| From 051c48cc4696d97f23694b4e525b9254b1608d35 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 13 Apr 2022 10:35:42 -0700 |
| Subject: net/sched: cls_u32: fix possible leak in u32_init_knode() |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit ec5b0f605b105457f257f2870acad4a5d463984b ] |
| |
| While investigating a related syzbot report, |
| I found that whenever call to tcf_exts_init() |
| from u32_init_knode() is failing, we end up |
| with an elevated refcount on ht->refcnt |
| |
| To avoid that, only increase the refcount after |
| all possible errors have been evaluated. |
| |
| Fixes: b9a24bb76bf6 ("net_sched: properly handle failure case of tcf_exts_init()") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: Cong Wang <xiyou.wangcong@gmail.com> |
| Cc: Jiri Pirko <jiri@resnulli.us> |
| Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/sched/cls_u32.c | 8 ++++---- |
| 1 file changed, 4 insertions(+), 4 deletions(-) |
| |
| diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c |
| index 8cfd5460493c..ed8d26e6468c 100644 |
| --- a/net/sched/cls_u32.c |
| +++ b/net/sched/cls_u32.c |
| @@ -816,10 +816,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, |
| new->flags = n->flags; |
| RCU_INIT_POINTER(new->ht_down, ht); |
| |
| - /* bump reference count as long as we hold pointer to structure */ |
| - if (ht) |
| - ht->refcnt++; |
| - |
| #ifdef CONFIG_CLS_U32_PERF |
| /* Statistics may be incremented by readers during update |
| * so we must keep them in tact. When the node is later destroyed |
| @@ -841,6 +837,10 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, |
| return NULL; |
| } |
| |
| + /* bump reference count as long as we hold pointer to structure */ |
| + if (ht) |
| + ht->refcnt++; |
| + |
| return new; |
| } |
| |
| -- |
| 2.35.1 |
| |
