[PATCH 1/6] netprio_cgroup: fix an off-by-one bug

From: Li Zefan
Date: Wed Feb 01 2012 - 01:52:33 EST


# 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@xxxxxxxxxxxxxx>
---
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
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