[PATCH 3.2 45/46] net: fix infoleak in rtnetlink

Ben Hutchings
2016-06-12T21:35:57Z

From: Kangjie Lu <kangjielu@gmail.com>

commit 5f8e44741f9f216e33736ea4ec65ca9ac03036e6 upstream.

The stack object “map” has a total size of 32 bytes. Its last 4
bytes are padding generated by compiler. These padding bytes are
not initialized and sent out via “nla_put”.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/core/rtnetlink.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -920,14 +920,16 @@ static int rtnl_fill_ifinfo(struct sk_bu
NLA_PUT_STRING(skb, IFLA_IFALIAS, dev->ifalias);

if (1) {
- struct rtnl_link_ifmap map = {
- .mem_start = dev->mem_start,
- .mem_end = dev->mem_end,
- .base_addr = dev->base_addr,
- .irq = dev->irq,
- .dma = dev->dma,
- .port = dev->if_port,
- };
+ struct rtnl_link_ifmap map;
+
+ memset(&map, 0, sizeof(map));
+ map.mem_start = dev->mem_start;
+ map.mem_end = dev->mem_end;
+ map.base_addr = dev->base_addr;
+ map.irq = dev->irq;
+ map.dma = dev->dma;
+ map.port = dev->if_port;
+
NLA_PUT(skb, IFLA_MAP, sizeof(map), &map);
}