Commit ed8ab6b2 authored by Herbert Xu's avatar Herbert Xu Committed by Ben Hutchings

netlink: Fix dump skb leak/double free

commit 92964c79 upstream.

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: 16b304f3 ("netlink: Eliminate kmalloc in netlink dump operation.")
Reported-by: default avatarBaozeng Ding <sploving1@gmail.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 36265cad
...@@ -2693,6 +2693,7 @@ static int netlink_dump(struct sock *sk) ...@@ -2693,6 +2693,7 @@ static int netlink_dump(struct sock *sk)
struct netlink_callback *cb; struct netlink_callback *cb;
struct sk_buff *skb = NULL; struct sk_buff *skb = NULL;
struct nlmsghdr *nlh; struct nlmsghdr *nlh;
struct module *module;
int len, err = -ENOBUFS; int len, err = -ENOBUFS;
int alloc_min_size; int alloc_min_size;
int alloc_size; int alloc_size;
...@@ -2773,9 +2774,11 @@ static int netlink_dump(struct sock *sk) ...@@ -2773,9 +2774,11 @@ static int netlink_dump(struct sock *sk)
cb->done(cb); cb->done(cb);
nlk->cb_running = false; nlk->cb_running = false;
module = cb->module;
skb = cb->skb;
mutex_unlock(nlk->cb_mutex); mutex_unlock(nlk->cb_mutex);
module_put(cb->module); module_put(module);
consume_skb(cb->skb); consume_skb(skb);
return 0; return 0;
errout_skb: errout_skb:
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment