linux/net/ipv6/ip6_offload.c
Artem Savkov 6b6ebb6b01 ip6_offload: check segs for NULL in ipv6_gso_segment.
segs needs to be checked for being NULL in ipv6_gso_segment() before calling
skb_shinfo(segs), otherwise kernel can run into a NULL-pointer dereference:

[   97.811262] BUG: unable to handle kernel NULL pointer dereference at 00000000000000cc
[   97.819112] IP: [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0
[   97.825214] PGD 0 [   97.827047]
[   97.828540] Oops: 0000 [#1] SMP
[   97.831678] Modules linked in: vhost_net vhost macvtap macvlan nfsv3 rpcsec_gss_krb5
nfsv4 dns_resolver nfs fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4
iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack
ipt_REJECT nf_reject_ipv4 tun ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter
bridge stp llc snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic snd_hda_intel
snd_hda_codec edac_mce_amd snd_hda_core edac_core snd_hwdep kvm_amd snd_seq kvm snd_seq_device
snd_pcm irqbypass snd_timer ppdev parport_serial snd parport_pc k10temp pcspkr soundcore parport
sp5100_tco shpchp sg wmi i2c_piix4 acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc
ip_tables xfs libcrc32c sr_mod cdrom sd_mod ata_generic pata_acpi amdkfd amd_iommu_v2 radeon
broadcom bcm_phy_lib i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
ttm ahci serio_raw tg3 firewire_ohci libahci pata_atiixp drm ptp libata firewire_core pps_core
i2c_core crc_itu_t fjes dm_mirror dm_region_hash dm_log dm_mod
[   97.927721] CPU: 1 PID: 3504 Comm: vhost-3495 Not tainted 4.9.0-7.el7.test.x86_64 #1
[   97.935457] Hardware name: AMD Snook/Snook, BIOS ESK0726A 07/26/2010
[   97.941806] task: ffff880129a1c080 task.stack: ffffc90001bcc000
[   97.947720] RIP: 0010:[<ffffffff816e52f9>]  [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0
[   97.956251] RSP: 0018:ffff88012fc43a10  EFLAGS: 00010207
[   97.961557] RAX: 0000000000000000 RBX: ffff8801292c8700 RCX: 0000000000000594
[   97.968687] RDX: 0000000000000593 RSI: ffff880129a846c0 RDI: 0000000000240000
[   97.975814] RBP: ffff88012fc43a68 R08: ffff880129a8404e R09: 0000000000000000
[   97.982942] R10: 0000000000000000 R11: ffff880129a84076 R12: 00000020002949b3
[   97.990070] R13: ffff88012a580000 R14: 0000000000000000 R15: ffff88012a580000
[   97.997198] FS:  0000000000000000(0000) GS:ffff88012fc40000(0000) knlGS:0000000000000000
[   98.005280] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   98.011021] CR2: 00000000000000cc CR3: 0000000126c5d000 CR4: 00000000000006e0
[   98.018149] Stack:
[   98.020157]  00000000ffffffff ffff88012fc43ac8 ffffffffa017ad0a 000000000000000e
[   98.027584]  0000001300000000 0000000077d59998 ffff8801292c8700 00000020002949b3
[   98.035010]  ffff88012a580000 0000000000000000 ffff88012a580000 ffff88012fc43a98
[   98.042437] Call Trace:
[   98.044879]  <IRQ> [   98.046803]  [<ffffffffa017ad0a>] ? tg3_start_xmit+0x84a/0xd60 [tg3]
[   98.053156]  [<ffffffff815eeee0>] skb_mac_gso_segment+0xb0/0x130
[   98.059158]  [<ffffffff815eefd3>] __skb_gso_segment+0x73/0x110
[   98.064985]  [<ffffffff815ef40d>] validate_xmit_skb+0x12d/0x2b0
[   98.070899]  [<ffffffff815ef5d2>] validate_xmit_skb_list+0x42/0x70
[   98.077073]  [<ffffffff81618560>] sch_direct_xmit+0xd0/0x1b0
[   98.082726]  [<ffffffff815efd86>] __dev_queue_xmit+0x486/0x690
[   98.088554]  [<ffffffff8135c135>] ? cpumask_next_and+0x35/0x50
[   98.094380]  [<ffffffff815effa0>] dev_queue_xmit+0x10/0x20
[   98.099863]  [<ffffffffa09ce057>] br_dev_queue_push_xmit+0xa7/0x170 [bridge]
[   98.106907]  [<ffffffffa09ce161>] br_forward_finish+0x41/0xc0 [bridge]
[   98.113430]  [<ffffffff81627cf2>] ? nf_iterate+0x52/0x60
[   98.118735]  [<ffffffff81627d6b>] ? nf_hook_slow+0x6b/0xc0
[   98.124216]  [<ffffffffa09ce32c>] __br_forward+0x14c/0x1e0 [bridge]
[   98.130480]  [<ffffffffa09ce120>] ? br_dev_queue_push_xmit+0x170/0x170 [bridge]
[   98.137785]  [<ffffffffa09ce4bd>] br_forward+0x9d/0xb0 [bridge]
[   98.143701]  [<ffffffffa09cfbb7>] br_handle_frame_finish+0x267/0x560 [bridge]
[   98.150834]  [<ffffffffa09d0064>] br_handle_frame+0x174/0x2f0 [bridge]
[   98.157355]  [<ffffffff8102fb89>] ? sched_clock+0x9/0x10
[   98.162662]  [<ffffffff810b63b2>] ? sched_clock_cpu+0x72/0xa0
[   98.168403]  [<ffffffff815eccf5>] __netif_receive_skb_core+0x1e5/0xa20
[   98.174926]  [<ffffffff813659f9>] ? timerqueue_add+0x59/0xb0
[   98.180580]  [<ffffffff815ed548>] __netif_receive_skb+0x18/0x60
[   98.186494]  [<ffffffff815ee625>] process_backlog+0x95/0x140
[   98.192145]  [<ffffffff815edccd>] net_rx_action+0x16d/0x380
[   98.197713]  [<ffffffff8170cff1>] __do_softirq+0xd1/0x283
[   98.203106]  [<ffffffff8170b2bc>] do_softirq_own_stack+0x1c/0x30
[   98.209107]  <EOI> [   98.211029]  [<ffffffff8108a5c0>] do_softirq+0x50/0x60
[   98.216166]  [<ffffffff815ec853>] netif_rx_ni+0x33/0x80
[   98.221386]  [<ffffffffa09eeff7>] tun_get_user+0x487/0x7f0 [tun]
[   98.227388]  [<ffffffffa09ef3ab>] tun_sendmsg+0x4b/0x60 [tun]
[   98.233129]  [<ffffffffa0b68932>] handle_tx+0x282/0x540 [vhost_net]
[   98.239392]  [<ffffffffa0b68c25>] handle_tx_kick+0x15/0x20 [vhost_net]
[   98.245916]  [<ffffffffa0abacfe>] vhost_worker+0x9e/0xf0 [vhost]
[   98.251919]  [<ffffffffa0abac60>] ? vhost_umem_alloc+0x40/0x40 [vhost]
[   98.258440]  [<ffffffff81003a47>] ? do_syscall_64+0x67/0x180
[   98.264094]  [<ffffffff810a44d9>] kthread+0xd9/0xf0
[   98.268965]  [<ffffffff810a4400>] ? kthread_park+0x60/0x60
[   98.274444]  [<ffffffff8170a4d5>] ret_from_fork+0x25/0x30
[   98.279836] Code: 8b 93 d8 00 00 00 48 2b 93 d0 00 00 00 4c 89 e6 48 89 df 66 89 93 c2 00 00 00 ff 10 48 3d 00 f0 ff ff 49 89 c2 0f 87 52 01 00 00 <41> 8b 92 cc 00 00 00 48 8b 80 d0 00 00 00 44 0f b7 74 10 06 66
[   98.299425] RIP  [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0
[   98.305612]  RSP <ffff88012fc43a10>
[   98.309094] CR2: 00000000000000cc
[   98.312406] ---[ end trace 726a2c7a2d2d78d0 ]---

Signed-off-by: Artem Savkov <asavkov@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-02 13:34:58 -05:00

386 lines
9.3 KiB
C

/*
* IPV6 GSO/GRO offload support
* Linux INET6 implementation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/socket.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/printk.h>
#include <net/protocol.h>
#include <net/ipv6.h>
#include <net/inet_common.h>
#include "ip6_offload.h"
static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
{
const struct net_offload *ops = NULL;
for (;;) {
struct ipv6_opt_hdr *opth;
int len;
if (proto != NEXTHDR_HOP) {
ops = rcu_dereference(inet6_offloads[proto]);
if (unlikely(!ops))
break;
if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
break;
}
if (unlikely(!pskb_may_pull(skb, 8)))
break;
opth = (void *)skb->data;
len = ipv6_optlen(opth);
if (unlikely(!pskb_may_pull(skb, len)))
break;
opth = (void *)skb->data;
proto = opth->nexthdr;
__skb_pull(skb, len);
}
return proto;
}
static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct ipv6hdr *ipv6h;
const struct net_offload *ops;
int proto;
struct frag_hdr *fptr;
unsigned int unfrag_ip6hlen;
unsigned int payload_len;
u8 *prevhdr;
int offset = 0;
bool encap, udpfrag;
int nhoff;
bool gso_partial;
skb_reset_network_header(skb);
nhoff = skb_network_header(skb) - skb_mac_header(skb);
if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
goto out;
encap = SKB_GSO_CB(skb)->encap_level > 0;
if (encap)
features &= skb->dev->hw_enc_features;
SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
ipv6h = ipv6_hdr(skb);
__skb_pull(skb, sizeof(*ipv6h));
segs = ERR_PTR(-EPROTONOSUPPORT);
proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
if (skb->encapsulation &&
skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
udpfrag = proto == IPPROTO_UDP && encap;
else
udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
ops = rcu_dereference(inet6_offloads[proto]);
if (likely(ops && ops->callbacks.gso_segment)) {
skb_reset_transport_header(skb);
segs = ops->callbacks.gso_segment(skb, features);
}
if (IS_ERR_OR_NULL(segs))
goto out;
gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
for (skb = segs; skb; skb = skb->next) {
ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
if (gso_partial)
payload_len = skb_shinfo(skb)->gso_size +
SKB_GSO_CB(skb)->data_offset +
skb->head - (unsigned char *)(ipv6h + 1);
else
payload_len = skb->len - nhoff - sizeof(*ipv6h);
ipv6h->payload_len = htons(payload_len);
skb->network_header = (u8 *)ipv6h - skb->head;
if (udpfrag) {
unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
fptr->frag_off = htons(offset);
if (skb->next)
fptr->frag_off |= htons(IP6_MF);
offset += (ntohs(ipv6h->payload_len) -
sizeof(struct frag_hdr));
}
if (encap)
skb_reset_inner_headers(skb);
}
out:
return segs;
}
/* Return the total length of all the extension hdrs, following the same
* logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
*/
static int ipv6_exthdrs_len(struct ipv6hdr *iph,
const struct net_offload **opps)
{
struct ipv6_opt_hdr *opth = (void *)iph;
int len = 0, proto, optlen = sizeof(*iph);
proto = iph->nexthdr;
for (;;) {
if (proto != NEXTHDR_HOP) {
*opps = rcu_dereference(inet6_offloads[proto]);
if (unlikely(!(*opps)))
break;
if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
break;
}
opth = (void *)opth + optlen;
optlen = ipv6_optlen(opth);
len += optlen;
proto = opth->nexthdr;
}
return len;
}
static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
const struct net_offload *ops;
struct sk_buff **pp = NULL;
struct sk_buff *p;
struct ipv6hdr *iph;
unsigned int nlen;
unsigned int hlen;
unsigned int off;
u16 flush = 1;
int proto;
off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
iph = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
iph = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!iph))
goto out;
}
skb_set_network_header(skb, off);
skb_gro_pull(skb, sizeof(*iph));
skb_set_transport_header(skb, skb_gro_offset(skb));
flush += ntohs(iph->payload_len) != skb_gro_len(skb);
rcu_read_lock();
proto = iph->nexthdr;
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive) {
__pskb_pull(skb, skb_gro_offset(skb));
proto = ipv6_gso_pull_exthdrs(skb, proto);
skb_gro_pull(skb, -skb_transport_offset(skb));
skb_reset_transport_header(skb);
__skb_push(skb, skb_gro_offset(skb));
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive)
goto out_unlock;
iph = ipv6_hdr(skb);
}
NAPI_GRO_CB(skb)->proto = proto;
flush--;
nlen = skb_network_header_len(skb);
for (p = *head; p; p = p->next) {
const struct ipv6hdr *iph2;
__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
if (!NAPI_GRO_CB(p)->same_flow)
continue;
iph2 = (struct ipv6hdr *)(p->data + off);
first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
/* All fields must match except length and Traffic Class.
* XXX skbs on the gro_list have all been parsed and pulled
* already so we don't need to compare nlen
* (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
* memcmp() alone below is suffcient, right?
*/
if ((first_word & htonl(0xF00FFFFF)) ||
memcmp(&iph->nexthdr, &iph2->nexthdr,
nlen - offsetof(struct ipv6hdr, nexthdr))) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
/* flush if Traffic Class fields are different */
NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
NAPI_GRO_CB(p)->flush |= flush;
/* If the previous IP ID value was based on an atomic
* datagram we can overwrite the value and ignore it.
*/
if (NAPI_GRO_CB(skb)->is_atomic)
NAPI_GRO_CB(p)->flush_id = 0;
}
NAPI_GRO_CB(skb)->is_atomic = true;
NAPI_GRO_CB(skb)->flush |= flush;
skb_gro_postpull_rcsum(skb, iph, nlen);
pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
out_unlock:
rcu_read_unlock();
out:
NAPI_GRO_CB(skb)->flush |= flush;
return pp;
}
static struct sk_buff **sit_ip6ip6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
/* Common GRO receive for SIT and IP6IP6 */
if (NAPI_GRO_CB(skb)->encap_mark) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
NAPI_GRO_CB(skb)->encap_mark = 1;
return ipv6_gro_receive(head, skb);
}
static struct sk_buff **ip4ip6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
/* Common GRO receive for SIT and IP6IP6 */
if (NAPI_GRO_CB(skb)->encap_mark) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
NAPI_GRO_CB(skb)->encap_mark = 1;
return inet_gro_receive(head, skb);
}
static int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct net_offload *ops;
struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
int err = -ENOSYS;
if (skb->encapsulation)
skb_set_inner_network_header(skb, nhoff);
iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
rcu_read_lock();
nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out_unlock;
err = ops->callbacks.gro_complete(skb, nhoff);
out_unlock:
rcu_read_unlock();
return err;
}
static int sit_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
return ipv6_gro_complete(skb, nhoff);
}
static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
return ipv6_gro_complete(skb, nhoff);
}
static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
return inet_gro_complete(skb, nhoff);
}
static struct packet_offload ipv6_packet_offload __read_mostly = {
.type = cpu_to_be16(ETH_P_IPV6),
.callbacks = {
.gso_segment = ipv6_gso_segment,
.gro_receive = ipv6_gro_receive,
.gro_complete = ipv6_gro_complete,
},
};
static const struct net_offload sit_offload = {
.callbacks = {
.gso_segment = ipv6_gso_segment,
.gro_receive = sit_ip6ip6_gro_receive,
.gro_complete = sit_gro_complete,
},
};
static const struct net_offload ip4ip6_offload = {
.callbacks = {
.gso_segment = inet_gso_segment,
.gro_receive = ip4ip6_gro_receive,
.gro_complete = ip4ip6_gro_complete,
},
};
static const struct net_offload ip6ip6_offload = {
.callbacks = {
.gso_segment = ipv6_gso_segment,
.gro_receive = sit_ip6ip6_gro_receive,
.gro_complete = ip6ip6_gro_complete,
},
};
static int __init ipv6_offload_init(void)
{
if (tcpv6_offload_init() < 0)
pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
if (ipv6_exthdrs_offload_init() < 0)
pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
dev_add_offload(&ipv6_packet_offload);
inet_add_offload(&sit_offload, IPPROTO_IPV6);
inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
return 0;
}
fs_initcall(ipv6_offload_init);