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:   Mon, 01 Apr 2019 11:00:22 +0800
From:   lifonghsu <>
To:     David Miller <>
Subject: Re: net: fix routing encapsulated packets when binding a socket to a
 tunnel interface

David Miller 於 2019-03-30 01:40 寫到:
> From: lifonghsu <>
> Date: Thu, 28 Mar 2019 16:30:37 +0800
>> Indeed, skb_iif is used as receive site indication to present "device
>> the packet arrived on".
>> This commit keeps the previous arrived device (similar to the concept
>> of "device the packet arrived on") in skb_iif field to prevent kernel
>> from referring sk_bound_dev_if again. Otherwise, we might need to add
>> a new field to sk_buff structure for our purpose.
> Therefore, you are deciding to arbitrarily repurpose an RX side piece
> of state for TX purposes.
> Do not do this.
> It confuses anyone trying to understand how skb_iif works.
> You must use something with a different name, and clear semantics, to
> achieve this goal.
> For example, you could use an anonymous union:
> 	union {
> 		int	skb_iif;
> 		bool	bound_dev_already_applied;
> 	};
> You never actually _USE_ the value of skb_iif, it is just merely a
> boolean indicating whether sk_bound_dev_if was applied already.

Since we are not sure whether there is any code referring to the value 
skb_iff in transmit site or not, it is risky to set an invalid interface
index to skb_iif in an anonymous union.
What if we add a bit (e.g., __u8 bound_dev_already_applied:1;) to 

Powered by blists - more mailing lists