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authorHerbert Xu <herbert@gondor.apana.org.au>2016-05-16 17:28:16 +0800
committerDavid S. Miller <davem@davemloft.net>2016-05-16 22:05:15 -0400
commit92964c79b357efd980812c4de5c1fd2ec8bb5520 (patch)
tree4fdcb3313923315bb1d2065bbf1c2b522d8854b5
parent45e093ae2830cd1264677d47ff9a95a71f5d9f9c (diff)
netlink: Fix dump skb leak/double free
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>
-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 aeefe12..627f898 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2059,6 +2059,7 @@ 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_min_size;
int alloc_size;
@@ -2134,9 +2135,11 @@ 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: