On Wed, Jan 27, 2021 at 3:32 PM Heiner Kallweit <hkallwe...@gmail.com> wrote: > > On 27.01.2021 20:54, Willem de Bruijn wrote: > > On Wed, Jan 27, 2021 at 2:40 PM Heiner Kallweit <hkallwe...@gmail.com> > > wrote: > >> > >> On 27.01.2021 19:07, Willem de Bruijn wrote: > >>> On Tue, Jan 26, 2021 at 2:40 PM Heiner Kallweit <hkallwe...@gmail.com> > >>> wrote: > >>>> > >>>> It was reported that on RTL8125 network breaks under heavy UDP load, > >>>> e.g. torrent traffic ([0], from comment 27). Realtek confirmed a hw bug > >>>> and provided me with a test version of the r8125 driver including a > >>>> workaround. Tests confirmed that the workaround fixes the issue. > >>>> I modified the original version of the workaround to meet mainline > >>>> code style. > >>>> > >>>> [0] https://bugzilla.kernel.org/show_bug.cgi?id=209839 > >>>> > >>>> Fixes: f1bce4ad2f1c ("r8169: add support for RTL8125") > >>>> Tested-by: xplo <xplo...@gmail.com> > >>>> Signed-off-by: Heiner Kallweit <hkallwe...@gmail.com> > >>>> --- > >>>> drivers/net/ethernet/realtek/r8169_main.c | 64 ++++++++++++++++++++--- > >>>> 1 file changed, 58 insertions(+), 6 deletions(-) > >>>> > >>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c > >>>> b/drivers/net/ethernet/realtek/r8169_main.c > >>>> index fb67d8f79..90052033b 100644 > >>>> --- a/drivers/net/ethernet/realtek/r8169_main.c > >>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c > >>>> @@ -28,6 +28,7 @@ > >>>> #include <linux/bitfield.h> > >>>> #include <linux/prefetch.h> > >>>> #include <linux/ipv6.h> > >>>> +#include <linux/ptp_classify.h> > >>>> #include <asm/unaligned.h> > >>>> #include <net/ip6_checksum.h> > >>>> > >>>> @@ -4007,17 +4008,64 @@ static int rtl8169_xmit_frags(struct > >>>> rtl8169_private *tp, struct sk_buff *skb, > >>>> return -EIO; > >>>> } > >>>> > >>>> -static bool rtl_test_hw_pad_bug(struct rtl8169_private *tp) > >>>> +static bool rtl_skb_is_udp(struct sk_buff *skb) > >>>> { > >>>> + switch (vlan_get_protocol(skb)) { > >>>> + case htons(ETH_P_IP): > >>>> + return ip_hdr(skb)->protocol == IPPROTO_UDP; > >>>> + case htons(ETH_P_IPV6): > >>>> + return ipv6_hdr(skb)->nexthdr == IPPROTO_UDP; > >> > >> The workaround was provided by Realtek, I just modified it to match > >> mainline code style. For your reference I add the original version below. > >> I don't know where the magic numbers come from, Realtek releases > >> neither data sheets nor errata information. > > > > Okay. I don't know what is customary for this process. > > > > But I would address the possible out of bounds read by trusting ip > > header integrity in rtl_skb_is_udp. > > > I don't know tun/virtio et al good enough to judge which header elements > may be trustworthy and which may be not. What should be checked where?
It requires treating the transmit path similar to the receive path: assume malicious or otherwise faulty packets. So do not trust that a protocol of ETH_P_IPV6 implies a packet with 40B of space to hold a full ipv6 header. That is the extent of it, really.
