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Use AccessCheck for current user effective file permissions

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On Windows, QFileInfo.isWritable() was returning true in situations
where the file would only be writable with elevated privileges. Using
AccessCheck instead of GetEffectiveRightsFromAcl to get the correct
results.

Done-with: Friedemann Kleint <Friedemann.Kleint@qt.io>
Done-with: Edward Welbourne <edward.welbourne@qt.io>
Task-number: QTBUG-30148
Change-Id: I7a3468ac069bf782ca312078e3a84107b6cd468c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
This commit is contained in:
Dyami Caliri 2014-09-15 14:09:22 -07:00 committed by Friedemann Kleint
parent 83fa66b6d2
commit ffc8409aa5
2 changed files with 74 additions and 15 deletions
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64
src/corelib/io/qfilesystemengine_win.cpp Normal file → Executable file
View File

@ -178,6 +178,7 @@ static TRUSTEE_W currentUserTrusteeW;
static TRUSTEE_W worldTrusteeW;
static PSID currentUserSID = 0;
static PSID worldSID = 0;
static HANDLE currentUserImpersonatedToken = nullptr;
/*
Deletes the allocated SIDs during global static cleanup
@ -198,6 +199,11 @@ SidCleanup::~SidCleanup()
::FreeSid(worldSID);
worldSID = 0;
}
if (currentUserImpersonatedToken) {
::CloseHandle(currentUserImpersonatedToken);
currentUserImpersonatedToken = nullptr;
}
}
Q_GLOBAL_STATIC(SidCleanup, initSidCleanup)
@ -254,6 +260,12 @@ static void resolveLibs()
::CloseHandle(token);
}
token = nullptr;
if (::OpenProcessToken(hnd, TOKEN_IMPERSONATE | TOKEN_QUERY | TOKEN_DUPLICATE | STANDARD_RIGHTS_READ, &token)) {
::DuplicateToken(token, SecurityImpersonation, &currentUserImpersonatedToken);
::CloseHandle(token);
}
typedef BOOL (WINAPI *PtrAllocateAndInitializeSid)(PSID_IDENTIFIER_AUTHORITY, BYTE, DWORD, DWORD, DWORD, DWORD, DWORD, DWORD, DWORD, DWORD, PSID*);
PtrAllocateAndInitializeSid ptrAllocateAndInitializeSid = (PtrAllocateAndInitializeSid)GetProcAddress(advapiHnd, "AllocateAndInitializeSid");
if (ptrAllocateAndInitializeSid) {
@ -721,15 +733,49 @@ bool QFileSystemEngine::fillPermissions(const QFileSystemEntry &entry, QFileSyst
ACCESS_MASK access_mask;
TRUSTEE_W trustee;
if (what & QFileSystemMetaData::UserPermissions) { // user
data.knownFlagsMask |= QFileSystemMetaData::UserPermissions;
if(ptrGetEffectiveRightsFromAclW(pDacl, &currentUserTrusteeW, &access_mask) != ERROR_SUCCESS)
access_mask = (ACCESS_MASK)-1;
if(access_mask & ReadMask)
data.entryFlags |= QFileSystemMetaData::UserReadPermission;
if(access_mask & WriteMask)
data.entryFlags|= QFileSystemMetaData::UserWritePermission;
if(access_mask & ExecMask)
data.entryFlags|= QFileSystemMetaData::UserExecutePermission;
// Using AccessCheck because GetEffectiveRightsFromAcl doesn't account for elevation
if (currentUserImpersonatedToken) {
GENERIC_MAPPING mapping = {FILE_GENERIC_READ, FILE_GENERIC_WRITE, FILE_GENERIC_EXECUTE, FILE_ALL_ACCESS};
PRIVILEGE_SET privileges;
DWORD grantedAccess;
BOOL result;
data.knownFlagsMask |= QFileSystemMetaData::UserPermissions;
DWORD genericAccessRights = GENERIC_READ;
::MapGenericMask(&genericAccessRights, &mapping);
DWORD privilegesLength = sizeof(privileges);
if (::AccessCheck(pSD, currentUserImpersonatedToken, genericAccessRights,
&mapping, &privileges, &privilegesLength, &grantedAccess, &result) && result) {
data.entryFlags |= QFileSystemMetaData::UserReadPermission;
}
privilegesLength = sizeof(privileges);
genericAccessRights = GENERIC_WRITE;
::MapGenericMask(&genericAccessRights, &mapping);
if (::AccessCheck(pSD, currentUserImpersonatedToken, genericAccessRights,
&mapping, &privileges, &privilegesLength, &grantedAccess, &result) && result) {
data.entryFlags |= QFileSystemMetaData::UserWritePermission;
}
privilegesLength = sizeof(privileges);
genericAccessRights = GENERIC_EXECUTE;
::MapGenericMask(&genericAccessRights, &mapping);
if (::AccessCheck(pSD, currentUserImpersonatedToken, genericAccessRights,
&mapping, &privileges, &privilegesLength, &grantedAccess, &result) && result) {
data.entryFlags |= QFileSystemMetaData::UserExecutePermission;
}
} else { // fallback to GetEffectiveRightsFromAcl
data.knownFlagsMask |= QFileSystemMetaData::UserPermissions;
if (ptrGetEffectiveRightsFromAclW(pDacl, &currentUserTrusteeW, &access_mask) != ERROR_SUCCESS)
access_mask = ACCESS_MASK(-1);
if (access_mask & ReadMask)
data.entryFlags |= QFileSystemMetaData::UserReadPermission;
if (access_mask & WriteMask)
data.entryFlags|= QFileSystemMetaData::UserWritePermission;
if (access_mask & ExecMask)
data.entryFlags|= QFileSystemMetaData::UserExecutePermission;
}
}
if (what & QFileSystemMetaData::OwnerPermissions) { // owner
data.knownFlagsMask |= QFileSystemMetaData::OwnerPermissions;

25
tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp Normal file → Executable file
View File

@ -64,6 +64,14 @@
#define Q_NO_SYMLINKS
#endif
#if defined(Q_OS_WIN)
QT_BEGIN_NAMESPACE
extern Q_CORE_EXPORT int qt_ntfs_permission_lookup;
QT_END_NAMESPACE
# ifndef Q_OS_WINRT
bool IsUserAdmin();
# endif
#endif
#if defined(Q_OS_UNIX) && !defined(Q_OS_VXWORKS)
inline bool qt_isEvilFsTypeName(const char *name)
@ -1634,6 +1642,15 @@ void tst_QFileInfo::isWritable()
QVERIFY2(fi.exists(), msgDoesNotExist(fi.absoluteFilePath()).constData());
QVERIFY(!fi.isWritable());
#endif
#if defined (Q_OS_WIN) && !defined(Q_OS_WINRT)
QScopedValueRollback<int> ntfsMode(qt_ntfs_permission_lookup);
qt_ntfs_permission_lookup = 1;
QFileInfo fi2(QFile::decodeName(qgetenv("SystemRoot") + "/system.ini"));
QVERIFY(fi2.exists());
QCOMPARE(fi2.isWritable(), IsUserAdmin());
#endif
#if defined (Q_OS_QNX) // On QNX /etc is usually on a read-only filesystem
QVERIFY(!QFileInfo("/etc/passwd").isWritable());
#elif defined (Q_OS_UNIX) && !defined(Q_OS_VXWORKS) // VxWorks does not have users/groups
@ -1807,7 +1824,7 @@ void tst_QFileInfo::detachingOperations()
}
#if defined(Q_OS_WIN) && !defined(Q_OS_WINRT)
BOOL IsUserAdmin()
bool IsUserAdmin()
{
BOOL b;
SID_IDENTIFIER_AUTHORITY NtAuthority = SECURITY_NT_AUTHORITY;
@ -1825,13 +1842,9 @@ BOOL IsUserAdmin()
FreeSid(AdministratorsGroup);
}
return(b);
return b != FALSE;
}
QT_BEGIN_NAMESPACE
extern Q_CORE_EXPORT int qt_ntfs_permission_lookup;
QT_END_NAMESPACE
#endif // Q_OS_WIN && !Q_OS_WINRT
#ifndef Q_OS_WINRT