Alba Mendez mildsunrise

Making Hetzner Storage Box authentication make sense

The documentation for this is pretty terrible and we had to figure this out by trial and error.

The storage box has a password, which is secret and random if not provided. It can be reset to an arbitrary one in the console ("Reset password" in the dropdown menu). Cannot be disabled. It's the only way to use WebDAV and SMB. Always accepted by SSH (and thus SFTP) on either port. It is the only way to recover a storage container you have locked yourself out of after losing SSH keys.

The SSH server on port 22 rejects shell, but it allows spawning the SFTP backend. Requests for any other command or subsystem seem to fail, so it seems to be made specifically for SFTP use.

The SSH server on port 23 offers a limited shell (rsh) with rsync, restic and a few other whitelisted commands. No redirections, pipes or other common shell features you'd expect. (dd is whitelisted, so yo

BK7231 flash structure

When BK7231 MCUs load the SPI flash contents into memory, they do not simply copy the bytes; every 32 bytes are followed by 2 bytes of CRC, which the bootloader supposedly checks and removes. In addition, the flash contents can optionally be encrypted with a key stored in eFuse, so the bootloader would also decrypt them before copying to memory.

In the other direction, both of these tasks are performed by the encrypt tool in the SDK: this takes the built code, inserts CRC bytes and (optionally) encrypts with the eFuse key. This image is almost but not quite ready to flash: some spots of the image must then be overwritten with bootloader (RBL) and partition table (FAL) markers; these are stored in plaintext so they can be interpreted before decryption has taken place. These markers respect the 2-byte CRCs, so they are discontinuous in the flash memory if they're bigger than 1 block, and cause the CRC numbers to be updated.

resources to find what Apple/Asahi acronyms mean:

check out this table
search with site:asahilinux.org (maybe they talked about it in the blog)
grep the linux and m1n1 repos

some other random acronyms, mostly peripherals of the SoC:

AIC → Apple Interrupt Controller
AP → Application Processor (where the OS runs)
DART → Device Address Resolution Table (IOMMU)

	/** WASM-accelerated version. Except for very small sizes it's usually much faster,
	and performs on the same ballpark as PulseFFT. */

	const wasmSrc = `
	AGFzbQEAAAABDwJgBX9/f39/AGADf39/AAMGBQABAAEABQMBAAAHXwYMY29tcGxleFBoYXNlAAANcmVhbFBoYXNlSW5pdAABCXJlYWxQaGFzZQACFHJlYWxQaGFzZUluaXRJbnZlcnNl
	AAMQcmVhbFBoYXNlSW52ZXJzZQAEBm1lbW9yeQIACusHBbwBAgZ/B30gAEECdCIGIAJ2IgJBAWsiB0F/cyEAA0AgBSAGSARAIAUgB3EgACAFcSIIQQF0ciIJIANqIgoqAgAhCyAKKgIE
	IQwgBCAFaiIKIAsgASAIaiIIKgIAIhAgAyACIAlqaiIJKgIAIhGUIAgqAgQiDSAJKgIEIg6UkyIPkjgCACAKIAwgECAOlCANIBGUkiINkjgCBCAGIApqIgggCyAPkzgCACAIIAwgDZM4
	AgQgBUEIaiEFDAELCwtPAgN/An0gAEEBdCEEA0AgAyAESARAIAIgA0EBdGoiBSABIANqIgAqAgAiBiAAIARqKgIAIgeSOAIAIAUgBiAHkzgCBCADQQRqIQMMAQsLC7wCAgl/B30gAEEB
	dCIGIAJBAWt1IgJBAWsiB0F/cyEIA0AgAiAFSgRAIAMgBWoiACoCACEOIAAqAgQhDyADIAIgBWpqIgAqAgAhECAAKgIEIREgBCAFaiIAIA4gEJI4AgAgACAOIBCTOAIEIAAgBmoiACAP
	OAIAIAAgEYw4AgQgBUEIaiEFDAELCyAGQQF0IQogAiEAA0AgACAGSARAIAAgB3EiCyAAIAhxIgVBAXRqIgwgA2oiCSoCACERIAkqAgQhDiAAIARqIgkgESABIAVqIg0qAgAiDyADIAIg

	import Mathlib.Data.Real.Basic
	import Mathlib.Data.Real.Archimedean
	import Mathlib.Algebra.BigOperators.Group.Finset.Basic
	import Mathlib.Algebra.BigOperators.Ring.Finset
	import Mathlib.Algebra.BigOperators.Intervals
	open Finset (range)

	-- STATEMENT

	def IsSpecial (x : ℝ) :=

	// old trait definition:

	trait OldBorrow<Borrowed: ?Sized> {
	fn borrow(&self) -> &Borrowed;
	}

	// new trait definition:

	trait Borrow<Borrowed> {
	fn borrow(self) -> Borrowed;

	// pseudocode contained in H.264 spec syntax tables:
	// - category column becomes a /* C = ... */ comment
	// - descriptor column becomes `= DESC('...')`
	// - added missing { or } in a few places
	// - remove space in "\| \|" "= =" "! =" "- -" "< =" "> ="
	// - prepend _ to 2 identifiers beginning with "3d"
	// - prepend "function" to each table

	function nal_unit(NumBytesInNALunit) {
	forbidden_zero_bit = DESC('f(1)') /* C = All */

	class MUint:
	'''
	a bit vector (unsigned integer) which is the result of an affine map.
	except for the 'algebra-specific operations', like apply, instances of this
	class behave like `int` values when operated on. this includes a subset of
	the operations possible on ints, namely bitwise operations:
	- and (`&`) and or (`\|`) are allowed as long as the other operand is an `int`
	- xor (`^`) are allowed with both ints and other MUints
	- shifts (`>>`, `<<`) are allowed (the shift amount must be an `int`)
	- not (`~`) is only allowed on FixedMUint (the operation makes no sense on unsigned ints without width)

	#!/usr/bin/env python3
	'''
	Converts a Chromium cookie store to its decrypted form.

	## Background

	Chromium stores cookies in a file named 'Cookies' under the profile
	directory. Each cookie can be in encrypted or unencrypted form.
	When stored in encrypted form, the decryption key is stored in an
	OS-dependent facility (for Linux, it is usually libsecret or

	def der_tag(tag_type: int, composed = False, tag_class = 0):
	assert 0 <= tag_class < 4 and 0 <= tag_type < 31 # FIXME: long tag types not implemented
	return bytes([ tag_class << 6 \| int(composed) << 5 \| tag_type ])
	def der_length(x: int):
	if x < 128: return bytes([x])
	n = (x.bit_length() + 7) // 8
	assert n < 127
	return bytes([ 128 \| n ]) + x.to_bytes(n)
	def der_wrap(payload: bytes, raw: bool, tag_type: int, composed = False, tag_class = 0):
	if raw: return payload