| Message ID | 20190924073615.31704-1-Jason@zx2c4.com |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule | expand |
Hey Wei, I meant to CC you but slipped up. Sorry about that. Take a look at this thread if you have a chance. Thanks, Jason On Tue, Sep 24, 2019 at 10:03 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > 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> > --- > net/ipv6/fib6_rules.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c > index d22b6c140f23..f9e8fe3ff0c5 100644 > --- a/net/ipv6/fib6_rules.c > +++ b/net/ipv6/fib6_rules.c > @@ -287,7 +287,8 @@ static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg > return false; > > suppress_route: > - ip6_rt_put(rt); > + if (!(arg->flags & FIB_LOOKUP_NOREF)) > + ip6_rt_put(rt); > return true; > } > > -- > 2.21.0 On Tue, Sep 24, 2019 at 10:03 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > 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> > --- > net/ipv6/fib6_rules.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c > index d22b6c140f23..f9e8fe3ff0c5 100644 > --- a/net/ipv6/fib6_rules.c > +++ b/net/ipv6/fib6_rules.c > @@ -287,7 +287,8 @@ static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg > return false; > > suppress_route: > - ip6_rt_put(rt); > + if (!(arg->flags & FIB_LOOKUP_NOREF)) > + ip6_rt_put(rt); > return true; > } > > -- > 2.21.0
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.
On Tue, Sep 24, 2019 at 2:53 PM David Miller <davem@davemloft.net> wrote: > Please make such test cases integratabe into the selftests area for networking > and submit it along with this fix. That link is for a WireGuard test-case. When we get that upstream, those will all live in selftests/ all the same as you'd like. For now, it's running for every kernel on https://build.wireguard.com/ which in turn runs for every new commit.
From: "Jason A. Donenfeld" <Jason@zx2c4.com> Date: Tue, 24 Sep 2019 14:55:04 +0200 > On Tue, Sep 24, 2019 at 2:53 PM David Miller <davem@davemloft.net> wrote: >> Please make such test cases integratabe into the selftests area for networking >> and submit it along with this fix. > > That link is for a WireGuard test-case. When we get that upstream, > those will all live in selftests/ all the same as you'd like. For now, > it's running for every kernel on https://build.wireguard.com/ which in > turn runs for every new commit. I'm asking you to make a non-wireguard test that triggers the problem. Or would you like a situation you're interested in to break from time to time. Jason, please don't be difficult about this and write a proper test case just like I would ask anyone else fixing bugs like this to write. Thank you.
On Tue, Sep 24, 2019 at 3:30 PM David Miller <davem@davemloft.net> wrote > I'm asking you to make a non-wireguard test that triggers the problem. Oh, gotcha. No problem. > > Or would you like a situation you're interested in to break from time > to time. My test suite should catch it in the future now that it's there, so I'm fine. > Jason, please don't be difficult about this and write a proper test > case just like I would ask anyone else fixing bugs like this to write. I'm not being difficult. I just thought you didn't see what the test case I linked to actually was. I have no qualms about reimplementing it with the dummy interface, for a v2 of this patch. Coming your way shortly.
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c index d22b6c140f23..f9e8fe3ff0c5 100644 --- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -287,7 +287,8 @@ static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg return false; suppress_route: - ip6_rt_put(rt); + if (!(arg->flags & FIB_LOOKUP_NOREF)) + ip6_rt_put(rt); return true; }
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> --- net/ipv6/fib6_rules.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)