From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FC30C43603 for ; Fri, 6 Dec 2019 15:46:21 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5B4322064B for ; Fri, 6 Dec 2019 15:46:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IoTqg2mf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B4322064B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40028 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1idFoB-0000ZP-Sa for qemu-devel@archiver.kernel.org; Fri, 06 Dec 2019 10:46:19 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:33512) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1idEum-00021Z-Ju for qemu-devel@nongnu.org; Fri, 06 Dec 2019 09:49:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1idEul-0005zd-4z for qemu-devel@nongnu.org; Fri, 06 Dec 2019 09:49:04 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:49161 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1idEuk-0005yg-Vb for qemu-devel@nongnu.org; Fri, 06 Dec 2019 09:49:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575643742; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fMomInCBfwvP6AujEflBTyrGGKLFFe2gc1qzHaavmu0=; b=IoTqg2mfHfTkpUGZ4Y6kMLOdSUHGRbavyVq9gfTLPMPYjCb0apeBw3jqIHEnIEXgaI0uCR mBHB+ET54F0wSubOo9PwSYzhmMi8b9jXv5rEK+i6RYmWZZRRjpvVFjZ32reFRRBnALB3Z8 cZH/3PaZqQUTxw4ULcJz7CyYFdDg1P4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-267-ipD46liHOjS3bd5xI6_rug-1; Fri, 06 Dec 2019 02:46:41 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A5FE0DB60; Fri, 6 Dec 2019 07:46:40 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-134.ams2.redhat.com [10.36.116.134]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2051E608E5; Fri, 6 Dec 2019 07:46:40 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 8B69A1138606; Fri, 6 Dec 2019 08:46:38 +0100 (CET) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH 10/21] hw/core: Fix latent fit_load_fdt() error handling bug References: <20191130194240.10517-1-armbru@redhat.com> <20191130194240.10517-11-armbru@redhat.com> Date: Fri, 06 Dec 2019 08:46:38 +0100 In-Reply-To: (Vladimir Sementsov-Ogievskiy's message of "Thu, 5 Dec 2019 16:23:48 +0000") Message-ID: <87tv6dnbfl.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: ipD46liHOjS3bd5xI6_rug-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "qemu-devel@nongnu.org" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Vladimir Sementsov-Ogievskiy writes: > 30.11.2019 22:42, Markus Armbruster wrote: >> fit_load_fdt() recovers from fit_image_addr() failing with ENOENT. >> Except it doesn't when its @errp argument is &error_fatal or >> &error_abort, because it blindly passes @errp to fit_image_addr(). >> Messed up in commit 3eb99edb48 "loader-fit: Wean off error_printf()". >>=20 >> The bug can't bite as no caller actually passes &error_fatal or >> &error_abort. Fix it anyway. >>=20 >> Signed-off-by: Markus Armbruster > > Reviewed-by: Vladimir Sementsov-Ogievskiy > > Hmm, actually it makes my > "[PATCH v7 01/21] hw/core/loader-fit: fix freeing errp in fit_load_fdt" > unnecessary. If you want you may drop my 01 (as it covers less problems), Yes. > and in this case you may note in your cover letter, that > errp =3D NULL is broken here too (may be nobady pass it?), You're right, null @errp is wrong, too. > and normal errp is handled wrong, as *errp doesn't set to NULL after > error_free(*errp) Yes, that's wrong, too. fit_load_fdt() itself doesn't use *errp after freeing it, but it sets a trap for its callers. =20 > (still, the only caller rely on return value more than = on > err, so the problem can't be triggered with current code) True. New commit message (based on v2's): hw/core: Fix fit_load_fdt() error API violations fit_load_fdt() passes @errp to fit_image_addr(), then recovers from ENOENT failures. Passing @errp is wrong, because it works only as long as @errp is neither @error_fatal nor @error_abort. Error recovery dereferences @errp. That's also wrong; see the big comment in error.h. Error recovery can leave *errp pointing to a freed Error object. Wrong, it must be null on success. Messed up in commit 3eb99edb48 "loader-fit: Wean off error_printf()". No caller actually passes such values, or uses *errp on success. Fix anyway: splice in a local Error *err, and error_propagate(). Signed-off-by: Markus Armbruster Okay? > >> --- >> hw/core/loader-fit.c | 15 ++++++++------- >> 1 file changed, 8 insertions(+), 7 deletions(-) >>=20 >> diff --git a/hw/core/loader-fit.c b/hw/core/loader-fit.c >> index 953b16bc82..c465921b8f 100644 >> --- a/hw/core/loader-fit.c >> +++ b/hw/core/loader-fit.c >> @@ -178,11 +178,12 @@ static int fit_load_fdt(const struct fit_loader *l= dr, const void *itb, >> int cfg, void *opaque, const void *match_data, >> hwaddr kernel_end, Error **errp) >> { >> + Error *err =3D NULL; >> const char *name; >> const void *data; >> const void *load_data; >> hwaddr load_addr; >> - int img_off, err; >> + int img_off; >> size_t sz; >> int ret; >> =20 >> @@ -197,13 +198,13 @@ static int fit_load_fdt(const struct fit_loader *l= dr, const void *itb, >> return -EINVAL; >> } >> =20 >> - err =3D fit_image_addr(itb, img_off, "load", &load_addr, errp); >> - if (err =3D=3D -ENOENT) { >> + ret =3D fit_image_addr(itb, img_off, "load", &load_addr, &err); >> + if (ret =3D=3D -ENOENT) { >> load_addr =3D ROUND_UP(kernel_end, 64 * KiB) + (10 * MiB); >> - error_free(*errp); >> - } else if (err) { >> - error_prepend(errp, "unable to read FDT load address from FIT: = "); >> - ret =3D err; >> + error_free(err); >> + } else if (ret) { >> + error_propagate_prepend(errp, err, >> + "unable to read FDT load address from F= IT: "); >> goto out; >> } >> =20 >>=20 > > So much attention to that function :) > > I'd also propose the following: > > diff --git a/hw/core/loader-fit.c b/hw/core/loader-fit.c > index c465921b8f..2c9efeef7a 100644 > --- a/hw/core/loader-fit.c > +++ b/hw/core/loader-fit.c > @@ -180,8 +180,8 @@ static int fit_load_fdt(const struct fit_loader *ldr,= const void *itb, > { > Error *err =3D NULL; > const char *name; > - const void *data; > - const void *load_data; > + void *data; > + void *load_data; > hwaddr load_addr; > int img_off; > size_t sz; > @@ -218,9 +218,9 @@ static int fit_load_fdt(const struct fit_loader *ldr,= const void *itb, > > ret =3D 0; > out: > - g_free((void *) data); > + g_free(data); > if (data !=3D load_data) { > - g_free((void *) load_data); > + g_free(load_data); > } > return ret; > } > > > Or, even better: > > --- a/hw/core/loader-fit.c > +++ b/hw/core/loader-fit.c > @@ -180,7 +180,8 @@ static int fit_load_fdt(const struct fit_loader *ldr,= const void *itb, > { > Error *err =3D NULL; > const char *name; > - const void *data; > + g_autofree void *data =3D NULL; > + g_autofree void *fdt_filter_data =3D NULL; > const void *load_data; > hwaddr load_addr; > int img_off; > @@ -202,27 +203,23 @@ static int fit_load_fdt(const struct fit_loader *ld= r, const void *itb, > if (ret =3D=3D -ENOENT) { > load_addr =3D ROUND_UP(kernel_end, 64 * KiB) + (10 * MiB); > error_free(err); > + return 0; > } else if (ret) { > error_propagate_prepend(errp, err, > "unable to read FDT load address from F= IT: "); > - goto out; > + return ret; > } > > if (ldr->fdt_filter) { > - load_data =3D ldr->fdt_filter(opaque, data, match_data, &load_ad= dr); > + load_data =3D fdt_filter_data =3D > + ldr->fdt_filter(opaque, data, match_data, &load_addr); > } > > load_addr =3D ldr->addr_to_phys(opaque, load_addr); > sz =3D fdt_totalsize(load_data); > rom_add_blob_fixed(name, load_data, sz, load_addr); > > - ret =3D 0; > -out: > - g_free((void *) data); > - if (data !=3D load_data) { > - g_free((void *) load_data); > - } > - return ret; > + return 0; > } Looks like a sensible separate cleanup patch to me. Care to post it? Thanks!