Re: [PATCH] ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule
From: David Miller <davem@davemloft.net>
Date: 2019-09-24 12:53:03
Also in:
lkml, stable
From: "Jason A. Donenfeld" <Jason@zx2c4.com> Date: Tue, 24 Sep 2019 09:36:15 +0200
Commit 7d9e5f422150 removed references from certain dsts, but accounting
for this never translated down into the fib6 suppression code. This bug
was triggered by WireGuard users who use wg-quick(8), which uses the
"suppress-prefix" directive to ip-rule(8) for routing all of their
internet traffic without routing loops. The test case in the link of
this commit reliably triggers various crashes due to the use-after-free
caused by the reference underflow.
Cc: stable@vger.kernel.org
Fixes: 7d9e5f422150 ("ipv6: convert major tx path to use RT6_LOOKUP_F_DST_NOREF")
Test-case: https://git.zx2c4.com/WireGuard/commit/?id=ad66532000f7a20b149e47c5eb3a957362c8e161
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>Please make such test cases integratabe into the selftests area for networking and submit it along with this fix. Otherwise this code will regress. Thank you.