keepassxc/src/core/Bootstrap.cpp
Jonathan White dab7047113 Fix file dialog not appearing on snap build
Fix #7607 - Don't disable core dumps when building for snap distribution. Doing so will not allow the xdg-desktop-portal from opening the file dialog. This is because the portal attempts to call entries from /proc/[pid]/xxxx which are restricted to root when core dumps are disabled.
2022-06-05 07:04:11 -04:00

244 lines
8.0 KiB
C++

/*
* Copyright (C) 2020 KeePassXC Team <team@keepassxc.org>
*
* 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 2 or (at your option)
* version 3 of the License.
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include "Bootstrap.h"
#include "config-keepassx.h"
#include "core/Translator.h"
#ifdef Q_OS_WIN
#include <aclapi.h> // for createWindowsDACL()
#include <windows.h> // for Sleep(), SetDllDirectoryA(), SetSearchPathMode(), ...
#undef MessageBox
#endif
#if defined(HAVE_RLIMIT_CORE)
#include <sys/resource.h>
#endif
#if defined(HAVE_PR_SET_DUMPABLE)
#include <sys/prctl.h>
#endif
#ifdef HAVE_PT_DENY_ATTACH
// clang-format off
#include <sys/types.h>
#include <sys/ptrace.h>
// clang-format on
#endif
namespace Bootstrap
{
/**
* When QNetworkAccessManager is instantiated it regularly starts polling
* all network interfaces to see if anything changes and if so, what. This
* creates a latency spike every 10 seconds on Mac OS 10.12+ and Windows 7 >=
* when on a wifi connection.
* So here we disable it for lack of better measure.
* This will also cause this message: QObject::startTimer: Timers cannot
* have negative intervals
* For more info see:
* - https://bugreports.qt.io/browse/QTBUG-40332
* - https://bugreports.qt.io/browse/QTBUG-46015
*/
static inline void applyEarlyQNetworkAccessManagerWorkaround()
{
qputenv("QT_BEARER_POLL_TIMEOUT", QByteArray::number(-1));
}
/**
* Perform early application bootstrapping that does not rely on a QApplication
* being present.
*/
void bootstrap()
{
#ifdef QT_NO_DEBUG
disableCoreDumps();
#endif
setupSearchPaths();
applyEarlyQNetworkAccessManagerWorkaround();
Translator::installTranslators();
}
// LCOV_EXCL_START
void disableCoreDumps()
{
// default to true
// there is no point in printing a warning if this is not implemented on the platform
bool success = true;
#if defined(HAVE_RLIMIT_CORE)
struct rlimit limit;
limit.rlim_cur = 0;
limit.rlim_max = 0;
success = success && (setrlimit(RLIMIT_CORE, &limit) == 0);
#endif
// NOTE: Dumps cannot be disabled for snap builds as it prevents desktop portals from working
// See https://github.com/keepassxreboot/keepassxc/issues/7607#issuecomment-1109005206
#if defined(HAVE_PR_SET_DUMPABLE) && !defined(KEEPASSXC_DIST_SNAP)
success = success && (prctl(PR_SET_DUMPABLE, 0) == 0);
#endif
// Mac OS X
#ifdef HAVE_PT_DENY_ATTACH
success = success && (ptrace(PT_DENY_ATTACH, 0, 0, 0) == 0);
#endif
#ifdef Q_OS_WIN
success = success && createWindowsDACL();
#endif
if (!success) {
qWarning("Unable to disable core dumps.");
}
}
//
// This function grants the user associated with the process token minimal access rights and
// denies everything else on Windows. This includes PROCESS_QUERY_INFORMATION and
// PROCESS_VM_READ access rights that are required for MiniDumpWriteDump() or ReadProcessMemory().
// We do this using a discretionary access control list (DACL). Effectively this prevents
// crash dumps and disallows other processes from accessing our memory. This works as long
// as you do not have admin privileges, since then you are able to grant yourself the
// SeDebugPrivilege or SeTakeOwnershipPrivilege and circumvent the DACL.
//
bool createWindowsDACL()
{
bool bSuccess = false;
#ifdef Q_OS_WIN
// Process token and user
HANDLE hToken = nullptr;
PTOKEN_USER pTokenUser = nullptr;
DWORD cbBufferSize = 0;
PSID pLocalSystemSid = nullptr;
DWORD pLocalSystemSidSize = SECURITY_MAX_SID_SIZE;
// Access control list
PACL pACL = nullptr;
DWORD cbACL = 0;
// Open the access token associated with the calling process
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken)) {
goto Cleanup;
}
// Retrieve the token information in a TOKEN_USER structure
GetTokenInformation(hToken, TokenUser, nullptr, 0, &cbBufferSize);
pTokenUser = static_cast<PTOKEN_USER>(HeapAlloc(GetProcessHeap(), 0, cbBufferSize));
if (pTokenUser == nullptr) {
goto Cleanup;
}
if (!GetTokenInformation(hToken, TokenUser, pTokenUser, cbBufferSize, &cbBufferSize)) {
goto Cleanup;
}
if (!IsValidSid(pTokenUser->User.Sid)) {
goto Cleanup;
}
// Retrieve LocalSystem account SID
pLocalSystemSid = static_cast<PSID>(HeapAlloc(GetProcessHeap(), 0, pLocalSystemSidSize));
if (pLocalSystemSid == nullptr) {
goto Cleanup;
}
if (!CreateWellKnownSid(WinLocalSystemSid, nullptr, pLocalSystemSid, &pLocalSystemSidSize)) {
goto Cleanup;
}
// Calculate the amount of memory that must be allocated for the DACL
cbACL = sizeof(ACL) + sizeof(ACCESS_ALLOWED_ACE) + GetLengthSid(pTokenUser->User.Sid)
+ sizeof(ACCESS_ALLOWED_ACE) + GetLengthSid(pLocalSystemSid);
// Create and initialize an ACL
pACL = static_cast<PACL>(HeapAlloc(GetProcessHeap(), 0, cbACL));
if (pACL == nullptr) {
goto Cleanup;
}
if (!InitializeAcl(pACL, cbACL, ACL_REVISION)) {
goto Cleanup;
}
// Add allowed access control entries, everything else is denied
if (!AddAccessAllowedAce(
pACL,
ACL_REVISION,
SYNCHRONIZE | PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_TERMINATE, // same as protected process
pTokenUser->User.Sid // pointer to the trustee's SID
)) {
goto Cleanup;
}
#ifdef WITH_XC_SSHAGENT
// OpenSSH for Windows ssh-agent service is running as LocalSystem
if (!AddAccessAllowedAce(pACL,
ACL_REVISION,
PROCESS_QUERY_INFORMATION | PROCESS_DUP_HANDLE, // just enough for ssh-agent
pLocalSystemSid // known LocalSystem sid
)) {
goto Cleanup;
}
#endif
// Set discretionary access control list
bSuccess = ERROR_SUCCESS
== SetSecurityInfo(GetCurrentProcess(), // object handle
SE_KERNEL_OBJECT, // type of object
DACL_SECURITY_INFORMATION, // change only the objects DACL
nullptr,
nullptr, // do not change owner or group
pACL, // DACL specified
nullptr // do not change SACL
);
Cleanup:
if (pACL != nullptr) {
HeapFree(GetProcessHeap(), 0, pACL);
}
if (pLocalSystemSid != nullptr) {
HeapFree(GetProcessHeap(), 0, pLocalSystemSid);
}
if (pTokenUser != nullptr) {
HeapFree(GetProcessHeap(), 0, pTokenUser);
}
if (hToken != nullptr) {
CloseHandle(hToken);
}
#endif
return bSuccess;
}
// LCOV_EXCL_STOP
void setupSearchPaths()
{
#ifdef Q_OS_WIN
// Make sure Windows doesn't load DLLs from the current working directory
SetDllDirectoryA("");
SetSearchPathMode(BASE_SEARCH_PATH_ENABLE_SAFE_SEARCHMODE);
#endif
}
} // namespace Bootstrap