[34-longterm 124/260] drivers/net/eql.c: prevent reading uninitialized stack memory

From: Paul Gortmaker
Date: Sun Jan 02 2011 - 02:53:21 EST

From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>

commit 44467187dc22fdd33a1a06ea0ba86ce20be3fe3c upstream.

Fixed formatting (tabs and line breaks).

The EQL_GETMASTRCFG device ioctl allows unprivileged users to read 16
bytes of uninitialized stack memory, because the "master_name" member of
the master_config_t struct declared on the stack in eql_g_master_cfg()
is not altered or zeroed before being copied back to the user. This
patch takes care of it.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
drivers/net/eql.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/net/eql.c b/drivers/net/eql.c
index b34a2dd..a8b982d 100644
--- a/drivers/net/eql.c
+++ b/drivers/net/eql.c
@@ -555,6 +555,8 @@ static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
equalizer_t *eql;
master_config_t mc;

+ memset(&mc, 0, sizeof(master_config_t));
if (eql_is_master(dev)) {
eql = netdev_priv(dev);
mc.max_slaves = eql->max_slaves;

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