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From: Li Zefan <lizf@cn.fujitsu.com>
To: David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Cgroups <cgroups@vger.kernel.org>,
	Neil Horman <nhorman@tuxdriver.com>
Subject: [PATCH 1/6] netprio_cgroup: fix an off-by-one bug
Date: Wed, 01 Feb 2012 14:55:13 +0800	[thread overview]
Message-ID: <4F28E1D1.900@cn.fujitsu.com> (raw)

  # mount -t cgroup xxx /mnt
  # mkdir /mnt/tmp
  # cat /mnt/tmp/net_prio.ifpriomap
  lo 0
  eth0 0
  virbr0 0
  # echo 'lo 999' > /mnt/tmp/net_prio.ifpriomap
  # cat /mnt/tmp/net_prio.ifpriomap
  lo 999
  eth0 0
  virbr0 4101267344

We got weired output, because we exceeded the boundary of the array.
We may even crash the kernel..

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 net/core/netprio_cgroup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 3a9fd48..a296cbb 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -107,7 +107,7 @@ static void extend_netdev_table(struct net_device *dev, u32 new_len)
 static void update_netdev_tables(void)
 {
 	struct net_device *dev;
-	u32 max_len = atomic_read(&max_prioidx);
+	u32 max_len = atomic_read(&max_prioidx) + 1;
 	struct netprio_map *map;
 
 	rtnl_lock();
-- 
1.7.3.1

             reply	other threads:[~2012-02-01  6:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-01  6:55 Li Zefan [this message]
2012-02-01  6:55 ` [PATCH 2/6] netprio_cgroup: don't allocate prio table when a device is registered Li Zefan
2012-02-01  6:55 ` [PATCH 3/6] netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m Li Zefan
2012-02-01  6:56 ` [PATCH 4/6] netprio_cgroup: use IS_ENABLED() and family Li Zefan
2012-02-01  6:59   ` David Miller
2012-02-01  7:06     ` Li Zefan
2012-02-01  7:07       ` David Miller
2012-02-01  7:22         ` Li Zefan
2012-02-01 12:02           ` Neil Horman
2012-02-01  6:56 ` [PATCH 5/6] cls_cgroup: " Li Zefan
2012-02-01  6:56 ` [PATCH 6/6] cls_cgroup: remove redundant rcu_read_lock/unlock Li Zefan
2012-02-01  7:07   ` Eric Dumazet
2012-02-01  7:10     ` David Miller
2012-02-01  7:20     ` Li Zefan
2012-02-01  7:23       ` Herbert Xu

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