From 1d9064bb2d8f0ea26a67b2ce74c6d1d461dcfe7d Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Tue, 15 Mar 2011 13:36:05 +0100 Subject: [PATCH] netfilter: ip_tables: fix infoleak to userspace commit 78b79876761b86653df89c48a7010b5cbd41a84a upstream. Structures ipt_replace, compat_ipt_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 and the third bugs were introduced before the git epoch; the second was introduced in 2722971c (v2.6.17-rc1). To trigger the bug one should have CAP_NET_ADMIN. Signed-off-by: Vasiliy Kulikov Signed-off-by: Patrick McHardy Signed-off-by: Paul Gortmaker --- net/ipv4/netfilter/ip_tables.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index b29c66df8d1f..c89ac490657b 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1294,6 +1294,7 @@ do_replace(struct net *net, const void __user *user, unsigned int len) /* 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) @@ -1838,6 +1839,7 @@ compat_do_replace(struct net *net, void __user *user, unsigned int len) 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) @@ -2067,6 +2069,7 @@ do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) ret = -EFAULT; break; } + rev.name[sizeof(rev.name)-1] = 0; if (cmd == IPT_SO_GET_REVISION_TARGET) target = 1; -- 2.39.5