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  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:	Thu, 27 Dec 2012 04:08:45 +0900
From:	YOSHIFUJI Hideaki <>
To:	Eric Dumazet <>
	YOSHIFUJI Hideaki <>
Subject: Re: [PATCH] ndisc: Ensure to reserve header space for encapsulation.

Eric Dumazet wrote:
> On Tue, 2012-12-25 at 23:39 +0900, YOSHIFUJI Hideaki wrote:
>> We allocate sk_buff of MAX_HEADER + LL_RESERVED_SPACE(dev) + packet
>> length + dev->needed_tailroom, but reserved LL_RESERVED_SPACE(dev)
>> only.  This means that space for encapsulation was placed at the end
>> of buffer.  This does not make sense.
>> Reserve the space correctly, like this:
>> head                       data                   tail       end
>> +--------------------------------------------------------------+
>> +                |           |                      |          |
>> +--------------------------------------------------------------+
>> |<--MAX_HEADER-->|<-hlen---->|<---ipv6 packet------>|<--tlen-->|
>>                    =LL_
>>                     RESERVED_
>>                     SPACE(dev)
>> Signed-off-by: YOSHIFUJI Hideaki <>
>> ---
> It looks like this MAX_HEADER reserve is not needed at all.
> Space for encapsulation should already be in 
> int hlen = LL_RESERVED_SPACE(dev);
> arp_create() for example doesnt add this MAX_HEADER 
> If extra encapsulation is needed (at head or at tail), it really should
> be documented.

Current code does not make sense, at least.

Please refer to my previous posting: "[GIT PULL net-next 01/17]
ndisc: Fix size calculation for headers." around Dec/19.

My previous patch did remove MAX_HEADER from allocation.

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

Powered by blists - more mailing lists