Coding Horrors: You can gather all your technical debt into one easy framework!

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Cavern of COBOL > Coding Horrors: You can gather all your technical debt into one easy framework!

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That Dang Lizard: Jul 13, 2016; what; an idiomt

Ola posted:

No idea about CANBUS security though, wouldn't surprise me if the planets could align and adjusting the volume sent you into a ditch.

It seems insane that they aren't using a data diode to link the main CAN bus to the entertainment system, so that the information could physically never travel the wrong way and interfere with the car.

# ? May 7, 2019 10:27

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# ? May 17, 2024 16:22

Soricidus: Oct 21, 2010; freedom-hating statist shill

Absurd Alhazred posted:

Mostly it beeps at you for things like "you are at 11 above the speed limit instead of 10" but only for the first few seconds, so that it actively discourages you from maintaining around that speed; either remain above or below, absolutely counter-productive, and "there is a car in front of you that has braked", which is great, except that I am looking forward so I saw that car and was reacting to it by slowing down, so I assumed something else had gone wrong, so I came to an abrupt halt. Or "there is a car in your blind spot", which admittedly could be useful.

I think one of the systems will actually brake for you if you get too close to a car within city limits or something.

my favorite is cars that beep at maximum volume, with no visual indication, about 100 yards before each speed camera in their database

they typically have no documented way to disable this behavior, because why would you ever not want to know about speed cameras, even when driving well below the speed limit, once you eventually figure out that that�s what the beep means?

note: some roads here have a lot of speed cameras

# ? May 7, 2019 12:05

Absurd Alhazred: Mar 27, 2010; by Athanatos

I did love when MobilEye's speed limit indicator and the internal Mazda ones disagreed.

# ? May 7, 2019 14:22

iospace: Jan 19, 2038

That Dang Lizard posted:

It seems insane that they aren't using a data diode to link the main CAN bus to the entertainment system, so that the information could physically never travel the wrong way and interfere with the car.

Those cost money. Why spend the money?

e: real talk here: Car companies are NOTORIOUSLY frugal, more so than most other industries. If they could save 1 cent more to make the car, they'd gladly do it. The fact of the matter is they have determined the chances of someone taking over your car via the infotainment system is low enough that they don't need to spend the extra money to prevent it. Or, "We're going to omit this pretty cheap part in the gas tank because we calculated the odds it coming into play and the potential costs to fix those incidents to be less than installing that part in all the cars that could use it."

That said, if enough outrage happens over it, well... you have the Pinto.

iospace fucked around with this message at 15:05 on May 7, 2019

# ? May 7, 2019 14:59

JawnV6: Jul 4, 2004; So hot ...

y'all have never actually worked with CAN, have you? It's being talked about like it's just another straightforward I2C/SPI and it is, uh, not.

:smug:

I would simply add a diode to my CAN interface
lmao

# ? May 7, 2019 15:20

iospace: Jan 19, 2038

JawnV6 posted:

y'all have never actually worked with CAN, have you? It's being talked about like it's just another straightforward I2C/SPI and it is, uh, not.

I would simply add a diode to my CAN interface
lmao

There's a significant difference between a traditional diode and a data diode.

# ? May 7, 2019 15:38

Remulak: Jun 8, 2001; I can't count to four.; Yams Fan

iospace posted:

There's a significant difference between a traditional diode and a data diode.

Efficacy

# ? May 7, 2019 15:44

JawnV6: Jul 4, 2004; So hot ...

iospace posted:

There's a significant difference between a traditional diode and a data diode.

hey here's the relevant question i think u missed it:

JawnV6 posted:

y'all have never actually worked with CAN, have you?

# ? May 7, 2019 15:53

Munkeymon: Aug 14, 2003; Motherfucker's got an
armor-piercing crowbar! Rigoddamndicu𝜆ous.

Absurd Alhazred posted:

I did love when MobilEye's speed limit indicator and the internal Mazda ones disagreed.

That'd be pretty easy if one is using wheel RPM and the other is using GPS or radar because the latter two would be a lot more accurate under most conditions.

# ? May 7, 2019 16:07

iospace: Jan 19, 2038

JawnV6 posted:

hey here's the relevant question i think u missed it:

Then explain instead of being all :jerkbag:

# ? May 7, 2019 17:18

Absurd Alhazred: Mar 27, 2010; by Athanatos

Munkeymon posted:

That'd be pretty easy if one is using wheel RPM and the other is using GPS or radar because the latter two would be a lot more accurate under most conditions.

Speed limit, not current speed. The speed indication seemed more or less consistent, but I think MobilEye uses computer vision while the Mazda system uses some kind of frequently updated database (or they use different databases), so they will sometimes disagree.

# ? May 8, 2019 01:17

Dylan16807: May 12, 2010

JawnV6 posted:

y'all have never actually worked with CAN, have you? It's being talked about like it's just another straightforward I2C/SPI and it is, uh, not.

I would simply add a diode to my CAN interface
lmao

If it needs to make queries or do anything bidirectional, then you put the chip responsible for that on the secure side of the data diode.

The entertainment system needs predefined information. The inner workings of the CAN bus don't matter at all when it comes to spitting that information onto a circuit trace, with either zero feedback or an enable pin.

# ? May 8, 2019 02:00

qsvui: Aug 23, 2003; some crazy thing

iospace posted:

Then explain instead of being all

no don't

# ? May 8, 2019 03:41

Foxfire_: Nov 8, 2010

/CAN

The thing car manufacturer's are trying to avoid is having to physically segregate the bus so they only have to route one cable. Unidirectional network things only even make sense when there are two buses and you are limiting what can be copied from one to another.

The situation you want to avoid is a subverted entertainment unit being able to say "Engine RPM: 100000!" and everyone else listening. You could do that with two buses linked by a widget that knows what IDs belong on each side, but you'd have to run two physical cables ($) and that widget would probably have to be semi-custom (it can't just do an echoing thing because of the electrical arbitration)

# ? May 8, 2019 05:25

Xarn: Jun 26, 2015

Yeah, the real problem is basically that having to run two cables for the two busses is expensive and lol at corps spending a cent more than they have to for things they can't market with.

# ? May 8, 2019 08:18

JawnV6: Jul 4, 2004; So hot ...

iospace posted:

Then explain instead of being all

why would i, cursed with knowledge, bother to help when you've got such luminaries in the thread unfettered by such vagaries and offended by the concept that it might be relevant

Dylan16807 posted:

The inner workings of the CAN bus don't matter at all when it comes to spitting that information onto a circuit trace, with either zero feedback or an enable pin.

Xarn posted:

Yeah, the real problem is basically that having to run two cables for the two busses is expensive and lol at corps spending a cent more than they have to for things they can't market with.

before you even get to "lol c'mon they won't even spring for another twisted pair" argument against optoisolators or whatever, you've got to deal with CAN being the shittiest noisiest most garbage differential transfer protocol that routinely sees +/-100V transients flitting about

# ? May 8, 2019 18:14

NtotheTC: Dec 31, 2007

JawnV6 posted:

why would i, cursed with knowledge, bother to help when you've got such luminaries in the thread unfettered by such vagaries

Are you from the EVE thread or something

# ? May 8, 2019 20:00

qsvui: Aug 23, 2003; some crazy thing

he's from my rear end

# ? May 9, 2019 03:30

Jazerus: May 24, 2011

NtotheTC posted:

Are you from the EVE thread or something

worse: the coding horrors thread

# ? May 9, 2019 04:32

Dross: Sep 26, 2006; Every night he puts his hot dogs in the trees so the pigeons can't get them.

senior dev coworker found it necessary to write his own ugly bespoke String.Contains() in C# for some reason, in the middle of an API controller

code:

private bool CheckSubString(string source, string subString)
{
	var ret = false;
	var index = -1;

	index = source.IndexOf(subString);
	if (index > -1)
	{
		ret = true;
	}

	return ret;
}

# ? May 9, 2019 22:04

CPColin: Sep 9, 2003; Big ol' smile.

Code golf is almost always bullshit, but god drat.

# ? May 9, 2019 22:42

Dirt Road Junglist: Oct 8, 2010; We will be cruel
And through our cruelty
They will know who we are

Dross posted:

senior dev coworker found it necessary to write his own ugly bespoke String.Contains() in C# for some reason, in the middle of an API controller
code:
private bool CheckSubString(string source, string subString)
{
	var ret = false;
	var index = -1;

	index = source.IndexOf(subString);
	if (index > -1)
	{
		ret = true;
	}

	return ret;
}

But...

# ? May 9, 2019 22:59

Hammerite: Mar 9, 2007; And you don't remember what I said here, either, but it was pompous and stupid.; Jade Ear Joe

Dross posted:

senior dev coworker found it necessary to write his own ugly bespoke String.Contains() in C# for some reason, in the middle of an API controller

I wondered whether it was a (bad) attempt to make sure the check was culture-insensitive, but checking the docs, string.Contains() already is culture-insensitive.

# ? May 9, 2019 23:24

NihilCredo: Jun 6, 2011; iram omni possibili modo preme:
plus una illa te diffamabit, quam multæ virtutes commendabunt

Hammerite posted:

I wondered whether it was a (bad) attempt to make sure the check was culture-insensitive, but checking the docs, string.Contains() already is culture-insensitive.

Even if that were the case, the right thing to do would be to make an extension method called .ContainsInvariant() and put it in the Utils module, not a random undiscoverable text function in a loving controller.

# ? May 10, 2019 00:11

ultrafilter: Aug 23, 2007; It's okay if you have any questions.

Today I learned that the IBM C++ linker only allocates 64k for its TOC unless you specify -bbigtoc on the command line. That's not a thing I should have to think about.

# ? May 10, 2019 00:12

dougdrums: Feb 25, 2005; CLIENT REQUESTED ELECTRONIC FUNDING RECEIPT (FUNDS NOW)

Dross posted:

senior dev coworker found it necessary to write his own ugly bespoke String.Contains() in C# for some reason, in the middle of an API controller

Awww yeah this is the hot poo poo

# ? May 10, 2019 01:00

Dylan16807: May 12, 2010

JawnV6 posted:

before you even get to "lol c'mon they won't even spring for another twisted pair" argument against optoisolators or whatever, you've got to deal with CAN being the shittiest noisiest most garbage differential transfer protocol that routinely sees +/-100V transients flitting about

You're making fun of a different question than the one that was actually asked.

It's not about adding a data diode into the actual CAN wires. It's about putting it anywhere at all.

Nobody is claiming anything about CAN except that the problems are already solved. The system already gets the data. Leave that circuit alone, tell it to display the data like it already does, and change what comes after it.

# ? May 10, 2019 01:13

JawnV6: Jul 4, 2004; So hot ...

Dylan16807 posted:

It's not about adding a data diode into the actual CAN wires. It's about putting it anywhere at all.

i'm pretty sure i know the question we're discussing and the paucity of experience you're bringing to bear. you've never professionally consumed a schematic, never specced a component much less a MCU, never done a design review on a board, yet you're confidently opining about system design questions for consumer electronics. "put it somewhere, idk the specifics" isn't the genius galaxy brain masterstroke you're expecting. do the CAN systems you've worked with NACK for any reason other than a CRC mismatch? can that information be shuffled back and forth across the data diode you've selected for this application? what would the failure mode be if the CAN node didn't respect this area of the protocol?

do you let yokels from unaffiliated disciplines give you notes on the digital systems you design? why or why not?

# ? May 10, 2019 18:27

iospace: Jan 19, 2038

JawnV6 posted:

i'm pretty sure i know the question we're discussing and the paucity of experience you're bringing to bear. you've never professionally consumed a schematic, never specced a component much less a MCU, never done a design review on a board, yet you're confidently opining about system design questions for consumer electronics. "put it somewhere, idk the specifics" isn't the genius galaxy brain masterstroke you're expecting. do the CAN systems you've worked with NACK for any reason other than a CRC mismatch? can that information be shuffled back and forth across the data diode you've selected for this application? what would the failure mode be if the CAN node didn't respect this area of the protocol?

do you let yokels from unaffiliated disciplines give you notes on the digital systems you design? why or why not?

We get it dude, you've worked on it.

Now are you capable of responding without being a jackass? Looks like that answer is no.

# ? May 10, 2019 19:21

Dylan16807: May 12, 2010

JawnV6 posted:

i'm pretty sure i know the question we're discussing and the paucity of experience you're bringing to bear. you've never professionally consumed a schematic, never specced a component much less a MCU, never done a design review on a board, yet you're confidently opining about system design questions for consumer electronics. "put it somewhere, idk the specifics" isn't the genius galaxy brain masterstroke you're expecting. do the CAN systems you've worked with NACK for any reason other than a CRC mismatch? can that information be shuffled back and forth across the data diode you've selected for this application? what would the failure mode be if the CAN node didn't respect this area of the protocol?

do you let yokels from unaffiliated disciplines give you notes on the digital systems you design? why or why not?

I don't know how I can be clearer than "You don't change the CAN communication. It already works." :shrug:

# ? May 10, 2019 21:49

RPATDO_LAMD: Mar 22, 2013; 🐘🪠🍆

well clearly it doesn't already work (or at least not well) if the insecure car radio has to have permission to touch the steering system

# ? May 10, 2019 21:56

Simulated: Sep 28, 2001; Lowtax giveth, and Lowtax taketh away.; College Slice

zergstain posted:

You�re saying it�s physically possible for the entertainment system to override the throttle? I just watched a couple of YouTube videos on CAN. Wouldn�t the entertainment system being a low priority solve that problem?

And steering has no business being under computer control on a car without self-driving capability.

Yes

fishmech posted:

It could be possible, although likely that car is not set up in such a way that you can successfully exploit the entertainment system for spurious brake/steering controls.

Oh sweet summer child...

In theory CAN is supposed to be segmented despite using a single actual bus but in reality all the firmware is so full of holes it's insane. Think original WindowsXP connected directly to the internet, only worse. Oh and it's all unauthenticated. Not like "let me spoof the ignition after I get RE on the infotainment bluetooth module which has DMA access to all of ram, allowing me to immediately upgrade to full ownage, then I can pretend to be a different device on the CAN bus"... but like -any- device on the bus can ask the ECU to kill the engine and it will.

# ? May 11, 2019 05:45

Spatial: Nov 15, 2007

i wonder what fun things you can do with the battery on an electric car via firmware. can you blow it up?

there's actually a full size electric car battery in one of the labs where i work, i should ask the guys who work on it the kind of poo poo you can pull.

fun osha thing: the giant battery sits on a pyre of cardboard boxes with two tiny fire extinguishers beside it as a safety gesture. it's fully charged and if it actually failed in any way it would literally destroy the entire building

# ? May 11, 2019 19:25

spiritual bypass: Feb 19, 2008; Grimey Drawer

Foxfire_ posted:

/CAN

The thing car manufacturer's are trying to avoid is having to physically segregate the bus

That's illegal now, too

# ? May 11, 2019 19:41

zergstain: Dec 15, 2005

Simulated posted:

Yes

I suppose that means the answer to my second question is 'no'.

# ? May 11, 2019 21:14

Remulak: Jun 8, 2001; I can't count to four.; Yams Fan

rt4 posted:

That's illegal now, too

This is cool, I�ve done entertainment stuff forever and have no exposure to this. What�s illegal, segmenting or not-segmenting?

# ? May 11, 2019 21:29

Winter Stormer: Oct 17, 2012

Remulak posted:

This is cool, I�ve done entertainment stuff forever and have no exposure to this. What�s illegal, segmenting or not-segmenting?

it's a Rosa Parks joke

# ? May 11, 2019 21:52

ToxicFrog: Apr 26, 2008

This is more a toolchain horror than a coding horror per se, but: ARM cross-compiling on SUSE (and, apparently, Ubuntu).

Apparently whoever built the packages for these systems hosed up, and as a result it sometimes picks the wrong version of libc to link against. So you can, for example, build a Cortex-M0 binary (a chip that uses a subset of the THUMB 1/2 ISAs) and the linker will cheerfully link it against the ARM version of the stdlib, producing a binary that the chip is incapable of executing. Enabling the "warn on mismatched libraries" linker option doesn't detect this, either.

The solution is just to use the prebuilt cross-compiler from developers.arm.com, but seriously, what the gently caress.

# ? May 12, 2019 03:26

hexate: Sep 13, 2012; What do you mean it's not Tom Cruise?

A perennial favorite of mine - pure, undistilled fuckery. This if continues into a business logic pyramid of doom...

code:


	String property = getString(PROPERTY_NAME);
	//if property is allowed.
	if(property.equals("DISALLOW")
	{

Is the comment wrong? Is the conditional wrong? Or is this some sick joke where "DISALLOW" means allowed?

Every customer has their own opinion. This gem was written a decade ago, and both the product owner and developer have long since moved on

# ? May 13, 2019 03:09

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# ? May 17, 2024 16:22

feedmegin: Jul 30, 2008

ToxicFrog posted:

So you can, for example, build a Cortex-M0 binary (a chip that uses a subset of the THUMB 1/2 ISAs)

Teeechnically a superset of THUMB1 iirc :shobon:

I guess it's not bitching because if you're using something beefier than a Cortex-M then mixing Thumb and ARM classic code in the same binary is normal and expected, it's not the same as if you were trying to link against an x86 libc or w/e

# ? May 13, 2019 12:26

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