Skip to content

net/sched: cls_fw: Fix improper refcount update leads to use-after-free

Davide Caratti requested to merge dcaratti/centos-stream-9:bz2225102 into main

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2225102
CVE: CVE-2023-3776
Upstream Status: net.git commit 0323bce598ee
Tested: boot-tested only
Conflicts: none

commit 0323bce598eea038714f941ce2b22541c46d488f
Author: M A Ramdhan ramdhan@starlabs.sg
Date: Wed Jul 5 12:15:30 2023 -0400

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>

Signed-off-by: Davide Caratti dcaratti@redhat.com

Merge request reports