42 points ledoge 1 hour ago 13 comments

paulpauper 1 hour ago | parent

it's like the weak hardware wallet entropy bug

jeffbee 56 minutes ago | parent

You'd have to be completely off your rocker to use a PDF tool written in C anyway.

lirolero 46 minutes ago | parent

Genuine question, since I'm not very knowledgeable about this: why is using C for a PDF tool such a bad idea?

recursive 3 minutes ago | parent

buffer overflow vulnerability in code dealing with user generated data and a complex file format.

tptacek 3 minutes ago | parent

I think the claim is hyperbolic, since most people memory-unsafe PDF implementations, but PDF is a monster format, a metaformat that brings in virtually every conceivable display format, and their renderer implementations with them, often poorly-maintained, never-touched reference implementations from the before times. PDF is pretty scary.

cowlevel 41 minutes ago | parent

What are the alternatives?

advisedwang 33 minutes ago | parent

very VERY few people judge tools like this by the language used to develop them.

jeffbee 24 minutes ago | parent

How many people judge their tools based on the AES key entropy?

OptionX 9 minutes ago | parent

A lot actually.

You're confusing just assuming by default its enough for purpose rather than not caring at all.

JonChesterfield 29 minutes ago | parent

Wonderful.

ubutler 15 minutes ago | parent

Rule #1 of rolling your own RNG: don’t.

Rule #2? Please don’t.

j16sdiz 3 minutes ago | parent

That's why we use the system RNG !

tptacek 4 minutes ago | parent

"MuPDF versions before 1.28.5 use an implementation of the drand48 family" yeah, ok, so they're basically not doing real encryption. The number of bits in the key space isn't the real story; the keys simply aren't cryptographically random.