From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Date: Wed, 15 Jul 2026 18:57:14 +0000 (+0300)
Subject: wifi: iwlwifi: mvm: fix a possible underflow
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0cb5260a1027a43f8cdb961e128f2ddd42e46832;p=thirdparty%2Fkernel%2Flinux.git

wifi: iwlwifi: mvm: fix a possible underflow

We shouldn't trust the firmware about the length of the wowlan packet.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260715215523.fbd989cc85e2.If68de403bfa4943732c025961154c20b01b09e83@changeid
---

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
index 4eaba0bc4a1e..109265149963 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
@@ -1509,6 +1509,10 @@ static void iwl_mvm_report_wakeup_reasons(struct iwl_mvm *mvm,
 		if (WARN_ON_ONCE(truncated < 0))
 			truncated = 0;
 
+		/* this would be a firmware bug */
+		if (WARN_ON_ONCE(pktsize < sizeof(*hdr)))
+			return;
+
 		if (ieee80211_is_data(hdr->frame_control)) {
 			int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 			int ivlen = 0, icvlen = 4; /* also FCS */
@@ -1517,10 +1521,6 @@ static void iwl_mvm_report_wakeup_reasons(struct iwl_mvm *mvm,
 			if (!pkt)
 				goto report;
 
-			skb_put_data(pkt, pktdata, hdrlen);
-			pktdata += hdrlen;
-			pktsize -= hdrlen;
-
 			if (ieee80211_has_protected(hdr->frame_control)) {
 				/*
 				 * This is unlocked and using gtk_i(c)vlen,
@@ -1546,6 +1546,17 @@ static void iwl_mvm_report_wakeup_reasons(struct iwl_mvm *mvm,
 				truncated = 0;
 			}
 
+			if (IWL_FW_CHECK(mvm,
+					 pktsize <= hdrlen + ivlen + icvlen,
+					 "pktsize is too small %d\n",
+					 pktsize)) {
+				kfree_skb(pkt);
+				return;
+			}
+
+			skb_put_data(pkt, pktdata, hdrlen);
+			pktdata += hdrlen;
+			pktsize -= hdrlen;
 			pktsize -= ivlen + icvlen;
 			pktdata += ivlen;