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121d57af30
Validate gso_type during segmentation as SKB_GSO_DODGY sources
may pass packets where the gso_type does not match the contents.
Syzkaller was able to enter the SCTP gso handler with a packet of
gso_type SKB_GSO_TCPV4.
On entry of transport layer gso handlers, verify that the gso_type
matches the transport protocol.
Fixes: 90017accff ("sctp: Add GSO support")
Link: http://lkml.kernel.org/r/<001a1137452496ffc305617e5fe0@google.com>
Reported-by: syzbot+fee64147a25aecd48055@syzkaller.appspotmail.com
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
130 lines
3.0 KiB
C
130 lines
3.0 KiB
C
/*
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* sctp_offload - GRO/GSO Offloading for SCTP
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*
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* Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/socket.h>
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#include <linux/sctp.h>
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#include <linux/proc_fs.h>
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/kfifo.h>
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#include <linux/time.h>
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#include <net/net_namespace.h>
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#include <linux/skbuff.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/checksum.h>
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#include <net/protocol.h>
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static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
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{
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skb->ip_summed = CHECKSUM_NONE;
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skb->csum_not_inet = 0;
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return sctp_compute_cksum(skb, skb_transport_offset(skb));
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}
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static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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struct sctphdr *sh;
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP))
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goto out;
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sh = sctp_hdr(skb);
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if (!pskb_may_pull(skb, sizeof(*sh)))
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goto out;
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__skb_pull(skb, sizeof(*sh));
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
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/* Packet is from an untrusted source, reset gso_segs. */
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struct skb_shared_info *pinfo = skb_shinfo(skb);
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struct sk_buff *frag_iter;
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pinfo->gso_segs = 0;
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if (skb->len != skb->data_len) {
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/* Means we have chunks in here too */
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pinfo->gso_segs++;
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}
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skb_walk_frags(skb, frag_iter)
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pinfo->gso_segs++;
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segs = NULL;
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goto out;
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}
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segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
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if (IS_ERR(segs))
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goto out;
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/* All that is left is update SCTP CRC if necessary */
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if (!(features & NETIF_F_SCTP_CRC)) {
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for (skb = segs; skb; skb = skb->next) {
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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sh = sctp_hdr(skb);
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sh->checksum = sctp_gso_make_checksum(skb);
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}
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}
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}
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out:
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return segs;
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}
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static const struct net_offload sctp_offload = {
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.callbacks = {
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.gso_segment = sctp_gso_segment,
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},
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};
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static const struct net_offload sctp6_offload = {
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.callbacks = {
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.gso_segment = sctp_gso_segment,
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},
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};
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static const struct skb_checksum_ops crc32c_csum_ops = {
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.update = sctp_csum_update,
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.combine = sctp_csum_combine,
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};
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int __init sctp_offload_init(void)
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{
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int ret;
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ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
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if (ret)
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goto out;
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ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
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if (ret)
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goto ipv4;
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crc32c_csum_stub = &crc32c_csum_ops;
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return ret;
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ipv4:
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inet_del_offload(&sctp_offload, IPPROTO_SCTP);
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out:
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return ret;
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}
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