From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Moore Subject: [PATCH v2] cipso: handle CIPSO options correctly when NetLabel is disabled Date: Fri, 01 Jun 2012 11:54:56 -0400 Message-ID: <20120601155456.5114.68007.stgit@sifl> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-security-module@vger.kernel.org To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:23563 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964952Ab2FAPzE (ORCPT ); Fri, 1 Jun 2012 11:55:04 -0400 Sender: netdev-owner@vger.kernel.org List-ID: When NetLabel is not enabled, e.g. CONFIG_NETLABEL=n, and the system receives a CIPSO tagged packet it is dropped (cipso_v4_validate() returns non-zero). In most cases this is the correct and desired behavior, however, in the case where we are simply forwarding the traffic, e.g. acting as a network bridge, this becomes a problem. This patch fixes the forwarding problem by providing the basic CIPSO validation code directly in ip_options_compile() without the need for the NetLabel or CIPSO code. The new validation code can not perform any of the CIPSO option label/value verification that cipso_v4_validate() does, but it can verify the basic CIPSO option format. The behavior when NetLabel is enabled is unchanged. CC: stable@vger.kernel.org Signed-off-by: Paul Moore -- ChangeLog -v2 * Moved the CONFIG_NETLABEL=n code into cipso_ipv4.h -v1 * Initial version --- include/net/cipso_ipv4.h | 29 ++++++++++++++++++++++++++++- 1 files changed, 28 insertions(+), 1 deletions(-) diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h index 9808877..a7a683e 100644 --- a/include/net/cipso_ipv4.h +++ b/include/net/cipso_ipv4.h @@ -42,6 +42,7 @@ #include #include #include +#include /* known doi values */ #define CIPSO_V4_DOI_UNKNOWN 0x00000000 @@ -285,7 +286,33 @@ static inline int cipso_v4_skbuff_getattr(const struct sk_buff *skb, static inline int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) { - return -ENOSYS; + unsigned char *opt = *option; + unsigned char err_offset = 0; + u8 opt_len = opt[1]; + u8 opt_iter; + + if (opt_len < 8) { + err_offset = 1; + goto out; + } + + if (get_unaligned_be32(&opt[2]) == 0) { + err_offset = 2; + goto out; + } + + for (opt_iter = 6; opt_iter < opt_len;) { + if (opt[opt_iter + 1] > (opt_len - opt_iter)) { + err_offset = opt_iter + 1; + goto out; + } + opt_iter += opt[opt_iter + 1]; + } + +out: + *option = opt + err_offset; + return err_offset; + } #endif /* CONFIG_NETLABEL */