On Mon, Nov 09, 2020 at 11:07:27AM +0100, Andrea Parri (Microsoft) wrote: > From: Andres Beltran <lkmlabelt@xxxxxxxxx> > > Pointers to ring-buffer packets sent by Hyper-V are used within the > guest VM. Hyper-V can send packets with erroneous values or modify > packet fields after they are processed by the guest. To defend > against these scenarios, return a copy of the incoming VMBus packet > after validating its length and offset fields in hv_pkt_iter_first(). > In this way, the packet can no longer be modified by the host. > > Signed-off-by: Andres Beltran <lkmlabelt@xxxxxxxxx> > Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx> > Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx> > Cc: netdev@xxxxxxxxxxxxxxx > Cc: linux-scsi@xxxxxxxxxxxxxxx Ping, other suggestions about this patch? Thanks, Andrea > --- > Applies on 5.10-rc3 with the series: > https://lkml.kernel.org/r/20201109100402.8946-1-parri.andrea@xxxxxxxxx > > drivers/hv/channel.c | 9 ++-- > drivers/hv/hv_fcopy.c | 1 + > drivers/hv/hv_kvp.c | 1 + > drivers/hv/hyperv_vmbus.h | 2 +- > drivers/hv/ring_buffer.c | 85 +++++++++++++++++++++++++++---- > drivers/net/hyperv/hyperv_net.h | 3 ++ > drivers/net/hyperv/netvsc.c | 2 + > drivers/net/hyperv/rndis_filter.c | 2 + > drivers/scsi/storvsc_drv.c | 10 ++++ > include/linux/hyperv.h | 48 ++++++++++++++--- > net/vmw_vsock/hyperv_transport.c | 4 +- > 11 files changed, 142 insertions(+), 25 deletions(-) > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c > index 6fb0c76bfbf81..0d63862d65518 100644 > --- a/drivers/hv/channel.c > +++ b/drivers/hv/channel.c > @@ -597,12 +597,15 @@ static int __vmbus_open(struct vmbus_channel *newchannel, > newchannel->onchannel_callback = onchannelcallback; > newchannel->channel_callback_context = context; > > - err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages); > + if (!newchannel->max_pkt_size) > + newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE; > + > + err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages, 0); > if (err) > goto error_clean_ring; > > - err = hv_ringbuffer_init(&newchannel->inbound, > - &page[send_pages], recv_pages); > + err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages], > + recv_pages, newchannel->max_pkt_size); > if (err) > goto error_clean_ring; > > diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c > index 59ce85e00a028..660036da74495 100644 > --- a/drivers/hv/hv_fcopy.c > +++ b/drivers/hv/hv_fcopy.c > @@ -349,6 +349,7 @@ int hv_fcopy_init(struct hv_util_service *srv) > { > recv_buffer = srv->recv_buffer; > fcopy_transaction.recv_channel = srv->channel; > + fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2; > > /* > * When this driver loads, the user level daemon that > diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c > index b49962d312cef..c698592b83e42 100644 > --- a/drivers/hv/hv_kvp.c > +++ b/drivers/hv/hv_kvp.c > @@ -757,6 +757,7 @@ hv_kvp_init(struct hv_util_service *srv) > { > recv_buffer = srv->recv_buffer; > kvp_transaction.recv_channel = srv->channel; > + kvp_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 4; > > /* > * When this driver loads, the user level daemon that > diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h > index 02f3e89888366..e2064bf2b557d 100644 > --- a/drivers/hv/hyperv_vmbus.h > +++ b/drivers/hv/hyperv_vmbus.h > @@ -174,7 +174,7 @@ extern int hv_synic_cleanup(unsigned int cpu); > void hv_ringbuffer_pre_init(struct vmbus_channel *channel); > > int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, > - struct page *pages, u32 pagecnt); > + struct page *pages, u32 pagecnt, u32 max_pkt_size); > > void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info); > > diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c > index 35833d4d1a1dc..bd70b7f1ffe60 100644 > --- a/drivers/hv/ring_buffer.c > +++ b/drivers/hv/ring_buffer.c > @@ -190,7 +190,7 @@ void hv_ringbuffer_pre_init(struct vmbus_channel *channel) > > /* Initialize the ring buffer. */ > int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, > - struct page *pages, u32 page_cnt) > + struct page *pages, u32 page_cnt, u32 max_pkt_size) > { > int i; > struct page **pages_wraparound; > @@ -232,6 +232,14 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, > sizeof(struct hv_ring_buffer); > ring_info->priv_read_index = 0; > > + /* Initialize buffer that holds copies of incoming packets */ > + if (max_pkt_size) { > + ring_info->pkt_buffer = kzalloc(max_pkt_size, GFP_KERNEL); > + if (!ring_info->pkt_buffer) > + return -ENOMEM; > + ring_info->pkt_buffer_size = max_pkt_size; > + } > + > spin_lock_init(&ring_info->ring_lock); > > return 0; > @@ -244,6 +252,9 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) > vunmap(ring_info->ring_buffer); > ring_info->ring_buffer = NULL; > mutex_unlock(&ring_info->ring_buffer_mutex); > + > + kfree(ring_info->pkt_buffer); > + ring_info->pkt_buffer_size = 0; > } > > /* Write to the ring buffer. */ > @@ -385,7 +396,7 @@ int hv_ringbuffer_read(struct vmbus_channel *channel, > memcpy(buffer, (const char *)desc + offset, packetlen); > > /* Advance ring index to next packet descriptor */ > - __hv_pkt_iter_next(channel, desc); > + __hv_pkt_iter_next(channel, desc, true); > > /* Notify host of update */ > hv_pkt_iter_close(channel); > @@ -411,6 +422,22 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi) > return (rbi->ring_datasize - priv_read_loc) + write_loc; > } > > +/* > + * Get first vmbus packet without copying it out of the ring buffer > + */ > +struct vmpacket_descriptor *hv_pkt_iter_first_raw(struct vmbus_channel *channel) > +{ > + struct hv_ring_buffer_info *rbi = &channel->inbound; > + > + hv_debug_delay_test(channel, MESSAGE_DELAY); > + > + if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) > + return NULL; > + > + return (struct vmpacket_descriptor *)(hv_get_ring_buffer(rbi) + rbi->priv_read_index); > +} > +EXPORT_SYMBOL_GPL(hv_pkt_iter_first_raw); > + > /* > * Get first vmbus packet from ring buffer after read_index > * > @@ -419,17 +446,52 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi) > struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel) > { > struct hv_ring_buffer_info *rbi = &channel->inbound; > - struct vmpacket_descriptor *desc; > + struct vmpacket_descriptor *desc, *desc_copy; > + u32 bytes_avail, pkt_len, pkt_offset; > > - hv_debug_delay_test(channel, MESSAGE_DELAY); > - if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) > + desc = hv_pkt_iter_first_raw(channel); > + if (!desc) > return NULL; > > - desc = hv_get_ring_buffer(rbi) + rbi->priv_read_index; > - if (desc) > - prefetch((char *)desc + (desc->len8 << 3)); > + bytes_avail = hv_pkt_iter_avail(rbi); > + > + /* > + * Ensure the compiler does not use references to incoming Hyper-V values (which > + * could change at any moment) when reading local variables later in the code > + */ > + pkt_len = READ_ONCE(desc->len8) << 3; > + pkt_offset = READ_ONCE(desc->offset8) << 3; > + > + /* > + * If pkt_len is invalid, set it to the smaller of hv_pkt_iter_avail() and > + * rbi->pkt_buffer_size > + */ > + if (rbi->pkt_buffer_size < bytes_avail) > + bytes_avail = rbi->pkt_buffer_size; > + > + if (pkt_len < sizeof(struct vmpacket_descriptor) || pkt_len > bytes_avail) > + pkt_len = bytes_avail; > + > + /* > + * If pkt_offset is invalid, arbitrarily set it to > + * the size of vmpacket_descriptor > + */ > + if (pkt_offset < sizeof(struct vmpacket_descriptor) || pkt_offset > pkt_len) > + pkt_offset = sizeof(struct vmpacket_descriptor); > + > + /* Copy the Hyper-V packet out of the ring buffer */ > + desc_copy = (struct vmpacket_descriptor *)rbi->pkt_buffer; > + memcpy(desc_copy, desc, pkt_len); > + > + /* > + * Hyper-V could still change len8 and offset8 after the earlier read. > + * Ensure that desc_copy has legal values for len8 and offset8 that > + * are consistent with the copy we just made > + */ > + desc_copy->len8 = pkt_len >> 3; > + desc_copy->offset8 = pkt_offset >> 3; > > - return desc; > + return desc_copy; > } > EXPORT_SYMBOL_GPL(hv_pkt_iter_first); > > @@ -441,7 +503,8 @@ EXPORT_SYMBOL_GPL(hv_pkt_iter_first); > */ > struct vmpacket_descriptor * > __hv_pkt_iter_next(struct vmbus_channel *channel, > - const struct vmpacket_descriptor *desc) > + const struct vmpacket_descriptor *desc, > + bool copy) > { > struct hv_ring_buffer_info *rbi = &channel->inbound; > u32 packetlen = desc->len8 << 3; > @@ -454,7 +517,7 @@ __hv_pkt_iter_next(struct vmbus_channel *channel, > rbi->priv_read_index -= dsize; > > /* more data? */ > - return hv_pkt_iter_first(channel); > + return copy ? hv_pkt_iter_first(channel) : hv_pkt_iter_first_raw(channel); > } > EXPORT_SYMBOL_GPL(__hv_pkt_iter_next); > > diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h > index 2a87cfa27ac02..7ea6936f86efa 100644 > --- a/drivers/net/hyperv/hyperv_net.h > +++ b/drivers/net/hyperv/hyperv_net.h > @@ -860,9 +860,12 @@ static inline u32 netvsc_rqstor_size(unsigned long ringbytes) > ringbytes / NETVSC_MIN_IN_MSG_SIZE; > } > > +#define NETVSC_MAX_XFER_PAGE_RANGES 375 > #define NETVSC_XFER_HEADER_SIZE(rng_cnt) \ > (offsetof(struct vmtransfer_page_packet_header, ranges) + \ > (rng_cnt) * sizeof(struct vmtransfer_page_range)) > +#define NETVSC_MAX_PKT_SIZE (NETVSC_XFER_HEADER_SIZE(NETVSC_MAX_XFER_PAGE_RANGES) + \ > + sizeof(struct nvsp_message) + (sizeof(u32) * VRSS_SEND_TAB_SIZE)) > > struct multi_send_data { > struct sk_buff *skb; /* skb containing the pkt */ > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c > index 4dbc0055aed0e..8ace0c80f3734 100644 > --- a/drivers/net/hyperv/netvsc.c > +++ b/drivers/net/hyperv/netvsc.c > @@ -1530,6 +1530,8 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device, > > /* Open the channel */ > device->channel->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes); > + device->channel->max_pkt_size = NETVSC_MAX_PKT_SIZE; > + > ret = vmbus_open(device->channel, netvsc_ring_bytes, > netvsc_ring_bytes, NULL, 0, > netvsc_channel_cb, net_device->chan_table); > diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c > index 6ae43319ece68..3835d9bea1005 100644 > --- a/drivers/net/hyperv/rndis_filter.c > +++ b/drivers/net/hyperv/rndis_filter.c > @@ -1173,6 +1173,8 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc) > nvchan->channel = new_sc; > > new_sc->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes); > + new_sc->max_pkt_size = NETVSC_MAX_PKT_SIZE; > + > ret = vmbus_open(new_sc, netvsc_ring_bytes, > netvsc_ring_bytes, NULL, 0, > netvsc_channel_cb, nvchan); > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index 369a6c6266729..331a33a04f1ad 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -414,6 +414,14 @@ static void storvsc_on_channel_callback(void *context); > #define STORVSC_IDE_MAX_TARGETS 1 > #define STORVSC_IDE_MAX_CHANNELS 1 > > +/* > + * Upper bound on the size of a storvsc packet. vmscsi_size_delta is not > + * included in the calculation because it is set after STORVSC_MAX_PKT_SIZE > + * is used in storvsc_connect_to_vsp > + */ > +#define STORVSC_MAX_PKT_SIZE (sizeof(struct vmpacket_descriptor) +\ > + sizeof(struct vstor_packet)) > + > struct storvsc_cmd_request { > struct scsi_cmnd *cmd; > > @@ -698,6 +706,7 @@ static void handle_sc_creation(struct vmbus_channel *new_sc) > return; > > memset(&props, 0, sizeof(struct vmstorage_channel_properties)); > + new_sc->max_pkt_size = STORVSC_MAX_PKT_SIZE; > > /* > * The size of vmbus_requestor is an upper bound on the number of requests > @@ -1280,6 +1289,7 @@ static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size, > > memset(&props, 0, sizeof(struct vmstorage_channel_properties)); > > + device->channel->max_pkt_size = STORVSC_MAX_PKT_SIZE; > /* > * The size of vmbus_requestor is an upper bound on the number of requests > * that can be in-progress at any one time across all channels. > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > index 696857aa038c0..2ea967bc17adf 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -181,6 +181,10 @@ struct hv_ring_buffer_info { > * being freed while the ring buffer is being accessed. > */ > struct mutex ring_buffer_mutex; > + > + /* Buffer that holds a copy of an incoming host packet */ > + void *pkt_buffer; > + u32 pkt_buffer_size; > }; > > > @@ -787,6 +791,8 @@ struct vmbus_device { > bool perf_device; > }; > > +#define VMBUS_DEFAULT_MAX_PKT_SIZE 4096 > + > struct vmbus_channel { > struct list_head listentry; > > @@ -1008,6 +1014,9 @@ struct vmbus_channel { > /* request/transaction ids for VMBus */ > struct vmbus_requestor requestor; > u32 rqstor_size; > + > + /* The max size of a packet on this channel */ > + u32 max_pkt_size; > }; > > u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr); > @@ -1649,32 +1658,55 @@ static inline u32 hv_pkt_datalen(const struct vmpacket_descriptor *desc) > } > > > +struct vmpacket_descriptor * > +hv_pkt_iter_first_raw(struct vmbus_channel *channel); > + > struct vmpacket_descriptor * > hv_pkt_iter_first(struct vmbus_channel *channel); > > struct vmpacket_descriptor * > __hv_pkt_iter_next(struct vmbus_channel *channel, > - const struct vmpacket_descriptor *pkt); > + const struct vmpacket_descriptor *pkt, > + bool copy); > > void hv_pkt_iter_close(struct vmbus_channel *channel); > > -/* > - * Get next packet descriptor from iterator > - * If at end of list, return NULL and update host. > - */ > static inline struct vmpacket_descriptor * > -hv_pkt_iter_next(struct vmbus_channel *channel, > - const struct vmpacket_descriptor *pkt) > +hv_pkt_iter_next_pkt(struct vmbus_channel *channel, > + const struct vmpacket_descriptor *pkt, > + bool copy) > { > struct vmpacket_descriptor *nxt; > > - nxt = __hv_pkt_iter_next(channel, pkt); > + nxt = __hv_pkt_iter_next(channel, pkt, copy); > if (!nxt) > hv_pkt_iter_close(channel); > > return nxt; > } > > +/* > + * Get next packet descriptor without copying it out of the ring buffer > + * If at end of list, return NULL and update host. > + */ > +static inline struct vmpacket_descriptor * > +hv_pkt_iter_next_raw(struct vmbus_channel *channel, > + const struct vmpacket_descriptor *pkt) > +{ > + return hv_pkt_iter_next_pkt(channel, pkt, false); > +} > + > +/* > + * Get next packet descriptor from iterator > + * If at end of list, return NULL and update host. > + */ > +static inline struct vmpacket_descriptor * > +hv_pkt_iter_next(struct vmbus_channel *channel, > + const struct vmpacket_descriptor *pkt) > +{ > + return hv_pkt_iter_next_pkt(channel, pkt, true); > +} > + > #define foreach_vmbus_pkt(pkt, channel) \ > for (pkt = hv_pkt_iter_first(channel); pkt; \ > pkt = hv_pkt_iter_next(channel, pkt)) > diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c > index 630b851f8150f..cd8b7c1ca9f15 100644 > --- a/net/vmw_vsock/hyperv_transport.c > +++ b/net/vmw_vsock/hyperv_transport.c > @@ -600,7 +600,7 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg, > return -EOPNOTSUPP; > > if (need_refill) { > - hvs->recv_desc = hv_pkt_iter_first(hvs->chan); > + hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan); > ret = hvs_update_recv_data(hvs); > if (ret) > return ret; > @@ -614,7 +614,7 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg, > > hvs->recv_data_len -= to_read; > if (hvs->recv_data_len == 0) { > - hvs->recv_desc = hv_pkt_iter_next(hvs->chan, hvs->recv_desc); > + hvs->recv_desc = hv_pkt_iter_next_raw(hvs->chan, hvs->recv_desc); > if (hvs->recv_desc) { > ret = hvs_update_recv_data(hvs); > if (ret) > -- > 2.25.1 >
