From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shakil A Khan Subject: [PATCH] Freeing dst when the reference count <0 causes general protection fault, it could be a major security flaw as rogue app can modify dst to crash kernel. Date: Sat, 13 Sep 2014 01:27:13 -0700 Message-ID: <1410596833-2548-1-git-send-email-shakilk1729@gmail.com> Cc: edumazet@google.com, davem@davemloft.net, Shakil A Khan To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Signed-off-by: Shakil A Khan --- net/core/dst.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/core/dst.c b/net/core/dst.c index a028409..6a848b0 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -284,7 +284,10 @@ void dst_release(struct dst_entry *dst) int newrefcnt; newrefcnt = atomic_dec_return(&dst->__refcnt); - WARN_ON(newrefcnt < 0); + + if (WARN(newrefcnt < 0, "dst reference count less than zero")) + return; + if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt) call_rcu(&dst->rcu_head, dst_destroy_rcu); } -- 1.9.3