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-rw-r--r--net/netlink/af_netlink.c46
1 files changed, 16 insertions, 30 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 8648a99..980fe4a 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1406,7 +1406,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
struct netlink_sock *nlk = nlk_sk(sk);
int noblock = flags&MSG_DONTWAIT;
size_t copied;
- struct sk_buff *skb, *frag __maybe_unused = NULL;
+ struct sk_buff *skb, *data_skb;
int err;
if (flags&MSG_OOB)
@@ -1418,45 +1418,35 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
if (skb == NULL)
goto out;
+ data_skb = skb;
+
#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
if (unlikely(skb_shinfo(skb)->frag_list)) {
- bool need_compat = !!(flags & MSG_CMSG_COMPAT);
-
/*
- * If this skb has a frag_list, then here that means that
- * we will have to use the frag_list skb for compat tasks
- * and the regular skb for non-compat tasks.
+ * If this skb has a frag_list, then here that means that we
+ * will have to use the frag_list skb's data for compat tasks
+ * and the regular skb's data for normal (non-compat) tasks.
*
- * The skb might (and likely will) be cloned, so we can't
- * just reset frag_list and go on with things -- we need to
- * keep that. For the compat case that's easy -- simply get
- * a reference to the compat skb and free the regular one
- * including the frag. For the non-compat case, we need to
- * avoid sending the frag to the user -- so assign NULL but
- * restore it below before freeing the skb.
+ * If we need to send the compat skb, assign it to the
+ * 'data_skb' variable so that it will be used below for data
+ * copying. We keep 'skb' for everything else, including
+ * freeing both later.
*/
- if (need_compat) {
- struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
- skb_get(compskb);
- kfree_skb(skb);
- skb = compskb;
- } else {
- frag = skb_shinfo(skb)->frag_list;
- skb_shinfo(skb)->frag_list = NULL;
- }
+ if (flags & MSG_CMSG_COMPAT)
+ data_skb = skb_shinfo(skb)->frag_list;
}
#endif
msg->msg_namelen = 0;
- copied = skb->len;
+ copied = data_skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;
copied = len;
}
- skb_reset_transport_header(skb);
- err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
+ skb_reset_transport_header(data_skb);
+ err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
if (msg->msg_name) {
struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
@@ -1476,11 +1466,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
}
siocb->scm->creds = *NETLINK_CREDS(skb);
if (flags & MSG_TRUNC)
- copied = skb->len;
-
-#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
- skb_shinfo(skb)->frag_list = frag;
-#endif
+ copied = data_skb->len;
skb_free_datagram(sk, skb);