From adae1e931acd8b430d31141a283ea06d4b705417 Mon Sep 17 00:00:00 2001 From: Andres Beltran Date: Thu, 8 Apr 2021 18:14:39 +0200 Subject: Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer 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 Co-developed-by: Andrea Parri (Microsoft) Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210408161439.341988-1-parri.andrea@gmail.com Signed-off-by: Wei Liu --- drivers/hv/ring_buffer.c | 82 +++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 71 insertions(+), 11 deletions(-) (limited to 'drivers/hv/ring_buffer.c') diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 374f8afbf8a5..e621f8d9b436 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -181,7 +181,7 @@ 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; @@ -223,6 +223,14 @@ 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; @@ -235,6 +243,9 @@ 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. */ @@ -375,7 +386,7 @@ 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); @@ -401,6 +412,22 @@ 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 * @@ -409,17 +436,49 @@ 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 = min(rbi->pkt_buffer_size, 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 (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); @@ -431,7 +490,8 @@ 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; @@ -444,7 +504,7 @@ __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); -- cgit v1.2.3 From bf5fd8cae3c8f0d1e6f71a076e0ce2bd17645d0b Mon Sep 17 00:00:00 2001 From: "Andrea Parri (Microsoft)" Date: Mon, 10 May 2021 23:08:41 +0200 Subject: scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDs Use blk_mq_unique_tag() to generate requestIDs for StorVSC, avoiding all issues with allocating enough entries in the VMbus requestor. Suggested-by: Michael Kelley Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Acked-by: Martin K. Petersen Link: https://lore.kernel.org/r/20210510210841.370472-1-parri.andrea@gmail.com Signed-off-by: Wei Liu --- drivers/hv/channel.c | 14 +++--- drivers/hv/ring_buffer.c | 13 +++--- drivers/net/hyperv/netvsc.c | 8 ++-- drivers/net/hyperv/rndis_filter.c | 2 + drivers/scsi/storvsc_drv.c | 94 ++++++++++++++++++++++++++------------- include/linux/hyperv.h | 13 +++++- 6 files changed, 95 insertions(+), 49 deletions(-) (limited to 'drivers/hv/ring_buffer.c') diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index bfbca4eeb773..f3761c73b074 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -1189,15 +1189,14 @@ EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw); * vmbus_next_request_id - Returns a new request id. It is also * the index at which the guest memory address is stored. * Uses a spin lock to avoid race conditions. - * @rqstor: Pointer to the requestor struct + * @channel: Pointer to the VMbus channel struct * @rqst_add: Guest memory address to be stored in the array */ -u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr) +u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) { + struct vmbus_requestor *rqstor = &channel->requestor; unsigned long flags; u64 current_id; - const struct vmbus_channel *channel = - container_of(rqstor, const struct vmbus_channel, requestor); /* Check rqstor has been initialized */ if (!channel->rqstor_size) @@ -1231,16 +1230,15 @@ EXPORT_SYMBOL_GPL(vmbus_next_request_id); /* * vmbus_request_addr - Returns the memory address stored at @trans_id * in @rqstor. Uses a spin lock to avoid race conditions. - * @rqstor: Pointer to the requestor struct + * @channel: Pointer to the VMbus channel struct * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's * next request id. */ -u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id) +u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) { + struct vmbus_requestor *rqstor = &channel->requestor; unsigned long flags; u64 req_addr; - const struct vmbus_channel *channel = - container_of(rqstor, const struct vmbus_channel, requestor); /* Check rqstor has been initialized */ if (!channel->rqstor_size) diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index e621f8d9b436..2aee356840a2 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -312,10 +312,12 @@ int hv_ringbuffer_write(struct vmbus_channel *channel, */ if (desc->flags == VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED) { - rqst_id = vmbus_next_request_id(&channel->requestor, requestid); - if (rqst_id == VMBUS_RQST_ERROR) { - spin_unlock_irqrestore(&outring_info->ring_lock, flags); - return -EAGAIN; + if (channel->next_request_id_callback != NULL) { + rqst_id = channel->next_request_id_callback(channel, requestid); + if (rqst_id == VMBUS_RQST_ERROR) { + spin_unlock_irqrestore(&outring_info->ring_lock, flags); + return -EAGAIN; + } } } desc = hv_get_ring_buffer(outring_info) + old_write; @@ -343,7 +345,8 @@ int hv_ringbuffer_write(struct vmbus_channel *channel, if (channel->rescind) { if (rqst_id != VMBUS_NO_RQSTOR) { /* Reclaim request ID to avoid leak of IDs */ - vmbus_request_addr(&channel->requestor, rqst_id); + if (channel->request_addr_callback != NULL) + channel->request_addr_callback(channel, rqst_id); } return -ENODEV; } diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index 067077138e52..7bd935412853 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -757,7 +757,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev, int queue_sends; u64 cmd_rqst; - cmd_rqst = vmbus_request_addr(&channel->requestor, (u64)desc->trans_id); + cmd_rqst = channel->request_addr_callback(channel, (u64)desc->trans_id); if (cmd_rqst == VMBUS_RQST_ERROR) { netdev_err(ndev, "Incorrect transaction id\n"); return; @@ -817,8 +817,8 @@ static void netvsc_send_completion(struct net_device *ndev, /* First check if this is a VMBUS completion without data payload */ if (!msglen) { - cmd_rqst = vmbus_request_addr(&incoming_channel->requestor, - (u64)desc->trans_id); + cmd_rqst = incoming_channel->request_addr_callback(incoming_channel, + (u64)desc->trans_id); if (cmd_rqst == VMBUS_RQST_ERROR) { netdev_err(ndev, "Invalid transaction id\n"); return; @@ -1649,6 +1649,8 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device, netvsc_poll, NAPI_POLL_WEIGHT); /* Open the channel */ + device->channel->next_request_id_callback = vmbus_next_request_id; + device->channel->request_addr_callback = vmbus_request_addr; device->channel->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes); device->channel->max_pkt_size = NETVSC_MAX_PKT_SIZE; diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c index d7ff9ddcbae2..983bf362466a 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -1259,6 +1259,8 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc) /* Set the channel before opening.*/ nvchan->channel = new_sc; + new_sc->next_request_id_callback = vmbus_next_request_id; + new_sc->request_addr_callback = vmbus_request_addr; new_sc->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes); new_sc->max_pkt_size = NETVSC_MAX_PKT_SIZE; diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 07149fa72b68..403753929320 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -696,6 +696,23 @@ old_is_alloced: spin_unlock_irqrestore(&stor_device->lock, flags); } +static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) +{ + struct storvsc_cmd_request *request = + (struct storvsc_cmd_request *)(unsigned long)rqst_addr; + + if (rqst_addr == VMBUS_RQST_INIT) + return VMBUS_RQST_INIT; + if (rqst_addr == VMBUS_RQST_RESET) + return VMBUS_RQST_RESET; + + /* + * Cannot return an ID of 0, which is reserved for an unsolicited + * message from Hyper-V. + */ + return (u64)blk_mq_unique_tag(request->cmd->request) + 1; +} + static void handle_sc_creation(struct vmbus_channel *new_sc) { struct hv_device *device = new_sc->primary_channel->device_obj; @@ -711,11 +728,7 @@ static void handle_sc_creation(struct vmbus_channel *new_sc) 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 - * that can be in-progress at any one time across all channels. - */ - new_sc->rqstor_size = scsi_driver.can_queue; + new_sc->next_request_id_callback = storvsc_next_request_id; ret = vmbus_open(new_sc, storvsc_ringbuffer_size, @@ -782,7 +795,7 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta), - (unsigned long)request, + VMBUS_RQST_INIT, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); @@ -851,7 +864,7 @@ static int storvsc_execute_vstor_op(struct hv_device *device, ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta), - (unsigned long)request, + VMBUS_RQST_INIT, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); if (ret != 0) @@ -1253,6 +1266,7 @@ static void storvsc_on_channel_callback(void *context) const struct vmpacket_descriptor *desc; struct hv_device *device; struct storvsc_device *stor_device; + struct Scsi_Host *shost; if (channel->primary_channel != NULL) device = channel->primary_channel->device_obj; @@ -1263,20 +1277,12 @@ static void storvsc_on_channel_callback(void *context) if (!stor_device) return; - foreach_vmbus_pkt(desc, channel) { - void *packet = hv_pkt_data(desc); - struct storvsc_cmd_request *request; - u64 cmd_rqst; - - cmd_rqst = vmbus_request_addr(&channel->requestor, - desc->trans_id); - if (cmd_rqst == VMBUS_RQST_ERROR) { - dev_err(&device->device, - "Incorrect transaction id\n"); - continue; - } + shost = stor_device->host; - request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst; + foreach_vmbus_pkt(desc, channel) { + struct vstor_packet *packet = hv_pkt_data(desc); + struct storvsc_cmd_request *request = NULL; + u64 rqst_id = desc->trans_id; if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta) { @@ -1284,14 +1290,44 @@ static void storvsc_on_channel_callback(void *context) continue; } - if (request == &stor_device->init_request || - request == &stor_device->reset_request) { - memcpy(&request->vstor_packet, packet, - (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta)); - complete(&request->wait_event); + if (rqst_id == VMBUS_RQST_INIT) { + request = &stor_device->init_request; + } else if (rqst_id == VMBUS_RQST_RESET) { + request = &stor_device->reset_request; } else { + /* Hyper-V can send an unsolicited message with ID of 0 */ + if (rqst_id == 0) { + /* + * storvsc_on_receive() looks at the vstor_packet in the message + * from the ring buffer. If the operation in the vstor_packet is + * COMPLETE_IO, then we call storvsc_on_io_completion(), and + * dereference the guest memory address. Make sure we don't call + * storvsc_on_io_completion() with a guest memory address that is + * zero if Hyper-V were to construct and send such a bogus packet. + */ + if (packet->operation == VSTOR_OPERATION_COMPLETE_IO) { + dev_err(&device->device, "Invalid packet with ID of 0\n"); + continue; + } + } else { + struct scsi_cmnd *scmnd; + + /* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */ + scmnd = scsi_host_find_tag(shost, rqst_id - 1); + if (scmnd == NULL) { + dev_err(&device->device, "Incorrect transaction ID\n"); + continue; + } + request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd); + } + storvsc_on_receive(stor_device, packet, request); + continue; } + + memcpy(&request->vstor_packet, packet, + (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta)); + complete(&request->wait_event); } } @@ -1304,11 +1340,7 @@ 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. - */ - device->channel->rqstor_size = scsi_driver.can_queue; + device->channel->next_request_id_callback = storvsc_next_request_id; ret = vmbus_open(device->channel, ring_size, @@ -1634,7 +1666,7 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd) ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta), - (unsigned long)&stor_device->reset_request, + VMBUS_RQST_RESET, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); if (ret != 0) diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 3932446f215f..2e859d2f9609 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -794,7 +794,11 @@ struct vmbus_requestor { #define VMBUS_NO_RQSTOR U64_MAX #define VMBUS_RQST_ERROR (U64_MAX - 1) +/* NetVSC-specific */ #define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2) +/* StorVSC-specific */ +#define VMBUS_RQST_INIT (U64_MAX - 2) +#define VMBUS_RQST_RESET (U64_MAX - 3) struct vmbus_device { u16 dev_type; @@ -1024,6 +1028,11 @@ struct vmbus_channel { u32 fuzz_testing_interrupt_delay; u32 fuzz_testing_message_delay; + /* callback to generate a request ID from a request address */ + u64 (*next_request_id_callback)(struct vmbus_channel *channel, u64 rqst_addr); + /* callback to retrieve a request address from a request ID */ + u64 (*request_addr_callback)(struct vmbus_channel *channel, u64 rqst_id); + /* request/transaction ids for VMBus */ struct vmbus_requestor requestor; u32 rqstor_size; @@ -1032,8 +1041,8 @@ struct vmbus_channel { u32 max_pkt_size; }; -u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr); -u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id); +u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr); +u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id); static inline bool is_hvsock_channel(const struct vmbus_channel *c) { -- cgit v1.2.3