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 --- include/net/pkt_cls.h | 33 +++++++++++++++++++-------------- include/net/sch_generic.h | 3 ++- 2 files changed, 21 insertions(+), 15 deletions(-) (limited to 'include/net') diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index ce036492986a..a972244ab193 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -141,31 +141,38 @@ __cls_set_class(unsigned long *clp, unsigned long cl) return xchg(clp, cl); } -static inline unsigned long -cls_set_class(struct Qdisc *q, unsigned long *clp, unsigned long cl) +static inline void +__tcf_bind_filter(struct Qdisc *q, struct tcf_result *r, unsigned long base) { - unsigned long old_cl; + unsigned long cl; - sch_tree_lock(q); - old_cl = __cls_set_class(clp, cl); - sch_tree_unlock(q); - return old_cl; + cl = q->ops->cl_ops->bind_tcf(q, base, r->classid); + cl = __cls_set_class(&r->class, cl); + if (cl) + q->ops->cl_ops->unbind_tcf(q, cl); } static inline void tcf_bind_filter(struct tcf_proto *tp, struct tcf_result *r, unsigned long base) { struct Qdisc *q = tp->chain->block->q; - unsigned long cl; /* Check q as it is not set for shared blocks. In that case, * setting class is not supported. */ if (!q) return; - cl = q->ops->cl_ops->bind_tcf(q, base, r->classid); - cl = cls_set_class(q, &r->class, cl); - if (cl) + sch_tree_lock(q); + __tcf_bind_filter(q, r, base); + sch_tree_unlock(q); +} + +static inline void +__tcf_unbind_filter(struct Qdisc *q, struct tcf_result *r) +{ + unsigned long cl; + + if ((cl = __cls_set_class(&r->class, 0)) != 0) q->ops->cl_ops->unbind_tcf(q, cl); } @@ -173,12 +180,10 @@ static inline void tcf_unbind_filter(struct tcf_proto *tp, struct tcf_result *r) { struct Qdisc *q = tp->chain->block->q; - unsigned long cl; if (!q) return; - if ((cl = __cls_set_class(&r->class, 0)) != 0) - q->ops->cl_ops->unbind_tcf(q, cl); + __tcf_unbind_filter(q, r); } struct tcf_exts { diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index fceddf89592a..151208704ed2 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -318,7 +318,8 @@ struct tcf_proto_ops { void *type_data); void (*hw_del)(struct tcf_proto *tp, void *type_data); - void (*bind_class)(void *, u32, unsigned long); + void (*bind_class)(void *, u32, unsigned long, + void *, unsigned long); void * (*tmplt_create)(struct net *net, struct tcf_chain *chain, struct nlattr **tca, -- cgit v1.2.3-59-g8ed1b