Opened 5 years ago

Closed 5 years ago

#14788 closed enhancement (wontfix)

Use unpredictability better on Windows

Reported by: anon Owned by:
Priority: Medium Milestone: Tor: 0.2.7.x-final
Component: Core Tor/Tor Version:
Severity: Keywords:
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

Use unpredictability better on Windows

On Win32 / Win64 and using either CryptGenRandom or RtlGenRandom read and drop first 128Kbytes of *GenRandom before

calling again for entropy to be used for key material or deterministic generators.

This is due to possibly insecure/exposed PRNG state on some win32 hosts this read past the first 128Kbytes of generator output before is explained in http://eprint.iacr.org/2007/419

See:

gitweb.torproject.org/tor.git/tree/src/common/crypto.c#n2457 crypto_strongest_rand();

Also,

<skruffy> https://privatepaste.com/45ff1fac9f here another idea used mingw specific of crt, simple and no any extra linking.

Child Tickets

Change History (4)

comment:1 Changed 5 years ago by nickm

Milestone: Tor: 0.2.7.x-final

Wow, windows just looks worse and worse, huh?

Do we know anything about what post-XP windows does here? I don't think we support windows 2000, right?

Did anybody save that privatepaste thing? It seems to have expired.

comment:2 Changed 5 years ago by cypherpunks

ask someone else

Last edited 5 years ago by cypherpunks (previous) (diff)

comment:3 Changed 5 years ago by nickm

Status: newassigned

comment:4 Changed 5 years ago by nickm

Resolution: wontfix
Status: assignedclosed

All of the versions of windows with this RNG bug are deprecated and not getting security patches; trying to make them more secure is unlikely to be fruitful.

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