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-rw-r--r--net/netlink/af_netlink.c135
1 files changed, 129 insertions, 6 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 6560635fd25c..90504a0e42ab 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -116,6 +116,11 @@ static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
}
+static bool netlink_tx_is_mmaped(struct sock *sk)
+{
+ return nlk_sk(sk)->tx_ring.pg_vec != NULL;
+}
+
static __pure struct page *pgvec_to_page(const void *addr)
{
if (is_vmalloc_addr(addr))
@@ -438,6 +443,9 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock,
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int mask;
+ if (nlk->cb != NULL && nlk->rx_ring.pg_vec != NULL)
+ netlink_dump(sk);
+
mask = datagram_poll(file, sock, wait);
spin_lock_bh(&sk->sk_receive_queue.lock);
@@ -483,10 +491,110 @@ static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
NETLINK_CB(skb).sk = sk;
}
+
+static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
+ u32 dst_portid, u32 dst_group,
+ struct sock_iocb *siocb)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct netlink_ring *ring;
+ struct nl_mmap_hdr *hdr;
+ struct sk_buff *skb;
+ unsigned int maxlen;
+ bool excl = true;
+ int err = 0, len = 0;
+
+ /* Netlink messages are validated by the receiver before processing.
+ * In order to avoid userspace changing the contents of the message
+ * after validation, the socket and the ring may only be used by a
+ * single process, otherwise we fall back to copying.
+ */
+ if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
+ atomic_read(&nlk->mapped) > 1)
+ excl = false;
+
+ mutex_lock(&nlk->pg_vec_lock);
+
+ ring = &nlk->tx_ring;
+ maxlen = ring->frame_size - NL_MMAP_HDRLEN;
+
+ do {
+ hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
+ if (hdr == NULL) {
+ if (!(msg->msg_flags & MSG_DONTWAIT) &&
+ atomic_read(&nlk->tx_ring.pending))
+ schedule();
+ continue;
+ }
+ if (hdr->nm_len > maxlen) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ netlink_frame_flush_dcache(hdr);
+
+ if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
+ skb = alloc_skb_head(GFP_KERNEL);
+ if (skb == NULL) {
+ err = -ENOBUFS;
+ goto out;
+ }
+ sock_hold(sk);
+ netlink_ring_setup_skb(skb, sk, ring, hdr);
+ NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
+ __skb_put(skb, hdr->nm_len);
+ netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
+ atomic_inc(&ring->pending);
+ } else {
+ skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
+ if (skb == NULL) {
+ err = -ENOBUFS;
+ goto out;
+ }
+ __skb_put(skb, hdr->nm_len);
+ memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
+ netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
+ }
+
+ netlink_increment_head(ring);
+
+ NETLINK_CB(skb).portid = nlk->portid;
+ NETLINK_CB(skb).dst_group = dst_group;
+ NETLINK_CB(skb).creds = siocb->scm->creds;
+
+ err = security_netlink_send(sk, skb);
+ if (err) {
+ kfree_skb(skb);
+ goto out;
+ }
+
+ if (unlikely(dst_group)) {
+ atomic_inc(&skb->users);
+ netlink_broadcast(sk, skb, dst_portid, dst_group,
+ GFP_KERNEL);
+ }
+ err = netlink_unicast(sk, skb, dst_portid,
+ msg->msg_flags & MSG_DONTWAIT);
+ if (err < 0)
+ goto out;
+ len += err;
+
+ } while (hdr != NULL ||
+ (!(msg->msg_flags & MSG_DONTWAIT) &&
+ atomic_read(&nlk->tx_ring.pending)));
+
+ if (len > 0)
+ err = len;
+out:
+ mutex_unlock(&nlk->pg_vec_lock);
+ return err;
+}
#else /* CONFIG_NETLINK_MMAP */
#define netlink_skb_is_mmaped(skb) false
+#define netlink_tx_is_mmaped(sk) false
#define netlink_mmap sock_no_mmap
#define netlink_poll datagram_poll
+#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
#endif /* CONFIG_NETLINK_MMAP */
static void netlink_destroy_callback(struct netlink_callback *cb)
@@ -517,11 +625,16 @@ static void netlink_skb_destructor(struct sk_buff *skb)
hdr = netlink_mmap_hdr(skb);
sk = NETLINK_CB(skb).sk;
- if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
- hdr->nm_len = 0;
- netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
+ if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
+ netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
+ ring = &nlk_sk(sk)->tx_ring;
+ } else {
+ if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
+ hdr->nm_len = 0;
+ netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
+ }
+ ring = &nlk_sk(sk)->rx_ring;
}
- ring = &nlk_sk(sk)->rx_ring;
WARN_ON(atomic_read(&ring->pending) == 0);
atomic_dec(&ring->pending);
@@ -1230,8 +1343,9 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
nlk = nlk_sk(sk);
- if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
- test_bit(NETLINK_CONGESTED, &nlk->state)) {
+ if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
+ test_bit(NETLINK_CONGESTED, &nlk->state)) &&
+ !netlink_skb_is_mmaped(skb)) {
DECLARE_WAITQUEUE(wait, current);
if (!*timeo) {
if (!ssk || netlink_is_kernel(ssk))
@@ -1291,6 +1405,8 @@ static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
int delta;
WARN_ON(skb->sk != NULL);
+ if (netlink_skb_is_mmaped(skb))
+ return skb;
delta = skb->end - skb->tail;
if (delta * 2 < skb->truesize)
@@ -1815,6 +1931,13 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
goto out;
}
+ if (netlink_tx_is_mmaped(sk) &&
+ msg->msg_iov->iov_base == NULL) {
+ err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
+ siocb);
+ goto out;
+ }
+
err = -EMSGSIZE;
if (len > sk->sk_sndbuf - 32)
goto out;