Messages in this thread | | | Date | Tue, 1 Aug 2023 10:24:32 +0200 | From | Greg KH <> | Subject | Re: [PATCH 4.14] net/sched: cls_u32: Fix reference counter leak leading to overflow |
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On Thu, Jul 27, 2023 at 07:15:54PM +0000, Rishabh Bhatnagar wrote: > From: Lee Jones <lee@kernel.org> > > Upstream commit 04c55383fa5689357bcdd2c8036725a55ed632bc. > > In the event of a failure in tcf_change_indev(), u32_set_parms() will > immediately return without decrementing the recently incremented > reference counter. If this happens enough times, the counter will > rollover and the reference freed, leading to a double free which can be > used to do 'bad things'. > > In order to prevent this, move the point of possible failure above the > point where the reference counter is incremented. Also save any > meaningful return values to be applied to the return data at the > appropriate point in time. > > This issue was caught with KASAN. > > Fixes: 705c7091262d ("net: sched: cls_u32: no need to call tcf_exts_change for newly allocated struct") > Suggested-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Lee Jones <lee@kernel.org> > Reviewed-by: Eric Dumazet <edumazet@google.com> > Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com> > --- > net/sched/cls_u32.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-)
We need a 4.19.y backport before we can apply a 4.14.y version, as you do not want to upgrade and have a regression.
thanks,
greg k-h
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