> Date: Sun, 31 Jan 2016 20:57:29 +0100
> From: Stefan Sperling <s...@stsp.name>
>
> On Sun, Jan 31, 2016 at 03:14:46PM +0100, Mark Kettenis wrote:
> > I think you should add a TCHECK somewhere at the top for the qos frame
> > size otherwise this might look beyond the end of the buffer for
> > specially crafted frames.
>
> Oh yes, indeed.
ok kettenis@
> Index: print-802_11.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/tcpdump/print-802_11.c,v
> retrieving revision 1.28
> diff -u -p -r1.28 print-802_11.c
> --- print-802_11.c 12 Jan 2016 09:28:10 -0000 1.28
> +++ print-802_11.c 31 Jan 2016 19:56:07 -0000
> @@ -153,14 +153,25 @@ int
> ieee80211_data(struct ieee80211_frame *wh, u_int len)
> {
> u_int8_t *t = (u_int8_t *)wh;
> - struct ieee80211_frame_addr4 *w4;
> u_int datalen;
> int data = !(wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_NODATA);
> + int hasqos = ((wh->i_fc[0] &
> + (IEEE80211_FC0_TYPE_MASK | IEEE80211_FC0_SUBTYPE_QOS)) ==
> + (IEEE80211_FC0_TYPE_DATA | IEEE80211_FC0_SUBTYPE_QOS));
> u_char *esrc = NULL, *edst = NULL;
>
> - TCHECK(*wh);
> - t += sizeof(struct ieee80211_frame);
> - datalen = len - sizeof(struct ieee80211_frame);
> + if (hasqos) {
> + struct ieee80211_qosframe *wq;
> +
> + wq = (struct ieee80211_qosframe *) wh;
> + TCHECK(*wq);
> + t += sizeof(*wq);
> + datalen = len - sizeof(*wq);
> + } else {
> + TCHECK(*wh);
> + t += sizeof(*wh);
> + datalen = len - sizeof(*wh);
> + }
>
> switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
> case IEEE80211_FC1_DIR_TODS:
> @@ -176,12 +187,25 @@ ieee80211_data(struct ieee80211_frame *w
> edst = wh->i_addr1;
> break;
> case IEEE80211_FC1_DIR_DSTODS:
> - w4 = (struct ieee80211_frame_addr4 *) wh;
> - TCHECK(*w4);
> - t = (u_int8_t *) (w4 + 1);
> - datalen = len - sizeof(*w4);
> - esrc = w4->i_addr4;
> - edst = w4->i_addr3;
> + if (hasqos) {
> + struct ieee80211_qosframe_addr4 *w4;
> +
> + w4 = (struct ieee80211_qosframe_addr4 *) wh;
> + TCHECK(*w4);
> + t = (u_int8_t *) (w4 + 1);
> + datalen = len - sizeof(*w4);
> + esrc = w4->i_addr4;
> + edst = w4->i_addr3;
> + } else {
> + struct ieee80211_frame_addr4 *w4;
> +
> + w4 = (struct ieee80211_frame_addr4 *) wh;
> + TCHECK(*w4);
> + t = (u_int8_t *) (w4 + 1);
> + datalen = len - sizeof(*w4);
> + esrc = w4->i_addr4;
> + edst = w4->i_addr3;
> + }
> break;
> }
>
>
