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Commit 78b79876 authored by Vasiliy Kulikov's avatar Vasiliy Kulikov Committed by Patrick McHardy
Browse files

netfilter: ip_tables: fix infoleak to userspace 



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: default avatarVasiliy Kulikov <segoon@openwall.com>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
parent 42eab94f

net/ipv4/netfilter/ip_tables.c

+3 −0
Original line number Diff line number Diff line
@@ -1262,6 +1262,7 @@ 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)
@@ -1807,6 +1808,7 @@ 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)
@@ -2036,6 +2038,7 @@ 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;