From: Vasiliy Kulikov Date: Mon, 14 Feb 2011 15:49:23 +0000 (+0100) Subject: bridge: netfilter: fix information leak X-Git-Tag: v2.6.34.10~7 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=41c6364db6028e2776250be12961b30f4a2ffbf9;p=thirdparty%2Fkernel%2Fstable.git bridge: netfilter: fix information leak 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 Signed-off-by: Patrick McHardy Signed-off-by: Paul Gortmaker --- diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index f0865fd1e3eca..2b8c983eeab68 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1112,6 +1112,8 @@ static int do_replace(struct net *net, const void __user *user, 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)