Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix unaligned access to FILE_NOTIFY_INFORMATION #647

Merged
merged 1 commit into from
Nov 24, 2024
+16 −9
Merged

Fix unaligned access to FILE_NOTIFY_INFORMATION #647

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 16 additions & 9 deletions notify/src/windows.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -331,11 +331,18 @@ unsafe extern "system" fn handle_event(
// string as its last member. Each struct contains an offset for getting the next entry in
// the buffer.
let mut cur_offset: *const u8 = request.buffer.as_ptr();
let mut cur_entry = cur_offset as *const FILE_NOTIFY_INFORMATION;
// In Wine, FILE_NOTIFY_INFORMATION structs are packed placed in the buffer;
// they are aligned to 16bit (WCHAR) boundary instead of 32bit required by FILE_NOTIFY_INFORMATION.
// Hence, we need to use `read_unaligned` here to avoid UB.
let mut cur_entry = ptr::read_unaligned(cur_offset as *const FILE_NOTIFY_INFORMATION);
loop {
// filename length is size in bytes, so / 2
let len = (*cur_entry).FileNameLength as usize / 2;
let encoded_path: &[u16] = slice::from_raw_parts((*cur_entry).FileName.as_ptr(), len);
let len = cur_entry.FileNameLength as usize / 2;
let encoded_path: &[u16] = slice::from_raw_parts(
cur_offset.offset(std::mem::offset_of!(FILE_NOTIFY_INFORMATION, FileName) as isize)
as _,
len,
);
// prepend root to get a full path
let path = request
.data
Expand All @@ -353,7 +360,7 @@ unsafe extern "system" fn handle_event(
log::trace!(
"Event: path = `{}`, action = {:?}",
path.display(),
(*cur_entry).Action
cur_entry.Action
);

let newe = Event::new(EventKind::Any).add_path(path);
Expand All @@ -367,14 +374,14 @@ unsafe extern "system" fn handle_event(

let event_handler = |res| emit_event(&request.event_handler, res);

if (*cur_entry).Action == FILE_ACTION_RENAMED_OLD_NAME {
if cur_entry.Action == FILE_ACTION_RENAMED_OLD_NAME {
let mode = RenameMode::From;
let kind = ModifyKind::Name(mode);
let kind = EventKind::Modify(kind);
let ev = newe.set_kind(kind);
event_handler(Ok(ev))
} else {
match (*cur_entry).Action {
match cur_entry.Action {
FILE_ACTION_RENAMED_NEW_NAME => {
let kind = EventKind::Modify(ModifyKind::Name(RenameMode::To));
let ev = newe.set_kind(kind);
Expand All @@ -400,11 +407,11 @@ unsafe extern "system" fn handle_event(
}
}

if (*cur_entry).NextEntryOffset == 0 {
if cur_entry.NextEntryOffset == 0 {
break;
}
cur_offset = cur_offset.offset((*cur_entry).NextEntryOffset as isize);
cur_entry = cur_offset as *const FILE_NOTIFY_INFORMATION;
cur_offset = cur_offset.offset(cur_entry.NextEntryOffset as isize);
cur_entry = ptr::read_unaligned(cur_offset as *const FILE_NOTIFY_INFORMATION);
}
}

Expand Down
Loading