[Hardy] SRU: Fix for TCP stack bugs related to F-RTO

Stefan Bader stefan.bader at canonical.com
Tue Jun 8 14:05:42 UTC 2010


https://bugs.launchpad.net/ubuntu/+source/linux/+bug/567394

SRU justification:

Impact: Several flaws in the F-RTO (forward retransmission timeout)
implementation in 2.6.24 which causes packets under certain circumstances
to get silently dropped while the client will accept longer and longer
re-transmit timeouts.
This can lead to resource exhaustion and thus to DOS vulnerability.
There is no CVE assigned to this issue and the class of change should likely
be done using the retention period in proposed. So this is submitted as a
normal proposed update.

Fix: This set of three patches which has been picked from 2.6.25.y has been
verified to cure the problem. Tester reported successful avoidance of the
problem with a test kernel provided and has seen no regressions.

Testcase: Unfortunately this seems to be observed only in a certain
environment and with certain steps which are not public.






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