netdev - Re: [PATCH] sctp: don't compare hb_timer expire date before starting it

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] [day] [month] [year] [list]

Date:   Fri, 22 Feb 2019 11:22:22 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     kwiecienmaciek@...il.com
Cc:     linux-sctp@...r.kernel.org, netdev@...r.kernel.org,
        alexander.sverdlin@...ia.com, maciej.kwiecien@...ia.com
Subject: Re: [PATCH] sctp: don't compare hb_timer expire date before
 starting it

From: kwiecienmaciek@...il.com
Date: Fri, 22 Feb 2019 09:45:26 +0100

> From: Maciej Kwiecien <maciej.kwiecien@...ia.com>
> 
> hb_timer might not start at all for a particular transport because its
> start is conditional. In a result a node is not sending heartbeats.
> 
> Function sctp_transport_reset_hb_timer has two roles:
>     - initial start of hb_timer for a given transport,
>     - update expire date of hb_timer for a given transport.
> The function is optimized to update timer's expire only if it is before
> a new calculated one but this comparison is invalid for a timer which
> has not yet started. Such a timer has expire == 0 and if a new expire
> value is bigger than (MAX_JIFFIES / 2 + 2) then "time_before" macro will
> fail and timer will not start resulting in no heartbeat packets send by
> the node.
> 
> This was found when association was initialized within first 5 mins
> after system boot due to jiffies init value which is near to MAX_JIFFIES.
> 
> Test kernel version: 4.9.154 (ARCH=arm)
> hb_timer.expire = 0;                //initialized, not started timer
> new_expire = MAX_JIFFIES / 2 + 2;   //or more
> time_before(hb_timer.expire, new_expire) == false
> 
> Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often")
> Reported-by: Marcin Stojek <marcin.stojek@...ia.com>
> Tested-by: Marcin Stojek <marcin.stojek@...ia.com>
> Signed-off-by: Maciej Kwiecien <maciej.kwiecien@...ia.com>

Applied and queued up for -stable, thank you.