netfilter information leak http://seclists.org/oss-sec/2011/q1/309
>From d846f71195d57b0bbb143382647c2c6638b04c5a Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov <[email protected]> Date: Mon, 14 Feb 2011 16:49:23 +0100 Subject: [PATCH] bridge: netfilter: fix information leak
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 <[email protected]> Signed-off-by: Patrick McHardy <[email protected]> --- net/bridge/netfilter/ebtables.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 5f1825d..893669c 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1107,6 +1107,8 @@ 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) -- 1.7.4.2
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