C can be memory safe, part 2
This post from last year was posted to a forum, so I thought I'd write up some rebuttals to their comments.
The first comment is by David Chisnall, creator of CHERI C/C++, which proposes we can solve the problem with CPU instruction set extensions. It's a good idea, but after 14 years, CPUs haven't had their instruction-sets upgraded. Even mainstream RISC V processors haven't been created using those extensions.
Chisnall: "If your safety requires you to insert explicit checks, it’s not safe". This is true from one perspective, false from another. My proposal includes compilers spitting out warnings whenever bounds information doesn't exist.
C is full of problems in theory that doesn't exist in practice because the compiler spits out warnings telling programmers to fix the problem. Warnings can also note cases where programmers probably made mistakes. We can't achieve perfect guarantees, because programmers can still make mistakes, but we can certainly achieve "good enough".
Chisnall: ....tread safety..... I'm not sure I full understand the comment. I understand that CHERI can guarantee atomicity of bounds checking, which would require multiple (interruptible) instructions otherwise. The number of cases where this is a problem, and the C proposal would be Continue reading
C can be memory-safe
The idea of memory-safe languages is in the news lately. C/C++ is famous for being the world's system language (that runs most things) but also infamous for being unsafe. Many want to solve this by hard-forking the world's system code, either by changing C/C++ into something that's memory-safe, or rewriting everything in Rust.
Forking is a foolish idea. The core principle of computer-science is that we need to live with legacy, not abandon it.
And there's no need. Modern C compilers already have the ability to be memory-safe, we just need to make minor -- and compatible -- changes to turn it on. Instead of a hard-fork that abandons legacy system, this would be a soft-fork that enables memory-safety for new systems.
Consider the most recent memory-safety flaw in OpenSSL. They fixed it by first adding a memory-bounds, then putting every access to the memory behind a macro PUSHC() that checks the memory-bounds:
size_t maxsize CHK_SIZE(outptr) = out ? *outlen : 0;
This would link the memory-bounds maxsize with the memory outptr. The compiler can then be relied upon to do all the bounds checking to prevent buffer Continue reading
I’m still bitter about Slammer
Today is the 20th anniversary of the Slammer worm. I'm still angry over it, so I thought I'd write up my anger. This post will be of interest to nobody, it's just me venting my bitterness and get off my lawn!!
Back in the day, I wrote "BlackICE", an intrusion detection and prevention system that ran as both a desktop version and a network appliance. Most cybersec people from that time remember it as the desktop version, but the bulk of our sales came from the network appliance.
The network appliance competed against other IDSs at the time, such as Snort, an open-source product. For much the cybersec industry, IDS was Snort -- they had no knowledge of how intrusion-detection would work other than this product, because it was open-source.
My intrusion-detection technology was radically different. The thing that makes me angry is that I couldn't explain the differences to the community because they weren't technical enough.
When Slammer hit, Snort and Snort-like products failed. Mine succeeded extremely well. Yet, I didn't get the credit for this.
The first difference is that I used a custom poll-mode driver instead of interrupts. This the now the norm in the industry, such Continue reading
The RISC Deprogrammer
I should write up a larger technical document on this, but in the meanwhile is this short (-ish) blogpost. Everything you know about RISC is wrong. It's some weird nerd cult. Techies frequently mention RISC in conversation, with other techies nodding their head in agreement, but it's all wrong. Somehow everyone has been mind controlled to believe in wrong concepts.
An example is this recent blogpost which starts out saying that "RISC is a set of design principles". No, it wasn't. Let's start from this sort of viewpoint to discuss this odd cult.
What is RISC?
Because of the march of Moore's Law, every year, more and more parts of a computer could be included onto a single chip. When chip densities reached the point where we could almost fit an entire computer on a chip, designers made tradeoffs, discarding unimportant stuff to make the fit happen. They made tradeoffs, deciding what needed to be included, what needed to change, and what needed to be discarded.
RISC is a set of creative tradeoffs, meaningful at the time (early 1980s), but which were meaningless by the late 1990s.
The interesting parts of CPU evolution are the three decades from 1964 with Continue reading
DS620slim tiny home server
That's right, laptop 2.5 inch drives. It makes this a tiny server that you can hold in your hand.
The purpose of a NAS is reliable storage. All disk drives eventually fail. If you stick a USB external drive on your desktop for backups, it'll eventually crash, losing any data on it. A failure is unlikely tomorrow, but a spinning disk will almost certainly fail some time in the next 10 years. If you want to keep things, like photos, for the rest of your life, you need to do something different.
The solution is RAID, an array of redundant disks such that when one fails (or even two), you don't lose any data. You simply buy a new disk to replace the failed one and keep going. With occasional replacements (as failures happen) it can last decades. My older NAS is 10 years old and I've replaced all Continue reading
No, a researcher didn’t find Olympics app spying on you
For the Beijing 2022 Winter Olympics, the Chinese government requires everyone to download an app onto their phone. It has many security/privacy concerns, as CitizenLab documents. However, another researcher goes further, claiming his analysis proves the app is recording all audio all the time. His analysis is fraudulent. He shows a lot of technical content that looks plausible, but nowhere does he show anything that substantiates his claims.
Average techies may not be able to see this. It all looks technical. Therefore, I thought I'd describe one example of the problems with this data -- something the average techie can recognize.
His "evidence" consists screenshots from reverse-engineering tools, with red arrows pointing to the suspicious bits. An example of one of these screenshots is this on:
This screenshot is that of a reverse-engineering tool (Hopper, I think) that takes code and "disassembles" it. When you dump something into a reverse-engineering tool, it'll make a few assumptions about what it sees. These assumptions are usually wrong. There's a process where the human user looks at the analyzed output, does a "sniff-test" on whether it looks reasonable, and works with the tool until it gets the assumptions correct.
That's the red flag Continue reading
Journalists: stop selling NFTs that you don’t understand
The reason you don't really understand NFTs is because the journalists describing them to you don't understand them, either. We can see that when they attempt to sell an NFT as part of their stories (e.g. AP and NYTimes). They get important details wrong.
The latest is Reason.com magazine selling an NFT. As libertarians, you'd think at least they'd get the technical details right. But they didn't. Instead of selling an NFT of the artwork, it's just an NFT of a URL. The URL points to OpenSea, which is known to remove artwork from its site (such as in response to DMCA takedown requests).
If you buy that Reason.com NFT, what you'll actually get is a token pointing to:
This is just the metadata, which in turn contains a link to the claimed artwork:
If either OpenSea or Google removes the linked content, then any connection between the NFT and the artwork disappears.
It doesn't have to be this way. The correct way to do NFT artwork is to point to a "hash" instead which uniquely identifies the work regardless of where it's located. That $69 million Beeple piece was Continue reading
Example: forensicating the Mesa County system image
Tina Peters, the election clerk in Mesa County (Colorado) went rogue and dumped disk images of an election computer on the Internet. They are available on the Internet via BitTorrent [Mesa1][Mesa2], The Colorado Secretary of State is now suing her over the incident.
The lawsuit describes the facts of the case, how she entered the building with an accomplice on Sunday, May 23, 2021. I thought I'd do some forensics on the image to get more details.
Specifically, I see from the Mesa1 image that she logged on at 4:24pm and was done acquiring the image by 4:30pm, in and (presumably) out in under 7 minutes.
In this blogpost, I go into more detail about how to get that information.
The image
To download the Mesa1 image, you need a program that can access BitTorrent, such as the Brave web browser or a BitTorrent client like qBittorrent. Either click on the "magnet" link or copy/paste into the program you'll use to download. It takes a minute to gather all the "metadata" associated with the link, but it'll soon start the download:
What you get is file named EMSSERVER.E01. This is a container file that contains Continue reading
Debunking: that Jones Alfa-Trump report
The Alfa-Trump conspiracy-theory has gotten a new life. Among the new things is a report done by Democrat operative Daniel Jones [*]. In this blogpost, I debunk that report.
If you'll recall, the conspiracy-theory comes from anomalous DNS traffic captured by cybersecurity researchers. In the summer of 2016, while Trump was denying involvement with Russian banks, the Alfa Bank in Russia was doing lookups on the name "mail1.trump-email.com". During this time, additional lookups were also coming from two other organizations with suspicious ties to Trump, Spectrum Health and Heartland Payments.
This is certainly suspicious, but people have taken it further. They have crafted a conspiracy-theory to explain the anomaly, namely that these organizations were secretly connecting to a Trump server.
We know this explanation to be false. There is no Trump server, no real server at all, and no connections. Instead, the name was created and controlled by Cendyn. The server the name points to for transmitting bulk email and isn't really configured to accept connections. It's built for outgoing spam, not incoming connections. The Trump Org had no control over the name or the server. As Cendyn explains, the contract with the Trump Org ended in Continue reading
Review: Dune (2021)
One of the most important classic sci-fi stories is the book "Dune" from Frank Herbert. It was recently made into a movie. I thought I'd write a quick review.
The summary is this: just read the book. It's a classic for a good reason, and you'll be missing a lot by not reading it.
But the movie Dune (2021) movie is very good. The most important thing to know is see it in IMAX. IMAX is this huge screen technology that partly wraps around the viewer, and accompanied by huge speakers that overwhelm you with sound. If you watch it in some other format, what was visually stunning becomes merely very pretty.
This is Villeneuve's trademark, which you can see in his other works, like his sequel to Bladerunner. The purpose is to marvel at the visuals in every scene. The story telling is just enough to hold the visuals together. I mean, he also seems to do a good job with the story telling, but it's just not the reason to go see the movie. (I can't tell -- I've read the book, so see the story differently than those of you who haven't).
Beyond the story Continue reading
Fact check: that “forensics” of the Mesa image is crazy
Tina Peters, the elections clerk from Mesa County (Colorado) went rogue, creating a "disk-image" of the election server, and posting that image to the public Internet. Conspiracy theorists have been analyzing the disk-image trying to find anomalies supporting their conspiracy-theories. A recent example is this "forensics" report. In this blogpost, I debunk that report.
I suppose calling somebody a "conspiracy theorist" is insulting, but there's three objective ways we can identify them as such.
The first is when they use the logic "everything we can't explain is proof of the conspiracy". In other words, since there's no other rational explanation, the only remaining explanation is the conspiracy-theory. But there can be other possible explanations -- just ones unknown to the person because they aren't smart enough to understand them. We see that here: the person writing this report doesn't understand some basic concepts, like "airgapped" networks.
This leads to the second way to recognize a conspiracy-theory, when it demands this one thing that'll clear things up. Here, it's demanding that a manual audit/recount of Mesa County be performed. But it won't satisfy them. The Maricopa audit in neighboring Colorado, whose recount found no fraud, didn't clear anything up Continue reading
100 terabyte home NAS
So, as a nerd, let's say you need 100 terabytes of home storage. What do you do?
My solution would be a commercial NAS RAID, like from Synology, QNAP, or Asustor. I'm a nerd, and I have setup my own Linux systems with RAID, but I'd rather get a commercial product. When a disk fails, and a disk will always eventually fail, then I want something that will loudly beep at me and make it easy to replace the drive and repair the RAID.
Some choices you have are:
- vendor (Synology, QNAP, and Asustor are the vendors I know and trust the most)
- number of bays (you want 8 to 12)
- redundancy (you want at least 2 if not 3 disks)
- filesystem (btrfs or ZFS) [not btrfs-raid builtin, but btrfs on top of RAID]
- drives (NAS optimized between $20/tb and $30/tb)
- networking (at least 2-gbps bonded, but box probably can't use all of 10gbps)
- backup (big external USB drives)
The products I link above all have at least 8 drive bays. When you google "NAS", you'll get a list of smaller products. You don't want them. You want somewhere between 8 and 12 drives.
The reason is that Continue reading
Check: that Republican audit of Maricopa
Author: Robert Graham (@erratarob)
Later today (Friday, September 24, 2021), Republican auditors release their final report on the found with elections in Maricopa county. Draft copies have circulated online. In this blogpost, I write up my comments on the cybersecurity portions of their draft.
https://arizonaagenda.substack.com/p/we-got-the-senate-audit-report
The three main problems are:
- They misapply cybersecurity principles that are meaningful for normal networks, but which don’t really apply to the air gapped networks we see here.
- They make some errors about technology, especially networking.
- They are overstretching themselves to find dirt, claiming the things they don't understand are evidence of something bad.
In the parts below, I pick apart individual pieces from that document to demonstrate these criticisms. I focus on section 7, the cybersecurity section, and ignore the other parts of the document, where others are more qualified than I to opine.
In short, when corrected, section 7 is nearly empty of any content.
7.5.2.1.1 Software and Patch Management, part 1
They claim Dominion is defective at one of the best-known cyber-security issues: applying patches.
It’s not true. The systems are “air gapped”, disconnected from the typical sort of threat that exploits unpatched systems. The primary Continue reading
That Alfa-Trump Sussman indictment
Five years ago, online magazine Slate broke a story about how DNS packets showed secret communications between Alfa Bank in Russia and the Trump Organization, proving a link that Trump denied. I was the only prominent tech expert that debunked this as just a conspiracy-theory[*][*][*].
Last week, I was vindicated by the indictment of a lawyer involved, a Michael Sussman. It tells a story of where this data came from, and some problems with it.
But we should first avoid reading too much into this indictment. It cherry picks data supporting its argument while excluding anything that disagrees with it. We see chat messages expressing doubt in the DNS data. If chat messages existed expressing confidence in the data, we wouldn't see them in the indictment.
In addition, the indictment tries to make strong ties to the Hillary campaign and the Steele Dossier, but ultimately, it's weak. It looks to me like an outsider trying to ingratiated themselves with the Hillary campaign rather than there being part of a grand Clinton-lead conspiracy against Trump.
With these caveats, we do see some important things about where the data came from.
We see how Tech-Executive-1 used Continue reading
How not to get caught in law-enforcement geofence requests
I thought I'd write up a response to this question from well-known 4th Amendment and CFAA lawyer Orin Kerr:
Question for tech people related to "geofence" warrants served on Google: How easy is it for a cell phone user, either of an Android or an iPhone, to stop Google from generating the detailed location info needed to be responsive to a geofence warrant? What do you need to do?
— Orin Kerr (@OrinKerr) September 15, 2021
(FWIW, I'm seeking info from people who actually know the answer based on their expertise, not from those who are just guessing, or are who are now googling around to figure out what the answer may be,)
— Orin Kerr (@OrinKerr) September 15, 2021
First, let me address the second part of his tweet, whether I'm technically qualified to answer this. I'm not sure, I have only 80% confidence that I am. Hence, I'm writing this answer as blogpost hoping people will correct me if I'm wrong.
There is a simple answer and it's this: just disable "Location" tracking in the settings on the phone. Both iPhone and Android have a one-click button to tap that disables everything.
Of course you can’t trust scientists on politics
Many people make the same claim as this tweet. It's obviously wrong. Yes,, the right-wing has a problem with science, but this isn't it.If you think you don't trust scientists, you're mistaken. You trust scientists in a million different ways every time you step on a plane, or for that matter turn on your tap or open a can of beans. The fact that you're unaware of this doesn't mean it's not so.
— Paul Graham (@paulg) July 26, 2021
First of all, people trust airplanes because of their long track record of safety, not because of any claims made by scientists. Secondly, people distrust "scientists" when politics is involved because of course scientists are human and can get corrupted by their political (or religious) beliefs.
And thirdly, the concept of "trusting scientific authority" is wrong, since the bedrock principle of science is distrusting authority. What defines sciences is how often prevailing scientific beliefs are challenged.
Carl Sagan has many quotes along these lines that eloquently expresses this:
A central lesson of science is that to understand complex issues (or even simple ones), we must try to free our minds of dogma and to guarantee the freedom to publish, Continue reading
Risk analysis for DEF CON 2021
It's the second year of the pandemic and the DEF CON hacker conference wasn't canceled. However, the Delta variant is spreading. I thought I'd do a little bit of risk analysis. TL;DR: I'm not canceling my ticket, but changing my plans what I do in Vegas during the convention.
First, a note about risk analysis. For many people, "risk" means something to avoid. They work in a binary world, labeling things as either "risky" (to be avoided) or "not risky". But real risk analysis is about shades of gray, trying to quantify things.
The Delta variant is a mutation out of India that, at the moment, is particularly affecting the UK. Cases are nearly up to their pre-vaccination peaks in that country.
Note that the UK has already vaccinated nearly 70% of their population -- more than the United States. In both the UK and US there are few preventive measures in place (no lockdowns, no masks) other than vaccines.
Thus, the UK graph is somewhat predictive of what will happen in the United States. If we time things from when the latest wave hit the same levels as peak of the first wave, then it looks like the Continue reading
Ransomware: Quis custodiet ipsos custodes
Many claim that "ransomware" is due to cybersecurity failures. It's not really true. We are adequately protecting users and computers. The failure is in the inability of cybersecurity guardians to protect themselves. Ransomware doesn't make the news when it only accesses the files normal users have access to. The big ransomware news events happened because ransomware elevated itself to that of an "administrator" over the network, giving it access to all files, including online backups.
Generic improvements in cybersecurity will help only a little, because they don't specifically address this problem. Likewise, blaming ransomware on how it breached perimeter defenses (phishing, patches, password reuse) will only produce marginal improvements. Ransomware solutions need to instead focus on looking at the typical human-operated ransomware killchain, identify how they typically achieve "administrator" credentials, and fix those problems. In particular, large organizations need to redesign how they handle Windows "domains" and "segment" networks.
I read a lot of lazy op-eds on ransomware. Most of them claim that the problem is due to some sort of moral weakness (laziness, stupidity, greed, slovenliness, lust). They suggest things like "taking cybersecurity more seriously" or "do better at basic cyber hygiene". These are "unfalsifiable" -- things that nobody Continue reading
Some quick notes on SDR
I'm trying to create perfect screen captures of SDR to explain the world of radio around us. In this blogpost, I'm going to discuss some of the imperfect captures I'm getting, specifically, some notes about WiFi and Bluetooth.
An SDR is a "software defined radio" which digitally samples radio waves and uses number crunching to decode the signal into data. Among the simplest thing an SDR can do is look at a chunk of spectrum and see signal strength. This is shown below, where I'm monitoring part of the famous 2.4 GHz pectrum used by WiFi/Bluetooth/microwave-ovens:
There are two panes. The top shows the current signal strength as graph. The bottom pane is the "waterfall" graph showing signal strength over time, display strength as colors: black means almost no signal, blue means some, and yellow means a strong signal.
The signal strength graph is a bowl shape, because we are actually sampling at a specific frequency of 2.42 GHz, and the further away from this "center", the less accurate the analysis. Thus, the algorithms think there is more signal the further away from the center we are.
What we do see here is two peaks, at 2.402 Continue reading
When we’ll get a 128-bit CPU
On Hacker News, this article claiming "You won't live to see a 128-bit CPU" is trending". Sadly, it was non-technical, so didn't really contain anything useful. I thought I'd write up some technical notes.
The issue isn't the CPU, but memory. It's not about the size of computations, but when CPUs will need more than 64-bits to address all the memory future computers will have. It's a simple question of math and Moore's Law.
Today, Intel's server CPUs support 48-bit addresses, which is enough to address 256-terabytes of memory -- in theory. In practice, Amazon's AWS cloud servers are offered up to 24-terabytes, or 45-bit addresses, in the year 2020.
Doing the math, it means we have 19-bits or 38-years left before we exceed the 64-bit registers in modern processors. This means that by the year 2058, we'll exceed the current address size and need to move 128-bits. Most people reading this blogpost will be alive to see that, though probably retired.
There are lots of reasons to suspect that this event will come both sooner and later.
It could come sooner if storage merges with memory. We are moving away from rotating platters of rust toward solid-state Continue reading