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Use language-invariant ACL
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@zooba
zooba committed May 9, 2024
1 parent b1d09a7 commit a30cbb2
Showing 1 changed file with 22 additions and 155 deletions.
177 changes: 22 additions & 155 deletions Modules/posixmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4431,147 +4431,6 @@ os__path_splitroot_impl(PyObject *module, path_t *path)

#endif /* MS_WINDOWS */


#ifdef MS_WINDOWS

/* We centralise SECURITY_ATTRIBUTE initialization based around
templates that will probably mostly match common POSIX mode settings.
The _Py_SECURITY_ATTRIBUTE_DATA structure contains temporary data, as
a constructed SECURITY_ATTRIBUTE structure typically refers to memory
that has to be alive while it's being used.
Typical use will look like:
SECURITY_ATTRIBUTES *pSecAttr = NULL;
struct _Py_SECURITY_ATTRIBUTE_DATA secAttrData;
int error, error2;
Py_BEGIN_ALLOW_THREADS
switch (mode) {
case 0x1C0: // 0o700
error = initializeMkdir700SecurityAttributes(&pSecAttr, &secAttrData);
break;
...
default:
error = initializeDefaultSecurityAttributes(&pSecAttr, &secAttrData);
break;
}
if (!error) {
// do operation, passing pSecAttr
}
// Unconditionally clear secAttrData.
error2 = clearSecurityAttributes(&pSecAttr, &secAttrData);
if (!error) {
error = error2;
}
Py_END_ALLOW_THREADS
if (error) {
PyErr_SetFromWindowsErr(error);
return NULL;
}
*/

struct _Py_SECURITY_ATTRIBUTE_DATA {
SECURITY_ATTRIBUTES securityAttributes;
PACL acl;
SECURITY_DESCRIPTOR sd;
EXPLICIT_ACCESS_W ea[4];
char sid[64];
};

static int
initializeDefaultSecurityAttributes(
PSECURITY_ATTRIBUTES *securityAttributes,
struct _Py_SECURITY_ATTRIBUTE_DATA *data
) {
assert(securityAttributes);
assert(data);
*securityAttributes = NULL;
memset(data, 0, sizeof(*data));
return 0;
}

static int
initializeMkdir700SecurityAttributes(
PSECURITY_ATTRIBUTES *securityAttributes,
struct _Py_SECURITY_ATTRIBUTE_DATA *data
) {
assert(securityAttributes);
assert(data);
*securityAttributes = NULL;
memset(data, 0, sizeof(*data));

if (!InitializeSecurityDescriptor(&data->sd, SECURITY_DESCRIPTOR_REVISION)
|| !SetSecurityDescriptorGroup(&data->sd, NULL, TRUE)) {
return GetLastError();
}

int use_alias = 0;
DWORD cbSid = sizeof(data->sid);
if (!CreateWellKnownSid(WinCreatorOwnerRightsSid, NULL, (PSID)data->sid, &cbSid)) {
use_alias = 1;
}

data->securityAttributes.nLength = sizeof(SECURITY_ATTRIBUTES);
data->ea[0].grfAccessPermissions = GENERIC_ALL;
data->ea[0].grfAccessMode = SET_ACCESS;
data->ea[0].grfInheritance = SUB_CONTAINERS_AND_OBJECTS_INHERIT;
if (use_alias) {
data->ea[0].Trustee.TrusteeForm = TRUSTEE_IS_NAME;
data->ea[0].Trustee.TrusteeType = TRUSTEE_IS_ALIAS;
data->ea[0].Trustee.ptstrName = L"CURRENT_USER";
} else {
data->ea[0].Trustee.TrusteeForm = TRUSTEE_IS_SID;
data->ea[0].Trustee.TrusteeType = TRUSTEE_IS_WELL_KNOWN_GROUP;
data->ea[0].Trustee.ptstrName = (LPWCH)(SID*)data->sid;
}

data->ea[1].grfAccessPermissions = GENERIC_ALL;
data->ea[1].grfAccessMode = SET_ACCESS;
data->ea[1].grfInheritance = SUB_CONTAINERS_AND_OBJECTS_INHERIT;
data->ea[1].Trustee.TrusteeForm = TRUSTEE_IS_NAME;
data->ea[1].Trustee.TrusteeType = TRUSTEE_IS_ALIAS;
data->ea[1].Trustee.ptstrName = L"SYSTEM";

data->ea[2].grfAccessPermissions = GENERIC_ALL;
data->ea[2].grfAccessMode = SET_ACCESS;
data->ea[2].grfInheritance = SUB_CONTAINERS_AND_OBJECTS_INHERIT;
data->ea[2].Trustee.TrusteeForm = TRUSTEE_IS_NAME;
data->ea[2].Trustee.TrusteeType = TRUSTEE_IS_ALIAS;
data->ea[2].Trustee.ptstrName = L"ADMINISTRATORS";

int r = SetEntriesInAclW(3, data->ea, NULL, &data->acl);
if (r) {
return r;
}
if (!SetSecurityDescriptorDacl(&data->sd, TRUE, data->acl, FALSE)) {
return GetLastError();
}
data->securityAttributes.lpSecurityDescriptor = &data->sd;
*securityAttributes = &data->securityAttributes;
return 0;
}

static int
clearSecurityAttributes(
PSECURITY_ATTRIBUTES *securityAttributes,
struct _Py_SECURITY_ATTRIBUTE_DATA *data
) {
assert(securityAttributes);
assert(data);
*securityAttributes = NULL;
if (data->acl) {
if (LocalFree((void *)data->acl)) {
return GetLastError();
}
}
return 0;
}

#endif

/*[clinic input]
os.mkdir
Expand Down Expand Up @@ -4603,8 +4462,8 @@ os_mkdir_impl(PyObject *module, path_t *path, int mode, int dir_fd)
#ifdef MS_WINDOWS
int error = 0;
int pathError = 0;
SECURITY_ATTRIBUTES secAttr = { sizeof(secAttr) };
SECURITY_ATTRIBUTES *pSecAttr = NULL;
struct _Py_SECURITY_ATTRIBUTE_DATA secAttrData;
#endif
#ifdef HAVE_MKDIRAT
int mkdirat_unavailable = 0;
Expand All @@ -4617,26 +4476,34 @@ os_mkdir_impl(PyObject *module, path_t *path, int mode, int dir_fd)

#ifdef MS_WINDOWS
Py_BEGIN_ALLOW_THREADS
switch (mode) {
case 0x1C0: // 0o700
error = initializeMkdir700SecurityAttributes(&pSecAttr, &secAttrData);
break;
default:
error = initializeDefaultSecurityAttributes(&pSecAttr, &secAttrData);
break;
if (mode == 0700 /* 0o700 */) {
ULONG sdSize;
pSecAttr = &secAttr;
// Set a discreationary ACL (D) that is protected (P) and includes
// inheritable (OICI) entries that allow (A) full control (FA) to
// SYSTEM (SY), Administrators (BA), and the owner (OW).
if (!ConvertStringSecurityDescriptorToSecurityDescriptorW(
L"D:P(A;OICI;FA;;;SY)(A;OICI;FA;;;BA)(A;OICI;FA;;;OW)",
SDDL_REVISION_1,
&secAttr.lpSecurityDescriptor,
&sdSize
)) {
error = GetLastError();
}
}
if (!error) {
result = CreateDirectoryW(path->wide, pSecAttr);
error = clearSecurityAttributes(&pSecAttr, &secAttrData);
} else {
// Ignore error from "clear" - we have a more interesting one already
clearSecurityAttributes(&pSecAttr, &secAttrData);
if (secAttr.lpSecurityDescriptor &&
// uncommonly, LocalFree returns non-zero on error, but still uses
// GetLastError() to see what the error code is
LocalFree(secAttr.lpSecurityDescriptor)) {
error = GetLastError();
}
}
Py_END_ALLOW_THREADS

if (error) {
PyErr_SetFromWindowsErr(error);
return NULL;
return PyErr_SetFromWindowsErr(error);
}
if (!result) {
return path_error(path);
Expand Down

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