From 2e24cd755552350b94a7617617c6877b8cbcb701 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 23 Jan 2020 16:26:18 -0800 Subject: net_sched: fix ops->bind_class() implementations The current implementations of ops->bind_class() are merely searching for classid and updating class in the struct tcf_result, without invoking either of cl_ops->bind_tcf() or cl_ops->unbind_tcf(). This breaks the design of them as qdisc's like cbq use them to count filters too. This is why syzbot triggered the warning in cbq_destroy_class(). In order to fix this, we have to call cl_ops->bind_tcf() and cl_ops->unbind_tcf() like the filter binding path. This patch does so by refactoring out two helper functions __tcf_bind_filter() and __tcf_unbind_filter(), which are lockless and accept a Qdisc pointer, then teaching each implementation to call them correctly. Note, we merely pass the Qdisc pointer as an opaque pointer to each filter, they only need to pass it down to the helper functions without understanding it at all. Fixes: 07d79fc7d94e ("net_sched: add reverse binding for tc class") Reported-and-tested-by: syzbot+0a0596220218fcb603a8@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+63bdb6006961d8c917c6@syzkaller.appspotmail.com Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/sch_api.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'net/sched/sch_api.c') diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 1047825d9f48..943ad3425380 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1891,8 +1891,9 @@ static int tclass_del_notify(struct net *net, struct tcf_bind_args { struct tcf_walker w; - u32 classid; + unsigned long base; unsigned long cl; + u32 classid; }; static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg) @@ -1903,7 +1904,7 @@ static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg) struct Qdisc *q = tcf_block_q(tp->chain->block); sch_tree_lock(q); - tp->ops->bind_class(n, a->classid, a->cl); + tp->ops->bind_class(n, a->classid, a->cl, q, a->base); sch_tree_unlock(q); } return 0; @@ -1936,6 +1937,7 @@ static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid, arg.w.fn = tcf_node_bind; arg.classid = clid; + arg.base = cl; arg.cl = new_cl; tp->ops->walk(tp, &arg.w, true); } -- cgit v1.2.3-70-g09d2 From 760d228e322e99cdf6d81b4b60a268b8f13cf67a Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 23 Jan 2020 17:27:08 -0800 Subject: net_sched: walk through all child classes in tc_bind_tclass() In a complex TC class hierarchy like this: tc qdisc add dev eth0 root handle 1:0 cbq bandwidth 100Mbit \ avpkt 1000 cell 8 tc class add dev eth0 parent 1:0 classid 1:1 cbq bandwidth 100Mbit \ rate 6Mbit weight 0.6Mbit prio 8 allot 1514 cell 8 maxburst 20 \ avpkt 1000 bounded tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 match ip \ sport 80 0xffff flowid 1:3 tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 match ip \ sport 25 0xffff flowid 1:4 tc class add dev eth0 parent 1:1 classid 1:3 cbq bandwidth 100Mbit \ rate 5Mbit weight 0.5Mbit prio 5 allot 1514 cell 8 maxburst 20 \ avpkt 1000 tc class add dev eth0 parent 1:1 classid 1:4 cbq bandwidth 100Mbit \ rate 3Mbit weight 0.3Mbit prio 5 allot 1514 cell 8 maxburst 20 \ avpkt 1000 where filters are installed on qdisc 1:0, so we can't merely search from class 1:1 when creating class 1:3 and class 1:4. We have to walk through all the child classes of the direct parent qdisc. Otherwise we would miss filters those need reverse binding. Fixes: 07d79fc7d94e ("net_sched: add reverse binding for tc class") Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/sch_api.c | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) (limited to 'net/sched/sch_api.c') diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 943ad3425380..50794125bf02 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1910,22 +1910,24 @@ static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg) return 0; } -static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid, - unsigned long new_cl) +struct tc_bind_class_args { + struct qdisc_walker w; + unsigned long new_cl; + u32 portid; + u32 clid; +}; + +static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl, + struct qdisc_walker *w) { + struct tc_bind_class_args *a = (struct tc_bind_class_args *)w; const struct Qdisc_class_ops *cops = q->ops->cl_ops; struct tcf_block *block; struct tcf_chain *chain; - unsigned long cl; - cl = cops->find(q, portid); - if (!cl) - return; - if (!cops->tcf_block) - return; block = cops->tcf_block(q, cl, NULL); if (!block) - return; + return 0; for (chain = tcf_get_next_chain(block, NULL); chain; chain = tcf_get_next_chain(block, chain)) { @@ -1936,12 +1938,29 @@ static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid, struct tcf_bind_args arg = {}; arg.w.fn = tcf_node_bind; - arg.classid = clid; + arg.classid = a->clid; arg.base = cl; - arg.cl = new_cl; + arg.cl = a->new_cl; tp->ops->walk(tp, &arg.w, true); } } + + return 0; +} + +static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid, + unsigned long new_cl) +{ + const struct Qdisc_class_ops *cops = q->ops->cl_ops; + struct tc_bind_class_args args = {}; + + if (!cops->tcf_block) + return; + args.portid = portid; + args.clid = clid; + args.new_cl = new_cl; + args.w.fn = tc_bind_class_walker; + q->ops->cl_ops->walk(q, &args.w); } #else -- cgit v1.2.3-70-g09d2