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]
Message-Id: <20080622233448.4b27c131.akpm@linux-foundation.org>
Date:	Sun, 22 Jun 2008 23:34:48 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Michael Buesch <mb@...sch.de>
Cc:	Arnd Bergmann <arnd@...db.de>,
	"linux-kernel" <linux-kernel@...r.kernel.org>,
	Jens Axboe <axboe@...nel.dk>, Jan Kara <jack@....cz>
Subject: Re: Oops when using growisofs

On Mon, 23 Jun 2008 00:28:20 +0200 Michael Buesch <mb@...sch.de> wrote:

> On Monday 23 June 2008 00:05:51 Michael Buesch wrote:
> > > Note: r9 and r3 are both NULL pointers. r3 is the value returned from alloc_page_buffers.
> > > R9 is a copy of that, which gets accessed.
> > 
> > Hm, yeah. I looked at that code already, but I can't see how it could return
> > a NULL pointer.
> 
> Well, actually, it can return a NULL pointer.
> 
>  928         head = NULL;
>  929         offset = PAGE_SIZE;
>  930         while ((offset -= size) >= 0) {
> ...
>  949         }
>  950         return head;
> 
> So if size, which is a passed in as parameter, is > PAGE_SIZE it will return NULL.
> 
> The size parameter is calculated by doing
> blocksize = 1 << inode->i_blkbits;
> in an earlier function in the callchain.

Yes, that's a more likely scenario.  isofs has a history of passing
garbage into the VFS.

> So, well. I dunno what i_blkbits is. There's no docs in struct inode.

It's log2 of the filesystem blocksize.  It'd be interesting to work out
what value isofs is setting it to, and why.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ