From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F7AF3D3002; Wed, 30 Sep 2026 19:19:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795968; cv=none; b=JzFdm6iJwdkdV8VT277FqH99+wyefxjpfAfXBFVq2gBFGoKnzHbyUHVXiAf//s134TnkHbNMaJ24Q/5RRetcQCQD8fZ4lG1P+gDslsMv2EDUWYPyiPzd4MadaGpdl49JRe0zb9X9twlzm7ybblLK1O8GiC+ZKlYIVzALOR+8EP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795968; c=relaxed/simple; bh=ysbeOOeOfepOz5SVaC6baC5hvyCA36G/CQNBAVQfMFg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SVHT8fuUo12pC2u2pCp91q+IenMU8lnZj7SVuDTzal4p33hAKAYbTLTWdGrJreJXSX5cR9vEjrEGH3MbW0SXhvX56udRLkki+wiTlfBBgTr+CxBfe1+8CVyghIZrni2tUrgDdPW7gD6rmhDlS0AGSmWDEw1MxAKz+ZmL88aJRxA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XCyYyZD8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XCyYyZD8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C3421F00898; Wed, 30 Sep 2026 19:19:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790795967; bh=3/Vs0CrzhnDRDBjpbLtsGo3Hmx44OgFgrTxNDvQriOU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XCyYyZD82t717ZueiDD43DWMQS8mSuc3TY7rEcOCe7a86ynkoqDnP0ftwrrd+1APp uWBdfsKmeJRDAehdKZM3Y9fl22ANml+xQHTZdG2XZMCCKKitFT3rdKXw8A+OGYM0Tz HWbJB4IEInqJwrh4xAGoJmI1/2ME1sj2Q0/TSjyI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+878ddc3962f792e9af59@syzkaller.appspotmail.com, Johannes Berg , Sasha Levin Subject: [PATCH 6.6 0746/1193] wifi: cfg80211: check IP header size in cfg80211_classify8021d() Date: Wed, 30 Sep 2026 17:23:50 +0200 Message-ID: <20260930152450.824965716@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg [ Upstream commit 48b2c5c628b09cf36cbeca53e0432fc2a7518be7 ] A frame that looks like IP can be transmitted, but be too short, so the DS field is read incorrectly: BUG: KMSAN: uninit-value in cfg80211_classify8021d+0x99d/0x12b0 net/wireless/util.c:1027 cfg80211_classify8021d+0x99d/0x12b0 net/wireless/util.c:1027 ieee80211_select_queue+0x37a/0x9e0 net/mac80211/wme.c:180 __ieee80211_subif_start_xmit+0x60f/0x1d90 net/mac80211/tx.c:4304 ieee80211_subif_start_xmit+0xa8/0x6d0 net/mac80211/tx.c:4538 ... packet_sendmsg+0x9173/0xa2a0 net/packet/af_packet.c:3108 Use skb_header_pointer() like the MPLS case. Assisted-by: LLM Fixes: e31a16d6f64e ("wireless: move some utility functions from mac80211 to cfg80211") Reported-by: syzbot+878ddc3962f792e9af59@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=878ddc3962f792e9af59 Link: https://patch.msgid.link/20260904165614.5e61a4c80b92.I37d68d3f406cb3b90b32e6943418d66070b65197@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/wireless/util.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 640ec502e82d2..40788274d4a77 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -995,12 +995,30 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb, } switch (skb->protocol) { - case htons(ETH_P_IP): - dscp = ipv4_get_dsfield(ip_hdr(skb)) & 0xfc; + case htons(ETH_P_IP): { + const struct iphdr *iph; + struct iphdr _iph; + + iph = skb_header_pointer(skb, sizeof(struct ethhdr), + sizeof(*iph), &_iph); + if (!iph) + return 0; + + dscp = ipv4_get_dsfield(iph) & 0xfc; break; - case htons(ETH_P_IPV6): - dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & 0xfc; + } + case htons(ETH_P_IPV6): { + const struct ipv6hdr *ip6h; + struct ipv6hdr _ip6h; + + ip6h = skb_header_pointer(skb, sizeof(struct ethhdr), + sizeof(*ip6h), &_ip6h); + if (!ip6h) + return 0; + + dscp = ipv6_get_dsfield(ip6h) & 0xfc; break; + } case htons(ETH_P_MPLS_UC): case htons(ETH_P_MPLS_MC): { struct mpls_label mpls_tmp, *mpls; -- 2.53.0