Re: [PATCH v3 1/5] staging: rtl8723bs: fix heap buffer overflow in recvframe_defrag()

[Dan Carpenter <error27@gmail.com>]

On Wed, Apr 15, 2026 at 06:24:10PM +0300, Dan Carpenter wrote:
> > diff --git a/drivers/staging/rtl8723bs/core/rtw_recv.c b/drivers/staging/rtl8723bs/core/rtw_recv.c
> > index f78194d508dfc..717e0594d983a 100644
> > --- a/drivers/staging/rtl8723bs/core/rtw_recv.c
> > +++ b/drivers/staging/rtl8723bs/core/rtw_recv.c
> > @@ -1132,7 +1132,13 @@ static union recv_frame *recvframe_defrag(struct adapter *adapter,
> >  		/* append  to first fragment frame's tail (if privacy frame, pull the ICV) */
> >  		recvframe_pull_tail(prframe, pfhdr->attrib.icv_len);
> 
> There is no error checking on these pull calls.  They're supposed
> to return NULL if pfhdr->attrib.icv_len is too big.  (There is a similar
> caller earlier on the line before).
>

Actually if these fail

> >  
> > -		/* memcpy */
> > +		/* Verify the receiving buffer has enough space for the fragment */
> > +		if (pnfhdr->len > (uint)(pfhdr->rx_end - pfhdr->rx_tail)) {
> 

then the pfhdr->rx_end and pfhdr->rx_tail pointers are wrong.  So you
really do need to add the error checking before you do the resend.

regards,
dan carpenter