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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 799BDC35249 for ; Sun, 2 Feb 2020 17:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B071206D3 for ; Sun, 2 Feb 2020 17:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726885AbgBBRiG convert rfc822-to-8bit (ORCPT ); Sun, 2 Feb 2020 12:38:06 -0500 Received: from mail.fireflyinternet.com ([77.68.26.236]:51322 "EHLO fireflyinternet.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726525AbgBBRiG (ORCPT ); Sun, 2 Feb 2020 12:38:06 -0500 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 20092098-1500050 for multiple; Sun, 02 Feb 2020 17:37:33 +0000 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT To: DRI Development , Daniel Vetter From: Chris Wilson In-Reply-To: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> Cc: Intel Graphics Development , Daniel Vetter , Dan Carpenter , Hillf Danton , stable@vger.kernel.org, Emil Velikov , Sean Paul , Eric Anholt , Sam Ravnborg , Rob Clark , Daniel Vetter References: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> Message-ID: <158066505178.17828.178213696291677257@skylake-alporthouse-com> User-Agent: alot/0.6 Subject: Re: [PATCH] drm/vgem: Close use-after-free race in vgem_gem_create Date: Sun, 02 Feb 2020 17:37:31 +0000 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Quoting Daniel Vetter (2020-02-02 13:21:33) > There's two references floating around here (for the object reference, > not the handle_count reference, that's a different thing): > > - The temporary reference held by vgem_gem_create, acquired by > creating the object and released by calling > drm_gem_object_put_unlocked. > > - The reference held by the object handle, created by > drm_gem_handle_create. This one generally outlives the function, > except if a 2nd thread races with a GEM_CLOSE ioctl call. > > So usually everything is correct, except in that race case, where the > access to gem_object->size could be looking at freed data already. > Which again isn't a real problem (userspace shot its feet off already > with the race, we could return garbage), but maybe someone can exploit > this as an information leak. > > Cc: Dan Carpenter > Cc: Hillf Danton > Cc: Reported-by: syzbot+0dc4444774d419e916c8@syzkaller.appspotmail.com > Cc: stable@vger.kernel.org > Cc: Emil Velikov > Cc: Daniel Vetter > Cc: Sean Paul > Cc: Chris Wilson > Cc: Eric Anholt > Cc: Sam Ravnborg > Cc: Rob Clark > Signed-off-by: Daniel Vetter > --- > drivers/gpu/drm/vgem/vgem_drv.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index 5bd60ded3d81..909eba43664a 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -196,9 +196,10 @@ static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, > return ERR_CAST(obj); > > ret = drm_gem_handle_create(file, &obj->base, handle); > - drm_gem_object_put_unlocked(&obj->base); > - if (ret) > + if (ret) { > + drm_gem_object_put_unlocked(&obj->base); > return ERR_PTR(ret); > + } > > return &obj->base; > } > @@ -221,7 +222,9 @@ static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, > args->size = gem_object->size; > args->pitch = pitch; > > - DRM_DEBUG("Created object of size %lld\n", size); > + drm_gem_object_put_unlocked(gem_object); > + > + DRM_DEBUG("Created object of size %llu\n", args->size); I was thinking we either should return size from vgem_gem_create (the strategy we took in i915) or simply remove the vgem_gem_create() as that doesn't improve readability. -static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, - struct drm_file *file, - unsigned int *handle, - unsigned long size) +static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, + struct drm_mode_create_dumb *args) { struct drm_vgem_gem_object *obj; - int ret; + u64 pitch, size; + u32 handle; + + pitch = args->width * DIV_ROUND_UP(args->bpp, 8); + size = mul_u32_u32(args->height, pitch); + if (size == 0 || pitch < args->width) + return -EINVAL; obj = __vgem_gem_create(dev, size); if (IS_ERR(obj)) - return ERR_CAST(obj); + return PTR_ERR(obj); + + size = obj->base.size; - ret = drm_gem_handle_create(file, &obj->base, handle); + ret = drm_gem_handle_create(file, &obj->base, &handle); drm_gem_object_put_unlocked(&obj->base); if (ret) return ERR_PTR(ret); - return &obj->base; -} - -static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, - struct drm_mode_create_dumb *args) -{ - struct drm_gem_object *gem_object; - u64 pitch, size; - - pitch = args->width * DIV_ROUND_UP(args->bpp, 8); - size = args->height * pitch; - if (size == 0) - return -EINVAL; - - gem_object = vgem_gem_create(dev, file, &args->handle, size); - if (IS_ERR(gem_object)) - return PTR_ERR(gem_object); - - args->size = gem_object->size; + args->size = size; args->pitch = pitch; + args->handle = handle; At the end of the day, it makes no difference, Reviewed-by: Chris Wilson -Chris 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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 44C13C35249 for ; Sun, 2 Feb 2020 17:38:37 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 296702067C for ; Sun, 2 Feb 2020 17:38:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 296702067C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 56C886EB18; Sun, 2 Feb 2020 17:38:34 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9C6F46E086; Sun, 2 Feb 2020 17:38:32 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 20092098-1500050 for multiple; Sun, 02 Feb 2020 17:37:33 +0000 MIME-Version: 1.0 To: DRI Development , Daniel Vetter From: Chris Wilson In-Reply-To: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> References: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> Message-ID: <158066505178.17828.178213696291677257@skylake-alporthouse-com> User-Agent: alot/0.6 Subject: Re: [PATCH] drm/vgem: Close use-after-free race in vgem_gem_create Date: Sun, 02 Feb 2020 17:37:31 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Clark , Hillf Danton , Daniel Vetter , Intel Graphics Development , stable@vger.kernel.org, Sean Paul , Daniel Vetter , Sam Ravnborg , Dan Carpenter , Emil Velikov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Quoting Daniel Vetter (2020-02-02 13:21:33) > There's two references floating around here (for the object reference, > not the handle_count reference, that's a different thing): > > - The temporary reference held by vgem_gem_create, acquired by > creating the object and released by calling > drm_gem_object_put_unlocked. > > - The reference held by the object handle, created by > drm_gem_handle_create. This one generally outlives the function, > except if a 2nd thread races with a GEM_CLOSE ioctl call. > > So usually everything is correct, except in that race case, where the > access to gem_object->size could be looking at freed data already. > Which again isn't a real problem (userspace shot its feet off already > with the race, we could return garbage), but maybe someone can exploit > this as an information leak. > > Cc: Dan Carpenter > Cc: Hillf Danton > Cc: Reported-by: syzbot+0dc4444774d419e916c8@syzkaller.appspotmail.com > Cc: stable@vger.kernel.org > Cc: Emil Velikov > Cc: Daniel Vetter > Cc: Sean Paul > Cc: Chris Wilson > Cc: Eric Anholt > Cc: Sam Ravnborg > Cc: Rob Clark > Signed-off-by: Daniel Vetter > --- > drivers/gpu/drm/vgem/vgem_drv.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index 5bd60ded3d81..909eba43664a 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -196,9 +196,10 @@ static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, > return ERR_CAST(obj); > > ret = drm_gem_handle_create(file, &obj->base, handle); > - drm_gem_object_put_unlocked(&obj->base); > - if (ret) > + if (ret) { > + drm_gem_object_put_unlocked(&obj->base); > return ERR_PTR(ret); > + } > > return &obj->base; > } > @@ -221,7 +222,9 @@ static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, > args->size = gem_object->size; > args->pitch = pitch; > > - DRM_DEBUG("Created object of size %lld\n", size); > + drm_gem_object_put_unlocked(gem_object); > + > + DRM_DEBUG("Created object of size %llu\n", args->size); I was thinking we either should return size from vgem_gem_create (the strategy we took in i915) or simply remove the vgem_gem_create() as that doesn't improve readability. -static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, - struct drm_file *file, - unsigned int *handle, - unsigned long size) +static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, + struct drm_mode_create_dumb *args) { struct drm_vgem_gem_object *obj; - int ret; + u64 pitch, size; + u32 handle; + + pitch = args->width * DIV_ROUND_UP(args->bpp, 8); + size = mul_u32_u32(args->height, pitch); + if (size == 0 || pitch < args->width) + return -EINVAL; obj = __vgem_gem_create(dev, size); if (IS_ERR(obj)) - return ERR_CAST(obj); + return PTR_ERR(obj); + + size = obj->base.size; - ret = drm_gem_handle_create(file, &obj->base, handle); + ret = drm_gem_handle_create(file, &obj->base, &handle); drm_gem_object_put_unlocked(&obj->base); if (ret) return ERR_PTR(ret); - return &obj->base; -} - -static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, - struct drm_mode_create_dumb *args) -{ - struct drm_gem_object *gem_object; - u64 pitch, size; - - pitch = args->width * DIV_ROUND_UP(args->bpp, 8); - size = args->height * pitch; - if (size == 0) - return -EINVAL; - - gem_object = vgem_gem_create(dev, file, &args->handle, size); - if (IS_ERR(gem_object)) - return PTR_ERR(gem_object); - - args->size = gem_object->size; + args->size = size; args->pitch = pitch; + args->handle = handle; At the end of the day, it makes no difference, Reviewed-by: Chris Wilson -Chris _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 C469FC35249 for ; Sun, 2 Feb 2020 17:38:34 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 A3A4A2067C for ; Sun, 2 Feb 2020 17:38:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3A4A2067C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EE70A6E086; Sun, 2 Feb 2020 17:38:33 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9C6F46E086; Sun, 2 Feb 2020 17:38:32 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 20092098-1500050 for multiple; Sun, 02 Feb 2020 17:37:33 +0000 MIME-Version: 1.0 To: DRI Development , Daniel Vetter From: Chris Wilson In-Reply-To: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> References: <20200202132133.1891846-1-daniel.vetter@ffwll.ch> Message-ID: <158066505178.17828.178213696291677257@skylake-alporthouse-com> User-Agent: alot/0.6 Date: Sun, 02 Feb 2020 17:37:31 +0000 Subject: Re: [Intel-gfx] [PATCH] drm/vgem: Close use-after-free race in vgem_gem_create X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Clark , Hillf Danton , Daniel Vetter , Intel Graphics Development , stable@vger.kernel.org, Eric Anholt , Sean Paul , Daniel Vetter , Sam Ravnborg , Dan Carpenter , Emil Velikov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Daniel Vetter (2020-02-02 13:21:33) > There's two references floating around here (for the object reference, > not the handle_count reference, that's a different thing): > > - The temporary reference held by vgem_gem_create, acquired by > creating the object and released by calling > drm_gem_object_put_unlocked. > > - The reference held by the object handle, created by > drm_gem_handle_create. This one generally outlives the function, > except if a 2nd thread races with a GEM_CLOSE ioctl call. > > So usually everything is correct, except in that race case, where the > access to gem_object->size could be looking at freed data already. > Which again isn't a real problem (userspace shot its feet off already > with the race, we could return garbage), but maybe someone can exploit > this as an information leak. > > Cc: Dan Carpenter > Cc: Hillf Danton > Cc: Reported-by: syzbot+0dc4444774d419e916c8@syzkaller.appspotmail.com > Cc: stable@vger.kernel.org > Cc: Emil Velikov > Cc: Daniel Vetter > Cc: Sean Paul > Cc: Chris Wilson > Cc: Eric Anholt > Cc: Sam Ravnborg > Cc: Rob Clark > Signed-off-by: Daniel Vetter > --- > drivers/gpu/drm/vgem/vgem_drv.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index 5bd60ded3d81..909eba43664a 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -196,9 +196,10 @@ static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, > return ERR_CAST(obj); > > ret = drm_gem_handle_create(file, &obj->base, handle); > - drm_gem_object_put_unlocked(&obj->base); > - if (ret) > + if (ret) { > + drm_gem_object_put_unlocked(&obj->base); > return ERR_PTR(ret); > + } > > return &obj->base; > } > @@ -221,7 +222,9 @@ static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, > args->size = gem_object->size; > args->pitch = pitch; > > - DRM_DEBUG("Created object of size %lld\n", size); > + drm_gem_object_put_unlocked(gem_object); > + > + DRM_DEBUG("Created object of size %llu\n", args->size); I was thinking we either should return size from vgem_gem_create (the strategy we took in i915) or simply remove the vgem_gem_create() as that doesn't improve readability. -static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, - struct drm_file *file, - unsigned int *handle, - unsigned long size) +static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, + struct drm_mode_create_dumb *args) { struct drm_vgem_gem_object *obj; - int ret; + u64 pitch, size; + u32 handle; + + pitch = args->width * DIV_ROUND_UP(args->bpp, 8); + size = mul_u32_u32(args->height, pitch); + if (size == 0 || pitch < args->width) + return -EINVAL; obj = __vgem_gem_create(dev, size); if (IS_ERR(obj)) - return ERR_CAST(obj); + return PTR_ERR(obj); + + size = obj->base.size; - ret = drm_gem_handle_create(file, &obj->base, handle); + ret = drm_gem_handle_create(file, &obj->base, &handle); drm_gem_object_put_unlocked(&obj->base); if (ret) return ERR_PTR(ret); - return &obj->base; -} - -static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev, - struct drm_mode_create_dumb *args) -{ - struct drm_gem_object *gem_object; - u64 pitch, size; - - pitch = args->width * DIV_ROUND_UP(args->bpp, 8); - size = args->height * pitch; - if (size == 0) - return -EINVAL; - - gem_object = vgem_gem_create(dev, file, &args->handle, size); - if (IS_ERR(gem_object)) - return PTR_ERR(gem_object); - - args->size = gem_object->size; + args->size = size; args->pitch = pitch; + args->handle = handle; At the end of the day, it makes no difference, Reviewed-by: Chris Wilson -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx