4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mathias Krause <minipli@xxxxxxxxxxxxxx>
[ Upstream commit 4775cc1f2d5abca894ac32774eefc22c45347d1c ]
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@xxxxxxxxxxxxxx>
Cc: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/rtnetlink.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3886,6 +3886,9 @@ static int rtnl_stats_get(struct sk_buff
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);
@@ -3935,6 +3938,9 @@ static int rtnl_stats_dump(struct sk_buf
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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