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authorvalis <sec@valis.email>2023-07-29 08:32:00 -0400
committerJakub Kicinski <kuba@kernel.org>2023-07-31 20:10:36 -0700
commit3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 (patch)
tree41e6c1ea46e446d29b299e91102fcf7f43cc0882 /net
parent611e1b016c7beceec5ae82ac62d4a7ca224c8f9d (diff)
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 <sec@valis.email> Reported-by: M A Ramdhan <ramdhan@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/20230729123202.72406-2-jhs@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/sched/cls_u32.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 907e58841fe8..da4c179a4d41 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);