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55667441c8
UDP IPv6 packets auto flowlabels are using a 32bit secret (static u32 hashrnd in net/core/flow_dissector.c) and apply jhash() over fields known by the receivers. Attackers can easily infer the 32bit secret and use this information to identify a device and/or user, since this 32bit secret is only set at boot time. Really, using jhash() to generate cookies sent on the wire is a serious security concern. Trying to change the rol32(hash, 16) in ip6_make_flowlabel() would be a dead end. Trying to periodically change the secret (like in sch_sfq.c) could change paths taken in the network for long lived flows. Let's switch to siphash, as we did in commitdf453700e8("inet: switch IP ID generator to siphash") Using a cryptographically strong pseudo random function will solve this privacy issue and more generally remove other weak points in the stack. Packet schedulers using skb_get_hash_perturb() benefit from this change. Fixes:b56774163f("ipv6: Enable auto flow labels by default") Fixes:42240901f7("ipv6: Implement different admin modes for automatic flow labels") Fixes:67800f9b1f("ipv6: Call skb_get_hash_flowi6 to get skb->hash in ip6_make_flowlabel") Fixes:cb1ce2ef38("ipv6: Implement automatic flow label generation on transmit") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Jonathan Berger <jonathann1@walla.com> Reported-by: Amit Klein <aksecurity@gmail.com> Reported-by: Benny Pinkas <benny@pinkas.net> Cc: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
104 lines
2.7 KiB
C
104 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (c) 2016 Qualcomm Atheros, Inc
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*
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* Based on net/sched/sch_fq_codel.c
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*/
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#ifndef __NET_SCHED_FQ_H
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#define __NET_SCHED_FQ_H
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struct fq_tin;
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/**
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* struct fq_flow - per traffic flow queue
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*
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* @tin: owner of this flow. Used to manage collisions, i.e. when a packet
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* hashes to an index which points to a flow that is already owned by a
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* different tin the packet is destined to. In such case the implementer
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* must provide a fallback flow
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* @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
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* (deficit round robin) based round robin queuing similar to the one
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* found in net/sched/sch_fq_codel.c
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* @backlogchain: can be linked to other fq_flow and fq. Used to keep track of
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* fat flows and efficient head-dropping if packet limit is reached
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* @queue: sk_buff queue to hold packets
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* @backlog: number of bytes pending in the queue. The number of packets can be
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* found in @queue.qlen
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* @deficit: used for DRR++
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*/
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struct fq_flow {
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struct fq_tin *tin;
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struct list_head flowchain;
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struct list_head backlogchain;
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struct sk_buff_head queue;
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u32 backlog;
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int deficit;
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};
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/**
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* struct fq_tin - a logical container of fq_flows
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*
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* Used to group fq_flows into a logical aggregate. DRR++ scheme is used to
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* pull interleaved packets out of the associated flows.
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*
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* @new_flows: linked list of fq_flow
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* @old_flows: linked list of fq_flow
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*/
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struct fq_tin {
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struct list_head new_flows;
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struct list_head old_flows;
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u32 backlog_bytes;
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u32 backlog_packets;
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u32 overlimit;
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u32 collisions;
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u32 flows;
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u32 tx_bytes;
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u32 tx_packets;
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};
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/**
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* struct fq - main container for fair queuing purposes
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*
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* @backlogs: linked to fq_flows. Used to maintain fat flows for efficient
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* head-dropping when @backlog reaches @limit
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* @limit: max number of packets that can be queued across all flows
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* @backlog: number of packets queued across all flows
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*/
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struct fq {
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struct fq_flow *flows;
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struct list_head backlogs;
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spinlock_t lock;
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u32 flows_cnt;
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siphash_key_t perturbation;
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u32 limit;
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u32 memory_limit;
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u32 memory_usage;
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u32 quantum;
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u32 backlog;
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u32 overlimit;
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u32 overmemory;
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u32 collisions;
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};
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typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
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struct fq_tin *,
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struct fq_flow *flow);
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typedef void fq_skb_free_t(struct fq *,
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struct fq_tin *,
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struct fq_flow *,
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struct sk_buff *);
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/* Return %true to filter (drop) the frame. */
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typedef bool fq_skb_filter_t(struct fq *,
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struct fq_tin *,
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struct fq_flow *,
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struct sk_buff *,
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void *);
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typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
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struct fq_tin *,
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int idx,
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struct sk_buff *);
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#endif
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