| Message ID | 20230103091710.81530-1-szymon.heidrich@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | usb: rndis_host: Secure rndis_query check against int overflow | expand |
diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c index f79333fe1..7b3739b29 100644 --- a/drivers/net/usb/rndis_host.c +++ b/drivers/net/usb/rndis_host.c @@ -255,7 +255,8 @@ static int rndis_query(struct usbnet *dev, struct usb_interface *intf, off = le32_to_cpu(u.get_c->offset); len = le32_to_cpu(u.get_c->len); - if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE)) + if (unlikely((off > CONTROL_BUFFER_SIZE - 8) || + (len > CONTROL_BUFFER_SIZE - 8 - off))) goto response_error; if (*reply_len != -1 && len != *reply_len)
Variables off and len typed as uint32 in rndis_query function are controlled by incoming RNDIS response message thus their value may be manipulated. Setting off to a unexpectetly large value will cause the sum with len and 8 to overflow and pass the implemented validation step. Consequently the response pointer will be referring to a location past the expected buffer boundaries allowing information leakage e.g. via RNDIS_OID_802_3_PERMANENT_ADDRESS OID. Fixes: ddda08624013 ("USB: rndis_host, various cleanups") Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com> --- drivers/net/usb/rndis_host.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)