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authorDavid Ahern <dsahern@gmail.com>2018-01-10 13:00:39 -0800
committerDavid S. Miller <davem@davemloft.net>2018-01-15 13:50:07 -0500
commitcbbdf8433a5f117b1a2119ea30fc651b61ef7570 (patch)
treef8db54b9ab381bbde880ab1d2b869730c48a3eaf
parent59b36613e85fb16ebf9feaf914570879cd5c2a21 (diff)
downloadlinux-cbbdf8433a5f117b1a2119ea30fc651b61ef7570.tar.bz2
netlink: extack needs to be reset each time through loop
syzbot triggered the WARN_ON in netlink_ack testing the bad_attr value. The problem is that netlink_rcv_skb loops over the skb repeatedly invoking the callback and without resetting the extack leaving potentially stale data. Initializing each time through avoids the WARN_ON. Fixes: 2d4bc93368f5a ("netlink: extended ACK reporting") Reported-by: syzbot+315fa6766d0f7c359327@syzkaller.appspotmail.com Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/netlink/af_netlink.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 79cc1bf36e4a..47ef2d8683d6 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2384,7 +2384,7 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
struct nlmsghdr *,
struct netlink_ext_ack *))
{
- struct netlink_ext_ack extack = {};
+ struct netlink_ext_ack extack;
struct nlmsghdr *nlh;
int err;
@@ -2405,6 +2405,7 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
goto ack;
+ memset(&extack, 0, sizeof(extack));
err = cb(skb, nlh, &extack);
if (err == -EINTR)
goto skip;