net: gtp: Fix Use-After-Free in gtp_dellink

[ Upstream commit f2a904107e ]

Since call_rcu, which is called in the hlist_for_each_entry_rcu traversal
of gtp_dellink, is not part of the RCU read critical section, it
is possible that the RCU grace period will pass during the traversal and
the key will be free.

To prevent this, it should be changed to hlist_for_each_entry_safe.

Fixes: 94dc550a50 ("gtp: fix an use-after-free in ipv4_pdp_find()")
Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Hyunwoo Kim 2024-04-22 05:39:30 -04:00 committed by Greg Kroah-Hartman
parent 9bda5e2f62
commit 0caff3e639

View file

@ -700,11 +700,12 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
static void gtp_dellink(struct net_device *dev, struct list_head *head)
{
struct gtp_dev *gtp = netdev_priv(dev);
struct hlist_node *next;
struct pdp_ctx *pctx;
int i;
for (i = 0; i < gtp->hash_size; i++)
hlist_for_each_entry_rcu(pctx, &gtp->tid_hash[i], hlist_tid)
hlist_for_each_entry_safe(pctx, next, &gtp->tid_hash[i], hlist_tid)
pdp_context_delete(pctx);
list_del_rcu(&gtp->list);