UB error when running on aarch64

[ashthespy]

Follow up from librespot-org/librespot#239
Seem to be having Bus errors running on aarch64 (32bit kernel).

Tested with this snippet.

extern crate aes_ctr;

use aes_ctr::stream_cipher::generic_array::GenericArray;
use aes_ctr::stream_cipher::{NewFixStreamCipher, StreamCipherCore};
use aes_ctr::Aes128Ctr;

const AUDIO_AESIV: [u8; 16] = [
    0x72, 0xe0, 0x67, 0xfb, 0xdd, 0xcb, 0xcf, 0x77, 0xeb, 0xe8, 0xbc, 0x64, 0x3f, 0x63, 0x0d, 0x93,
];

#[inline(never)]
fn new_cipher(key: &[u8]) -> Aes128Ctr {
    // println!("key {:?}", key);
    // Will not error if this prints
    Aes128Ctr::new(
        GenericArray::from_slice(key),
        GenericArray::from_slice(&AUDIO_AESIV),
    )
}

#[inline(never)]
fn encrypt(cipher: &mut Aes128Ctr) -> [u8; 10] {
    let mut data = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
    cipher.apply_keystream(&mut data);
    data
}

fn main() {
    let mut cipher = new_cipher(b"0123456789abcdef");
    let data = encrypt(&mut cipher);
    println!("{:?}", data);
}

Starting program: /home/ash/test_stream_ciphers
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".

Program received signal SIGBUS, Bus error.
0xaaab1d64 in _$LT$ctr..Ctr128$LT$C$GT$$u20$as$u20$stream_cipher..NewFixStreamCipher$GT$::new::h1cd20b0be966ea7c ()
(gdb) bt
#0  0xaaab1d64 in _$LT$ctr..Ctr128$LT$C$GT$$u20$as$u20$stream_cipher..NewFixStreamCipher$GT$::new::h1cd20b0be966ea7c ()
#1  0xaaab224c in test_stream_ciphers::new_cipher::h315560409baa366e ()
#2  0xaaab22e4 in test_stream_ciphers::main::h5cdcb843d2f82ea6 ()
#3  0xaaab1610 in std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::hb4152d57b6ff1750 ()
#4  0xaaab7984 in {{closure}} () at libstd/rt.rs:59
#5  std::panicking::try::do_call::h97d304993e5c755b () at libstd/panicking.rs:310
#6  0xaaac8ba0 in __rust_maybe_catch_panic () at libpanic_unwind/lib.rs:105
#7  0xaaab6bc4 in try<i32,closure> () at libstd/panicking.rs:289
#8  catch_unwind<closure,i32> () at libstd/panic.rs:392
#9  std::rt::lang_start_internal::h025c75f9b8aa9041 () at libstd/rt.rs:58
#10 0xaaab2388 in main ()
(gdb)

Cross compiled with:

/src# rustup show
Default host: x86_64-unknown-linux-gnu

installed targets for active toolchain
--------------------------------------

aarch64-unknown-linux-gnu
arm-unknown-linux-gnueabi
arm-unknown-linux-gnueabihf
i686-unknown-linux-gnu
x86_64-unknown-linux-gnu

active toolchain
----------------

stable-x86_64-unknown-linux-gnu (default)
rustc 1.29.2 (17a9dc751 2018-10-05)

root@3cd916fde064:/src# arm-linux-gnueabihf-gcc --version
arm-linux-gnueabihf-gcc (Debian 6.3.0-18) 6.3.0 20170516
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[newpavlov]

Can you please also test the following code?

const AUDIO_AESIV: [u8; 16] = [
    0x72, 0xe0, 0x67, 0xfb, 0xdd, 0xcb, 0xcf, 0x77,
    0xeb, 0xe8, 0xbc, 0x64, 0x3f, 0x63, 0x0d, 0x93,
];

#[inline(never)]
fn conv(bytes: &[u8; 16]) -> [u64; 2] {
    unsafe { std::mem::transmute_copy(bytes) }
}

fn main() {
    println!("{:?}", conv(b"0123456789abcdef"));
    println!("{:?}", conv(&AUDIO_AESIV));
}

I will create a Rust issue to see if problem is in compiler or in my code. (in the latter case transumte_copy docs should be updated accordingly)

[ashthespy]

@newpavlov reproducible with just the transmute_copy snippet.

[newpavlov]

Looks like it's a std bug. I've patched it in ctr v0.1.1. Can you rerun librespot tests and confirm the fix? Later I also will update dependencies in the PR.

[ashthespy]

@newpavlov tested librespot with aes-ctr 0.2.0 from this repo, and all is good :-)

[newpavlov]

Great! Thank you for testing!