Re: [PATCH-for-9.0? v2] hw/net/net_tx_pkt: Fix overrun in update_sctp_checksum()

[Jason Wang]

On Wed, Apr 10, 2024 at 3:06 PM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>
> On 2024/04/10 16:04, Philippe Mathieu-Daudé wrote:
> > If a fragmented packet size is too short, do not try to
> > calculate its checksum.
> >
> > Reproduced using:
> >
> >    $ cat << EOF | qemu-system-i386 -display none -nodefaults \
> >                                    -machine q35,accel=qtest -m 32M \
> >                                    -device igb,netdev=net0 \
> >                                    -netdev user,id=net0 \
> >                                    -qtest stdio
> >    outl 0xcf8 0x80000810
> >    outl 0xcfc 0xe0000000
> >    outl 0xcf8 0x80000804
> >    outw 0xcfc 0x06
> >    write 0xe0000403 0x1 0x02
> >    writel 0xe0003808 0xffffffff
> >    write 0xe000381a 0x1 0x5b
> >    write 0xe000381b 0x1 0x00
> >    EOF
> >    Assertion failed: (offset == 0), function iov_from_buf_full, file 
> > util/iov.c, line 39.
> >    #1 0x5575e81e952a in iov_from_buf_full qemu/util/iov.c:39:5
> >    #2 0x5575e6500768 in net_tx_pkt_update_sctp_checksum 
> > qemu/hw/net/net_tx_pkt.c:144:9
> >    #3 0x5575e659f3e1 in igb_setup_tx_offloads qemu/hw/net/igb_core.c:478:11
> >    #4 0x5575e659f3e1 in igb_tx_pkt_send qemu/hw/net/igb_core.c:552:10
> >    #5 0x5575e659f3e1 in igb_process_tx_desc qemu/hw/net/igb_core.c:671:17
> >    #6 0x5575e659f3e1 in igb_start_xmit qemu/hw/net/igb_core.c:903:9
> >    #7 0x5575e659f3e1 in igb_set_tdt qemu/hw/net/igb_core.c:2812:5
> >    #8 0x5575e657d6a4 in igb_core_write qemu/hw/net/igb_core.c:4248:9
> >
> > Cc: qemu-stable@nongnu.org
> > Reported-by: Zheyu Ma <zheyuma97@gmail.com>
> > Fixes: f199b13bc1 ("igb: Implement Tx SCTP CSO")
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2273
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>
> Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>

Fixes: CVE-2024-3567
Acked-by: Jason Wang <jasowang@redhat.com>

Peter, would you want to pick this for 9.0?

Thanks

>
> > ---
> > Since v1: check at offset 8 (Akihiko)
> > ---
> >   hw/net/net_tx_pkt.c | 4 ++++
> >   1 file changed, 4 insertions(+)
> >
> > diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
> > index 2134a18c4c..b7b1de816d 100644
> > --- a/hw/net/net_tx_pkt.c
> > +++ b/hw/net/net_tx_pkt.c
> > @@ -141,6 +141,10 @@ bool net_tx_pkt_update_sctp_checksum(struct NetTxPkt 
> > *pkt)
> >       uint32_t csum = 0;
> >       struct iovec *pl_start_frag = pkt->vec + NET_TX_PKT_PL_START_FRAG;
> >
> > +    if (iov_size(pl_start_frag, pkt->payload_frags) < 8 + sizeof(csum)) {
> > +        return false;
> > +    }
> > +
> >       if (iov_from_buf(pl_start_frag, pkt->payload_frags, 8, &csum, 
> > sizeof(csum)) < sizeof(csum)) {
> >           return false;
> >       }
>