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Tsirkin" To: linux-kernel@vger.kernel.org Cc: Willem de Bruijn , Chris Arges , =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , Phil Sutter , Jason Wang , Eugenio =?utf-8?B?UMOpcmV6?= , Xuan Zhuo , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, virtualization@lists.linux.dev, Max Krasnyansky , Rusty Russell Subject: [PATCH net v5 3/7] virtio_net: parse tunnel csum_start little-endian Message-ID: References: X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.51.2.2891.g4157995a80.dirty X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: -zinDGU1XSMP38Ke0Q-GlMa3WnLg3TuYpojUgv7FWtg_1792673899 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline All tunnel related virtio features are > 32, so none of this functionality can be enabled on legacy mixed-endian device. Accordingly, all tunnel header fields, csum_start included, are little-endian. The nested virtio net header import parses csum_start that way, but the inner transport offset is parsed with the endianness specified by the interface. If tun is misconfigured to legacy big-endian mode while the tunnel features are enabled, the two parses of this field disagree, and the value stored in skb->inner_transport_header - which is only bounds-checked from below - can point past the end of the packet, where GSO segmentation later dereferences it. To fix, parse the field little-endian in both places. Fixes: a2fb4bc4e2a6 ("net: implement virtio helpers to handle UDP GSO tunneling.") Cc: Paolo Abeni Signed-off-by: Michael S. Tsirkin --- include/linux/virtio_net.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index d6466f96cdd0..013c6c7e2dea 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -324,7 +324,7 @@ virtio_net_hdr_tnl_to_skb(struct sk_buff *skb, inner_l3min = virtio_l3min(inner_isv6); outer_l3min = ETH_HLEN + virtio_l3min(outer_isv6); - inner_th = __virtio16_to_cpu(little_endian, hdr->csum_start); + inner_th = __virtio16_to_cpu(true, hdr->csum_start); inner_nh = le16_to_cpu(vhdr->inner_nh_offset); outer_th = le16_to_cpu(vhdr->outer_th_offset); if (outer_th < outer_l3min || -- MST