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[209.51.188.17]) by mx.google.com with ESMTPS id p185si19407984vsd.180.2019.07.25.10.27.26 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 25 Jul 2019 10:27:26 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1]:34316 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqhWY-0001Yg-C1 for alex.bennee@linaro.org; Thu, 25 Jul 2019 13:27:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57289) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqhWU-0001YM-Ri for qemu-arm@nongnu.org; Thu, 25 Jul 2019 13:27:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqhWS-0001ct-LD for qemu-arm@nongnu.org; Thu, 25 Jul 2019 13:27:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57060) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqhWO-0001bs-VF; Thu, 25 Jul 2019 13:27:17 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6EE037F41; Thu, 25 Jul 2019 17:27:15 +0000 (UTC) Received: from work-vm (ovpn-117-187.ams2.redhat.com [10.36.117.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A82425DA9A; Thu, 25 Jul 2019 17:27:14 +0000 (UTC) Date: Thu, 25 Jul 2019 18:27:12 +0100 From: "Dr. David Alan Gilbert" To: Peter Maydell Message-ID: <20190725172712.GM2656@work-vm> References: <20190725163710.11703-1-peter.maydell@linaro.org> <20190725163710.11703-3-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190725163710.11703-3-peter.maydell@linaro.org> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 25 Jul 2019 17:27:16 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-arm] [PATCH for-4.1? 2/2] vmstate.h: Type check VMSTATE_STRUCT_VARRAY macros X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , qemu-arm@nongnu.org, qemu-devel@nongnu.org, Juan Quintela Errors-To: qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org Sender: "Qemu-arm" X-TUID: HRqdT5d3RceU * Peter Maydell (peter.maydell@linaro.org) wrote: > The VMSTATE_STRUCT_VARRAY_UINT32 macro is intended to handle > migrating a field which is an array of structs, but where instead of > migrating the entire array we only migrate a variable number of > elements of it. > > The VMSTATE_STRUCT_VARRAY_POINTER_UINT32 macro is intended to handle > migrating a field which is of pointer type, and points to a > dynamically allocated array of structs of variable size. > > We weren't actually checking that the field passed to > VMSTATE_STRUCT_VARRAY_UINT32 really is an array, with the result that > accidentally using it where the _POINTER_ macro was intended would > compile but silently corrupt memory on migration. > > Add type-checking that enforces that the field passed in is > really of the right array type. This applies to all the VMSTATE > macros which use flags including VMS_VARRAY_* but not VMS_POINTER. > > Signed-off-by: Peter Maydell > --- > include/migration/vmstate.h | 27 +++++++++++++++++++++------ > 1 file changed, 21 insertions(+), 6 deletions(-) > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > index ca68584eba4..2df333c3612 100644 > --- a/include/migration/vmstate.h > +++ b/include/migration/vmstate.h > @@ -227,8 +227,19 @@ extern const VMStateInfo vmstate_info_bitmap; > extern const VMStateInfo vmstate_info_qtailq; > > #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0) > +/* Check that t2 is an array of t1 of size n */ > #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0) I'd have to admit I don't understand why that does what you say; I'd expected something to index a t2 pointer with [n]. However, for the rest of it, from migration I'm happy: Reviewed-by: Dr. David Alan Gilbert given it's just fixing an ARM bug, and given it'll blow up straight away I think it's OK for 4.1; the only risk is if we find a compiler we don't like. > #define type_check_pointer(t1,t2) ((t1**)0 - (t2*)0) > +/* > + * type of element 0 of the specified (array) field of the type. > + * Note that if the field is a pointer then this will return the > + * pointed-to type rather than complaining. > + */ > +#define typeof_elt_of_field(type, field) typeof(((type *)0)->field[0]) > +/* Check that field f in struct type t2 is an array of t1, of any size */ > +#define type_check_varray(t1, t2, f) \ > + (type_check(t1, typeof_elt_of_field(t2, f)) \ > + + QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(((t2 *)0)->f))) > > #define vmstate_offset_value(_state, _field, _type) \ > (offsetof(_state, _field) + \ > @@ -253,6 +264,10 @@ extern const VMStateInfo vmstate_info_qtailq; > vmstate_offset_array(_state, _field, uint8_t, \ > sizeof(typeof_field(_state, _field))) > > +#define vmstate_offset_varray(_state, _field, _type) \ > + (offsetof(_state, _field) + \ > + type_check_varray(_type, _state, _field)) > + > /* In the macros below, if there is a _version, that means the macro's > * field will be processed only if the version being received is >= > * the _version specified. In general, if you add a new field, you > @@ -347,7 +362,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_UINT32|VMS_MULTIPLY_ELEMENTS, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_ARRAY_TEST(_field, _state, _num, _test, _info, _type) {\ > @@ -376,7 +391,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_INT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_VARRAY_INT32(_field, _state, _field_num, _version, _info, _type) {\ > @@ -416,7 +431,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_UINT16, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_VSTRUCT_TEST(_field, _state, _test, _version, _vmsd, _type, _struct_version) { \ > @@ -520,7 +535,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_UINT8, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > /* a variable length array (i.e. _type *_field) but we know the > @@ -573,7 +588,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_INT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_STRUCT_VARRAY_UINT32(_field, _state, _field_num, _version, _vmsd, _type) { \ > @@ -583,7 +598,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_UINT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_STRUCT_VARRAY_ALLOC(_field, _state, _field_num, _version, _vmsd, _type) {\ > -- > 2.20.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK 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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 4C2A9C76190 for ; 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Thu, 25 Jul 2019 13:27:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57060) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqhWO-0001bs-VF; Thu, 25 Jul 2019 13:27:17 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6EE037F41; Thu, 25 Jul 2019 17:27:15 +0000 (UTC) Received: from work-vm (ovpn-117-187.ams2.redhat.com [10.36.117.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A82425DA9A; Thu, 25 Jul 2019 17:27:14 +0000 (UTC) Date: Thu, 25 Jul 2019 18:27:12 +0100 From: "Dr. David Alan Gilbert" To: Peter Maydell Message-ID: <20190725172712.GM2656@work-vm> References: <20190725163710.11703-1-peter.maydell@linaro.org> <20190725163710.11703-3-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190725163710.11703-3-peter.maydell@linaro.org> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 25 Jul 2019 17:27:16 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH for-4.1? 2/2] vmstate.h: Type check VMSTATE_STRUCT_VARRAY macros 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: Damien Hedde , qemu-arm@nongnu.org, qemu-devel@nongnu.org, Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Peter Maydell (peter.maydell@linaro.org) wrote: > The VMSTATE_STRUCT_VARRAY_UINT32 macro is intended to handle > migrating a field which is an array of structs, but where instead of > migrating the entire array we only migrate a variable number of > elements of it. > > The VMSTATE_STRUCT_VARRAY_POINTER_UINT32 macro is intended to handle > migrating a field which is of pointer type, and points to a > dynamically allocated array of structs of variable size. > > We weren't actually checking that the field passed to > VMSTATE_STRUCT_VARRAY_UINT32 really is an array, with the result that > accidentally using it where the _POINTER_ macro was intended would > compile but silently corrupt memory on migration. > > Add type-checking that enforces that the field passed in is > really of the right array type. This applies to all the VMSTATE > macros which use flags including VMS_VARRAY_* but not VMS_POINTER. > > Signed-off-by: Peter Maydell > --- > include/migration/vmstate.h | 27 +++++++++++++++++++++------ > 1 file changed, 21 insertions(+), 6 deletions(-) > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > index ca68584eba4..2df333c3612 100644 > --- a/include/migration/vmstate.h > +++ b/include/migration/vmstate.h > @@ -227,8 +227,19 @@ extern const VMStateInfo vmstate_info_bitmap; > extern const VMStateInfo vmstate_info_qtailq; > > #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0) > +/* Check that t2 is an array of t1 of size n */ > #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0) I'd have to admit I don't understand why that does what you say; I'd expected something to index a t2 pointer with [n]. However, for the rest of it, from migration I'm happy: Reviewed-by: Dr. David Alan Gilbert given it's just fixing an ARM bug, and given it'll blow up straight away I think it's OK for 4.1; the only risk is if we find a compiler we don't like. > #define type_check_pointer(t1,t2) ((t1**)0 - (t2*)0) > +/* > + * type of element 0 of the specified (array) field of the type. > + * Note that if the field is a pointer then this will return the > + * pointed-to type rather than complaining. > + */ > +#define typeof_elt_of_field(type, field) typeof(((type *)0)->field[0]) > +/* Check that field f in struct type t2 is an array of t1, of any size */ > +#define type_check_varray(t1, t2, f) \ > + (type_check(t1, typeof_elt_of_field(t2, f)) \ > + + QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(((t2 *)0)->f))) > > #define vmstate_offset_value(_state, _field, _type) \ > (offsetof(_state, _field) + \ > @@ -253,6 +264,10 @@ extern const VMStateInfo vmstate_info_qtailq; > vmstate_offset_array(_state, _field, uint8_t, \ > sizeof(typeof_field(_state, _field))) > > +#define vmstate_offset_varray(_state, _field, _type) \ > + (offsetof(_state, _field) + \ > + type_check_varray(_type, _state, _field)) > + > /* In the macros below, if there is a _version, that means the macro's > * field will be processed only if the version being received is >= > * the _version specified. In general, if you add a new field, you > @@ -347,7 +362,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_UINT32|VMS_MULTIPLY_ELEMENTS, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_ARRAY_TEST(_field, _state, _num, _test, _info, _type) {\ > @@ -376,7 +391,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_INT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_VARRAY_INT32(_field, _state, _field_num, _version, _info, _type) {\ > @@ -416,7 +431,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .info = &(_info), \ > .size = sizeof(_type), \ > .flags = VMS_VARRAY_UINT16, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_VSTRUCT_TEST(_field, _state, _test, _version, _vmsd, _type, _struct_version) { \ > @@ -520,7 +535,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_UINT8, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > /* a variable length array (i.e. _type *_field) but we know the > @@ -573,7 +588,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_INT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_STRUCT_VARRAY_UINT32(_field, _state, _field_num, _version, _vmsd, _type) { \ > @@ -583,7 +598,7 @@ extern const VMStateInfo vmstate_info_qtailq; > .vmsd = &(_vmsd), \ > .size = sizeof(_type), \ > .flags = VMS_STRUCT|VMS_VARRAY_UINT32, \ > - .offset = offsetof(_state, _field), \ > + .offset = vmstate_offset_varray(_state, _field, _type), \ > } > > #define VMSTATE_STRUCT_VARRAY_ALLOC(_field, _state, _field_num, _version, _vmsd, _type) {\ > -- > 2.20.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK