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key_manager: Don't assume file seeks and reads will always succeed

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Given the filesystem should always be assumed to be volatile, we should
check and bail out if a seek operation isn't successful. This'll prevent
potentially writing/returning garbage data from the function in rare
cases.

This also allows removing a check to see if an offset is within the
bounds of a file before perfoming a seek operation. If a seek is
attempted beyond the end of a file, it will fail, so this essentially
combines two checks into one in one place.
This commit is contained in:
Lioncash 2018-10-13 08:12:00 -04:00
parent 82ea1cf35a
commit ef5639bfbb
1 changed files with 17 additions and 7 deletions
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28
src/core/crypto/key_manager.cpp
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@ -147,30 +147,38 @@ boost::optional<Key128> DeriveSDSeed() {
"rb+"); "rb+");
if (!save_43.IsOpen()) if (!save_43.IsOpen())
return boost::none; return boost::none;
const FileUtil::IOFile sd_private( const FileUtil::IOFile sd_private(
FileUtil::GetUserPath(FileUtil::UserPath::SDMCDir) + "/Nintendo/Contents/private", "rb+"); FileUtil::GetUserPath(FileUtil::UserPath::SDMCDir) + "/Nintendo/Contents/private", "rb+");
if (!sd_private.IsOpen()) if (!sd_private.IsOpen())
return boost::none; return boost::none;
std::array<u8, 0x10> private_seed{}; std::array<u8, 0x10> private_seed{};
if (sd_private.ReadBytes(private_seed.data(), private_seed.size()) != 0x10) if (sd_private.ReadBytes(private_seed.data(), private_seed.size()) != private_seed.size()) {
return boost::none; return boost::none;
}
std::array<u8, 0x10> buffer{}; std::array<u8, 0x10> buffer{};
std::size_t offset = 0; std::size_t offset = 0;
for (; offset + 0x10 < save_43.GetSize(); ++offset) { for (; offset + 0x10 < save_43.GetSize(); ++offset) {
save_43.Seek(offset, SEEK_SET); if (!save_43.Seek(offset, SEEK_SET)) {
save_43.ReadBytes(buffer.data(), buffer.size()); return boost::none;
if (buffer == private_seed)
break;
} }
if (offset + 0x10 >= save_43.GetSize()) save_43.ReadBytes(buffer.data(), buffer.size());
if (buffer == private_seed) {
break;
}
}
if (!save_43.Seek(offset + 0x10, SEEK_SET)) {
return boost::none; return boost::none;
}
Key128 seed{}; Key128 seed{};
save_43.Seek(offset + 0x10, SEEK_SET); if (save_43.ReadBytes(seed.data(), seed.size()) != seed.size()) {
save_43.ReadBytes(seed.data(), seed.size()); return boost::none;
}
return seed; return seed;
} }
@ -233,7 +241,9 @@ std::vector<TicketRaw> GetTicketblob(const FileUtil::IOFile& ticket_save) {
return {}; return {};
std::vector<u8> buffer(ticket_save.GetSize()); std::vector<u8> buffer(ticket_save.GetSize());
ticket_save.ReadBytes(buffer.data(), buffer.size()); if (ticket_save.ReadBytes(buffer.data(), buffer.size()) != buffer.size()) {
return {};
}
std::vector<TicketRaw> out; std::vector<TicketRaw> out;
u32 magic{}; u32 magic{};