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Test your applicationsThere is no fixed version for Centos:6
kernel
.
Note: Versions mentioned in the description apply only to the upstream kernel
package and not the kernel
package as distributed by Centos
.
See How to fix?
for Centos:6
relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereference in htb_next_rb_node() after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree(): |-> fq_codel_dequeue() |-> qdisc_tree_reduce_backlog() |-> htb_qlen_notify() |-> htb_deactivate() |-> htb_next_rb_node() |-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the clprio[prio]->ptr could be already set to NULL, which means htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again which triggers the warning inside.
To fix the issues here, we need to:
Many thanks to Alan for testing and for the reproducer.