Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/4] ozwpan: Use proper check to prevent heap overflow | From | "Charles (Chas) Williams" <> | Date | Sat, 16 May 2015 06:20:15 -0400 |
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On Fri, 2015-05-15 at 15:02 +0000, David Laight wrote: > From: Jason A. Donenfeld > > Sent: 13 May 2015 19:34 > > Since elt->length is a u8, we can make this variable a u8. Then we can > > do proper bounds checking more easily. Without this, a potentially > > negative value is passed to the memcpy inside oz_hcd_get_desc_cnf, > > resulting in a remotely exploitable heap overflow with network > > supplied data. > ... > > diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c > > index d434d8c..cd6c63e 100644 > > --- a/drivers/staging/ozwpan/ozusbsvc1.c > > +++ b/drivers/staging/ozwpan/ozusbsvc1.c > > @@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt) > > case OZ_GET_DESC_RSP: { > > struct oz_get_desc_rsp *body = > > (struct oz_get_desc_rsp *)usb_hdr; > > - int data_len = elt->length - > > + u8 data_len = elt->length - > > sizeof(struct oz_get_desc_rsp) + 1; > > + if (data_len > elt->length) > > + break;
This check already seems bogus? It's really:
if (sizeof(struct oz_get_desc_rsp) - 1 < 0)
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