[Not really OT] Crowdstrike Analysis: It was a NULL pointer from the memory unsafe C++ language.

[H. S. Teoh]

On Wed, Jul 24, 2024 at 05:12:28PM -0700, Walter Bright via Digitalmars-d wrote:
> I talked with a person who has more in depth knowledge about it.
> 
> The null pointer came from reading a file and treating it as a data
> structure. The file was unexpectedly full of zeros.

Reading a file and treating it as a data structure without verification
or at the very least sanity checking is a rather unwise thing to do.
Unfortunately this is a rather common practice in enterprise code.  Sad
to say, I've been guilty of this myself. :-P

Not catching this during testing, though, is rather disappointing.
Though also unsurprising... having worked for a few decades in the
industry dealing with very large codebases, I've seen firsthand how
testing is often skimped on, especially when there's a looming deadline
or some similar pressure to get it done quickly and move on to the next
item in a large pile of things that need to get down by last week.

And sometimes the tester also has no idea what he's testing and what
corner cases to watch out for; he also has a large pile of other work to
get to and so often just randomly does a couple of ordinary runs,
observes nothing unusual, and calls it done.  This is especially bad
with software that requires lots of repetitive testing of features
previously verified. The temptation to skimp out a few cases to speed
things up is very strong.  All sorts of things may slip through
unnoticed.

This is why D's built-in unittests, in spite of their warts, is a major
tool for improving software quality. You *want* tests to be as automated
as possible, because the rate of human error is especially high when it
comes to repetitive (but very necessary) testing of previously working
features.  Having the machine automatically verify previous working
features is a big step in eliminating human error (aka laziness) in this
area.


> Any language that allows casting a buffer read from the disk to a
> pointer would fail. This includes any language with unsafe blocks, or
> uses a FFI to get around the language protections.

Casting a buffer read from disk to a pointer is, in general, a risky and
unwise thing to do.  But the temptation to do it anyway is very strong,
especially in low level code or where performance is a concern.

At least, one should be thankful the file was filled with zeroes and not
something else, like malicious code or code that coincidentally did
something destructive like format the disk or overwriting the boot
sector.


T

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