From patchwork Mon Feb 27 20:54:55 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Perches X-Patchwork-Id: 9594243 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5C34E604AB for ; Mon, 27 Feb 2017 20:56:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4C0F028236 for ; Mon, 27 Feb 2017 20:56:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3FEC0283C2; Mon, 27 Feb 2017 20:56:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 2A2B428236 for ; Mon, 27 Feb 2017 20:56:01 +0000 (UTC) Received: (qmail 21618 invoked by uid 550); 27 Feb 2017 20:56:00 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 21563 invoked from network); 27 Feb 2017 20:55:53 -0000 X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: plant25_828ef19cd4225 X-Filterd-Recvd-Size: 2820 From: Joe Perches To: Andrew Morton , Andy Whitcroft Cc: "Roberts, William C" , kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org Date: Mon, 27 Feb 2017 12:54:55 -0800 Message-Id: <163a690510e636a23187c0dc9caa09ddac6d4cde.1488228427.git.joe@perches.com> X-Mailer: git-send-email 2.10.0.rc2.1.g053435c In-Reply-To: <476DC76E7D1DF2438D32BFADF679FC562307BAE6@ORSMSX103.amr.corp.intel.com> References: <476DC76E7D1DF2438D32BFADF679FC562307BAE6@ORSMSX103.amr.corp.intel.com> Subject: [kernel-hardening] [PATCH] checkpatch: Add ability to find bad uses of vsprintf %p extensions X-Virus-Scanned: ClamAV using ClamSMTP %pK was at least once misused at %pk in an out-of-tree module. This lead to some security concerns. Add the ability to track single and multiple line statements for misuses of %p. Signed-off-by: Joe Perches Acked-by: Kees Cook Acked-By: William Roberts --- Andrew, this has gone back and forth a few times. It's imperfect as a patch context with just a single function addition can be missed, but that's not new with $stat tests and just this patch. Perhaps one day the $stat identification mechanism can be improved. Until then, can you please apply this? Thanks. scripts/checkpatch.pl | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index ad5ea5c545b2..9293b8a1c121 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -5676,6 +5676,32 @@ sub process { } } + # check for vsprintf extension %p misuses + if ($^V && $^V ge 5.10.0 && + defined $stat && + $stat =~ /^\+(?![^\{]*\{\s*).*\b(\w+)\s*\(.*$String\s*,/s && + $1 !~ /^_*volatile_*$/) { + my $bad_extension = ""; + my $lc = $stat =~ tr@\n@@; + $lc = $lc + $linenr; + for (my $count = $linenr; $count <= $lc; $count++) { + my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0)); + $fmt =~ s/%%//g; + if ($fmt =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) { + $bad_extension = $1; + last; + } + } + if ($bad_extension ne "") { + my $stat_real = raw_line($linenr, 0); + for (my $count = $linenr + 1; $count <= $lc; $count++) { + $stat_real = $stat_real . "\n" . raw_line($count, 0); + } + WARN("VSPRINTF_POINTER_EXTENSION", + "Invalid vsprintf pointer extension '$bad_extension'\n" . "$here\n$stat_real\n"); + } + } + # Check for misused memsets if ($^V && $^V ge 5.10.0 && defined $stat &&