fq_codel: reject silly quantum parameters
stable inclusion from stable-5.10.68 commit 8c01c620ae61142760d8924ee96a3ff8eec00aa6 bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8c01c620ae61142760d8924ee96a3ff8eec00aa6 -------------------------------- [ Upstream commit c7c5e6ff ] syzbot found that forcing a big quantum attribute would crash hosts fast, essentially using this: tc qd replace dev eth0 root fq_codel quantum 4294967295 This is because fq_codel_dequeue() would have to loop ~2^31 times in : if (flow->deficit <= 0) { flow->deficit += q->quantum; list_move_tail(&flow->flowchain, &q->old_flows); goto begin; } SFQ max quantum is 2^19 (half a megabyte) Lets adopt a max quantum of one megabyte for FQ_CODEL. Fixes: 4b549a2e ("fq_codel: Fair Queue Codel AQM") Signed-off-by:Eric Dumazet <edumazet@google.com> Reported-by:
syzbot <syzkaller@googlegroups.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Sasha Levin <sashal@kernel.org> Signed-off-by:
Chen Jun <chenjun102@huawei.com> Acked-by:
Weilong Chen <chenweilong@huawei.com> Signed-off-by:
Chen Jun <chenjun102@huawei.com> Signed-off-by:
Zheng Zengkai <zhengzengkai@huawei.com>
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