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authorHerbert Xu <herbert@gondor.apana.org.au>2016-05-16 17:28:16 +0800
committerSasha Levin <sasha.levin@oracle.com>2016-07-12 08:48:21 -0400
commit57b26930c7149c9ed86ba29038523a7a23140220 (patch)
treeaf0d8aa39f219c6bf65e6346928027b534abe54e
parent624a4c6444aab7de3e262e4a27bdcbe9b9283527 (diff)
downloadlinux-linaro-stable-57b26930c7149c9ed86ba29038523a7a23140220.tar.gz
netlink: Fix dump skb leak/double free
[ Upstream commit 92964c79b357efd980812c4de5c1fd2ec8bb5520 ] When we free cb->skb after a dump, we do it after releasing the lock. This means that a new dump could have started in the time being and we'll end up freeing their skb instead of ours. This patch saves the skb and module before we unlock so we free the right memory. Fixes: 16b304f3404f ("netlink: Eliminate kmalloc in netlink dump operation.") Reported-by: Baozeng Ding <sploving1@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--net/netlink/af_netlink.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index fe106b50053e..15fc0938e1c4 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2630,6 +2630,7 @@ static int netlink_dump(struct sock *sk)
struct netlink_callback *cb;
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh;
+ struct module *module;
int len, err = -ENOBUFS;
int alloc_size;
@@ -2699,9 +2700,11 @@ static int netlink_dump(struct sock *sk)
cb->done(cb);
nlk->cb_running = false;
+ module = cb->module;
+ skb = cb->skb;
mutex_unlock(nlk->cb_mutex);
- module_put(cb->module);
- consume_skb(cb->skb);
+ module_put(module);
+ consume_skb(skb);
return 0;
errout_skb: