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Fix 4 code bugs: substr off-by-one, HANDLE* cast, TOCTOU GetLastError, sun_path overflow #14297

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Merged
benhillis merged 1 commit into from
Feb 27, 2026
Merged

Fix 4 code bugs: substr off-by-one, HANDLE* cast, TOCTOU GetLastError, sun_path overflow #14297

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7 changes: 5 additions & 2 deletions src/linux/init/plan9.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,9 @@ wil::unique_fd CreateUnixServerSocket(const char* path)
}
});

// Check if the path will fit in a sockaddr_un.
// Check if the path will fit in a sockaddr_un (with room for null terminator).
std::string_view pathView{path};
if (pathView.length() > sizeof(sockaddr_un::sun_path))
if (pathView.length() >= sizeof(sockaddr_un::sun_path))
{
// It won't, so split the parent path and child name.
auto index = pathView.find_last_of('/');
Expand All @@ -64,6 +64,9 @@ wil::unique_fd CreateUnixServerSocket(const char* path)
const std::string parent{pathView.substr(0, index)};
pathView = pathView.substr(index + 1);

// Ensure the child name fits in sun_path (with null terminator).
THROW_ERRNO_IF(ENAMETOOLONG, pathView.length() >= sizeof(sockaddr_un::sun_path));

// Get the current working directory to restore it later, and change to the socket's parent
// path.
oldCwd = getcwd(oldCwdBuffer, sizeof(oldCwdBuffer));
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4 changes: 2 additions & 2 deletions src/windows/service/exe/LxssHttpProxy.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -327,12 +327,12 @@ try
if (openBracket != ::std::wstring::npos)
{
const auto closeBracket = portRemoved.find_first_of(L"]");
if (closeBracket == ::std::wstring::npos || (openBracket + 1 >= closeBracket - 1))
if (closeBracket == ::std::wstring::npos || (openBracket + 1 >= closeBracket))
{
// no other of below checks can contain brackets
return UnsupportedProxyReason::Supported;
}
portRemoved = portRemoved.substr(openBracket + 1, closeBracket - 1);
portRemoved = portRemoved.substr(openBracket + 1, closeBracket - openBracket - 1);
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@OneBlue OneBlue Feb 26, 2026

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I wish there was an easy way to add test coverage for this.

If we ever factor IsUnsupportedProxy() in common I guess we could add coverage for this

}

in6_addr addrV6{};
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14 changes: 9 additions & 5 deletions src/windows/service/exe/LxssUserSession.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1737,11 +1737,15 @@ try
RETURN_HR_IF(WSL_E_DISTRO_NOT_STOPPED, m_runningInstances.contains(*DistroGuid));

const wil::unique_hfile vhd{::CreateFileW(configuration.VhdFilePath.c_str(), GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, 0, nullptr)};
if (const DWORD err = GetLastError(); err == ERROR_SHARING_VIOLATION)
if (!vhd)
{
THROW_HR_WITH_USER_ERROR(HRESULT_FROM_WIN32(err), wsl::shared::Localization::MessageVhdInUse());
const DWORD err = GetLastError();
if (err == ERROR_SHARING_VIOLATION)
{
THROW_HR_WITH_USER_ERROR(HRESULT_FROM_WIN32(err), wsl::shared::Localization::MessageVhdInUse());
}
THROW_WIN32(err);
}
THROW_LAST_ERROR_IF(!vhd);

FILE_SET_SPARSE_BUFFER buffer{
.SetSparse = Sparse,
Expand Down Expand Up @@ -1949,7 +1953,7 @@ HRESULT LxssUserSessionImpl::SetVersion(_In_ LPCGUID DistroGuid, _In_ ULONG Vers
auto wsl1Pipe = wsl::windows::common::wslutil::OpenAnonymousPipe(LX_RELAY_BUFFER_SIZE, true, true);

wsl::windows::common::relay::ScopedMultiRelay stdErrRelay(
std::vector<HANDLE>{wsl1Pipe.first.get(), reinterpret_cast<HANDLE*>(vmContext.errorSocket.get())}, onTarOutput);
std::vector<HANDLE>{wsl1Pipe.first.get(), reinterpret_cast<HANDLE>(vmContext.errorSocket.get())}, onTarOutput);

// Add mounts for the rootfs and tools.
auto mounts = _CreateSetupMounts(configuration);
Expand Down Expand Up @@ -2014,7 +2018,7 @@ HRESULT LxssUserSessionImpl::SetVersion(_In_ LPCGUID DistroGuid, _In_ ULONG Vers
auto wsl1Pipe = wsl::windows::common::wslutil::OpenAnonymousPipe(LX_RELAY_BUFFER_SIZE, true, true);

wsl::windows::common::relay::ScopedMultiRelay stdErrRelay(
std::vector<HANDLE>{wsl1Pipe.first.get(), reinterpret_cast<HANDLE*>(vmContext.errorSocket.get())}, onTarOutput);
std::vector<HANDLE>{wsl1Pipe.first.get(), reinterpret_cast<HANDLE>(vmContext.errorSocket.get())}, onTarOutput);

// Add mounts for the rootfs and tools.
auto mounts = _CreateSetupMounts(configuration);
Expand Down