From: Julia Lawall Subject: Re: [PATCH 1/2 v2] scripts/coccinelle: catch freeing cryptographic structures via kfree Date: Wed, 19 Nov 2014 10:41:37 +0100 (CET) Message-ID: References: <20141117151420.10739.16342.stgit@buzz> <20141118114920.13498.73584.stgit@buzz> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Biederman , Michal Marek , Herbert Xu , Gilles Muller , Nicolas Palix , Julia Lawall , linux-crypto@vger.kernel.org, "David S. Miller" To: Konstantin Khlebnikov Return-path: Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:55828 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211AbaKSJlz (ORCPT ); Wed, 19 Nov 2014 04:41:55 -0500 In-Reply-To: <20141118114920.13498.73584.stgit@buzz> Sender: linux-crypto-owner@vger.kernel.org List-ID: > +// Comments: There are false positives in crypto/ where they are > actually freed. I didn't really understand this comment. I ran the semantic patch and got around 10 results, but it wasn't clear to me how to see which were false positives. I would suggest to extend the rule a little bit to include information about where the allocation call is: /// /// Structures allocated by crypto_alloc_* must be freed using crypto_free_*. /// This finds freeing them by kfree. /// // Confidence: Moderate // Copyright: (C) 2014 Konstantin Khlebnikov, GPLv2. // Comments: There are false positives in crypto/ where they are actually freed. // Keywords: crypto, kfree // Options: --no-includes --include-headers virtual org virtual report virtual context @r depends on context || org || report@ expression x; position p1; @@ ( x = crypto_alloc_base@p1(...) | x = crypto_alloc_cipher@p1(...) | x = crypto_alloc_ablkcipher@p1(...) | x = crypto_alloc_aead@p1(...) | x = crypto_alloc_instance@p1(...) | x = crypto_alloc_instance2@p1(...) | x = crypto_alloc_comp@p1(...) | x = crypto_alloc_pcomp@p1(...) | x = crypto_alloc_hash@p1(...) | x = crypto_alloc_ahash@p1(...) | x = crypto_alloc_shash@p1(...) | x = crypto_alloc_rng@p1(...) ) @pb@ expression r.x; position p; @@ * kfree@p(x) @script:python depends on org@ p << pb.p; p1 << r.p1; @@ msg="WARNING: invalid free of crypto_alloc_* allocated data" coccilib.org.print_todo(p[0], msg) coccilib.org.print_link(p1[0], "allocation") @script:python depends on report@ p << pb.p; p1 << r.p1; @@ msg="WARNING: invalid free of crypto_alloc_* allocated data, allocated on line %s" % (p1[0].line) coccilib.report.print_report(p[0], msg)