From: Seungjin Bae <eeodqql09(a)gmail.com>
In the pegasus_notetaker driver, the pegasus_probe() function allocates
the URB transfer buffer using the wMaxPacketSize value from
the endpoint descriptor. An attacker can use a malicious USB descriptor
to force the allocation of a very small buffer.
Subsequently, if the device sends an interrupt packet with a specific
pattern (e.g., where the first byte is 0x80 or 0x42),
the pegasus_parse_packet() function parses the packet without checking
the allocated buffer size. This leads to an out-of-bounds memory access,
which could result in a system panic.
Fixes: 948bf18 ("Input: remove third argument of usb_maxpacket()")
Signed-off-by: Seungjin Bae <eeodqql09(a)gmail.com>
---
drivers/input/tablet/pegasus_notetaker.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
index 8d6b71d59793..6c4199712a4e 100644
--- a/drivers/input/tablet/pegasus_notetaker.c
+++ b/drivers/input/tablet/pegasus_notetaker.c
@@ -311,6 +311,11 @@ static int pegasus_probe(struct usb_interface *intf,
}
pegasus->data_len = usb_maxpacket(dev, pipe);
+ if (pegasus->data_len < 5) {
+ dev_err(&intf->dev, "Invalid number of wMaxPacketSize\n");
+ error = -EINVAL;
+ goto err_free_mem;
+ }
pegasus->data = usb_alloc_coherent(dev, pegasus->data_len, GFP_KERNEL,
&pegasus->data_dma);
--
2.43.0