Re: [PATCH v3 net] tcp: randomize timestamps on syncookies

2017-05-05 Thread David Miller
From: Eric Dumazet Date: Fri, 05 May 2017 06:56:54 -0700 > From: Eric Dumazet > > Whole point of randomization was to hide server uptime, but an attacker > can simply start a syn flood and TCP generates 'old style' timestamps, > directly revealing server jiffies value. > > Also, TSval sent by

[PATCH v3 net] tcp: randomize timestamps on syncookies

2017-05-05 Thread Eric Dumazet
From: Eric Dumazet Whole point of randomization was to hide server uptime, but an attacker can simply start a syn flood and TCP generates 'old style' timestamps, directly revealing server jiffies value. Also, TSval sent by the server to a particular remote address vary depending on syncookies be