| Message ID | 20180205194814.14006-1-tommi.t.rantala@nokia.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net,v3] sctp: fix dst refcnt leak in sctp_v4_get_dst | expand |
On Mon, Feb 05, 2018 at 09:48:14PM +0200, Tommi Rantala wrote: > Fix dst reference count leak in sctp_v4_get_dst() introduced in commit > 410f03831 ("sctp: add routing output fallback"): > > When walking the address_list, successive ip_route_output_key() calls > may return the same rt->dst with the reference incremented on each call. > > The code would not decrement the dst refcount when the dst pointer was > identical from the previous iteration, causing the dst refcnt leak. > > Testcase: > ip netns add TEST > ip netns exec TEST ip link set lo up > ip link add dummy0 type dummy > ip link add dummy1 type dummy > ip link add dummy2 type dummy > ip link set dev dummy0 netns TEST > ip link set dev dummy1 netns TEST > ip link set dev dummy2 netns TEST > ip netns exec TEST ip addr add 192.168.1.1/24 dev dummy0 > ip netns exec TEST ip link set dummy0 up > ip netns exec TEST ip addr add 192.168.1.2/24 dev dummy1 > ip netns exec TEST ip link set dummy1 up > ip netns exec TEST ip addr add 192.168.1.3/24 dev dummy2 > ip netns exec TEST ip link set dummy2 up > ip netns exec TEST sctp_test -H 192.168.1.2 -P 20002 -h 192.168.1.1 -p 20000 -s -B 192.168.1.3 > ip netns del TEST > > In 4.4 and 4.9 kernels this results to: > [ 354.179591] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 364.419674] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 374.663664] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 384.903717] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 395.143724] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 405.383645] unregister_netdevice: waiting for lo to become free. Usage count = 1 > ... > > Fixes: 410f03831 ("sctp: add routing output fallback") > Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") > Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Thanks > --- > > v2: unconditional dst_release() before breaking out of the loop: > - if dst == NULL, then dst_release() is no-op. > - if dst != &rt->dst, then drop reference to the first dst, we do not > need it after all. > - if dst == &rt->dst, then the refcnt was incremented twice for this > dst, so drop the second ref. > > net/sctp/protocol.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > index ba28d270eb24..aba2381d3cf9 100644 > --- a/net/sctp/protocol.c > +++ b/net/sctp/protocol.c > @@ -509,22 +509,20 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, > if (IS_ERR(rt)) > continue; > > - if (!dst) > - dst = &rt->dst; > - > /* Ensure the src address belongs to the output > * interface. > */ > odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, > false); > if (!odev || odev->ifindex != fl4->flowi4_oif) { > - if (&rt->dst != dst) > + if (!dst) > + dst = &rt->dst; > + else > dst_release(&rt->dst); > continue; > } > > - if (dst != &rt->dst) > - dst_release(dst); > + dst_release(dst); > dst = &rt->dst; > break; > } > -- > 2.15.1 >
On 2/5/18 12:48 PM, Tommi Rantala wrote: > Fix dst reference count leak in sctp_v4_get_dst() introduced in commit > 410f03831 ("sctp: add routing output fallback"): > > When walking the address_list, successive ip_route_output_key() calls > may return the same rt->dst with the reference incremented on each call. > > The code would not decrement the dst refcount when the dst pointer was > identical from the previous iteration, causing the dst refcnt leak. > ... > ... > > Fixes: 410f03831 ("sctp: add routing output fallback") > Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") any syzbot references for this bug?
On Mon, Feb 05, 2018 at 09:48:14PM +0200, Tommi Rantala wrote: > Fix dst reference count leak in sctp_v4_get_dst() introduced in commit > 410f03831 ("sctp: add routing output fallback"): > > When walking the address_list, successive ip_route_output_key() calls > may return the same rt->dst with the reference incremented on each call. > > The code would not decrement the dst refcount when the dst pointer was > identical from the previous iteration, causing the dst refcnt leak. > > Testcase: > ip netns add TEST > ip netns exec TEST ip link set lo up > ip link add dummy0 type dummy > ip link add dummy1 type dummy > ip link add dummy2 type dummy > ip link set dev dummy0 netns TEST > ip link set dev dummy1 netns TEST > ip link set dev dummy2 netns TEST > ip netns exec TEST ip addr add 192.168.1.1/24 dev dummy0 > ip netns exec TEST ip link set dummy0 up > ip netns exec TEST ip addr add 192.168.1.2/24 dev dummy1 > ip netns exec TEST ip link set dummy1 up > ip netns exec TEST ip addr add 192.168.1.3/24 dev dummy2 > ip netns exec TEST ip link set dummy2 up > ip netns exec TEST sctp_test -H 192.168.1.2 -P 20002 -h 192.168.1.1 -p 20000 -s -B 192.168.1.3 > ip netns del TEST > > In 4.4 and 4.9 kernels this results to: > [ 354.179591] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 364.419674] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 374.663664] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 384.903717] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 395.143724] unregister_netdevice: waiting for lo to become free. Usage count = 1 > [ 405.383645] unregister_netdevice: waiting for lo to become free. Usage count = 1 > ... > > Fixes: 410f03831 ("sctp: add routing output fallback") > Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") > Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> > --- > > v2: unconditional dst_release() before breaking out of the loop: > - if dst == NULL, then dst_release() is no-op. > - if dst != &rt->dst, then drop reference to the first dst, we do not > need it after all. > - if dst == &rt->dst, then the refcnt was incremented twice for this > dst, so drop the second ref. > > net/sctp/protocol.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > index ba28d270eb24..aba2381d3cf9 100644 > --- a/net/sctp/protocol.c > +++ b/net/sctp/protocol.c > @@ -509,22 +509,20 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, > if (IS_ERR(rt)) > continue; > > - if (!dst) > - dst = &rt->dst; > - > /* Ensure the src address belongs to the output > * interface. > */ > odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, > false); > if (!odev || odev->ifindex != fl4->flowi4_oif) { > - if (&rt->dst != dst) > + if (!dst) > + dst = &rt->dst; > + else > dst_release(&rt->dst); > continue; > } > > - if (dst != &rt->dst) > - dst_release(dst); > + dst_release(dst); > dst = &rt->dst; > break; > } > -- > 2.15.1 > > Acked-by: Neil Horman <nhorman@tuxdriver.com>
From: Tommi Rantala <tommi.t.rantala@nokia.com> Date: Mon, 5 Feb 2018 21:48:14 +0200 > Fix dst reference count leak in sctp_v4_get_dst() introduced in commit > 410f03831 ("sctp: add routing output fallback"): > > When walking the address_list, successive ip_route_output_key() calls > may return the same rt->dst with the reference incremented on each call. > > The code would not decrement the dst refcount when the dst pointer was > identical from the previous iteration, causing the dst refcnt leak. ... > Fixes: 410f03831 ("sctp: add routing output fallback") > Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") > Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> Applied and queued up for -stable, thanks.
On Tue, Feb 6, 2018 at 7:20 AM, David Ahern <dsahern@gmail.com> wrote: > On 2/5/18 12:48 PM, Tommi Rantala wrote: >> Fix dst reference count leak in sctp_v4_get_dst() introduced in commit >> 410f03831 ("sctp: add routing output fallback"): >> >> When walking the address_list, successive ip_route_output_key() calls >> may return the same rt->dst with the reference incremented on each call. >> >> The code would not decrement the dst refcount when the dst pointer was >> identical from the previous iteration, causing the dst refcnt leak. >> > ... >> ... >> >> Fixes: 410f03831 ("sctp: add routing output fallback") >> Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") > > any syzbot references for this bug? In Dmitry Vyukov mail, there was no syzbot reference provided. Not sure if there's another way to tell syzbot. > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Feb 6, 2018 at 6:06 AM, Xin Long <lucien.xin@gmail.com> wrote: > On Tue, Feb 6, 2018 at 7:20 AM, David Ahern <dsahern@gmail.com> wrote: >> On 2/5/18 12:48 PM, Tommi Rantala wrote: >>> Fix dst reference count leak in sctp_v4_get_dst() introduced in commit >>> 410f03831 ("sctp: add routing output fallback"): >>> >>> When walking the address_list, successive ip_route_output_key() calls >>> may return the same rt->dst with the reference incremented on each call. >>> >>> The code would not decrement the dst refcount when the dst pointer was >>> identical from the previous iteration, causing the dst refcnt leak. >>> >> ... >>> ... >>> >>> Fixes: 410f03831 ("sctp: add routing output fallback") >>> Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") >> >> any syzbot references for this bug? > In Dmitry Vyukov mail, there was no syzbot reference provided. > Not sure if there's another way to tell syzbot. If we are talking about "net: hang in unregister_netdevice: waiting for lo to become free": https://groups.google.com/d/msg/syzkaller/-06_laheMF0/xqezy58kAwAJ Then there is no syzbot tag. It was found with syzkaller, but not reported by syzbot because the manifestation is too tricky, it could have been reported as "no output from test machine" with no additional details, which is not too actionable.
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index ba28d270eb24..aba2381d3cf9 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -509,22 +509,20 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (IS_ERR(rt)) continue; - if (!dst) - dst = &rt->dst; - /* Ensure the src address belongs to the output * interface. */ odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, false); if (!odev || odev->ifindex != fl4->flowi4_oif) { - if (&rt->dst != dst) + if (!dst) + dst = &rt->dst; + else dst_release(&rt->dst); continue; } - if (dst != &rt->dst) - dst_release(dst); + dst_release(dst); dst = &rt->dst; break; }
Fix dst reference count leak in sctp_v4_get_dst() introduced in commit 410f03831 ("sctp: add routing output fallback"): When walking the address_list, successive ip_route_output_key() calls may return the same rt->dst with the reference incremented on each call. The code would not decrement the dst refcount when the dst pointer was identical from the previous iteration, causing the dst refcnt leak. Testcase: ip netns add TEST ip netns exec TEST ip link set lo up ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add dummy2 type dummy ip link set dev dummy0 netns TEST ip link set dev dummy1 netns TEST ip link set dev dummy2 netns TEST ip netns exec TEST ip addr add 192.168.1.1/24 dev dummy0 ip netns exec TEST ip link set dummy0 up ip netns exec TEST ip addr add 192.168.1.2/24 dev dummy1 ip netns exec TEST ip link set dummy1 up ip netns exec TEST ip addr add 192.168.1.3/24 dev dummy2 ip netns exec TEST ip link set dummy2 up ip netns exec TEST sctp_test -H 192.168.1.2 -P 20002 -h 192.168.1.1 -p 20000 -s -B 192.168.1.3 ip netns del TEST In 4.4 and 4.9 kernels this results to: [ 354.179591] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 364.419674] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 374.663664] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 384.903717] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 395.143724] unregister_netdevice: waiting for lo to become free. Usage count = 1 [ 405.383645] unregister_netdevice: waiting for lo to become free. Usage count = 1 ... Fixes: 410f03831 ("sctp: add routing output fallback") Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses") Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> --- v2: unconditional dst_release() before breaking out of the loop: - if dst == NULL, then dst_release() is no-op. - if dst != &rt->dst, then drop reference to the first dst, we do not need it after all. - if dst == &rt->dst, then the refcnt was incremented twice for this dst, so drop the second ref. net/sctp/protocol.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)