Patch "brcmfmac: add length check in brcmf_cfg80211_escan_handler()" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    brcmfmac: add length check in brcmf_cfg80211_escan_handler()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     brcmfmac-add-length-check-in-brcmf_cfg80211_escan_handler.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 17df6453d4be17910456e99c5a85025aa1b7a246 Mon Sep 17 00:00:00 2001
From: Arend Van Spriel <arend.vanspriel@broadcom.com>
Date: Tue, 12 Sep 2017 10:47:53 +0200
Subject: brcmfmac: add length check in brcmf_cfg80211_escan_handler()

From: Arend Van Spriel <arend.vanspriel@broadcom.com>

commit 17df6453d4be17910456e99c5a85025aa1b7a246 upstream.

Upon handling the firmware notification for scans the length was
checked properly and may result in corrupting kernel heap memory
due to buffer overruns. This fix addresses CVE-2017-0786.

Cc: Kevin Cernekee <cernekee@chromium.org>
Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c |   18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c
@@ -2914,6 +2914,7 @@ brcmf_cfg80211_escan_handler(struct brcm
 	struct brcmf_cfg80211_info *cfg = ifp->drvr->config;
 	s32 status;
 	struct brcmf_escan_result_le *escan_result_le;
+	u32 escan_buflen;
 	struct brcmf_bss_info_le *bss_info_le;
 	struct brcmf_bss_info_le *bss = NULL;
 	u32 bi_length;
@@ -2930,11 +2931,23 @@ brcmf_cfg80211_escan_handler(struct brcm
 
 	if (status == BRCMF_E_STATUS_PARTIAL) {
 		brcmf_dbg(SCAN, "ESCAN Partial result\n");
+		if (e->datalen < sizeof(*escan_result_le)) {
+			brcmf_err("invalid event data length\n");
+			goto exit;
+		}
 		escan_result_le = (struct brcmf_escan_result_le *) data;
 		if (!escan_result_le) {
 			brcmf_err("Invalid escan result (NULL pointer)\n");
 			goto exit;
 		}
+		escan_buflen = le32_to_cpu(escan_result_le->buflen);
+		if (escan_buflen > BRCMF_ESCAN_BUF_SIZE ||
+		    escan_buflen > e->datalen ||
+		    escan_buflen < sizeof(*escan_result_le)) {
+			brcmf_err("Invalid escan buffer length: %d\n",
+				  escan_buflen);
+			goto exit;
+		}
 		if (le16_to_cpu(escan_result_le->bss_count) != 1) {
 			brcmf_err("Invalid bss_count %d: ignoring\n",
 				  escan_result_le->bss_count);
@@ -2951,9 +2964,8 @@ brcmf_cfg80211_escan_handler(struct brcm
 		}
 
 		bi_length = le32_to_cpu(bss_info_le->length);
-		if (bi_length != (le32_to_cpu(escan_result_le->buflen) -
-					WL_ESCAN_RESULTS_FIXED_SIZE)) {
-			brcmf_err("Invalid bss_info length %d: ignoring\n",
+		if (bi_length != escan_buflen -	WL_ESCAN_RESULTS_FIXED_SIZE) {
+			brcmf_err("Ignoring invalid bss_info length: %d\n",
 				  bi_length);
 			goto exit;
 		}


Patches currently in stable-queue which might be from arend.vanspriel@broadcom.com are

queue-4.4/brcmfmac-add-length-check-in-brcmf_cfg80211_escan_handler.patch
queue-4.4/brcmfmac-setup-passive-scan-if-requested-by-user-space.patch