From: Johannes Berg <johannes@sipsolutions.net>
To: "Ranganath V N" <vnranganath.20@gmail.com>,
"Dave Täht" <dave.taht@bufferbloat.net>,
"John W. Linville" <linville@tuxdriver.com>
Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
skhan@linuxfoundation.org, david.hunter.linux@gmail.com,
khalid@kernel.org,
syzbot+878ddc3962f792e9af59@syzkaller.appspotmail.com
Subject: Re: [PATCH v2] wifi: cfg80211: Fix uninitialized header access in cfg80211_classify8021d
Date: Mon, 10 Nov 2025 10:28:23 +0100 [thread overview]
Message-ID: <f3a9797eb23d9c26007652798f14b76330aa1933.camel@sipsolutions.net> (raw)
In-Reply-To: <20251108-fifth-v2-1-405da01c6684@gmail.com> (sfid-20251107_193312_898584_A71B4CAD)
On Sat, 2025-11-08 at 00:03 +0530, Ranganath V N wrote:
>
> +++ b/net/wireless/util.c
> @@ -963,9 +963,13 @@ unsigned int cfg80211_classify8021d(struct sk_buff *skb,
>
> switch (skb->protocol) {
> case htons(ETH_P_IP):
> + if (!pskb_may_pull(skb, sizeof(struct iphdr)))
> + return 0;
> dscp = ipv4_get_dsfield(ip_hdr(skb)) & 0xfc;
> break;
That doesn't seem correct to me, passing only the IP header length to
pskb_may_pull() call assumes that ip_hdr(skb) == sbk->data, which is
almost certainly not true?
MPLS seems to not have this problem.
And maybe there's a similar issue for the VLAN tag?
johannes
next prev parent reply other threads:[~2025-11-10 9:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-07 18:33 Ranganath V N
2025-11-10 9:28 ` Johannes Berg [this message]
2025-11-11 18:29 ` Ranganath V N
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