From 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 Mon Sep 17 00:00:00 2001 From: valis Date: Sat, 29 Jul 2023 08:32:00 -0400 Subject: [PATCH 1/3] net/sched: cls_u32: No longer copy tcf_result on update to avoid use-after-free When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. Fix this by no longer copying the tcf_result struct from the old filter. Fixes: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers") Reported-by: valis Reported-by: M A Ramdhan Signed-off-by: valis Signed-off-by: Jamal Hadi Salim Reviewed-by: Victor Nogueira Reviewed-by: Pedro Tammela Reviewed-by: M A Ramdhan Link: https://lore.kernel.org/r/20230729123202.72406-2-jhs@mojatatu.com Signed-off-by: Jakub Kicinski --- net/sched/cls_u32.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 907e58841fe80..da4c179a4d418 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -826,7 +826,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, new->ifindex = n->ifindex; new->fshift = n->fshift; - new->res = n->res; new->flags = n->flags; RCU_INIT_POINTER(new->ht_down, ht); From 76e42ae831991c828cffa8c37736ebfb831ad5ec Mon Sep 17 00:00:00 2001 From: valis Date: Sat, 29 Jul 2023 08:32:01 -0400 Subject: [PATCH 2/3] net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. Fix this by no longer copying the tcf_result struct from the old filter. Fixes: e35a8ee5993b ("net: sched: fw use RCU") Reported-by: valis Reported-by: Bing-Jhong Billy Jheng Signed-off-by: valis Signed-off-by: Jamal Hadi Salim Reviewed-by: Victor Nogueira Reviewed-by: Pedro Tammela Reviewed-by: M A Ramdhan Link: https://lore.kernel.org/r/20230729123202.72406-3-jhs@mojatatu.com Signed-off-by: Jakub Kicinski --- net/sched/cls_fw.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index 8641f80593179..c49d6af0e0480 100644 --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -267,7 +267,6 @@ static int fw_change(struct net *net, struct sk_buff *in_skb, return -ENOBUFS; fnew->id = f->id; - fnew->res = f->res; fnew->ifindex = f->ifindex; fnew->tp = f->tp; From b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8 Mon Sep 17 00:00:00 2001 From: valis Date: Sat, 29 Jul 2023 08:32:02 -0400 Subject: [PATCH 3/3] net/sched: cls_route: No longer copy tcf_result on update to avoid use-after-free When route4_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. Fix this by no longer copying the tcf_result struct from the old filter. Fixes: 1109c00547fc ("net: sched: RCU cls_route") Reported-by: valis Reported-by: Bing-Jhong Billy Jheng Signed-off-by: valis Signed-off-by: Jamal Hadi Salim Reviewed-by: Victor Nogueira Reviewed-by: Pedro Tammela Reviewed-by: M A Ramdhan Link: https://lore.kernel.org/r/20230729123202.72406-4-jhs@mojatatu.com Signed-off-by: Jakub Kicinski --- net/sched/cls_route.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c index d0c53724d3e86..1e20bbd687f1d 100644 --- a/net/sched/cls_route.c +++ b/net/sched/cls_route.c @@ -513,7 +513,6 @@ static int route4_change(struct net *net, struct sk_buff *in_skb, if (fold) { f->id = fold->id; f->iif = fold->iif; - f->res = fold->res; f->handle = fold->handle; f->tp = fold->tp;