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authorM A Ramdhan <ramdhan@starlabs.sg>2023-07-05 19:15:30 +0300
committerJakub Kicinski <kuba@kernel.org>2023-07-07 05:10:49 +0300
commit0323bce598eea038714f941ce2b22541c46d488f (patch)
treead4ddf18f7d87b6201bc62b1d94245cc4a07e8a6 /net
parent525c469e5de9bf7e53574396196e80fc716ac9eb (diff)
downloadlinux-0323bce598eea038714f941ce2b22541c46d488f.tar.xz
net/sched: cls_fw: Fix improper refcount update leads to use-after-free
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. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: M A Ramdhan <ramdhan@starlabs.sg> Signed-off-by: M A Ramdhan <ramdhan@starlabs.sg> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Pedro Tammela <pctammela@mojatatu.com> Message-ID: <20230705161530.52003-1-ramdhan@starlabs.sg> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/sched/cls_fw.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index ae9439a6c56c..8641f8059317 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -212,11 +212,6 @@ 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);
@@ -233,6 +228,11 @@ 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;
}