PHPT VS src

In our latest story we show a couple of smart ways to get around some import conflicts in PHP.

The values [0, 15] represent 16 possible values, which is a power of 2.

The correct way to get an unbiased distribution from a sample of 2^x to a modulo that is not an even power of 2 is to use rejection sampling.

This is what RFC 6979 says to do https://datatracker.ietf.org/doc/html/rfc6979#section-3.2

But you can also see this technique in CSPRNG code; i.e. https://github.com/php/php-src/blob/d40726670fd2915dcd807673...

I am running this code on MacOS on Apple Silicon hardware which is crashing when using the JIT in a ZTS build of PHP, so the 1m 35s result is without JIT, it might be even faster if I could use it

49. PHP - $58,899

A little about me; I'm a web developer and have been for around 5 years, though I'd dabbled for years. I have experience with Perl and PHP but my day to day is JavaScript/TypeScript be it through NodeJS or ReactJS. I want to learn Rust for no specific reason other than it's fun to learn new things.

Consider a web application where requests are handled through NGINX as the web server and PHP as the dynamic backend language. Let’s say something in the application logic results in a fatal error or process termination. This doesn’t affect NGINX’s ability to serve a response to the client, which would most likely be an HTTP 503 - Service Unavailable message.

In the beginning, I used a technology called CGI to develop server applications written in Perl. This technology was later replaced by Microsoft’s ASP (Active Server Pages) and then PHP. PHP, which you may already know, is still powering over 77% of all the websites as of the time of writing (ever heard of WordPress?).

PHP

As Shopware is mostly based on the Symfony framework, which is in turn based on the PHP language, we should also consider learning about the basics, which will also be useful for other frameworks apart from Shopware, like Symfonycasts, symfony.com, php.net.

The OpenBSD project released 7.4 of their OS on 16 Oct 2023 as their 55th release 💫

Well since https://www.openbsd.org/ still says

> Only two remote holes in the default install, in a heck of a long time!

I'm assuming not, but I could always be mistaken.

> building a cat from scratch

> That would be an interesting project.

Here is the source code of the OpenBSD implementation of cat:

> https://github.com/openbsd/src/blob/master/bin/cat/cat.c

and here of the GNU coreutils implementation:

> https://github.com/coreutils/coreutils/blob/master/src/cat.c

Thus: I don't think building a cat from scratch or creating a tutorial about that topic is particularly hard (even though the HN audience would likely be interested in it). :-)

> I don't know how they define `MAX`, but I'm guessing it's a typical "a>b?a:b"

Indeed: https://github.com/openbsd/src/blob/master/sys/sys/param.h#L...

> Then `SYS_kbind` seems to be a signed int.

It's an untyped #define: https://github.com/openbsd/src/blob/master/sys/sys/syscall.h...

I believe your whole analysis is correct, that running an elf file with an openbsd.syscalls entry with .sysno > INT_MAX will allow an out-of-bounds write.

I can reproduce it. And this is the commit that causes the issue: https://github.com/openbsd/src/commit/d21788ce70be80e9c4ed0c52c149e01147c4a823

This doesn’t really change your conclusion, but I think that’s the wrong file. This is the real doas afaict: https://github.com/openbsd/src/blob/master/usr.bin/doas/doas...

Still just a tidy 1072 lines in that folder though.

I spent 5 minutes staring at your file trying to understand how on earth it does the things in the man page, but of course it doesn’t.

OpenBSD developers are making serious effort to kill off indirect syscalls, the base system is completely clean, take a look at the work Andrew Fresh did to adapt Perl. He write a complete syscall "dispatcher" or emulator for the Perl syscall function so that it calls the libc stubs.

https://github.com/openbsd/src/commit/312e26c80be876012ae979...

The ports tree is also being cleansed of syscall(2) usage, until they're all gone.

msyscall, pinsyscall, recent mandatory IBT/BTI, xonly. OpenBSD is making waves, but people aren't really seeing them yet.

Actually, I got it wrong, too many vulnerabilities in flight. They did fix it: https://github.com/openbsd/src/commit/375ccafb2eb77de6cf240e...