[074/105] bridge: netfilter: fix information leak

[Greg KH]

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>

commit d846f71195d57b0bbb143382647c2c6638b04c5a upstream.

Struct tmp is copied from userspace.  It is not checked whether the "name"
field is NULL terminated.  This may lead to buffer overflow and passing
contents of kernel stack as a module name to try_then_request_module() and,
consequently, to modprobe commandline.  It would be seen by all userspace
processes.

Signed-off-by: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/bridge/netfilter/ebtables.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1107,6 +1107,8 @@ static int do_replace(struct net *net, c
 	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
 		return -ENOMEM;
 
+	tmp.name[sizeof(tmp.name) - 1] = 0;
+
 	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
 	newinfo = vmalloc(sizeof(*newinfo) + countersize);
 	if (!newinfo)


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