_size) {
        RZ_LOG_ERROR("Truncated Code at [0x%llx]\n", offset);
        return 0;
    }
 
    /* Set Proto Member */
    proto->code_size = code_size * 4;
    proto->code_skipped = size_offset;
 
    return total_size;
}
 
static ut64 lua_parse_const_entry(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    LuaConstEntry *current_entry;
    ut64 base_offset;
    ut8 *recv_data;
    ut64 delta_offset;
    int data_len;
 
    current_entry = lua_new_const_entry();
    current_entry->offset = offset;
    base_offset = offset;
    delta_offset = 0;
 
    /* read TAG byte */
    if (offset + 1 > data_size) {
        return 0;
    }
 
    if (!rz_buf_read8_at(buffer, offset, &current_entry->tag)) {
        return 0;
    }
 
    offset += 1;
 
    /* read data */
    // TODO : replace 8 with Macro
    switch (current_entry->tag) {
    case LUA_VNUMFLT:
    case LUA_VNUMINT:
        data_len = 8;
        recv_data = RZ_NEWS(ut8, data_len);
        lua_load_block(buffer, recv_data, data_len, offset, data_size);
        if (offset + data_len > data_size) {
            return 0;
        }
        delta_offset = data_len;
        break;
    case LUA_VSHRSTR:
    case LUA_VLNGSTR:
        delta_offset = lua_parse_string(buffer, &recv_data, &data_len, offset, data_size);
        lua_check_error_offset(delta_offset);
        break;
    case LUA_VNIL:
    case LUA_VFALSE:
    case LUA_VTRUE:
    default:
        recv_data = NULL;
        data_len = 0;
        delta_offset = 0;
        break;
    }
 
    offset += delta_offset;
 
    current_entry->data = recv_data;
    current_entry->data_len = data_len;
 
    /* add to list */
    rz_list_append(proto->const_entries, current_entry);
 
    return offset - base_offset;
}
 
static ut64 lua_parse_consts(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    int consts_cnt;
    int i;
    ut64 base_offset;
    ut64 delta_offset;
 
    base_offset = offset;
 
    /* parse number of constants */
    delta_offset = lua_parse_szint(buffer, &consts_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
 
    for (i = 0; i < consts_cnt; ++i) {
        // add an entry of constant
        delta_offset = lua_parse_const_entry(proto, buffer, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
    }
 
    proto->const_size = offset - base_offset + 1;
    return offset - base_offset;
}
 
static ut64 lua_parse_upvalue_entry(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    LuaUpvalueEntry *current_entry;
    ut64 base_offset;
 
    base_offset = offset;
    current_entry = lua_new_upvalue_entry();
    current_entry->offset = base_offset;
 
    if (offset + 3 > data_size) {
        return 0;
    }
 
    /* read instack/idx/kind attr */
    if (!rz_buf_read8_at(buffer, offset + 0, &current_entry->instack)) {
        return 0;
    }
 
    if (!rz_buf_read8_at(buffer, offset + 1, &current_entry->idx)) {
        return 0;
    }
 
    if (!rz_buf_read8_at(buffer, offset + 2, &current_entry->kind)) {
        return 0;
    }
 
    offset += 3;
 
    /* add to list */
    rz_list_append(proto->upvalue_entries, current_entry);
 
    return offset - base_offset;
}
 
static ut64 lua_parse_upvalues(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    int upvalues_cnt;
    int i;
    ut64 base_offset;
    ut64 delta_offset;
 
    base_offset = offset;
 
    /* parse number of upvalues */
    delta_offset = lua_parse_szint(buffer, &upvalues_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
 
    for (i = 0; i < upvalues_cnt; ++i) {
        delta_offset = lua_parse_upvalue_entry(proto, buffer, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
    }
 
    proto->upvalue_size = offset - base_offset + 1;
 
    return offset - base_offset;
}
static ut64 lua_parse_debug(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    int entries_cnt;
    int i;
    ut64 base_offset;
    ut64 delta_offset;
 
    base_offset = offset;
 
    /* parse line info */
    delta_offset = lua_parse_szint(buffer, &entries_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
    LuaLineinfoEntry *info_entry;
    for (i = 0; i < entries_cnt; ++i) {
        info_entry = lua_new_lineinfo_entry();
        info_entry->offset = offset;
        ut8 tmp;
        if (!rz_buf_read8_at(buffer, offset, &tmp)) {
            free(info_entry);
            return 0;
        }
        info_entry->info_data = tmp;
        rz_list_append(proto->line_info_entries, info_entry);
        offset += 1;
    }
 
    /* parse absline info */
    delta_offset = lua_parse_szint(buffer, &entries_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
    LuaAbsLineinfoEntry *abs_info_entry;
    for (i = 0; i < entries_cnt; ++i) {
        abs_info_entry = lua_new_abs_lineinfo_entry();
        abs_info_entry->offset = offset;
 
        delta_offset = lua_parse_szint(buffer, &abs_info_entry->pc, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        delta_offset = lua_parse_szint(buffer, &abs_info_entry->line, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        rz_list_append(proto->abs_line_info_entries, abs_info_entry);
    }
 
    /* parse local vars */
    delta_offset = lua_parse_szint(buffer, &entries_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
    LuaLocalVarEntry *var_entry;
    for (i = 0; i < entries_cnt; ++i) {
        var_entry = lua_new_local_var_entry();
        var_entry->offset = offset;
 
        /* string */
        delta_offset = lua_parse_string(
            buffer,
            &var_entry->varname, &var_entry->varname_len,
            offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        /* start pc -- int */
        delta_offset = lua_parse_szint(buffer, &var_entry->start_pc, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        /* end pc -- int */
        delta_offset = lua_parse_szint(buffer, &var_entry->end_pc, offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        rz_list_append(proto->local_var_info_entries, var_entry);
    }
 
    /* parse upvalue */
    delta_offset = lua_parse_szint(buffer, &entries_cnt, offset, data_size);
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
    LuaDbgUpvalueEntry *dbg_upvalue_entry;
    for (i = 0; i < entries_cnt; ++i) {
        dbg_upvalue_entry = lua_new_dbg_upvalue_entry();
        dbg_upvalue_entry->offset = offset;
 
        delta_offset = lua_parse_string(
            buffer,
            &dbg_upvalue_entry->upvalue_name, &dbg_upvalue_entry->name_len,
            offset, data_size);
        lua_check_error_offset(delta_offset);
        offset += delta_offset;
 
        rz_list_append(proto->dbg_upvalue_entries, dbg_upvalue_entry);
    }
 
    proto->debug_size = offset - base_offset + 1;
    return offset - base_offset;
}
 
static ut64 lua_parse_protos(LuaProto *proto, RzBuffer *buffer, ut64 offset, ut64 data_size) {
    rz_return_val_if_fail(proto, 0);
 
    int proto_cnt;
    int i;
    ut64 base_offset;
    ut64 delta_offset;
 
    base_offset = offset; // store origin offset
    delta_offset = lua_parse_szint(buffer, &proto_cnt, offset, data_size); // skip size bytes
    lua_check_error_offset(delta_offset);
    offset += delta_offset;
 
    LuaProto *current_proto;
    for (i = 0; i < proto_cnt; ++i) {
        current_proto = lua_parse_body_54(buffer, offset, data_size);
        lua_return_if_null(current_proto);
        rz_list_append(proto->proto_entries, current_proto);
        offset += current_proto->size - 1; // update offset
    }
 
    // return the delta between offset and base_offset
    return offset - base_offset;
}
 
LuaProto *lua_parse_body_54(RzBuffer *buffer, ut64 base_offset, ut64 data_size) {
    LuaProto *ret_proto; /* construted proto for return */
    ut64 offset; /* record offset */
    ut64 delta_offset;
    rz_return_val_if_fail((ret_proto = lua_new_proto_entry()), NULL);
 
    // start parsing
    offset = base_offset;
 
    /* record offset of main proto */
    ret_proto->offset = offset;
 
    /* parse proto name of main proto */
    delta_offset = lua_parse_name(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* parse line defined info */
    delta_offset = lua_parse_line_defined(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* parse num params max_stack_size */
    if (offset + 3 > data_size) {
        lua_free_proto_entry(ret_proto);
        return NULL;
    }
 
    if (!rz_buf_read8_at(buffer, offset + 0, &ret_proto->num_params) ||
        !rz_buf_read8_at(buffer, offset + 1, &ret_proto->is_vararg) ||
        !rz_buf_read8_at(buffer, offset + 2, &ret_proto->max_stack_size)) {
        lua_free_proto_entry(ret_proto);
        return NULL;
    }
    offset += 3;
 
    /* parse code */
    ret_proto->code_offset = offset;
    delta_offset = lua_parse_code(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* parse constants */
    ret_proto->const_offset = offset;
    delta_offset = lua_parse_consts(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* parse upvalues */
    ret_proto->upvalue_offset = offset;
    delta_offset = lua_parse_upvalues(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* parse inner protos */
    ret_proto->inner_proto_offset = offset;
    delta_offset = lua_parse_protos(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    /* specially handle recursive protos size */
    ret_proto->inner_proto_size = offset - ret_proto->inner_proto_offset;
 
    /* parse debug */
    ret_proto->debug_offset = offset;
    delta_offset = lua_parse_debug(ret_proto, buffer, offset, data_size);
    lua_check_error_offset_proto(delta_offset, ret_proto);
    offset += delta_offset;
 
    ret_proto->size = offset - base_offset + 1;
 
    return ret_proto;
}
 
RzBinInfo *lua_parse_header_54(RzBinFile *bf, st32 major, st32 minor) {
    RzBinInfo *ret = NULL;
    RzBuffer *buffer;
 
    st64 reat = bf->size;
    if (reat < LUAC_54_HDRSIZE) {
        RZ_LOG_ERROR("Truncated Header\n");
        return NULL;
    }
    buffer = bf->buf;
 
    /* read header members from work buffer */
    ut8 luac_format;
    if (!rz_buf_read8_at(buffer, LUAC_54_FORMAT_OFFSET, &luac_format)) {
        return NULL;
    }
 
    ut8 instruction_size;
    if (!rz_buf_read8_at(buffer, LUAC_54_INSTRUCTION_SIZE_OFFSET, &instruction_size)) {
        return NULL;
    }
 
    ut8 integer_size;
    if (!rz_buf_read8_at(buffer, LUAC_54_INTEGER_SIZE_OFFSET, &integer_size)) {
        return NULL;
    }
 
    ut8 number_size;
    if (!rz_buf_read8_at(buffer, LUAC_54_NUMBER_SIZE_OFFSET, &number_size)) {
        return NULL;
    }
 
    ut64 int_valid = lua_load_integer(buffer, LUAC_54_INTEGER_VALID_OFFSET);
    double number_valid = lua_load_number(buffer, LUAC_54_NUMBER_VALID_OFFSET);
 
    /* Common Ret */
    if (!(ret = RZ_NEW0(RzBinInfo))) {
        return NULL;
    }
    ret->file = rz_str_new(bf->file);
    ret->type = rz_str_newf("Lua %c.%c compiled file", major + '0', minor + '0');
    ret->bclass = rz_str_new("Lua compiled file");
    ret->rclass = rz_str_new("luac");
    ret->arch = rz_str_new("luac");
    ret->machine = rz_str_newf("Lua %c.%c VM", major + '0', minor + '0');
    ret->os = rz_str_newf("%c.%c", major + '0', minor + '0');
    ret->cpu = rz_str_newf("%c.%c", major + '0', minor + '0');
    ret->bits = 8;
 
    /* official format ? */
    if (luac_format != LUAC_54_FORMAT) {
        ret->compiler = rz_str_new("Unofficial Lua Compiler");
        return ret;
    }
    ret->compiler = rz_str_new("Official Lua Compiler");
 
    /* Check Size */
    if ((instruction_size != sizeof(LUA_INSTRUCTION)) ||
        (integer_size != sizeof(LUA_INTEGER)) ||
        (number_size != sizeof(LUA_NUMBER))) {
        RZ_LOG_ERROR("Size definition does not match with the expected size\n");
        return ret;
    }
 
    /* Check endian */
    if (int_valid != LUAC_54_INT_VALIDATION) {
        RZ_LOG_ERROR("Integer format does not match with the expected integer\n");
        return ret;
    } else if (number_valid != LUAC_54_NUMBER_VALIDATION) {
        RZ_LOG_ERROR("Number format does not match with the expected number\n");
        return ret;
    }
 
    /* parse source file name */
    char *src_file_name = NULL;
    int name_len;
    lua_parse_string(buffer, ((ut8 **)&(src_file_name)), &name_len, LUAC_FILENAME_OFFSET, bf->size);
 
    /* put source file info into GUID */
    ret->guid = rz_str_new(src_file_name ? src_file_name : "stripped");
    free(src_file_name);
 
    return ret;
}