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Rollup merge of #93206 - ChrisDenton:ntopenfile, r=nagisa
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Use `NtCreateFile` instead of `NtOpenFile` to open a file

Generally the internal `Nt*` functions should be avoided but when we do need to use one we should stick to the most commonly used for the job. To that end, this PR replaces `NtOpenFile` with `NtCreateFile`.

NOTE: The initial version of this comment hypothesised that this may help with some recent false positives from malware scanners. This hypothesis proved wrong. Sorry for the distraction.
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matthiaskrgr authored Feb 8, 2022
2 parents a11e2b1 + ac02fcc commit 9cb39a6
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Showing 3 changed files with 18 additions and 7 deletions.
2 changes: 1 addition & 1 deletion library/std/src/fs.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2044,7 +2044,7 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
///
/// This function currently corresponds to `openat`, `fdopendir`, `unlinkat` and `lstat` functions
/// on Unix (except for macOS before version 10.10 and REDOX) and the `CreateFileW`,
/// `GetFileInformationByHandleEx`, `SetFileInformationByHandle`, and `NtOpenFile` functions on
/// `GetFileInformationByHandleEx`, `SetFileInformationByHandle`, and `NtCreateFile` functions on
/// Windows. Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
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12 changes: 9 additions & 3 deletions library/std/src/sys/windows/c.rs
Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,7 @@ pub const FILE_SHARE_DELETE: DWORD = 0x4;
pub const FILE_SHARE_READ: DWORD = 0x1;
pub const FILE_SHARE_WRITE: DWORD = 0x2;

pub const FILE_OPEN: ULONG = 0x00000001;
pub const FILE_OPEN_REPARSE_POINT: ULONG = 0x200000;
pub const OBJ_DONT_REPARSE: ULONG = 0x1000;

Expand Down Expand Up @@ -1228,15 +1229,20 @@ compat_fn! {

compat_fn! {
"ntdll":
pub fn NtOpenFile(
pub fn NtCreateFile(
FileHandle: *mut HANDLE,
DesiredAccess: ACCESS_MASK,
ObjectAttributes: *const OBJECT_ATTRIBUTES,
IoStatusBlock: *mut IO_STATUS_BLOCK,
AllocationSize: *mut i64,
FileAttributes: ULONG,
ShareAccess: ULONG,
OpenOptions: ULONG
CreateDisposition: ULONG,
CreateOptions: ULONG,
EaBuffer: *mut c_void,
EaLength: ULONG
) -> NTSTATUS {
panic!("`NtOpenFile` not available");
panic!("`NtCreateFile` not available");
}
pub fn RtlNtStatusToDosError(
Status: NTSTATUS
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11 changes: 8 additions & 3 deletions library/std/src/sys/windows/fs.rs
Original file line number Diff line number Diff line change
Expand Up @@ -712,11 +712,11 @@ impl<'a> Iterator for DirBuffIter<'a> {

/// Open a link relative to the parent directory, ensure no symlinks are followed.
fn open_link_no_reparse(parent: &File, name: &[u16], access: u32) -> io::Result<File> {
// This is implemented using the lower level `NtOpenFile` function as
// This is implemented using the lower level `NtCreateFile` function as
// unfortunately opening a file relative to a parent is not supported by
// win32 functions. It is however a fundamental feature of the NT kernel.
//
// See https://docs.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-ntopenfile
// See https://docs.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-ntcreatefile
unsafe {
let mut handle = ptr::null_mut();
let mut io_status = c::IO_STATUS_BLOCK::default();
Expand All @@ -732,14 +732,19 @@ fn open_link_no_reparse(parent: &File, name: &[u16], access: u32) -> io::Result<
Attributes: ATTRIBUTES.load(Ordering::Relaxed),
..c::OBJECT_ATTRIBUTES::default()
};
let status = c::NtOpenFile(
let status = c::NtCreateFile(
&mut handle,
access,
&object,
&mut io_status,
crate::ptr::null_mut(),
0,
c::FILE_SHARE_DELETE | c::FILE_SHARE_READ | c::FILE_SHARE_WRITE,
c::FILE_OPEN,
// If `name` is a symlink then open the link rather than the target.
c::FILE_OPEN_REPARSE_POINT,
crate::ptr::null_mut(),
0,
);
// Convert an NTSTATUS to the more familiar Win32 error codes (aka "DosError")
if c::nt_success(status) {
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