When RTM_GETSTATS was added the fields of its header struct were not all initialized when returning the result thus leaking 4 bytes of information to user-space per rtnl_fill_statsinfo call, so initialize them now. Thanks to Alexander Potapenko for the detailed report and bisection.
Reported-by: Alexander Potapenko <gli...@google.com> Fixes: 10c9ead9f3c6 ("rtnetlink: add new RTM_GETSTATS message to dump link stats") Signed-off-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com> --- net/core/rtnetlink.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index a78fd61da0ec..d4bcdcc68e92 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3854,6 +3854,9 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev, return -EMSGSIZE; ifsm = nlmsg_data(nlh); + ifsm->family = PF_UNSPEC; + ifsm->pad1 = 0; + ifsm->pad2 = 0; ifsm->ifindex = dev->ifindex; ifsm->filter_mask = filter_mask; -- 2.1.4