[PATCH 141/173] ipv6: netfilter: ip6_tables: fix infoleak to userspace

From: Willy Tarreau
Date: Mon Apr 25 2011 - 16:25:57 EST


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

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

From: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>

commit 6a8ab060779779de8aea92ce3337ca348f973f54 upstream.

Structures ip6t_replace, compat_ip6t_replace, and xt_get_revision are
copied from userspace. Fields of these structs that are
zero-terminated strings are not checked. When they are used as argument
to a format string containing "%s" in request_module(), some sensitive
information is leaked to userspace via argument of spawned modprobe
process.

The first bug was introduced before the git epoch; the second was
introduced in 3bc3fe5e (v2.6.25-rc1); the third is introduced by
6b7d31fc (v2.6.15-rc1). To trigger the bug one should have
CAP_NET_ADMIN.

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

---
net/ipv6/netfilter/ip6_tables.c | 3 +++
1 file changed, 3 insertions(+)

--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1323,6 +1323,7 @@ do_replace(struct net *net, void __user
/* overflow check */
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
+ tmp.name[sizeof(tmp.name)-1] = 0;

newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo)
@@ -1855,6 +1856,7 @@ compat_do_replace(struct net *net, void
return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
+ tmp.name[sizeof(tmp.name)-1] = 0;

newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo)
@@ -2079,6 +2081,7 @@ do_ip6t_get_ctl(struct sock *sk, int cmd
ret = -EFAULT;
break;
}
+ rev.name[sizeof(rev.name)-1] = 0;

if (cmd == IP6T_SO_GET_REVISION_TARGET)
target = 1;


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