From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Linus=20L=C3=BCssing?= Date: Sun, 16 Feb 2014 13:01:02 +0100 Message-Id: <1392552062-17927-1-git-send-email-linus.luessing@web.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: [B.A.T.M.A.N.] [PATCH] batman-adv: compat: fix null pointer exception for kernels < 3.9 Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: b.a.t.m.a.n@lists.open-mesh.org The compat code of the new multicast patchset leads to null pointer derefernces for kernels 3.9 in netdev_master_upper_dev_get_rcu(). This is because the initially NULL is assigned to upper, which is equal to dev. dev is dereferenced one line later, though, leading to a crash. Fixing this by assigning NULL only when we are sure that the according pointer is not going to be dereferenced anymore. Introduced by: 532cadf26cfbb1099ef31fae9ccafcbbfc37b9b5 ("batman-adv: Multicast Listener Announcements via Translation Table") Reported-by: Marek Lindner Signed-off-by: Linus Lüssing --- compat.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/compat.h b/compat.h index 7a3d235..7beba36 100644 --- a/compat.h +++ b/compat.h @@ -162,12 +162,13 @@ static inline int batadv_param_set_copystring(const char *val, #define NET_ADDR_RANDOM 0 #define netdev_master_upper_dev_get_rcu(dev) \ - NULL; \ + upper; \ if (dev->br_port ? 1 : 0) { \ rcu_read_unlock(); \ dev_hold(dev); \ return dev; \ - } + } else \ + dev = NULL; #endif /* < KERNEL_VERSION(2, 6, 36) */ @@ -371,12 +372,13 @@ static int __batadv_interface_tx(struct sk_buff *skb, \ #ifndef netdev_master_upper_dev_get_rcu #define netdev_master_upper_dev_get_rcu(dev) \ - NULL; \ + upper; \ if (dev->priv_flags & IFF_BRIDGE_PORT) { \ rcu_read_unlock(); \ dev_hold(dev); \ return dev; \ - } + } else \ + dev = NULL; #endif /* netdev_master_upper_dev_get_rcu */ -- 1.7.10.4