From: "Linus Lüssing" <linus.luessing@web.de>
To: b.a.t.m.a.n@lists.open-mesh.org
Subject: [B.A.T.M.A.N.] [PATCH] batman-adv: compat: fix null pointer exception for kernels < 3.9
Date: Sun, 16 Feb 2014 13:01:02 +0100 [thread overview]
Message-ID: <1392552062-17927-1-git-send-email-linus.luessing@web.de> (raw)
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 <mareklindner@neomailbox.ch>
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
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
next reply other threads:[~2014-02-16 12:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-16 12:01 Linus Lüssing [this message]
2014-02-16 13:39 ` [B.A.T.M.A.N.] [PATCH] batman-adv: compat: fix null pointer exception for kernels < 3.9 Antonio Quartulli
2014-02-16 18:09 ` Antonio Quartulli
2014-02-18 4:45 ` Marek Lindner
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