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 --- 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
