On 27.01.2021 21:35, Willem de Bruijn wrote: > 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. > OK, so what can I do? Check for skb_tail_pointer(skb) - skb_network_header(skb) >= sizeof(struct ipv6hdr) ?
On a side note: Why is IP6_HLEN defined in ptp_classify.h and not in any IPv6 header file? Does no IPv6 code need such a constant?
