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| author | Michael Bommarito <michael.bommarito@gmail.com> | 2026-07-09 22:28:53 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-08-27 14:34:40 +0200 |
| commit | 2529737763cb4bcfcaf397beeea2664656c865b4 (patch) | |
| tree | 6836b358dfb6f2b8082a107f14a7b8b4a97fb3b0 | |
| parent | f1b3ca06380531f49f988f4721d3ed30b0d7a5d2 (diff) | |
| download | linux-2529737763cb4bcfcaf397beeea2664656c865b4.tar.gz linux-2529737763cb4bcfcaf397beeea2664656c865b4.zip | |
HID: hyperv: validate initial device info bounds
commit 934b7778aa7b7c8f6bb073d2a73ba3674885bae0 upstream.
The Hyper-V synthetic HID host supplies SYNTH_HID_INITIAL_DEVICE_INFO
messages that contain a HID descriptor followed by the report descriptor
bytes. mousevsc_on_receive_device_info() trusts bLength and
wDescriptorLength without checking that the received packet contains both
byte ranges.
A malformed host or backend message can therefore make the guest read
past the received VMBus packet while copying the report descriptor. Pass
the received initial-device-info size into the parser and reject
descriptor lengths that exceed the packet.
Impact: A malicious Hyper-V host or backend can crash a guest by sending
a short initial device-info message with an oversized HID report
descriptor length.
Fixes: b95f5bcb811e ("HID: Move the hid-hyperv driver out of staging")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5-5-xhigh
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hid/hid-hyperv.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c index 7d2b0063df15..fd90196430e2 100644 --- a/drivers/hid/hid-hyperv.c +++ b/drivers/hid/hid-hyperv.c @@ -171,18 +171,32 @@ static void mousevsc_free_device(struct mousevsc_dev *device) } static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device, - struct synthhid_device_info *device_info) + struct synthhid_device_info *device_info, + u32 device_info_size) { int ret = 0; struct hid_descriptor *desc; struct mousevsc_prt_msg ack; + size_t desc_offset; + size_t desc_size; input_device->dev_info_status = -ENOMEM; + if (device_info_size < sizeof(*device_info)) { + input_device->dev_info_status = -EINVAL; + goto cleanup; + } + input_device->hid_dev_info = device_info->hid_dev_info; desc = &device_info->hid_descriptor; + desc_offset = offsetof(struct synthhid_device_info, hid_descriptor); + desc_size = device_info_size - desc_offset; if (desc->bLength == 0) goto cleanup; + if (desc->bLength < sizeof(*desc) || desc->bLength > desc_size) { + input_device->dev_info_status = -EINVAL; + goto cleanup; + } /* The pointer is not NULL when we resume from hibernation */ kfree(input_device->hid_desc); @@ -197,6 +211,10 @@ static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device, input_device->dev_info_status = -EINVAL; goto cleanup; } + if (input_device->report_desc_size > desc_size - desc->bLength) { + input_device->dev_info_status = -EINVAL; + goto cleanup; + } /* The pointer is not NULL when we resume from hibernation */ kfree(input_device->report_desc); @@ -273,14 +291,17 @@ static void mousevsc_on_receive(struct hv_device *device, break; case SYNTH_HID_INITIAL_DEVICE_INFO: - WARN_ON(pipe_msg->size < sizeof(struct hv_input_dev_info)); + if (WARN_ON_ONCE(pipe_msg->size < + sizeof(struct synthhid_device_info))) + break; /* * Parse out the device info into device attr, * hid desc and report desc */ mousevsc_on_receive_device_info(input_dev, - (struct synthhid_device_info *)pipe_msg->data); + (struct synthhid_device_info *)pipe_msg->data, + pipe_msg->size); break; case SYNTH_HID_INPUT_REPORT: input_report = |