4.14-stable review patch. If anyone has any objections, please let me know.
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From: valis sec@valis.email
commit 76e42ae831991c828cffa8c37736ebfb831ad5ec upstream.
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 [ Fixed small conflict as 'fnew->ifindex' assignment is not protected by CONFIG_NET_CLS_IND on upstream since a51486266c3 ] Signed-off-by: Luiz Capitulino luizcap@amazon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/cls_fw.c | 1 - 1 file changed, 1 deletion(-)
--- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -281,7 +281,6 @@ static int fw_change(struct net *net, st return -ENOBUFS;
fnew->id = f->id; - fnew->res = f->res; #ifdef CONFIG_NET_CLS_IND fnew->ifindex = f->ifindex; #endif /* CONFIG_NET_CLS_IND */