Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754961AbaGZTdK (ORCPT ); Sat, 26 Jul 2014 15:33:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:34552 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753166AbaGZTVC (ORCPT ); Sat, 26 Jul 2014 15:21:02 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Schulz , Daniel Borkmann , "David S. Miller" Subject: [PATCH 3.15 071/109] net: ppp: dont call sk_chk_filter twice Date: Sat, 26 Jul 2014 12:02:33 -0700 Message-Id: <20140726190226.014888929@linuxfoundation.org> X-Mailer: git-send-email 2.0.2 In-Reply-To: <20140726190223.834037485@linuxfoundation.org> References: <20140726190223.834037485@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Schulz [ Upstream commit 3916a3192793fd3c11f69d623ef0cdbdbf9ea10a ] Commit 568f194e8bd16c353ad50f9ab95d98b20578a39d ("net: ppp: use sk_unattached_filter api") causes sk_chk_filter() to be called twice when setting a PPP pass or active filter. This applies to both the generic PPP subsystem implemented by drivers/net/ppp/ppp_generic.c and the ISDN PPP subsystem implemented by drivers/isdn/i4l/isdn_ppp.c. The first call is from within get_filter(). The second one is through the call chain ppp_ioctl() or isdn_ppp_ioctl() --> sk_unattached_filter_create() --> __sk_prepare_filter() --> sk_chk_filter() The first call from within get_filter() should be deleted as get_filter() is called just before calling sk_unattached_filter_create() later on, which eventually calls sk_chk_filter() anyway. For 3.15.x, this proposed change is a bugfix rather than a pure optimization as in that branch, sk_chk_filter() may replace filter codes by other codes which are not recognized when executing sk_chk_filter() a second time. So with 3.15.x, if sk_chk_filter() is called twice, the second invocation may yield EINVAL (this depends on the filter codes found in the filter to be set, but because the replacement is done for frequently used codes, this is almost always the case). The net effect is that setting pass and/or active PPP filters does not work anymore, since sk_unattached_filter_create() always returns EINVAL due to the second call to sk_chk_filter(), regardless whether the filter was originally sane or not. Signed-off-by: Christoph Schulz Acked-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/isdn/i4l/isdn_ppp.c | 8 +------- drivers/net/ppp/ppp_generic.c | 8 +------- 2 files changed, 2 insertions(+), 14 deletions(-) --- a/drivers/isdn/i4l/isdn_ppp.c +++ b/drivers/isdn/i4l/isdn_ppp.c @@ -442,7 +442,7 @@ static int get_filter(void __user *arg, { struct sock_fprog uprog; struct sock_filter *code = NULL; - int len, err; + int len; if (copy_from_user(&uprog, arg, sizeof(uprog))) return -EFAULT; @@ -458,12 +458,6 @@ static int get_filter(void __user *arg, if (IS_ERR(code)) return PTR_ERR(code); - err = sk_chk_filter(code, uprog.len); - if (err) { - kfree(code); - return err; - } - *p = code; return uprog.len; } --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -539,7 +539,7 @@ static int get_filter(void __user *arg, { struct sock_fprog uprog; struct sock_filter *code = NULL; - int len, err; + int len; if (copy_from_user(&uprog, arg, sizeof(uprog))) return -EFAULT; @@ -554,12 +554,6 @@ static int get_filter(void __user *arg, if (IS_ERR(code)) return PTR_ERR(code); - err = sk_chk_filter(code, uprog.len); - if (err) { - kfree(code); - return err; - } - *p = code; return uprog.len; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/