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

Jump to bottom

fix AsByteSliceMut using raw pointers with bad provenance #780

Merged
merged 2 commits into from Apr 20, 2019
Merged

fix AsByteSliceMut using raw pointers with bad provenance #780

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
90501dc
fix AsByteSliceMut using raw pointers with bad provenance
RalfJung Apr 19, 2019
d9c611f
fix unaligned and illegal-provenance reads in next_u64
RalfJung Apr 19, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
5 changes: 3 additions & 2 deletions rand_core/src/block.rs
View file
Open in desktop
Expand Up @@ -51,7 +51,7 @@
//! [`fill_bytes`]: RngCore::fill_bytes

use core::convert::AsRef;
use core::fmt;
use core::{fmt, ptr};
use {RngCore, CryptoRng, SeedableRng, Error};
use impls::{fill_via_u32_chunks, fill_via_u64_chunks};

Expand Down Expand Up @@ -183,7 +183,8 @@ where <R as BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>
let read_u64 = |results: &[u32], index| {
if cfg!(any(target_arch = "x86", target_arch = "x86_64")) {
// requires little-endian CPU supporting unaligned reads:
unsafe { *(&results[index] as *const u32 as *const u64) }
let ptr: *const u64 = results[index..index+1].as_ptr() as *const u64;
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This range still only covers 1 element, not 2 elements, as it uses .. instead of ..=.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, I fixed that in #784

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Didn't notice that commit :)

unsafe { ptr::read_unaligned(ptr) }
} else {
let x = u64::from(results[index]);
let y = u64::from(results[index + 1]);
Expand Down
3 changes: 1 addition & 2 deletions src/lib.rs
View file
Open in desktop
Expand Up @@ -387,8 +387,7 @@ macro_rules! impl_as_byte_slice {
}
} else {
unsafe {
slice::from_raw_parts_mut(&mut self[0]
as *mut $t
slice::from_raw_parts_mut(self.as_mut_ptr()
as *mut u8,
self.len() * mem::size_of::<$t>()
)
Expand Down