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, 21 Feb 2012 10:36:53 -0600
From:	Eric Sandeen <>
To:	Xi Wang <>
CC:	Haogang Chen <>, Theodore Tso <>,
	Andreas Dilger <>,,,
	Yongqiang Yang <>,
	Andrew Morton <>
Subject: Re: [PATCH] FS: ext4: fix integer overflow in alloc_flex_gd()

On 02/21/2012 07:55 AM, Xi Wang wrote:
> On Feb 20, 2012, at 6:47 PM, Eric Sandeen wrote:
>> Hm this raises a few questions I think.
>> On the one hand, making sure the kmalloc arg doesn't overflow here is
>> certainly a good thing and probably the right thing to do in the short term.
>> So I guess:
>> Reviewed-by: Eric Sandeen <>
>> for that, to close the hole.
> Another possibility is to wait for knalloc/kmalloc_array in the -mm
> tree, which is basically the non-zeroing version of kcalloc that
> performs overflow checking.
>> Doesn't this also mean that a valid s_log_groups_per_flex (i.e. 31)
>> will fail in this resize code?  That would be an unexpected outcome.
>> 2^31 groups per flex is a little crazy, but still technically valid
>> according to the limits in the code.
> Or we could limit s_log_groups_per_flex/groups_per_flex to a
> reasonable upper bound in ext4_fill_flex_info(), right?

Depends on the "flex_bg" design intent, I guess.

I don't know if the 2^31 was an intended design limit, or just a
mathematical limit that based on container sizes etc...

I'd have to look at the resize code more carefully but I can't imagine
that it's imperative to allocate this stuff all at once.


> - xi

To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists