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] [day] [month] [year] [list]
Date:   Thu, 07 May 2020 18:19:30 -0700 (PDT)
From:   David Miller <>
Subject: Re: [Patch net v3] net: fix a potential recursive

From: Cong Wang <>
Date: Thu,  7 May 2020 12:19:03 -0700

> syzbot managed to trigger a recursive NETDEV_FEAT_CHANGE event
> between bonding master and slave. I managed to find a reproducer
> for this:
>   ip li set bond0 up
>   ifenslave bond0 eth0
>   brctl addbr br0
>   ethtool -K eth0 lro off
>   brctl addif br0 bond0
>   ip li set br0 up
> When a NETDEV_FEAT_CHANGE event is triggered on a bonding slave,
> it captures this and calls bond_compute_features() to fixup its
> master's and other slaves' features. However, when syncing with
> its lower devices by netdev_sync_lower_features() this event is
> triggered again on slaves when the LRO feature fails to change,
> so it goes back and forth recursively until the kernel stack is
> exhausted.
> Commit 17b85d29e82c intentionally lets __netdev_update_features()
> return -1 for such a failure case, so we have to just rely on
> the existing check inside netdev_sync_lower_features() and skip
> NETDEV_FEAT_CHANGE event only for this specific failure case.
> Fixes: fd867d51f889 ("net/core: generic support for disabling netdev features down stack")
> Reported-by:
> Reported-by:
> Cc: Jarod Wilson <>
> Cc: Nikolay Aleksandrov <>
> Cc: Josh Poimboeuf <>
> Cc: Jann Horn <>
> Reviewed-by: Jay Vosburgh <>
> Signed-off-by: Cong Wang <>

Applied and queued up for -stable, thanks Cong.

Powered by blists - more mailing lists