[PATCH 0/2] [backports] l2tp use-after-free fixes for 4.9 stable

From: Will Deacon
Date: Thu Apr 02 2020 - 13:32:06 EST


Hi Greg,

Syzbot has been complaining about KASAN splats due to use-after-free
issues in the l2tp code on 4.9 Android kernels (although I reproduced
with latest 4.9 stable on my laptop):

https://syzkaller.appspot.com/bug?id=3c27eae7bdba97293b68e79c9700ac110f977eed

These have been fixed upstream, but for some reason didn't get picked up
for stable. This series applies to 4.9.y and I'll send patches for 4.4.y
separately as there are a few dependencies to deal with over there.

Thanks,

Will

--->8

Guillaume Nault (2):
l2tp: ensure sessions are freed after their PPPOL2TP socket
l2tp: fix race between l2tp_session_delete() and
l2tp_tunnel_closeall()

net/l2tp/l2tp_core.c | 6 ++++++
net/l2tp/l2tp_core.h | 1 +
net/l2tp/l2tp_ppp.c | 8 ++++----
3 files changed, 11 insertions(+), 4 deletions(-)

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2.26.0.rc2.310.g2932bb562d-goog