From dbde6d0c7a5a462a1767a07c28eadd2c3dd08fb2 Mon Sep 17 00:00:00 2001 From: "Andrea Parri (Microsoft)" Date: Thu, 28 Apr 2022 16:51:05 +0200 Subject: [PATCH] hv_sock: Add validation for untrusted Hyper-V values 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) Reviewed-by: Michael Kelley Reviewed-by: Stefano Garzarella Link: https://lore.kernel.org/r/20220428145107.7878-4-parri.andrea@gmail.com Signed-off-by: Wei Liu --- include/linux/hyperv.h | 5 +++++ net/vmw_vsock/hyperv_transport.c | 10 ++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 460a716f4748..a01c9fd0a334 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1696,6 +1696,11 @@ 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 8c37d07017fc..fd98229e3db3 100644 --- a/net/vmw_vsock/hyperv_transport.c +++ b/net/vmw_vsock/hyperv_transport.c @@ -577,12 +577,18 @@ 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); + + 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) + if (payload_len > pkt_len - HVS_HEADER_LEN || + payload_len > HVS_MTU_SIZE) return -EIO; if (payload_len == 0)