Skip to content

Check that layout size fits in isize in Layout #362

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

Merged
merged 4 commits into from
Sep 18, 2022
Merged

Check that layout size fits in isize in Layout #362

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
bdd2461
Check that layout size fits in isize in Layout
JustForFun88 Sep 18, 2022
cd4c837
make corrections to the test
JustForFun88 Sep 18, 2022
3514c06
third attempt
JustForFun88 Sep 18, 2022
ec164bf
run fmt
JustForFun88 Sep 18, 2022
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
19 changes: 12 additions & 7 deletions src/map.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8044,27 +8044,32 @@ mod test_map {
fn test_try_reserve() {
use crate::TryReserveError::{AllocError, CapacityOverflow};

const MAX_USIZE: usize = usize::MAX;
const MAX_ISIZE: usize = isize::MAX as usize;

let mut empty_bytes: HashMap<u8, u8> = HashMap::new();

if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE) {
if let Err(CapacityOverflow) = empty_bytes.try_reserve(usize::MAX) {
} else {
panic!("usize::MAX should trigger an overflow!");
}

if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE / 16) {
if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_ISIZE) {
} else {
panic!("isize::MAX should trigger an overflow!");
}

if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_ISIZE / 5) {
} else {
// This may succeed if there is enough free memory. Attempt to
// allocate a few more hashmaps to ensure the allocation will fail.
let mut empty_bytes2: HashMap<u8, u8> = HashMap::new();
let _ = empty_bytes2.try_reserve(MAX_USIZE / 16);
let _ = empty_bytes2.try_reserve(MAX_ISIZE / 5);
let mut empty_bytes3: HashMap<u8, u8> = HashMap::new();
let _ = empty_bytes3.try_reserve(MAX_USIZE / 16);
let _ = empty_bytes3.try_reserve(MAX_ISIZE / 5);
let mut empty_bytes4: HashMap<u8, u8> = HashMap::new();
if let Err(AllocError { .. }) = empty_bytes4.try_reserve(MAX_USIZE / 16) {
if let Err(AllocError { .. }) = empty_bytes4.try_reserve(MAX_ISIZE / 5) {
} else {
panic!("usize::MAX / 8 should trigger an OOM!");
panic!("isize::MAX / 5 should trigger an OOM!");
}
}
}
Expand Down
15 changes: 6 additions & 9 deletions src/raw/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -248,6 +248,12 @@ impl TableLayout {
size.checked_mul(buckets)?.checked_add(ctrl_align - 1)? & !(ctrl_align - 1);
let len = ctrl_offset.checked_add(buckets + Group::WIDTH)?;

// We need an additional check to ensure that the allocation doesn't
// exceed `isize::MAX` (https://github.com/rust-lang/rust/pull/95295).
if len > isize::MAX as usize - (ctrl_align - 1) {
return None;
}

Some((
unsafe { Layout::from_size_align_unchecked(len, ctrl_align) },
ctrl_offset,
Expand Down Expand Up @@ -1078,15 +1084,6 @@ impl<A: Allocator + Clone> RawTableInner<A> {
None => return Err(fallibility.capacity_overflow()),
};

// We need an additional check to ensure that the allocation doesn't
// exceed `isize::MAX`. We can skip this check on 64-bit systems since
// such allocations will never succeed anyways.
//
// This mirrors what Vec does in the standard library.
if mem::size_of::<usize>() < 8 && layout.size() > isize::MAX as usize {
return Err(fallibility.capacity_overflow());
}

let ptr: NonNull<u8> = match do_alloc(&alloc, layout) {
Ok(block) => block.cast(),
Err(_) => return Err(fallibility.alloc_err(layout)),
Expand Down