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remarkable-linux/net/netfilter/nfnetlink_queue_core.c
Daniel Borkmann 6bb0fef489 netlink, mmap: fix edge-case leakages in nf queue zero-copy 
When netlink mmap on receive side is the consumer of nf queue data,
it can happen that in some edge cases, we write skb shared info into
the user space mmap buffer:

Assume a possible rx ring frame size of only 4096, and the network skb,
which is being zero-copied into the netlink skb, contains page frags
with an overall skb->len larger than the linear part of the netlink
skb.

skb_zerocopy(), which is generic and thus not aware of the fact that
shared info cannot be accessed for such skbs then tries to write and
fill frags, thus leaking kernel data/pointers and in some corner cases
possibly writing out of bounds of the mmap area (when filling the
last slot in the ring buffer this way).

I.e. the ring buffer slot is then of status NL_MMAP_STATUS_VALID, has
an advertised length larger than 4096, where the linear part is visible
at the slot beginning, and the leaked sizeof(struct skb_shared_info)
has been written to the beginning of the next slot (also corrupting
the struct nl_mmap_hdr slot header incl. status etc), since skb->end
points to skb->data + ring->frame_size - NL_MMAP_HDRLEN.

The fix adds and lets __netlink_alloc_skb() take the actual needed
linear room for the network skb + meta data into account. It's completely
irrelevant for non-mmaped netlink sockets, but in case mmap sockets
are used, it can be decided whether the available skb_tailroom() is
really large enough for the buffer, or whether it needs to internally
fallback to a normal alloc_skb().

>From nf queue side, the information whether the destination port is
an mmap RX ring is not really available without extra port-to-socket
lookup, thus it can only be determined in lower layers i.e. when
__netlink_alloc_skb() is called that checks internally for this. I
chose to add the extra ldiff parameter as mmap will then still work:
We have data_len and hlen in nfqnl_build_packet_message(), data_len
is the full length (capped at queue->copy_range) for skb_zerocopy()
and hlen some possible part of data_len that needs to be copied; the
rem_len variable indicates the needed remaining linear mmap space.

The only other workaround in nf queue internally would be after
allocation time by f.e. cap'ing the data_len to the skb_tailroom()
iff we deal with an mmap skb, but that would 1) expose the fact that
we use a mmap skb to upper layers, and 2) trim the skb where we
otherwise could just have moved the full skb into the normal receive
queue.

After the patch, in my test case the ring slot doesn't fit and therefore
shows NL_MMAP_STATUS_COPY, where a full skb carries all the data and
thus needs to be picked up via recv().

Fixes: 3ab1f683bf ("nfnetlink: add support for memory mapped netlink")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-09 21:43:22 -07:00

1417 lines
34 KiB
C
Raw Blame History

/*
* This is a module which is used for queueing packets and communicating with
* userspace via nfnetlink.
*
* (C) 2005 by Harald Welte <laforge@netfilter.org>
* (C) 2007 by Patrick McHardy <kaber@trash.net>
*
* Based on the old ipv4-only ip_queue.c:
* (C) 2000-2002 James Morris <jmorris@intercode.com.au>
* (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/proc_fs.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <linux/list.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/netfilter/nf_queue.h>
#include <net/netns/generic.h>
#include <net/netfilter/nfnetlink_queue.h>
#include <linux/atomic.h>
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
#include "../bridge/br_private.h"
#endif
#define NFQNL_QMAX_DEFAULT 1024
/* We're using struct nlattr which has 16bit nla_len. Note that nla_len
* includes the header length. Thus, the maximum packet length that we
* support is 65531 bytes. We send truncated packets if the specified length
* is larger than that. Userspace can check for presence of NFQA_CAP_LEN
* attribute to detect truncation.
*/
#define NFQNL_MAX_COPY_RANGE (0xffff - NLA_HDRLEN)
struct nfqnl_instance {
struct hlist_node hlist; /* global list of queues */
struct rcu_head rcu;
u32 peer_portid;
unsigned int queue_maxlen;
unsigned int copy_range;
unsigned int queue_dropped;
unsigned int queue_user_dropped;
u_int16_t queue_num; /* number of this queue */
u_int8_t copy_mode;
u_int32_t flags; /* Set using NFQA_CFG_FLAGS */
/*
* Following fields are dirtied for each queued packet,
* keep them in same cache line if possible.
*/
spinlock_t lock;
unsigned int queue_total;
unsigned int id_sequence; /* 'sequence' of pkt ids */
struct list_head queue_list; /* packets in queue */
};
typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long);
static int nfnl_queue_net_id __read_mostly;
#define INSTANCE_BUCKETS 16
struct nfnl_queue_net {
spinlock_t instances_lock;
struct hlist_head instance_table[INSTANCE_BUCKETS];
};
static struct nfnl_queue_net *nfnl_queue_pernet(struct net *net)
{
return net_generic(net, nfnl_queue_net_id);
}
static inline u_int8_t instance_hashfn(u_int16_t queue_num)
{
return ((queue_num >> 8) ^ queue_num) % INSTANCE_BUCKETS;
}
static struct nfqnl_instance *
instance_lookup(struct nfnl_queue_net *q, u_int16_t queue_num)
{
struct hlist_head *head;
struct nfqnl_instance *inst;
head = &q->instance_table[instance_hashfn(queue_num)];
hlist_for_each_entry_rcu(inst, head, hlist) {
if (inst->queue_num == queue_num)
return inst;
}
return NULL;
}
static struct nfqnl_instance *
instance_create(struct nfnl_queue_net *q, u_int16_t queue_num, u32 portid)
{
struct nfqnl_instance *inst;
unsigned int h;
int err;
spin_lock(&q->instances_lock);
if (instance_lookup(q, queue_num)) {
err = -EEXIST;
goto out_unlock;
}
inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
if (!inst) {
err = -ENOMEM;
goto out_unlock;
}
inst->queue_num = queue_num;
inst->peer_portid = portid;
inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
inst->copy_range = NFQNL_MAX_COPY_RANGE;
inst->copy_mode = NFQNL_COPY_NONE;
spin_lock_init(&inst->lock);
INIT_LIST_HEAD(&inst->queue_list);
if (!try_module_get(THIS_MODULE)) {
err = -EAGAIN;
goto out_free;
}
h = instance_hashfn(queue_num);
hlist_add_head_rcu(&inst->hlist, &q->instance_table[h]);
spin_unlock(&q->instances_lock);
return inst;
out_free:
kfree(inst);
out_unlock:
spin_unlock(&q->instances_lock);
return ERR_PTR(err);
}
static void nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn,
unsigned long data);
static void
instance_destroy_rcu(struct rcu_head *head)
{
struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
rcu);
nfqnl_flush(inst, NULL, 0);
kfree(inst);
module_put(THIS_MODULE);
}
static void
__instance_destroy(struct nfqnl_instance *inst)
{
hlist_del_rcu(&inst->hlist);
call_rcu(&inst->rcu, instance_destroy_rcu);
}
static void
instance_destroy(struct nfnl_queue_net *q, struct nfqnl_instance *inst)
{
spin_lock(&q->instances_lock);
__instance_destroy(inst);
spin_unlock(&q->instances_lock);
}
static inline void
__enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
list_add_tail(&entry->list, &queue->queue_list);
queue->queue_total++;
}
static void
__dequeue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
list_del(&entry->list);
queue->queue_total--;
}
static struct nf_queue_entry *
find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id)
{
struct nf_queue_entry *entry = NULL, *i;
spin_lock_bh(&queue->lock);
list_for_each_entry(i, &queue->queue_list, list) {
if (i->id == id) {
entry = i;
break;
}
}
if (entry)
__dequeue_entry(queue, entry);
spin_unlock_bh(&queue->lock);
return entry;
}
static void
nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data)
{
struct nf_queue_entry *entry, *next;
spin_lock_bh(&queue->lock);
list_for_each_entry_safe(entry, next, &queue->queue_list, list) {
if (!cmpfn || cmpfn(entry, data)) {
list_del(&entry->list);
queue->queue_total--;
nf_reinject(entry, NF_DROP);
}
}
spin_unlock_bh(&queue->lock);
}
static int
nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet,
bool csum_verify)
{
__u32 flags = 0;
if (packet->ip_summed == CHECKSUM_PARTIAL)
flags = NFQA_SKB_CSUMNOTREADY;
else if (csum_verify)
flags = NFQA_SKB_CSUM_NOTVERIFIED;
if (skb_is_gso(packet))
flags |= NFQA_SKB_GSO;
return flags ? nla_put_be32(nlskb, NFQA_SKB_INFO, htonl(flags)) : 0;
}
static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk)
{
const struct cred *cred;
if (!sk_fullsock(sk))
return 0;
read_lock_bh(&sk->sk_callback_lock);
if (sk->sk_socket && sk->sk_socket->file) {
cred = sk->sk_socket->file->f_cred;
if (nla_put_be32(skb, NFQA_UID,
htonl(from_kuid_munged(&init_user_ns, cred->fsuid))))
goto nla_put_failure;
if (nla_put_be32(skb, NFQA_GID,
htonl(from_kgid_munged(&init_user_ns, cred->fsgid))))
goto nla_put_failure;
}
read_unlock_bh(&sk->sk_callback_lock);
return 0;
nla_put_failure:
read_unlock_bh(&sk->sk_callback_lock);
return -1;
}
static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
{
u32 seclen = 0;
#if IS_ENABLED(CONFIG_NETWORK_SECMARK)
if (!skb || !sk_fullsock(skb->sk))
return 0;
read_lock_bh(&skb->sk->sk_callback_lock);
if (skb->secmark)
security_secid_to_secctx(skb->secmark, secdata, &seclen);
read_unlock_bh(&skb->sk->sk_callback_lock);
#endif
return seclen;
}
static struct sk_buff *
nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
struct nf_queue_entry *entry,
__be32 **packet_id_ptr)
{
size_t size;
size_t data_len = 0, cap_len = 0, rem_len = 0;
unsigned int hlen = 0;
struct sk_buff *skb;
struct nlattr *nla;
struct nfqnl_msg_packet_hdr *pmsg;
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
struct sk_buff *entskb = entry->skb;
struct net_device *indev;
struct net_device *outdev;
struct nf_conn *ct = NULL;
enum ip_conntrack_info uninitialized_var(ctinfo);
bool csum_verify;
char *secdata = NULL;
u32 seclen = 0;
size = nlmsg_total_size(sizeof(struct nfgenmsg))
+ nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
+ nla_total_size(sizeof(u_int32_t)) /* ifindex */
+ nla_total_size(sizeof(u_int32_t)) /* ifindex */
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
+ nla_total_size(sizeof(u_int32_t)) /* ifindex */
+ nla_total_size(sizeof(u_int32_t)) /* ifindex */
#endif
+ nla_total_size(sizeof(u_int32_t)) /* mark */
+ nla_total_size(sizeof(struct nfqnl_msg_packet_hw))
+ nla_total_size(sizeof(u_int32_t)) /* skbinfo */
+ nla_total_size(sizeof(u_int32_t)); /* cap_len */
if (entskb->tstamp.tv64)
size += nla_total_size(sizeof(struct nfqnl_msg_packet_timestamp));
if (entry->state.hook <= NF_INET_FORWARD ||
(entry->state.hook == NF_INET_POST_ROUTING && entskb->sk == NULL))
csum_verify = !skb_csum_unnecessary(entskb);
else
csum_verify = false;
outdev = entry->state.out;
switch ((enum nfqnl_config_mode)ACCESS_ONCE(queue->copy_mode)) {
case NFQNL_COPY_META:
case NFQNL_COPY_NONE:
break;
case NFQNL_COPY_PACKET:
if (!(queue->flags & NFQA_CFG_F_GSO) &&
entskb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_help(entskb))
return NULL;
data_len = ACCESS_ONCE(queue->copy_range);
if (data_len > entskb->len)
data_len = entskb->len;
hlen = skb_zerocopy_headlen(entskb);
hlen = min_t(unsigned int, hlen, data_len);
size += sizeof(struct nlattr) + hlen;
cap_len = entskb->len;
rem_len = data_len - hlen;
break;
}
if (queue->flags & NFQA_CFG_F_CONNTRACK)
ct = nfqnl_ct_get(entskb, &size, &ctinfo);
if (queue->flags & NFQA_CFG_F_UID_GID) {
size += (nla_total_size(sizeof(u_int32_t)) /* uid */
+ nla_total_size(sizeof(u_int32_t))); /* gid */
}
if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) {
seclen = nfqnl_get_sk_secctx(entskb, &secdata);
if (seclen)
size += nla_total_size(seclen);
}
skb = __netlink_alloc_skb(net->nfnl, size, rem_len, queue->peer_portid,
GFP_ATOMIC);
if (!skb) {
skb_tx_error(entskb);
return NULL;
}
nlh = nlmsg_put(skb, 0, 0,
NFNL_SUBSYS_QUEUE << 8 | NFQNL_MSG_PACKET,
sizeof(struct nfgenmsg), 0);
if (!nlh) {
skb_tx_error(entskb);
kfree_skb(skb);
return NULL;
}
nfmsg = nlmsg_data(nlh);
nfmsg->nfgen_family = entry->state.pf;
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = htons(queue->queue_num);
nla = __nla_reserve(skb, NFQA_PACKET_HDR, sizeof(*pmsg));
pmsg = nla_data(nla);
pmsg->hw_protocol = entskb->protocol;
pmsg->hook = entry->state.hook;
*packet_id_ptr = &pmsg->packet_id;
indev = entry->state.in;
if (indev) {
#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
if (nla_put_be32(skb, NFQA_IFINDEX_INDEV, htonl(indev->ifindex)))
goto nla_put_failure;
#else
if (entry->state.pf == PF_BRIDGE) {
/* Case 1: indev is physical input device, we need to
* look for bridge group (when called from
* netfilter_bridge) */
if (nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV,
htonl(indev->ifindex)) ||
/* this is the bridge group "brX" */
/* rcu_read_lock()ed by __nf_queue */
nla_put_be32(skb, NFQA_IFINDEX_INDEV,
htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
goto nla_put_failure;
} else {
int physinif;
/* Case 2: indev is bridge group, we need to look for
* physical device (when called from ipv4) */
if (nla_put_be32(skb, NFQA_IFINDEX_INDEV,
htonl(indev->ifindex)))
goto nla_put_failure;
physinif = nf_bridge_get_physinif(entskb);
if (physinif &&
nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV,
htonl(physinif)))
goto nla_put_failure;
}
#endif
}
if (outdev) {
#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, htonl(outdev->ifindex)))
goto nla_put_failure;
#else
if (entry->state.pf == PF_BRIDGE) {
/* Case 1: outdev is physical output device, we need to
* look for bridge group (when called from
* netfilter_bridge) */
if (nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV,
htonl(outdev->ifindex)) ||
/* this is the bridge group "brX" */
/* rcu_read_lock()ed by __nf_queue */
nla_put_be32(skb, NFQA_IFINDEX_OUTDEV,
htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
goto nla_put_failure;
} else {
int physoutif;
/* Case 2: outdev is bridge group, we need to look for
* physical output device (when called from ipv4) */
if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV,
htonl(outdev->ifindex)))
goto nla_put_failure;
physoutif = nf_bridge_get_physoutif(entskb);
if (physoutif &&
nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV,
htonl(physoutif)))
goto nla_put_failure;
}
#endif
}
if (entskb->mark &&
nla_put_be32(skb, NFQA_MARK, htonl(entskb->mark)))
goto nla_put_failure;
if (indev && entskb->dev &&
entskb->mac_header != entskb->network_header) {
struct nfqnl_msg_packet_hw phw;
int len;
memset(&phw, 0, sizeof(phw));
len = dev_parse_header(entskb, phw.hw_addr);
if (len) {
phw.hw_addrlen = htons(len);
if (nla_put(skb, NFQA_HWADDR, sizeof(phw), &phw))
goto nla_put_failure;
}
}
if (entskb->tstamp.tv64) {
struct nfqnl_msg_packet_timestamp ts;
struct timeval tv = ktime_to_timeval(entskb->tstamp);
ts.sec = cpu_to_be64(tv.tv_sec);
ts.usec = cpu_to_be64(tv.tv_usec);
if (nla_put(skb, NFQA_TIMESTAMP, sizeof(ts), &ts))
goto nla_put_failure;
}
if ((queue->flags & NFQA_CFG_F_UID_GID) && entskb->sk &&
nfqnl_put_sk_uidgid(skb, entskb->sk) < 0)
goto nla_put_failure;
if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata))
goto nla_put_failure;
if (ct && nfqnl_ct_put(skb, ct, ctinfo) < 0)
goto nla_put_failure;
if (cap_len > data_len &&
nla_put_be32(skb, NFQA_CAP_LEN, htonl(cap_len)))
goto nla_put_failure;
if (nfqnl_put_packet_info(skb, entskb, csum_verify))
goto nla_put_failure;
if (data_len) {
struct nlattr *nla;
if (skb_tailroom(skb) < sizeof(*nla) + hlen)
goto nla_put_failure;
nla = (struct nlattr *)skb_put(skb, sizeof(*nla));
nla->nla_type = NFQA_PAYLOAD;
nla->nla_len = nla_attr_size(data_len);
if (skb_zerocopy(skb, entskb, data_len, hlen))
goto nla_put_failure;
}
nlh->nlmsg_len = skb->len;
return skb;
nla_put_failure:
skb_tx_error(entskb);
kfree_skb(skb);
net_err_ratelimited("nf_queue: error creating packet message\n");
return NULL;
}
static int
__nfqnl_enqueue_packet(struct net *net, struct nfqnl_instance *queue,
struct nf_queue_entry *entry)
{
struct sk_buff *nskb;
int err = -ENOBUFS;
__be32 *packet_id_ptr;
int failopen = 0;
nskb = nfqnl_build_packet_message(net, queue, entry, &packet_id_ptr);
if (nskb == NULL) {
err = -ENOMEM;
goto err_out;
}
spin_lock_bh(&queue->lock);
if (queue->queue_total >= queue->queue_maxlen) {
if (queue->flags & NFQA_CFG_F_FAIL_OPEN) {
failopen = 1;
err = 0;
} else {
queue->queue_dropped++;
net_warn_ratelimited("nf_queue: full at %d entries, dropping packets(s)\n",
queue->queue_total);
}
goto err_out_free_nskb;
}
entry->id = ++queue->id_sequence;
*packet_id_ptr = htonl(entry->id);
/* nfnetlink_unicast will either free the nskb or add it to a socket */
err = nfnetlink_unicast(nskb, net, queue->peer_portid, MSG_DONTWAIT);
if (err < 0) {
queue->queue_user_dropped++;
goto err_out_unlock;
}
__enqueue_entry(queue, entry);
spin_unlock_bh(&queue->lock);
return 0;
err_out_free_nskb:
kfree_skb(nskb);
err_out_unlock:
spin_unlock_bh(&queue->lock);
if (failopen)
nf_reinject(entry, NF_ACCEPT);
err_out:
return err;
}
static struct nf_queue_entry *
nf_queue_entry_dup(struct nf_queue_entry *e)
{
struct nf_queue_entry *entry = kmemdup(e, e->size, GFP_ATOMIC);
if (entry) {
if (nf_queue_entry_get_refs(entry))
return entry;
kfree(entry);
}
return NULL;
}
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
/* When called from bridge netfilter, skb->data must point to MAC header
* before calling skb_gso_segment(). Else, original MAC header is lost
* and segmented skbs will be sent to wrong destination.
*/
static void nf_bridge_adjust_skb_data(struct sk_buff *skb)
{
if (skb->nf_bridge)
__skb_push(skb, skb->network_header - skb->mac_header);
}
static void nf_bridge_adjust_segmented_data(struct sk_buff *skb)
{
if (skb->nf_bridge)
__skb_pull(skb, skb->network_header - skb->mac_header);
}
#else
#define nf_bridge_adjust_skb_data(s) do {} while (0)
#define nf_bridge_adjust_segmented_data(s) do {} while (0)
#endif
static void free_entry(struct nf_queue_entry *entry)
{
nf_queue_entry_release_refs(entry);
kfree(entry);
}
static int
__nfqnl_enqueue_packet_gso(struct net *net, struct nfqnl_instance *queue,
struct sk_buff *skb, struct nf_queue_entry *entry)
{
int ret = -ENOMEM;
struct nf_queue_entry *entry_seg;
nf_bridge_adjust_segmented_data(skb);
if (skb->next == NULL) { /* last packet, no need to copy entry */
struct sk_buff *gso_skb = entry->skb;
entry->skb = skb;
ret = __nfqnl_enqueue_packet(net, queue, entry);
if (ret)
entry->skb = gso_skb;
return ret;
}
skb->next = NULL;
entry_seg = nf_queue_entry_dup(entry);
if (entry_seg) {
entry_seg->skb = skb;
ret = __nfqnl_enqueue_packet(net, queue, entry_seg);
if (ret)
free_entry(entry_seg);
}
return ret;
}
static int
nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
unsigned int queued;
struct nfqnl_instance *queue;
struct sk_buff *skb, *segs;
int err = -ENOBUFS;
struct net *net = dev_net(entry->state.in ?
entry->state.in : entry->state.out);
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
/* rcu_read_lock()ed by nf_hook_slow() */
queue = instance_lookup(q, queuenum);
if (!queue)
return -ESRCH;
if (queue->copy_mode == NFQNL_COPY_NONE)
return -EINVAL;
skb = entry->skb;
switch (entry->state.pf) {
case NFPROTO_IPV4:
skb->protocol = htons(ETH_P_IP);
break;
case NFPROTO_IPV6:
skb->protocol = htons(ETH_P_IPV6);
break;
}
if ((queue->flags & NFQA_CFG_F_GSO) || !skb_is_gso(skb))
return __nfqnl_enqueue_packet(net, queue, entry);
nf_bridge_adjust_skb_data(skb);
segs = skb_gso_segment(skb, 0);
/* Does not use PTR_ERR to limit the number of error codes that can be
* returned by nf_queue. For instance, callers rely on -ECANCELED to
* mean 'ignore this hook'.
*/
if (IS_ERR_OR_NULL(segs))
goto out_err;
queued = 0;
err = 0;
do {
struct sk_buff *nskb = segs->next;
if (err == 0)
err = __nfqnl_enqueue_packet_gso(net, queue,
segs, entry);
if (err == 0)
queued++;
else
kfree_skb(segs);
segs = nskb;
} while (segs);
if (queued) {
if (err) /* some segments are already queued */
free_entry(entry);
kfree_skb(skb);
return 0;
}
out_err:
nf_bridge_adjust_segmented_data(skb);
return err;
}
static int
nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff)
{
struct sk_buff *nskb;
if (diff < 0) {
if (pskb_trim(e->skb, data_len))
return -ENOMEM;
} else if (diff > 0) {
if (data_len > 0xFFFF)
return -EINVAL;
if (diff > skb_tailroom(e->skb)) {
nskb = skb_copy_expand(e->skb, skb_headroom(e->skb),
diff, GFP_ATOMIC);
if (!nskb) {
printk(KERN_WARNING "nf_queue: OOM "
"in mangle, dropping packet\n");
return -ENOMEM;
}
kfree_skb(e->skb);
e->skb = nskb;
}
skb_put(e->skb, diff);
}
if (!skb_make_writable(e->skb, data_len))
return -ENOMEM;
skb_copy_to_linear_data(e->skb, data, data_len);
e->skb->ip_summed = CHECKSUM_NONE;
return 0;
}
static int
nfqnl_set_mode(struct nfqnl_instance *queue,
unsigned char mode, unsigned int range)
{
int status = 0;
spin_lock_bh(&queue->lock);
switch (mode) {
case NFQNL_COPY_NONE:
case NFQNL_COPY_META:
queue->copy_mode = mode;
queue->copy_range = 0;
break;
case NFQNL_COPY_PACKET:
queue->copy_mode = mode;
if (range == 0 || range > NFQNL_MAX_COPY_RANGE)
queue->copy_range = NFQNL_MAX_COPY_RANGE;
else
queue->copy_range = range;
break;
default:
status = -EINVAL;
}
spin_unlock_bh(&queue->lock);
return status;
}
static int
dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
{
if (entry->state.in)
if (entry->state.in->ifindex == ifindex)
return 1;
if (entry->state.out)
if (entry->state.out->ifindex == ifindex)
return 1;
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
if (entry->skb->nf_bridge) {
int physinif, physoutif;
physinif = nf_bridge_get_physinif(entry->skb);
physoutif = nf_bridge_get_physoutif(entry->skb);
if (physinif == ifindex || physoutif == ifindex)
return 1;
}
#endif
return 0;
}
/* drop all packets with either indev or outdev == ifindex from all queue
* instances */
static void
nfqnl_dev_drop(struct net *net, int ifindex)
{
int i;
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
rcu_read_lock();
for (i = 0; i < INSTANCE_BUCKETS; i++) {
struct nfqnl_instance *inst;
struct hlist_head *head = &q->instance_table[i];
hlist_for_each_entry_rcu(inst, head, hlist)
nfqnl_flush(inst, dev_cmp, ifindex);
}
rcu_read_unlock();
}
static int
nfqnl_rcv_dev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
/* Drop any packets associated with the downed device */
if (event == NETDEV_DOWN)
nfqnl_dev_drop(dev_net(dev), dev->ifindex);
return NOTIFY_DONE;
}
static struct notifier_block nfqnl_dev_notifier = {
.notifier_call = nfqnl_rcv_dev_event,
};
static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long ops_ptr)
{
return entry->elem == (struct nf_hook_ops *)ops_ptr;
}
static void nfqnl_nf_hook_drop(struct net *net, struct nf_hook_ops *hook)
{
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
int i;
rcu_read_lock();
for (i = 0; i < INSTANCE_BUCKETS; i++) {
struct nfqnl_instance *inst;
struct hlist_head *head = &q->instance_table[i];
hlist_for_each_entry_rcu(inst, head, hlist)
nfqnl_flush(inst, nf_hook_cmp, (unsigned long)hook);
}
rcu_read_unlock();
}
static int
nfqnl_rcv_nl_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct netlink_notify *n = ptr;
struct nfnl_queue_net *q = nfnl_queue_pernet(n->net);
if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
int i;
/* destroy all instances for this portid */
spin_lock(&q->instances_lock);
for (i = 0; i < INSTANCE_BUCKETS; i++) {
struct hlist_node *t2;
struct nfqnl_instance *inst;
struct hlist_head *head = &q->instance_table[i];
hlist_for_each_entry_safe(inst, t2, head, hlist) {
if (n->portid == inst->peer_portid)
__instance_destroy(inst);
}
}
spin_unlock(&q->instances_lock);
}
return NOTIFY_DONE;
}
static struct notifier_block nfqnl_rtnl_notifier = {
.notifier_call = nfqnl_rcv_nl_event,
};
static const struct nla_policy nfqa_verdict_policy[NFQA_MAX+1] = {
[NFQA_VERDICT_HDR] = { .len = sizeof(struct nfqnl_msg_verdict_hdr) },
[NFQA_MARK] = { .type = NLA_U32 },
[NFQA_PAYLOAD] = { .type = NLA_UNSPEC },
[NFQA_CT] = { .type = NLA_UNSPEC },
[NFQA_EXP] = { .type = NLA_UNSPEC },
};
static const struct nla_policy nfqa_verdict_batch_policy[NFQA_MAX+1] = {
[NFQA_VERDICT_HDR] = { .len = sizeof(struct nfqnl_msg_verdict_hdr) },
[NFQA_MARK] = { .type = NLA_U32 },
};
static struct nfqnl_instance *
verdict_instance_lookup(struct nfnl_queue_net *q, u16 queue_num, u32 nlportid)
{
struct nfqnl_instance *queue;
queue = instance_lookup(q, queue_num);
if (!queue)
return ERR_PTR(-ENODEV);
if (queue->peer_portid != nlportid)
return ERR_PTR(-EPERM);
return queue;
}
static struct nfqnl_msg_verdict_hdr*
verdicthdr_get(const struct nlattr * const nfqa[])
{
struct nfqnl_msg_verdict_hdr *vhdr;
unsigned int verdict;
if (!nfqa[NFQA_VERDICT_HDR])
return NULL;
vhdr = nla_data(nfqa[NFQA_VERDICT_HDR]);
verdict = ntohl(vhdr->verdict) & NF_VERDICT_MASK;
if (verdict > NF_MAX_VERDICT || verdict == NF_STOLEN)
return NULL;
return vhdr;
}
static int nfq_id_after(unsigned int id, unsigned int max)
{
return (int)(id - max) > 0;
}
static int
nfqnl_recv_verdict_batch(struct sock *ctnl, struct sk_buff *skb,
const struct nlmsghdr *nlh,
const struct nlattr * const nfqa[])
{
struct nfgenmsg *nfmsg = nlmsg_data(nlh);
struct nf_queue_entry *entry, *tmp;
unsigned int verdict, maxid;
struct nfqnl_msg_verdict_hdr *vhdr;
struct nfqnl_instance *queue;
LIST_HEAD(batch_list);
u16 queue_num = ntohs(nfmsg->res_id);
struct net *net = sock_net(ctnl);
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
queue = verdict_instance_lookup(q, queue_num,
NETLINK_CB(skb).portid);
if (IS_ERR(queue))
return PTR_ERR(queue);
vhdr = verdicthdr_get(nfqa);
if (!vhdr)
return -EINVAL;
verdict = ntohl(vhdr->verdict);
maxid = ntohl(vhdr->id);
spin_lock_bh(&queue->lock);
list_for_each_entry_safe(entry, tmp, &queue->queue_list, list) {
if (nfq_id_after(entry->id, maxid))
break;
__dequeue_entry(queue, entry);
list_add_tail(&entry->list, &batch_list);
}
spin_unlock_bh(&queue->lock);
if (list_empty(&batch_list))
return -ENOENT;
list_for_each_entry_safe(entry, tmp, &batch_list, list) {
if (nfqa[NFQA_MARK])
entry->skb->mark = ntohl(nla_get_be32(nfqa[NFQA_MARK]));
nf_reinject(entry, verdict);
}
return 0;
}
static int
nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
const struct nlmsghdr *nlh,
const struct nlattr * const nfqa[])
{
struct nfgenmsg *nfmsg = nlmsg_data(nlh);
u_int16_t queue_num = ntohs(nfmsg->res_id);
struct nfqnl_msg_verdict_hdr *vhdr;
struct nfqnl_instance *queue;
unsigned int verdict;
struct nf_queue_entry *entry;
enum ip_conntrack_info uninitialized_var(ctinfo);
struct nf_conn *ct = NULL;
struct net *net = sock_net(ctnl);
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
queue = instance_lookup(q, queue_num);
if (!queue)
queue = verdict_instance_lookup(q, queue_num,
NETLINK_CB(skb).portid);
if (IS_ERR(queue))
return PTR_ERR(queue);
vhdr = verdicthdr_get(nfqa);
if (!vhdr)
return -EINVAL;
verdict = ntohl(vhdr->verdict);
entry = find_dequeue_entry(queue, ntohl(vhdr->id));
if (entry == NULL)
return -ENOENT;
if (nfqa[NFQA_CT]) {
ct = nfqnl_ct_parse(entry->skb, nfqa[NFQA_CT], &ctinfo);
if (ct && nfqa[NFQA_EXP]) {
nfqnl_attach_expect(ct, nfqa[NFQA_EXP],
NETLINK_CB(skb).portid,
nlmsg_report(nlh));
}
}
if (nfqa[NFQA_PAYLOAD]) {
u16 payload_len = nla_len(nfqa[NFQA_PAYLOAD]);
int diff = payload_len - entry->skb->len;
if (nfqnl_mangle(nla_data(nfqa[NFQA_PAYLOAD]),
payload_len, entry, diff) < 0)
verdict = NF_DROP;
if (ct)
nfqnl_ct_seq_adjust(entry->skb, ct, ctinfo, diff);
}
if (nfqa[NFQA_MARK])
entry->skb->mark = ntohl(nla_get_be32(nfqa[NFQA_MARK]));
nf_reinject(entry, verdict);
return 0;
}
static int
nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
const struct nlmsghdr *nlh,
const struct nlattr * const nfqa[])
{
return -ENOTSUPP;
}
static const struct nla_policy nfqa_cfg_policy[NFQA_CFG_MAX+1] = {
[NFQA_CFG_CMD] = { .len = sizeof(struct nfqnl_msg_config_cmd) },
[NFQA_CFG_PARAMS] = { .len = sizeof(struct nfqnl_msg_config_params) },
};
static const struct nf_queue_handler nfqh = {
.outfn = &nfqnl_enqueue_packet,
.nf_hook_drop = &nfqnl_nf_hook_drop,
};
static int
nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
const struct nlmsghdr *nlh,
const struct nlattr * const nfqa[])
{
struct nfgenmsg *nfmsg = nlmsg_data(nlh);
u_int16_t queue_num = ntohs(nfmsg->res_id);
struct nfqnl_instance *queue;
struct nfqnl_msg_config_cmd *cmd = NULL;
struct net *net = sock_net(ctnl);
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
int ret = 0;
if (nfqa[NFQA_CFG_CMD]) {
cmd = nla_data(nfqa[NFQA_CFG_CMD]);
/* Obsolete commands without queue context */
switch (cmd->command) {
case NFQNL_CFG_CMD_PF_BIND: return 0;
case NFQNL_CFG_CMD_PF_UNBIND: return 0;
}
}
rcu_read_lock();
queue = instance_lookup(q, queue_num);
if (queue && queue->peer_portid != NETLINK_CB(skb).portid) {
ret = -EPERM;
goto err_out_unlock;
}
if (cmd != NULL) {
switch (cmd->command) {
case NFQNL_CFG_CMD_BIND:
if (queue) {
ret = -EBUSY;
goto err_out_unlock;
}
queue = instance_create(q, queue_num,
NETLINK_CB(skb).portid);
if (IS_ERR(queue)) {
ret = PTR_ERR(queue);
goto err_out_unlock;
}
break;
case NFQNL_CFG_CMD_UNBIND:
if (!queue) {
ret = -ENODEV;
goto err_out_unlock;
}
instance_destroy(q, queue);
break;
case NFQNL_CFG_CMD_PF_BIND:
case NFQNL_CFG_CMD_PF_UNBIND:
break;
default:
ret = -ENOTSUPP;
break;
}
}
if (nfqa[NFQA_CFG_PARAMS]) {
struct nfqnl_msg_config_params *params;
if (!queue) {
ret = -ENODEV;
goto err_out_unlock;
}
params = nla_data(nfqa[NFQA_CFG_PARAMS]);
nfqnl_set_mode(queue, params->copy_mode,
ntohl(params->copy_range));
}
if (nfqa[NFQA_CFG_QUEUE_MAXLEN]) {
__be32 *queue_maxlen;
if (!queue) {
ret = -ENODEV;
goto err_out_unlock;
}
queue_maxlen = nla_data(nfqa[NFQA_CFG_QUEUE_MAXLEN]);
spin_lock_bh(&queue->lock);
queue->queue_maxlen = ntohl(*queue_maxlen);
spin_unlock_bh(&queue->lock);
}
if (nfqa[NFQA_CFG_FLAGS]) {
__u32 flags, mask;
if (!queue) {
ret = -ENODEV;
goto err_out_unlock;
}
if (!nfqa[NFQA_CFG_MASK]) {
/* A mask is needed to specify which flags are being
* changed.
*/
ret = -EINVAL;
goto err_out_unlock;
}
flags = ntohl(nla_get_be32(nfqa[NFQA_CFG_FLAGS]));
mask = ntohl(nla_get_be32(nfqa[NFQA_CFG_MASK]));
if (flags >= NFQA_CFG_F_MAX) {
ret = -EOPNOTSUPP;
goto err_out_unlock;
}
#if !IS_ENABLED(CONFIG_NETWORK_SECMARK)
if (flags & mask & NFQA_CFG_F_SECCTX) {
ret = -EOPNOTSUPP;
goto err_out_unlock;
}
#endif
spin_lock_bh(&queue->lock);
queue->flags &= ~mask;
queue->flags |= flags & mask;
spin_unlock_bh(&queue->lock);
}
err_out_unlock:
rcu_read_unlock();
return ret;
}
static const struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
[NFQNL_MSG_PACKET] = { .call_rcu = nfqnl_recv_unsupp,
.attr_count = NFQA_MAX, },
[NFQNL_MSG_VERDICT] = { .call_rcu = nfqnl_recv_verdict,
.attr_count = NFQA_MAX,
.policy = nfqa_verdict_policy },
[NFQNL_MSG_CONFIG] = { .call = nfqnl_recv_config,
.attr_count = NFQA_CFG_MAX,
.policy = nfqa_cfg_policy },
[NFQNL_MSG_VERDICT_BATCH]={ .call_rcu = nfqnl_recv_verdict_batch,
.attr_count = NFQA_MAX,
.policy = nfqa_verdict_batch_policy },
};
static const struct nfnetlink_subsystem nfqnl_subsys = {
.name = "nf_queue",
.subsys_id = NFNL_SUBSYS_QUEUE,
.cb_count = NFQNL_MSG_MAX,
.cb = nfqnl_cb,
};
#ifdef CONFIG_PROC_FS
struct iter_state {
struct seq_net_private p;
unsigned int bucket;
};
static struct hlist_node *get_first(struct seq_file *seq)
{
struct iter_state *st = seq->private;
struct net *net;
struct nfnl_queue_net *q;
if (!st)
return NULL;
net = seq_file_net(seq);
q = nfnl_queue_pernet(net);
for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
if (!hlist_empty(&q->instance_table[st->bucket]))
return q->instance_table[st->bucket].first;
}
return NULL;
}
static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
{
struct iter_state *st = seq->private;
struct net *net = seq_file_net(seq);
h = h->next;
while (!h) {
struct nfnl_queue_net *q;
if (++st->bucket >= INSTANCE_BUCKETS)
return NULL;
q = nfnl_queue_pernet(net);
h = q->instance_table[st->bucket].first;
}
return h;
}
static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
{
struct hlist_node *head;
head = get_first(seq);
if (head)
while (pos && (head = get_next(seq, head)))
pos--;
return pos ? NULL : head;
}
static void *seq_start(struct seq_file *s, loff_t *pos)
__acquires(nfnl_queue_pernet(seq_file_net(s))->instances_lock)
{
spin_lock(&nfnl_queue_pernet(seq_file_net(s))->instances_lock);
return get_idx(s, *pos);
}
static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
(*pos)++;
return get_next(s, v);
}
static void seq_stop(struct seq_file *s, void *v)
__releases(nfnl_queue_pernet(seq_file_net(s))->instances_lock)
{
spin_unlock(&nfnl_queue_pernet(seq_file_net(s))->instances_lock);
}
static int seq_show(struct seq_file *s, void *v)
{
const struct nfqnl_instance *inst = v;
seq_printf(s, "%5u %6u %5u %1u %5u %5u %5u %8u %2d\n",
inst->queue_num,
inst->peer_portid, inst->queue_total,
inst->copy_mode, inst->copy_range,
inst->queue_dropped, inst->queue_user_dropped,
inst->id_sequence, 1);
return 0;
}
static const struct seq_operations nfqnl_seq_ops = {
.start = seq_start,
.next = seq_next,
.stop = seq_stop,
.show = seq_show,
};
static int nfqnl_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &nfqnl_seq_ops,
sizeof(struct iter_state));
}
static const struct file_operations nfqnl_file_ops = {
.owner = THIS_MODULE,
.open = nfqnl_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
#endif /* PROC_FS */
static int __net_init nfnl_queue_net_init(struct net *net)
{
unsigned int i;
struct nfnl_queue_net *q = nfnl_queue_pernet(net);
for (i = 0; i < INSTANCE_BUCKETS; i++)
INIT_HLIST_HEAD(&q->instance_table[i]);
spin_lock_init(&q->instances_lock);
#ifdef CONFIG_PROC_FS
if (!proc_create("nfnetlink_queue", 0440,
net->nf.proc_netfilter, &nfqnl_file_ops))
return -ENOMEM;
#endif
return 0;
}
static void __net_exit nfnl_queue_net_exit(struct net *net)
{
#ifdef CONFIG_PROC_FS
remove_proc_entry("nfnetlink_queue", net->nf.proc_netfilter);
#endif
}
static struct pernet_operations nfnl_queue_net_ops = {
.init = nfnl_queue_net_init,
.exit = nfnl_queue_net_exit,
.id = &nfnl_queue_net_id,
.size = sizeof(struct nfnl_queue_net),
};
static int __init nfnetlink_queue_init(void)
{
int status;
status = register_pernet_subsys(&nfnl_queue_net_ops);
if (status < 0) {
pr_err("nf_queue: failed to register pernet ops\n");
goto out;
}
netlink_register_notifier(&nfqnl_rtnl_notifier);
status = nfnetlink_subsys_register(&nfqnl_subsys);
if (status < 0) {
pr_err("nf_queue: failed to create netlink socket\n");
goto cleanup_netlink_notifier;
}
register_netdevice_notifier(&nfqnl_dev_notifier);
nf_register_queue_handler(&nfqh);
return status;
cleanup_netlink_notifier:
netlink_unregister_notifier(&nfqnl_rtnl_notifier);
out:
return status;
}
static void __exit nfnetlink_queue_fini(void)
{
nf_unregister_queue_handler();
unregister_netdevice_notifier(&nfqnl_dev_notifier);
nfnetlink_subsys_unregister(&nfqnl_subsys);
netlink_unregister_notifier(&nfqnl_rtnl_notifier);
unregister_pernet_subsys(&nfnl_queue_net_ops);
rcu_barrier(); /* Wait for completion of call_rcu()'s */
}
MODULE_DESCRIPTION("netfilter packet queue handler");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_QUEUE);
module_init(nfnetlink_queue_init);
module_exit(nfnetlink_queue_fini);
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