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sceNp/vm: Fix strings read, implement safe string reader

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Eladash 2023-12-11 08:45:38 +02:00 • committed by Elad Ashkenazi
parent 8ebb7b4952
commit 60baa49007
6 changed files with 113 additions and 72 deletions
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78
rpcs3/Emu/Memory/vm.cpp
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@ -2323,6 +2323,54 @@ namespace vm
return 0;
}
bool read_string(u32 addr, u32 max_size, std::string& out_string, bool check_pages) noexcept
{
if (!max_size)
{
return true;
}
// Prevent overflow
const u32 size = 0 - max_size < addr ? (0 - addr) : max_size;
for (u32 i = addr, end = utils::align(addr + size, 4096) - 1; i <= end;)
{
if (check_pages && !vm::check_addr(i, vm::page_readable))
{
// Invalid string termination
return false;
}
const char* s_start = vm::get_super_ptr<const char>(i);
const u32 space = std::min<u32>(end - i + 1, 4096 - (i % 4096));
const char* s_end = s_start + space;
const char* s_null = std::find(s_start, s_end, '\0');
// Append string
out_string.append(s_start, s_null);
// Recheck for zeroes after append
const usz old_size = out_string.size();
out_string.erase(std::find(out_string.end() - (s_null - s_start), out_string.end(), '\0'), out_string.end());
if (out_string.size() != old_size || s_null != s_end)
{
// Null terminated
return true;
}
i += space;
if (!i)
{
break;
}
}
// Non-null terminated but terminated by size limit (so the string may continue)
return size == max_size;
}
}
void fmt_class_string<vm::_ptr_base<const void, u32>>::format(std::string& out, u64 arg)
@ -2339,8 +2387,8 @@ void fmt_class_string<vm::_ptr_base<const char, u32>>::format(std::string& out,
return;
}
// Filter certainly invalid addresses (TODO)
if (arg < 0x10000 || arg >= 0xf0000000)
// Filter certainly invalid addresses
if (!vm::check_addr(arg, vm::page_readable))
{
out += reinterpret_cast<const char*>(u8"«INVALID_ADDRESS:");
fmt_class_string<u32>::format(out, arg);
@ -2352,26 +2400,14 @@ void fmt_class_string<vm::_ptr_base<const char, u32>>::format(std::string& out,
out += reinterpret_cast<const char*>(u8"“");
for (vm::_ptr_base<const volatile char, u32> ptr = vm::cast(arg);; ptr++)
if (!vm::read_string(arg, umax, out, true))
{
if (!vm::check_addr(ptr.addr()))
{
// TODO: optimize checks
out.resize(start);
out += reinterpret_cast<const char*>(u8"«INVALID_ADDRESS:");
fmt_class_string<u32>::format(out, arg);
out += reinterpret_cast<const char*>(u8"»");
return;
}
if (const char ch = *ptr)
{
out += ch;
}
else
{
break;
}
// Revert changes
out.resize(start);
out += reinterpret_cast<const char*>(u8"«INVALID_ADDRESS:");
fmt_class_string<u32>::format(out, arg);
out += reinterpret_cast<const char*>(u8"»");
return;
}
out += reinterpret_cast<const char*>(u8"”");