UPSTREAM: net/sched: cls_fw: Fix improper refcount update leads to use-after-free
[ Upstream commit 0323bce598eea038714f941ce2b22541c46d488f ]
In the event of a failure in tcf_change_indev(), fw_set_parms() will
immediately return an error after incrementing or decrementing
reference counter in tcf_bind_filter(). If attacker can control
reference counter to zero and make reference freed, leading to
use after free.
In order to prevent this, move the point of possible failure above the
point where the TC_FW_CLASSID is handled.
Bug: 292252062
Bug: 297839626
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: M A Ramdhan <[email protected]>
Signed-off-by: M A Ramdhan <[email protected]>
Acked-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Pedro Tammela <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit c91fb29bb07ee4dd40aabd1e41f19c0f92ac3199)
Signed-off-by: Lee Jones <[email protected]>
(cherry picked from commit f686a35a77f8f22d155470b95a414173f8a26575)
Signed-off-by: Pindar Yang <[email protected]>
Change-Id: I9bf6f540b4eb23ea5641fb3efe6f3e621d7b6151
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index 8654b0c..ea52c32 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -210,11 +210,6 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp,
if (err < 0)
return err;
- if (tb[TCA_FW_CLASSID]) {
- f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
- tcf_bind_filter(tp, &f->res, base);
- }
-
if (tb[TCA_FW_INDEV]) {
int ret;
ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
@@ -231,6 +226,11 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp,
} else if (head->mask != 0xFFFFFFFF)
return err;
+ if (tb[TCA_FW_CLASSID]) {
+ f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
+ tcf_bind_filter(tp, &f->res, base);
+ }
+
return 0;
}
