4.14-stable review patch. If anyone has any objections, please let me know.
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From: Xin Long lucien.xin@gmail.com
[ Upstream commit cd443f1e91ca600a092e780e8250cd6a2954b763 ]
Move up the extack reset/initialization in netlink_rcv_skb, so that those 'goto ack' will not skip it. Otherwise, later on netlink_ack may use the uninitialized extack and cause kernel crash.
Fixes: cbbdf8433a5f ("netlink: extack needs to be reset each time through loop") Reported-by: syzbot+03bee3680a37466775e7@syzkaller.appspotmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: David Ahern dsahern@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2400,6 +2400,7 @@ int netlink_rcv_skb(struct sk_buff *skb, while (skb->len >= nlmsg_total_size(0)) { int msglen;
+ memset(&extack, 0, sizeof(extack)); nlh = nlmsg_hdr(skb); err = 0;
@@ -2414,7 +2415,6 @@ int netlink_rcv_skb(struct sk_buff *skb, if (nlh->nlmsg_type < NLMSG_MIN_TYPE) goto ack;
- memset(&extack, 0, sizeof(extack)); err = cb(skb, nlh, &extack); if (err == -EINTR) goto skip;