[PATCH 4.9 87/92] net: ieee802154: 6lowpan: fix frag reassembly

Greg Kroah-Hartman
2018-11-29T14:23:53Z

From: Alexander Aring <aring@mojatatu.com>

commit f18fa5de5ba7f1d6650951502bb96a6e4715a948 upstream.

This patch initialize stack variables which are used in
frag_lowpan_compare_key to zero. In my case there are padding bytes in the
structures ieee802154_addr as well in frag_lowpan_compare_key. Otherwise
the key variable contains random bytes. The result is that a compare of
two keys by memcmp works incorrect.

Fixes: 648700f76b03 ("inet: frags: use rhashtables for reassembly units")
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Reported-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/ieee802154/6lowpan/6lowpan_i.h | 4 ++--
net/ieee802154/6lowpan/reassembly.c | 14 +++++++-------
2 files changed, 9 insertions(+), 9 deletions(-)

--- a/net/ieee802154/6lowpan/6lowpan_i.h
+++ b/net/ieee802154/6lowpan/6lowpan_i.h
@@ -19,8 +19,8 @@ typedef unsigned __bitwise__ lowpan_rx_r
struct frag_lowpan_compare_key {
u16 tag;
u16 d_size;
- const struct ieee802154_addr src;
- const struct ieee802154_addr dst;
+ struct ieee802154_addr src;
+ struct ieee802154_addr dst;
};

/* Equivalent of ipv4 struct ipq
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -74,14 +74,14 @@ fq_find(struct net *net, const struct lo
{
struct netns_ieee802154_lowpan *ieee802154_lowpan =
net_ieee802154_lowpan(net);
- struct frag_lowpan_compare_key key = {
- .tag = cb->d_tag,
- .d_size = cb->d_size,
- .src = *src,
- .dst = *dst,
- };
+ struct frag_lowpan_compare_key key = {};
struct inet_frag_queue *q;

+ key.tag = cb->d_tag;
+ key.d_size = cb->d_size;
+ key.src = *src;
+ key.dst = *dst;
+
q = inet_frag_find(&ieee802154_lowpan->frags, &key);
if (!q)
return NULL;
@@ -371,7 +371,7 @@ int lowpan_frag_rcv(struct sk_buff *skb,
struct lowpan_frag_queue *fq;
struct net *net = dev_net(skb->dev);
struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
- struct ieee802154_hdr hdr;
+ struct ieee802154_hdr hdr = {};
int err;

if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)