From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 72D0F1DF254; Wed, 6 Nov 2024 12:13:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730895205; cv=none; b=EMdL5+F71JgsPwBHV90ojgU+Td0JH8mHDTMhKRoXesJl70d3qcYL3xinhpyzt5XBCJC7Z7veBPXkHVovJMfMRGp3G/OUfJ3LJnzGjONh64s2PboJoJF2t6UNdVS05QkbJRYOqqymzNLsgmkKuNLLcG86wxVROuBlo5RS0nDqY7s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730895205; c=relaxed/simple; bh=cg23v+I6wnSkHs0NcdsOsq3mdD/U8xEmpLuz/cfXe2s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kDBaeFURcG2x+8239EetQ72/iQgJT5DVZCoKy6Knclk4/BeN3DGYfcW3qYn3MAqleS+EyV9eRLKEo+Wjflr9/Epr/tpUkUiLawXOp++25CPgpBS2VIwQuqDtYBq7zdmG4MufpBtjzGmVOT7tnviCvS5bnHKZMZWpFEh6vGWDsME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=POFcIfoZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="POFcIfoZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA929C4CECD; Wed, 6 Nov 2024 12:13:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730895205; bh=cg23v+I6wnSkHs0NcdsOsq3mdD/U8xEmpLuz/cfXe2s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=POFcIfoZ2XgFkI4vp3CkJN5ilceMf4/VMnAdrpd3EsQN1mvr9ec3v8FQw5kVxobMn RU9P8FRwCg211t40zWJbazIXVn0Fqgbvx0otPLDr7OUkt+hx5HeE259WGmyGxBRnS5 /evbw1+slBpxmDTed6nLt4NaY0wiJaPe5SpGQGQs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Willem de Bruijn , David Ahern , Paolo Abeni , Sasha Levin Subject: [PATCH 4.19 140/350] net: add more sanity checks to qdisc_pkt_len_init() Date: Wed, 6 Nov 2024 13:01:08 +0100 Message-ID: <20241106120324.369745270@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120320.865793091@linuxfoundation.org> References: <20241106120320.865793091@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit ab9a9a9e9647392a19e7a885b08000e89c86b535 ] One path takes care of SKB_GSO_DODGY, assuming skb->len is bigger than hdr_len. virtio_net_hdr_to_skb() does not fully dissect TCP headers, it only make sure it is at least 20 bytes. It is possible for an user to provide a malicious 'GSO' packet, total length of 80 bytes. - 20 bytes of IPv4 header - 60 bytes TCP header - a small gso_size like 8 virtio_net_hdr_to_skb() would declare this packet as a normal GSO packet, because it would see 40 bytes of payload, bigger than gso_size. We need to make detect this case to not underflow qdisc_skb_cb(skb)->pkt_len. Fixes: 1def9238d4aa ("net_sched: more precise pkt_len computation") Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/core/dev.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 916a095eaee27..0409c051ed5d4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3443,10 +3443,14 @@ static void qdisc_pkt_len_init(struct sk_buff *skb) hdr_len += sizeof(struct udphdr); } - if (shinfo->gso_type & SKB_GSO_DODGY) - gso_segs = DIV_ROUND_UP(skb->len - hdr_len, - shinfo->gso_size); + if (unlikely(shinfo->gso_type & SKB_GSO_DODGY)) { + int payload = skb->len - hdr_len; + /* Malicious packet. */ + if (payload <= 0) + return; + gso_segs = DIV_ROUND_UP(payload, shinfo->gso_size); + } qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len; } } -- 2.43.0