HID: hyperv: Replace one-element array with flexible-array member

One-element arrays are deprecated, and we are replacing them with
flexible array members instead. So, replace one-element array with
flexible-array member in structs synthhid_msg, synthhid_input_report,
pipe_prt_msg and refactor the rest of the code accordingly.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/210
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Paulo Miguel Almeida 2022-10-17 20:51:22 +13:00 committed by Jiri Kosina
parent 79d11de963
commit 542f25a944

View file

@ -61,7 +61,7 @@ struct synthhid_msg_hdr {
struct synthhid_msg { struct synthhid_msg {
struct synthhid_msg_hdr header; struct synthhid_msg_hdr header;
char data[1]; /* Enclosed message */ char data[]; /* Enclosed message */
}; };
union synthhid_version { union synthhid_version {
@ -99,7 +99,7 @@ struct synthhid_device_info_ack {
struct synthhid_input_report { struct synthhid_input_report {
struct synthhid_msg_hdr header; struct synthhid_msg_hdr header;
char buffer[1]; char buffer[];
}; };
#pragma pack(pop) #pragma pack(pop)
@ -118,7 +118,7 @@ enum pipe_prot_msg_type {
struct pipe_prt_msg { struct pipe_prt_msg {
enum pipe_prot_msg_type type; enum pipe_prot_msg_type type;
u32 size; u32 size;
char data[1]; char data[];
}; };
struct mousevsc_prt_msg { struct mousevsc_prt_msg {
@ -232,7 +232,7 @@ static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device,
ret = vmbus_sendpacket(input_device->device->channel, ret = vmbus_sendpacket(input_device->device->channel,
&ack, &ack,
sizeof(struct pipe_prt_msg) - sizeof(unsigned char) + sizeof(struct pipe_prt_msg) +
sizeof(struct synthhid_device_info_ack), sizeof(struct synthhid_device_info_ack),
(unsigned long)&ack, (unsigned long)&ack,
VM_PKT_DATA_INBAND, VM_PKT_DATA_INBAND,
@ -271,16 +271,14 @@ static void mousevsc_on_receive(struct hv_device *device,
* malicious/buggy hypervisor/host, add a check here to * malicious/buggy hypervisor/host, add a check here to
* ensure we don't corrupt memory. * ensure we don't corrupt memory.
*/ */
if ((pipe_msg->size + sizeof(struct pipe_prt_msg) if (struct_size(pipe_msg, data, pipe_msg->size)
- sizeof(unsigned char))
> sizeof(struct mousevsc_prt_msg)) { > sizeof(struct mousevsc_prt_msg)) {
WARN_ON(1); WARN_ON(1);
break; break;
} }
memcpy(&input_dev->protocol_resp, pipe_msg, memcpy(&input_dev->protocol_resp, pipe_msg,
pipe_msg->size + sizeof(struct pipe_prt_msg) - struct_size(pipe_msg, data, pipe_msg->size));
sizeof(unsigned char));
complete(&input_dev->wait_event); complete(&input_dev->wait_event);
break; break;
@ -359,8 +357,7 @@ static int mousevsc_connect_to_vsp(struct hv_device *device)
request->request.version_requested.version = SYNTHHID_INPUT_VERSION; request->request.version_requested.version = SYNTHHID_INPUT_VERSION;
ret = vmbus_sendpacket(device->channel, request, ret = vmbus_sendpacket(device->channel, request,
sizeof(struct pipe_prt_msg) - sizeof(struct pipe_prt_msg) +
sizeof(unsigned char) +
sizeof(struct synthhid_protocol_request), sizeof(struct synthhid_protocol_request),
(unsigned long)request, (unsigned long)request,
VM_PKT_DATA_INBAND, VM_PKT_DATA_INBAND,