From 47aa7861b9bf8e8a540f3b11971e4a3f631e8ff4 Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Mon, 18 Jun 2018 07:41:34 -0500
Subject: [PATCH] mac80211: fix potential null pointer dereference
Git-commit: 47aa7861b9bf8e8a540f3b11971e4a3f631e8ff4
Patch-mainline: v4.19-rc1
References: FATE#326294
he_op is being dereferenced before it is null checked, hence there
is a potential null pointer dereference.
Fix this by moving the pointer dereference after he_op has been
properly null checked.
Notice that, currently, he_op is already being null checked before
calling this function at 4593:
4593 if (!he_oper ||
4594 !ieee80211_verify_sta_he_mcs_support(sband, he_oper))
4595 ifmgd->flags |= IEEE80211_STA_DISABLE_HE;
but in case ieee80211_verify_sta_he_mcs_support is ever called
without verifying he_oper is not null, we will end up having a
null pointer dereference. So, we better don't take any chances.
Addresses-coverity-id: 1470068 ("Dereference before null check")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/mac80211/mlme.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 0322d78007ad..f4513031f1bc 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -4458,12 +4458,14 @@ ieee80211_verify_sta_he_mcs_support(struct ieee80211_supported_band *sband,
{
const struct ieee80211_sta_he_cap *sta_he_cap =
ieee80211_get_he_sta_cap(sband);
- u16 ap_min_req_set = le16_to_cpu(he_op->he_mcs_nss_set);
+ u16 ap_min_req_set;
int i;
if (!sta_he_cap || !he_op)
return false;
+ ap_min_req_set = le16_to_cpu(he_op->he_mcs_nss_set);
+
/* Need to go over for 80MHz, 160MHz and for 80+80 */
for (i = 0; i < 3; i++) {
const struct ieee80211_he_mcs_nss_supp *sta_mcs_nss_supp =
--
2.19.2