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dingusppc/devices/common/ofnvram.cpp
joevt 439509b408 Fix New World NVRAM limits calculations. 
It was possible to corrupt New World nvram using dingusppc setenv command.

- setenv must call get_config_vars to set data_length so that it can calculate free space.
- data_length represents the number of bytes taken by nvram variables including the terminating null for the value (name, '=', value, '\0'). Previously, it did not include the terminating null.
- The list of variables and values ends at a '\0' or at pos == 4096 bytes. Previously, data_length wouldn't get set if pos >= 4096.
- Allow setenv to create new nvram variables.
- Since data_length now represents the total number of used bytes, free_space now represents the actual free space, so use > free_space (instead of >= free_space) to determine insufficient space.
- While parsing nvram variable name, do not read beyond 4096 bytes.
- Use a different error message for each problem that can occur while parsing nvram variable name.
2023-08-04 20:11:59 -07:00

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/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-23 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/** Utilities for working with Apple Open Firmware and CHRP NVRAM partitions. */
#include <devices/common/ofnvram.h>
#include <endianswap.h>
#include <loguru.hpp>
#include <machines/machinebase.h>
#include <memaccess.h>
#include <cinttypes>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <sstream>
#include <string>
#include <tuple>
using namespace std;
static std::string hex2str(uint32_t n)
{
std::stringstream ss;
ss << setw(8) << setfill('0') << hex << n;
return ss.str();
}
static uint32_t str2env(string& num_str) {
try {
return (uint32_t)stoul(num_str, NULL, 0);
} catch (invalid_argument& exc) {
try {
string num_str2 = string("0x") + num_str;
return std::stoul(num_str2, NULL, 0);
} catch (invalid_argument& exc) {
throw invalid_argument(string("Cannot convert ") + num_str);
}
}
}
bool OfConfigAppl::validate() {
int i;
OfConfigHdrAppl hdr;
if (this->nvram_obj == nullptr)
return false;
// read OF partition header
for (i = 0; i < sizeof(OfConfigHdrAppl); i++) {
((uint8_t*)&hdr)[i] = this->nvram_obj->read_byte(OF_NVRAM_OFFSET + i);
}
// validate partition signature and version
if (BYTESWAP_16(hdr.sig) != OF_NVRAM_SIG || hdr.version != 5)
return false;
this->size = hdr.num_pages * 256;
if (this->size != OF_CFG_SIZE)
return false;
// read the entire partition into the local buffer
for (i = 0; i < this->size; i++) {
this->buf[i] = this->nvram_obj->read_byte(OF_NVRAM_OFFSET + i);
}
// verify partition checksum
if (this->checksum_partition() ^ 0xFFFFU)
return false;
return true;
}
uint16_t OfConfigAppl::checksum_partition() {
uint32_t acc = 0;
for (int i = 0; i < this->size; i += 2) {
acc += READ_WORD_BE_A(&this->buf[i]);
}
return acc + (acc >> 16);
}
static const string flag_names[8] = {
"little-endian?",
"real-mode?",
"auto-boot?",
"diag-switch?",
"fcode-debug?",
"oem-banner?",
"oem-logo?",
"use-nvramrc?"
};
static const map<string, std::tuple<int, uint16_t>> of_vars = {
// name, type, offset
{"real-base", {OF_VAR_TYPE_INT, 0x10}},
{"real-size", {OF_VAR_TYPE_INT, 0x14}},
{"virt-base", {OF_VAR_TYPE_INT, 0x18}},
{"virt-size", {OF_VAR_TYPE_INT, 0x1C}},
{"load-base", {OF_VAR_TYPE_INT, 0x20}},
{"pci-probe-list", {OF_VAR_TYPE_INT, 0x24}},
{"screen-#columns", {OF_VAR_TYPE_INT, 0x28}},
{"screen-#rows", {OF_VAR_TYPE_INT, 0x2C}},
{"selftest-#megs", {OF_VAR_TYPE_INT, 0x30}},
{"boot-device", {OF_VAR_TYPE_STR, 0x34}},
{"boot-file", {OF_VAR_TYPE_STR, 0x38}},
{"diag-device", {OF_VAR_TYPE_STR, 0x3C}},
{"diag-file", {OF_VAR_TYPE_STR, 0x40}},
{"input-device", {OF_VAR_TYPE_STR, 0x44}},
{"output-device", {OF_VAR_TYPE_STR, 0x48}},
{"oem-banner", {OF_VAR_TYPE_STR, 0x4C}},
{"oem-logo", {OF_VAR_TYPE_STR, 0x50}},
{"nvramrc", {OF_VAR_TYPE_STR, 0x54}},
{"boot-command", {OF_VAR_TYPE_STR, 0x58}},
};
const OfConfigImpl::config_dict& OfConfigAppl::get_config_vars() {
this->_config_vars.clear();
if (!this->validate())
return _config_vars;
uint8_t of_flags = this->buf[12];
// populate flags
for (int i = 0; i < 8; i++) {
_config_vars.push_back(std::make_pair(flag_names[i],
((of_flags << i) & 0x80) ? "true" : "false"));
}
// populate the remaining variables
for (auto& var : of_vars) {
auto name = var.first;
auto type = std::get<0>(var.second);
auto offset = std::get<1>(var.second);
switch (type) {
case OF_VAR_TYPE_INT:
_config_vars.push_back(std::make_pair(name,
hex2str(READ_DWORD_BE_A(&this->buf[offset]))));
break;
case OF_VAR_TYPE_STR:
uint16_t str_offset = READ_WORD_BE_A(&this->buf[offset]) - OF_NVRAM_OFFSET;
uint16_t str_len = READ_WORD_BE_A(&this->buf[offset+2]);
if ((str_offset + str_len) > OF_CFG_SIZE) {
cout << "string property too long - skip it" << endl;
break;
}
char prop_val[OF_CFG_SIZE] = "";
memcpy(prop_val, &this->buf[str_offset], str_len);
prop_val[str_len] = '\0';
_config_vars.push_back(std::make_pair(name, prop_val));
}
}
return _config_vars;
}
void OfConfigAppl::update_partition() {
// set checksum in the header to zero
this->buf[4] = 0;
this->buf[5] = 0;
// calculate new checksum
uint16_t checksum = this->checksum_partition();
checksum = checksum ? ~checksum : 0xFFFFU;
// stuff checksum into the header
WRITE_WORD_BE_A(&this->buf[4], checksum);
// write the entire partition back to NVRAM
for (int i = 0; i < this->size; i++) {
this->nvram_obj->write_byte(OF_NVRAM_OFFSET + i, this->buf[i]);
}
}
bool OfConfigAppl::set_var(std::string& var_name, std::string& value) {
int i, flag;
if (!this->validate())
return false;
// check if the user tries to change a flag
for (i = 0; i < 8; i++) {
if (var_name == flag_names[i]) {
if (value == "true")
flag = 1;
else if (value == "false")
flag = 0;
else {
cout << "Invalid property value: " << value << endl;
return false;
}
uint8_t flag_bit = 0x80U >> i;
uint8_t of_flags = this->buf[12];
if (flag)
of_flags |= flag_bit;
else
of_flags &= ~flag_bit;
this->buf[12] = of_flags;
this->update_partition();
return true;
}
}
// see if one of the standard properties should be changed
if (of_vars.find(var_name) == of_vars.end()) {
cout << "Attempt to change unknown variable " << var_name << endl;
return false;
}
auto type = std::get<0>(of_vars.at(var_name));
auto offset = std::get<1>(of_vars.at(var_name));
if (type == OF_VAR_TYPE_INT) {
uint32_t num;
try {
num = str2env(value);
} catch (invalid_argument& exc) {
cout << exc.what() << endl;
return false;
}
WRITE_DWORD_BE_A(&this->buf[offset], num);
this->update_partition();
cout << " ok" << endl; // mimic Forth
} else {
uint16_t str_offset = READ_WORD_BE_A(&this->buf[offset]);
uint16_t str_len = READ_WORD_BE_A(&this->buf[offset+2]);
OfConfigHdrAppl *hdr = (OfConfigHdrAppl *)&this->buf[0];
uint16_t here = READ_WORD_BE_A(&hdr->here);
uint16_t top = READ_WORD_BE_A(&hdr->top);
// check if there is enough space in the heap for the new string
// the heap is grown down from offset 0x2000 and cannot be lower than here (0x185c)
uint16_t new_top = top + str_len - value.length();
if (new_top < here) {
cout << "No room in the heap!" << endl;
return false;
}
// remove the old string
std::memmove(&this->buf[top + str_len - OF_NVRAM_OFFSET],
&this->buf[top - OF_NVRAM_OFFSET], str_offset - top);
for (auto& var : of_vars) {
auto type = std::get<0>(var.second);
auto offset = std::get<1>(var.second);
if (type == OF_VAR_TYPE_STR) {
uint16_t i_str_offset = READ_WORD_BE_A(&this->buf[offset]);
if (i_str_offset < str_offset) {
WRITE_WORD_BE_A(&this->buf[offset], i_str_offset + str_len);
}
}
}
top = new_top;
// copy new string into NVRAM buffer char by char
i = 0;
for(char& ch : value) {
this->buf[top + i - OF_NVRAM_OFFSET] = ch == '\x0A' ? '\x0D' : ch;
i++;
}
// stuff new values into the variable state
WRITE_WORD_BE_A(&this->buf[offset+0], top);
WRITE_WORD_BE_A(&this->buf[offset+2], value.length());
// update partition header
WRITE_WORD_BE_A(&hdr->top, top);
// update physical NVRAM
this->update_partition();
}
return true;
}
uint8_t OfConfigChrp::checksum_hdr(const uint8_t* data)
{
uint16_t sum = data[0];
for (int i = 2; i < 16; i++) {
sum += data[i];
if (sum >= 256)
sum = (sum + 1) & 0xFFU;
}
return sum;
}
bool OfConfigChrp::validate()
{
int i, pos, len;
uint8_t sig;
bool wip = true;
bool of_part_found = false;
// search the entire 8KB NVRAM for CHRP OF config partition.
// Bail out if an unknown partition or free space is encountered.
// Skip over known partitions.
for (pos = 0; wip && pos < 8192;) {
sig = this->nvram_obj->read_byte(pos);
switch (sig) {
case NVRAM_SIG_OF_ENV:
of_part_found = true;
// fall-through
case NVRAM_SIG_FREE:
wip = false;
break;
case NVRAM_SIG_VPD:
case NVRAM_SIG_DIAG:
case NVRAM_SIG_OF_CFG:
case NVRAM_SIG_MAC_OS:
case NVRAM_SIG_ERR_LOG:
// skip valid partitions we're not interested in
len = (this->nvram_obj->read_byte(pos + 2) << 8) |
this->nvram_obj->read_byte(pos + 3);
if (!len || (len * 16) >= 8192)
break;
pos += len * 16;
break;
default:
wip = false;
}
}
if (!of_part_found)
return false;
OfConfigHdrChrp hdr;
// read OF partition header
for (i = 0; i < sizeof(OfConfigHdrChrp); i++) {
((uint8_t*)&hdr)[i] = this->nvram_obj->read_byte(pos + i);
}
len = BYTESWAP_16(hdr.length) * 16;
// sanity checks
if (hdr.sig != NVRAM_SIG_OF_ENV || len < 16 || len > (4096 + sizeof(OfConfigHdrChrp)))
return false;
// calculate partition header checksum
uint8_t chk_sum = this->checksum_hdr((uint8_t*)&hdr);
if (chk_sum != hdr.checksum)
return false;
len -= sizeof(OfConfigHdrChrp);
pos += sizeof(OfConfigHdrChrp);
this->data_offset = pos;
// read the entire partition into the local buffer
for (i = 0; i < len; i++) {
this->buf[i] = this->nvram_obj->read_byte(pos + i);
}
return true;
}
const OfConfigImpl::config_dict& OfConfigChrp::get_config_vars() {
int len;
this->_config_vars.clear();
this->data_length = 0;
if (!this->validate())
return _config_vars;
for (int pos = 0; pos < 4096;) {
char *pname = (char *)&this->buf[pos];
bool got_name = false;
// scan property name until '=' is encountered
// or max length is reached
for (len = 0; ; pos++, len++) {
if (len >= 32) {
cout << "name > 31 chars" << endl;
break;
}
if (pos >= 4096) {
cout << "no = sign before end of partition" << endl;
break;
}
if (pname[len] == '=') {
if (len) {
got_name = true;
}
else {
cout << "got = sign but no name" << endl;
}
break;
}
if (pname[len] == '\0') {
if (len) {
cout << "no = sign before termminating null" << endl;
}
else {
// empty property name -> free space reached
}
break;
}
}
if (!got_name) {
break;
}
char prop_name[32];
memcpy(prop_name, pname, len);
prop_name[len] = '\0';
pos++; // skip past '='
char *pval = (char *)&this->buf[pos];
// determine property value length
for (len = 0; pos < 4096; pos++, len++) {
if (pval[len] == '\0')
break;
}
// ensure each property value is null-terminated
if (pos >= 4096) {
cout << "ran off partition end" << endl;
break;
}
this->_config_vars.push_back(std::make_pair(prop_name, pval));
pos++; // skip past null terminator
this->data_length = pos; // point to after null
}
//cout << "Read " << this->data_length << " bytes from nvram." << endl;
return this->_config_vars;
}
bool OfConfigChrp::update_partition() {
unsigned pos = 0;
memset(this->buf, 0, 4096);
for (auto& var : this->_config_vars) {
if ((pos + var.first.length() + var.second.length() + 2) > 4096) {
cout << "No room in the partition!" << endl;
return false;
}
memcpy(&this->buf[pos], var.first.c_str(), var.first.length());
pos += var.first.length();
this->buf[pos++] = '=';
memcpy(&this->buf[pos], var.second.c_str(), var.second.length());
pos += var.second.length();
this->buf[pos++] = '\0';
}
// write the entire partition back to NVRAM
for (int i = 0; i < 4096; i++) {
this->nvram_obj->write_byte(this->data_offset + i, this->buf[i]);
}
//cout << "Wrote " << pos << " bytes to nvram." << endl;
return true;
}
bool OfConfigChrp::set_var(std::string& var_name, std::string& value) {
if (!this->validate())
return false;
// see if we're about to change a flag
if (var_name.back() == '?') {
if (value != "true" && value != "false") {
cout << "Flag value can be 'true' or 'false'" << endl;
return false;
}
}
unsigned free_space = 4096 - this->data_length;
bool found = false;
// see if the user tries to change an existing property
for (auto& var : this->_config_vars) {
if (var.first == var_name) {
found = true;
if (value.length() > var.second.length()) {
if ((value.length() - var.second.length()) > free_space) {
cout << "No room for updated nvram variable!" << endl;
return false;
}
}
var.second = value;
break;
}
}
if (!found) {
if ((var_name.length() + value.length() + 2) > free_space) {
cout << "No room for new nvram variable!" << endl;
return false;
}
this->_config_vars.push_back(std::make_pair(var_name, value));
}
return this->update_partition();
}
int OfConfigUtils::init()
{
this->nvram_obj = dynamic_cast<NVram*>(gMachineObj->get_comp_by_name("NVRAM"));
return this->nvram_obj == nullptr;
}
bool OfConfigUtils::open_container() {
OfConfigImpl* cfg_obj;
if (this->cfg_impl == nullptr) {
cfg_obj = new OfConfigAppl(this->nvram_obj);
if (cfg_obj->validate()) {
this->cfg_impl = std::unique_ptr<OfConfigImpl>(cfg_obj);
return true;
} else {
delete(cfg_obj);
cfg_obj = new OfConfigChrp(this->nvram_obj);
if (cfg_obj->validate()) {
this->cfg_impl = std::unique_ptr<OfConfigImpl>(cfg_obj);
return true;
} else {
delete(cfg_obj);
}
}
} else {
return this->cfg_impl->validate();
}
cout << "No valid Open Firmware partition found!" << endl;
return false;
}
static std::string ReplaceAll(std::string& str, const std::string& from, const std::string& to) {
size_t start_pos = 0;
while((start_pos = str.find(from, start_pos)) != std::string::npos) {
str.replace(start_pos, from.length(), to);
start_pos += to.length(); // Handles case where 'to' is a substring of 'from'
}
return str;
}
void OfConfigUtils::printenv() {
if (!this->open_container())
return;
OfConfigImpl::config_dict vars = this->cfg_impl->get_config_vars();
for (auto& var : vars) {
std::string val = var.second;
ReplaceAll(val, "\r\n", "\n");
ReplaceAll(val, "\r", "\n");
ReplaceAll(val, "\n", "\n "); // 34 spaces
cout << setw(34) << left << var.first << val << endl; // name column has width 34
}
}
void OfConfigUtils::setenv(string var_name, string value)
{
if (!this->open_container())
return;
OfConfigImpl::config_dict vars = this->cfg_impl->get_config_vars();
if (!this->cfg_impl->set_var(var_name, value)) {
cout << " Please try again" << endl;
} else {
cout << " ok" << endl; // mimic Forth
}
}
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