Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 8 Feb 2018 14:33:58 -0500
From: Daniel Micay <>
To: Matthew Wilcox <>
Cc: Jann Horn <>,, 
	Kernel Hardening <>, 
	kernel list <>, 
	"Kirill A. Shutemov" <>
Subject: Re: [RFC] Warn the user when they could overflow mapcount

I don't think the kernel can get away with the current approach.
Object sizes and counts on 64-bit should be 64-bit unless there's a
verifiable reason they can get away with 32-bit. Having it use leak
memory isn't okay, just much less bad than vulnerabilities exploitable
beyond just denial of service.

Every 32-bit reference count should probably have a short comment
explaining why it can't overflow on 64-bit... if that can't be written
or it's too complicated to demonstrate, it probably needs to be
64-bit. It's one of many pervasive forms of integer overflows in the
kernel... :(

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.