Follow Slashdot stories on Twitter


Forgot your password?

Comment: Re:um, no (Score 2) 216

by Kiwikwi (#48302969) Attached to: Scotland Builds Power Farms of the Future Under the Sea


Solar is the real eye opener and should serve as a lesson on blindly trusting hype and "What seems obvious." Solar panels are terrible for the environment,

It's always important to remember that there's no such thing as free energy. That said, the linked graph doesn't say anything about solar being "terrible for the environment", only that other sources of electricity consumes* very little silver compared to solar (as Scientific American also notes in the graph). Importantly, it does not show how that use compares to e.g. worldwide silver use.

* "consumes"? "wastes"? "produces as a byproduct"? Pretty sure that oil energy (or biomass!) doesn't consume uranium, even if drilling for oil produces it as a byproduct. Not sure what exactly is being graphed here, honestly. Unfortunately, the cited report is paywalled.

Anyway, if you look at the other report cited by Scientific American as the graph source, in figure 4 on page 19, it shows the global material requirements (in giga-grams, that is, kilotons) under various energy mix scenarios. Neither silver or tin use even registers on the graph in the so-called "non-fossil" scenario (mix of solar, wind and hydro - and no nuclear). In other words, in the "non-fossil" scenario, silver and tin usage for power is less than 1 kiloton a year. Worldwide silver use in 2013 was 34 kt.

As a bonus, silver recycles better than aluminum, with energy savings of 96% (table 4.4).

Comment: Re:Fedora fork too (Score 1) 555

by Kiwikwi (#48199021) Attached to: Debian's Systemd Adoption Inspires Threat of Fork

It seems whenever people want to show how simple a SysV init script can be, they pull out examples that don't do half of what the (still much shorter) SystemD unit file does.

In this example from Slackware:

- 'sendmail' is a globally reserved name for a binary; only the system-wide sendmail daemon may use it.
- you cannot query the service status.
- there's no automatic preprocesing of sendmail config files (rehashing etc.)
- there's no dependency information

And that's just what's missing compared to the Fedora SysV init script.

The Fedora SystemD unit file adds at least the following features:

- the ability to reliably stop or restart the service
- automatic restart if the service dies

Comment: Re:2,266,800 (Score 4, Informative) 407

by Kiwikwi (#48168677) Attached to: As Prison Population Sinks, Jails Are a Steal

1.6M? The U.S. prison population is 2,266,800 according to Wikipedia. It's been over 2M for years, and was 2,418,352 in 2008.

In the U.S., the word "prison" is more specific than you think. Look at the third figure from the top at your own link.

In 2010, the U.S. prison population was ~1,518,000 (state and federal prisons). The U.S. jail population was ~749,000. The sum of those is 2,267,000; then comes another ~90,000 in juvenile detention (see the table below the figure). Add all these (and a bunch of smaller numbers, such as holding facilities for immigrants, and military facilities), you get the number of incarcerated people, which is the number you mention.

But yes, AFAIK the U.S. still incarcerates more people than any other country in the world, both as a fraction of the population, and in absolute numbers. There's a long way down to the next on the list.

Comment: Re:Charging amperage (Score 2) 395

Enh, seems to be only off by a factor 10, though IANAEE (I am not an electrical engineer). Forgive me if I'm missing a factor 1.44 or something, below.

Obviously you don't charge an electric car battery at 12 V. What the individual cells do is irrelevant, since they charge in parallel; the bottle neck is the cable attached to the car (and cooling, but hey, we're assuming magic new wonder battery tech, so I'll conveniently ignore that issue).

The highest power available using standard CEE (IEC 60309) plugs and mainline voltage is 3 x 125A x 230V, or about 86 kW. This is not normal in a home, obviously, but you can easily get a couple of these in commercial installations.

Ignoring losses (I know, I know), 86 kW means one hour to fully charge a Tesla Model S with the big 85 kWh battery pack, but that's also a big battery pack.

Charging the 48 kWh battery of the upcoming Model E to 70 % will take: 70% x 48 kWh / 86 kW = 23 minutes.

Now, I would've thought 3 x 125 A x 230V was about the limit, simple due to the weight (those cables are very heavy!). But apparently, Tesla Superchargers go beyond this, to more than 120 kW (340 A x 360 V), with possible plans for 135 kW or even 150 kW. (I guess if the cable is short enough, and you increase voltage beyond mains voltage...) This gives you 70% x 48 kWh charging times in as little as 17 minutes (120 kW) or even 13 minutes (150 kW). Still a far cry from 2 minutes, but then the 17 minute figure is using current mass-market technology.

Comment: Re:The water wars are coming (Score 5, Insightful) 151

by Kiwikwi (#48037819) Attached to: Aral Sea Basin Almost Completely Dry

Yup, this is what you get when a short-sighted totalitarian government messes with the water cycle to enable farming in a desert, consequences be damned.

Come to think of it, California is what you get when a short-sighted democratic government messes with the water cycle to enable farming in a desert, consequences be damned.

Let's face it, environmental concerns wasn't really on any government's radar until the 70s. (And a lot of countries still try to ignore them...)

Comment: Re:~/.cshrc (Score 3, Interesting) 208

by Kiwikwi (#48012793) Attached to: Apple Yet To Push Patch For "Shellshock" Bug

It really has nothing to do with the default shell. It won't matter what shell is the default when your CGI script starts with #!/bin/bash.

No, no, no, no... People really don't get the scope of this.

It doesn't matter what the default user shell is, or what language a CGI script is written in. Bash is the most common system shell, which means it's invoked all the time when other programs run commands.

Obviously, I can't know this, but OP is probably not using csh as his system shell, because that's not POSIX compliant and would cause major breakage.

If /bin/sh is Bash, you're vulnerable, no matter what shell you're using yourself, or what language your CGI script is written in.

Also, CGI scripts is only the most obvious attack vector; others that have been identified so far are the CUPS printing daemon, the ISC DHCP client and locked down SSH shells like those commonly used to host Git repositories. But there are without doubt many more. The only safe thing to do is to upgrade or remove Bash from your system immediately.

Comment: Re:"could be worse than Heartbleed" (Score 1) 318

by Kiwikwi (#48001199) Attached to: Flurry of Scans Hint That Bash Vulnerability Could Already Be In the Wild

No, it is any CGI program that sets an environment variable to unchecked user input and then invokes a shell or calls any other program that invokes a shell.

Got that?

No, it's not the CGI program that sets the HTTP_USER_AGENT environment variable, and this is not a vulnerability in the CGI program nor the CGI protocol. The fault lies 100% with Bash, which executes arbitrary shell code from arbitrary environment variables.

Comment: Re:"could be worse than Heartbleed" (Score 2) 318

by Kiwikwi (#47998023) Attached to: Flurry of Scans Hint That Bash Vulnerability Could Already Be In the Wild

any CGI program + any non-Debian Linux => vulnerable

No, only CGI programs that use system/popen/etc to call out to things that may be bash.

Enh, good luck auditing even just a resonably complex CGI program for direct and indirect invocations of the system shell.

For instance, care to guess whether this one is safe?

For once, the PHP programmers are ahead security wise due to the ubiquity of mod_php...)

Well for one most languages the equivalent facility is available and usually used since it is a requirement to scale.

I know, mod_perl and mod_wsgi on Apache, and of course, Fast CGI. But CGI is still common in a lot of setups.

For another, even the silly 'fork and exec' perl or php or python isn't vulnerable if said script avoids system/popen/backticks/whathaveyou.

Even if you don't call out to the shell yourself, the standard library might.

Pop quiz 1: How is the PHP mail function implemented?

Pop quiz 2: What parts of the Python standard library module uuid are safe to use, and what parts will render your CGI script vulnerable?

I guess I was wrong to play down the severity of bash, but my hope was for people to just consider themselves to make a mistake by ever potentially having bash in a cgi context, for reasons beyond this exploit.

It's the system shell. It's everywhere. The real lesson here is to not use a big bulky program like Bash as the system shell.

Answers to pop quiz:

1. popen to execute sendmail program.

2. The following Python CGI script is vulnerable: import uuid (that's it). (uuid uses ctypes.util.find_library, which uses popen).

These examples took me less than 20 minutes of grepping to come up with, and I'm not even trying to hack any computers...

Comment: Re:So flog the bash developer who checked this in. (Score 2) 318

by Kiwikwi (#47997593) Attached to: Flurry of Scans Hint That Bash Vulnerability Could Already Be In the Wild

In those days [late 80s/early 90s] revision control wasn't universally used. Even as late as the early 00's I was training engineers coming out of master's degree IT programs who had no idea how to use a revision control system.

Linus didn't use a revision control system for the Linux kernel until 2002.

(Aw... comparisons between CVS and the "soon to be finished" Subversion. How quaint.)

Comment: Re:This exposes systemic insecurities (Score 4, Informative) 318

by Kiwikwi (#47996901) Attached to: Flurry of Scans Hint That Bash Vulnerability Could Already Be In the Wild

Basically, this Bash bug is really only exploitable by remote users because of some questionable decisions made in designing the software stack.

Hm, no, the fault here lies squarely with Bash choosing to interpret an environment variable called HTTP_USER_AGENT as a program to execute.

This is not about accepting arbitrary environment variables; CGI puts data in a few, well-defined variables. This is a perfectly legimiate use of environment variables. (And Windows does the exact same thing.)

You're right that using a "full-bore shell program" such as Bash as the system shell is moronic. It is, unfortunately, still the norm on all major Linux distros except Debian and derivatives (which use the limited Dash shell, which is not vulnerable).

Primarily, I think this is a wake up call for Fedora, SUSE and the others: Bash is a huge, complex component, evidently with insufficient security review, and should not be used as the system shell. Debian dropped it for performance reasons, but now we can add security concerns to the list. It can stay around for use as an interactive shell (though why you'd do that when you have zsh, I don't know...)

Comment: Re:"could be worse than Heartbleed" (Score 5, Informative) 318

by Kiwikwi (#47996703) Attached to: Flurry of Scans Hint That Bash Vulnerability Could Already Be In the Wild

Outside of malicious HTTP headers landing in environment variable in CGI land, I'm hard pressed to think of another reasonable vector for this bug to be a problem...

Unfortunately, attackers do not share your lack of imagination.

First of all, the CGI vulnerability is not about CGI scripts written in Bash, this is about any CGI script that at any point invokes a shell or invokes a program that invokes a shell (e.g. using the system call), irrespective of the actual shell command, on a system that uses Bash as the system shell (so pretty much all non-Debian based Linux distros).

Got that? any CGI program + any non-Debian Linux => vulnerable. (For once, the PHP programmers are ahead security wise due to the ubiquity of mod_php...)

Second of all, there are all kinds of non-CGI situations in which untrusted data is passed in environment variables. This is normally not a problem... unless that environment variable at any point is inherited by Bash.

The ISC DHCP client (dhclient) is the canonical example, as it runs a distro-specific shell script to set up the network once it gets a DHCP lease. Unustrusted values from the DHCP server are passed - you guessed it - in environment variables.

Comment: Re:In lost the will to live ... (Score 2) 795

by Kiwikwi (#47968461) Attached to: How Our Botched Understanding of "Science" Ruins Everything

Why is causing pain to others bad? Why do you care about what other people feel?

Quid pro quo. I care about them and don't cause them pain; and in return, they care about me and don't cause me pain. It's also called the social contract.

You may argue, "prisoner's dilemma" style, that an individual can then gain an advantage by breaking the social contract, and indeed some people do that. Bruce Schneier wrote a whole book about that topic. But as it turns out, most people don't break the social contract, due to 1) intense social conditioning (religious or otherwise) and/or 2) the threat of punishment if they're caught.

The social contract predates Christianity by millenias; heck, it presumably existed in a primitive form in stone age hunter-gatherer culture.

But even ignoring social conditioning and even the evolutionary traits that have developed to promote that contract (e.g. increased empathy), abiding by the contract still makes sense: Civilization depends on the majority following the social contract, and indeed, most people find that the immediate benefit of breaking the contract is outweighed by the threat of civilization falling apart. Of course, once people start to break the social contract in larger numbers, the cost-benefit ratio changes, and civilization crumbles quickly.

Surely you've heard of the Golden Rule? This requires zero belief in the supernatural or any sort of sacredness.

Except that it doesn't explain why you should follow it. Most people seem to use "karma" (or "what comes around goes around") as a not-quite-as-supernatural-as-an-omnipotent-God reason for following the Golden Rule.

I'd argue that karma is a real thing, only global, not personal. When you do a good thing for others, you increase global karma, ever so slightly increasing the odds of good things happening to you, too. (But it's a big world; I think you'll find playing the lottery has better ROI.)

Personal karma AKA the "just world" belief is of course a myth. The fact that so many people believe in it is a testament to the aforementioned social conditioning.

"'Tis true, 'tis pity, and pity 'tis 'tis true." -- Poloniouius, in Willie the Shake's _Hamlet, Prince of Darkness_