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authorvalis <sec@valis.email>2023-07-29 15:32:01 +0300
committerJakub Kicinski <kuba@kernel.org>2023-08-01 06:10:36 +0300
commit76e42ae831991c828cffa8c37736ebfb831ad5ec (patch)
treea4063cc30b4cb2f170728aa91a793d58e49e35d3
parent3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 (diff)
downloadlinux-76e42ae831991c828cffa8c37736ebfb831ad5ec.tar.xz
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 <sec@valis.email> Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg> Signed-off-by: valis <sec@valis.email> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Victor Nogueira <victor@mojatatu.com> Reviewed-by: Pedro Tammela <pctammela@mojatatu.com> Reviewed-by: M A Ramdhan <ramdhan@starlabs.sg> Link: https://lore.kernel.org/r/20230729123202.72406-3-jhs@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--net/sched/cls_fw.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index 8641f8059317..c49d6af0e048 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;