[PATCH 4/6] brcmfmac: add length checks in scheduled scan result handler

[Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>]

Assure the event data buffer is long enough to hold the array
of netinfo items and that SSID length does not exceed the maximum
of 32 characters as per 802.11 spec.

Reviewed-by: Hante Meuleman <hante.meuleman@xxxxxxxxxxxx>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@xxxxxxxxxxxx>
Reviewed-by: Franky Lin <franky.lin@xxxxxxxxxxxx>
Signed-off-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index 89ac124..760781f 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -3300,6 +3300,7 @@ static int brcmf_start_internal_escan(struct brcmf_if *ifp,
 	struct brcmf_pno_scanresults_le *pfn_result;
 	u32 result_count;
 	u32 status;
+	u32 datalen;
 
 	brcmf_dbg(SCAN, "Enter\n");
 
@@ -3326,6 +3327,14 @@ static int brcmf_start_internal_escan(struct brcmf_if *ifp,
 		brcmf_err("FALSE PNO Event. (pfn_count == 0)\n");
 		goto out_err;
 	}
+
+	netinfo_start = brcmf_get_netinfo_array(pfn_result);
+	datalen = e->datalen - ((void *)netinfo_start - (void *)pfn_result);
+	if (datalen < result_count * sizeof(*netinfo)) {
+		brcmf_err("insufficient event data\n");
+		goto out_err;
+	}
+
 	request = brcmf_alloc_internal_escan_request(wiphy,
 						     result_count);
 	if (!request) {
@@ -3333,8 +3342,6 @@ static int brcmf_start_internal_escan(struct brcmf_if *ifp,
 		goto out_err;
 	}
 
-	netinfo_start = brcmf_get_netinfo_array(pfn_result);
-
 	for (i = 0; i < result_count; i++) {
 		netinfo = &netinfo_start[i];
 		if (!netinfo) {
@@ -3344,6 +3351,8 @@ static int brcmf_start_internal_escan(struct brcmf_if *ifp,
 			goto out_err;
 		}
 
+		if (netinfo->SSID_len > IEEE80211_MAX_SSID_LEN)
+			netinfo->SSID_len = IEEE80211_MAX_SSID_LEN;
 		brcmf_dbg(SCAN, "SSID:%.32s Channel:%d\n",
 			  netinfo->SSID, netinfo->channel);
 		err = brcmf_internal_escan_add_info(request,
-- 
1.9.1