linux-kernel - Re: 4.7-rc7: use-after-free in proc_map_files

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 19 Jul 2016 20:38:57 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Dave Jones <davej@...emonkey.org.uk>,
	Alexey Dobriyan <adobriyan@...il.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: 4.7-rc7: use-after-free in proc_map_files_readdir

On Tue, Jul 19, 2016 at 02:33:27PM -0400, Dave Jones wrote:
>  > Could you dump the relevant part of vmlinux objdump, rather than whatever
>  > you've used on base.o?  Having relocations resolved makes it much easier
>  > to figure out...  Or just dump that vmlinux on anonftp somewhere...
> 
> http://codemonkey.org.uk/junk/vmlinux.gz

OK, it's actually about fetching ->f_mode in
                        info.mode = vma->vm_file->f_mode;

%r15 points contains vma->vm_file at that point, and 0x84 is the offset of
f_mode in struct file on your config from hell (due to spinlock_t size
exploding on lockdep et.al.)

Interesting...  Do you have a reproducer for that?