From: Andrea Parri (Microsoft) <[email protected]> Sent: Wednesday, April 20, 2022 1:07 PM > > For additional robustness in the face of Hyper-V errors or malicious > behavior, validate all values that originate from packets that Hyper-V > has sent to the guest in the host-to-guest ring buffer. Ensure that > invalid values cannot cause data being copied out of the bounds of the > source buffer in hvs_stream_dequeue(). > > Signed-off-by: Andrea Parri (Microsoft) <[email protected]> > --- > include/linux/hyperv.h | 5 +++++ > net/vmw_vsock/hyperv_transport.c | 11 +++++++++-- > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > index fe2e0179ed51e..55478a6810b60 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -1663,6 +1663,11 @@ static inline u32 hv_pkt_datalen(const struct > vmpacket_descriptor *desc) > return (desc->len8 << 3) - (desc->offset8 << 3); > } > > +/* Get packet length associated with descriptor */ > +static inline u32 hv_pkt_len(const struct vmpacket_descriptor *desc) > +{ > + return desc->len8 << 3; > +} > > struct vmpacket_descriptor * > hv_pkt_iter_first_raw(struct vmbus_channel *channel); > diff --git a/net/vmw_vsock/hyperv_transport.c > b/net/vmw_vsock/hyperv_transport.c > index 8c37d07017fc4..092cadc2c866d 100644 > --- a/net/vmw_vsock/hyperv_transport.c > +++ b/net/vmw_vsock/hyperv_transport.c > @@ -577,12 +577,19 @@ static bool hvs_dgram_allow(u32 cid, u32 port) > static int hvs_update_recv_data(struct hvsock *hvs) > { > struct hvs_recv_buf *recv_buf; > - u32 payload_len; > + u32 pkt_len, payload_len; > + > + pkt_len = hv_pkt_len(hvs->recv_desc); > + > + /* Ensure the packet is big enough to read its header */ > + if (pkt_len < HVS_HEADER_LEN) > + return -EIO; > > recv_buf = (struct hvs_recv_buf *)(hvs->recv_desc + 1); > payload_len = recv_buf->hdr.data_size; > > - if (payload_len > HVS_MTU_SIZE) > + /* Ensure the packet is big enough to read its payload */ > + if (payload_len > pkt_len - HVS_HEADER_LEN || payload_len > > HVS_MTU_SIZE) > return -EIO; > > if (payload_len == 0) > -- > 2.25.1
Reviewed-by: Michael Kelley <[email protected]> _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
