From 4775cc1f2d5abca894ac32774eefc22c45347d1c Mon Sep 17 00:00:00 2001
From: Mathias Krause <minipli@googlemail.com>
Date: Wed, 28 Dec 2016 17:52:15 +0100
Subject: [PATCH] rtnl: stats - add missing netlink message size checks
We miss to check if the netlink message is actually big enough to contain
a struct if_stats_msg.
Add a check to prevent userland from sending us short messages that would
make us access memory beyond the end of the message.
Fixes: 10c9ead9f3c6 ("rtnetlink: add new RTM_GETSTATS message to dump...")
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/rtnetlink.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 18b5aae99becf..75e3ea7bda08f 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3898,6 +3898,9 @@ static int rtnl_stats_get(struct sk_buff *skb, struct nlmsghdr *nlh)
u32 filter_mask;
int err;
+ if (nlmsg_len(nlh) < sizeof(*ifsm))
+ return -EINVAL;
+
ifsm = nlmsg_data(nlh);
if (ifsm->ifindex > 0)
dev = __dev_get_by_index(net, ifsm->ifindex);
@@ -3947,6 +3950,9 @@ static int rtnl_stats_dump(struct sk_buff *skb, struct netlink_callback *cb)
cb->seq = net->dev_base_seq;
+ if (nlmsg_len(cb->nlh) < sizeof(*ifsm))
+ return -EINVAL;
+
ifsm = nlmsg_data(cb->nlh);
filter_mask = ifsm->filter_mask;
if (!filter_mask)
--
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