From: Justus Winter <4winter@informatik.uni-hamburg.de> Date: Mon, 24 Sep 2012 12:55:10 +0000 (+0200) Subject: Re: [PATCH 2/2] Avoid potentially dereferencing a NULL pointer X-Git-Url: http://git.tremily.us/gitweb.cgi?a=commitdiff_plain;h=a22e33ff737eea338e672422b5e22029ef2c2be1;p=notmuch-archives.git Re: [PATCH 2/2] Avoid potentially dereferencing a NULL pointer --- diff --git a/44/4fb86601429657167d7155249fb2739abce845 b/44/4fb86601429657167d7155249fb2739abce845 new file mode 100644 index 000000000..0e3074444 --- /dev/null +++ b/44/4fb86601429657167d7155249fb2739abce845 @@ -0,0 +1,94 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 8FE61431FC0 + for ; Mon, 24 Sep 2012 05:55:15 -0700 (PDT) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: 0 +X-Spam-Level: +X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none] + autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id mlNKwC8iiedZ for ; + Mon, 24 Sep 2012 05:55:14 -0700 (PDT) +Received: from mail.cryptobitch.de (cryptobitch.de [88.198.7.68]) + (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) + (No client certificate requested) + by olra.theworths.org (Postfix) with ESMTPS id B8EA4431FAF + for ; Mon, 24 Sep 2012 05:55:14 -0700 (PDT) +Received: from mail.jade-hamburg.de (mail.jade-hamburg.de [85.183.11.228]) + (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) + (No client certificate requested) + by mail.cryptobitch.de (Postfix) with ESMTPSA id 88A7C5AB202 + for ; Mon, 24 Sep 2012 14:55:13 +0200 (CEST) +Received: by mail.jade-hamburg.de (Postfix, from userid 401) + id F2819DF2A3; Mon, 24 Sep 2012 14:55:12 +0200 (CEST) +Received: from thinkbox.jade-hamburg.de (mail.jade-hamburg.de [85.183.11.228]) + (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) + (No client certificate requested) (Authenticated sender: teythoon) + by mail.jade-hamburg.de (Postfix) with ESMTPSA id F3FFDDF2A1; + Mon, 24 Sep 2012 14:55:11 +0200 (CEST) +Received: from teythoon by thinkbox.jade-hamburg.de with local (Exim 4.80) + (envelope-from ) + id 1TG8Bq-0003kp-SR; Mon, 24 Sep 2012 14:55:10 +0200 +Content-Type: text/plain; charset="utf-8" +MIME-Version: 1.0 +Content-Transfer-Encoding: quoted-printable +To: Austin Clements , +From: Justus Winter <4winter@informatik.uni-hamburg.de> +In-Reply-To: <20120922161908.GF26662@mit.edu> +References: + <1348231837-21700-1-git-send-email-4winter@informatik.uni-hamburg.de> + <1348231837-21700-2-git-send-email-4winter@informatik.uni-hamburg.de> + <20120922161908.GF26662@mit.edu> +Message-ID: <20120924125510.13910.18774@thinkbox.jade-hamburg.de> +User-Agent: alot/0.3.3+ +Subject: Re: [PATCH 2/2] Avoid potentially dereferencing a NULL pointer +Date: Mon, 24 Sep 2012 14:55:10 +0200 +Cc: notmuch@notmuchmail.org +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Mon, 24 Sep 2012 12:55:15 -0000 + +Quoting Austin Clements (2012-09-22 18:19:08) +> Quoth Justus Winter on Sep 21 at 2:50 pm: +> > GMIME_IS_MULTIPART and GMIME_IS_MESSAGE both handle NULL pointers +> > gracefully, but the G_OBJECT_TYPE used in the error handling block +> > dereferences it without checking it first. +> > = + +> > Fix this by checking whether parent->part is valid. +> > = + +> > Found using the clang static analyzer. +> = + +> Neat. + +Yes. Besides this the code turns up no warnings (modulo one false +positive, clang doesn't understand that progress_notify is never +called if it's NULL in notmuch_database_upgrade b/c the signal handler +isn't set up then). + +> Can this actually happen, though? If so, I think this point is too +> late to be checking for a NULL part field. It should probably be +> checked when the mime_node_t is created so that mime_node_t never has +> a NULL part field. + +I'm not sure actually. Then again this patch isn't hacky at all and +being somewhat defensive isn't bad imho. + +Justus