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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 076ACC433F5 for ; Tue, 12 Oct 2021 09:06:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9FF661039 for ; Tue, 12 Oct 2021 09:06:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235682AbhJLJIU (ORCPT ); Tue, 12 Oct 2021 05:08:20 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:43800 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S235515AbhJLJIL (ORCPT ); Tue, 12 Oct 2021 05:08:11 -0400 X-UUID: 7ab4f167e4e14508a0f398268e47d28f-20211012 X-UUID: 7ab4f167e4e14508a0f398268e47d28f-20211012 Received: from mtkcas10.mediatek.inc [(172.21.101.39)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1131730382; Tue, 12 Oct 2021 17:06:04 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Tue, 12 Oct 2021 17:06:03 +0800 Received: from mszswglt01.gcn.mediatek.inc (10.16.20.20) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 12 Oct 2021 17:06:02 +0800 From: To: CC: , , , , , , , , , , Guangming Cao Subject: Re: [PATCH v2] dma-buf: acquire name lock before read/write dma_buf.name Date: Tue, 12 Oct 2021 17:07:55 +0800 Message-ID: <20211012090755.177441-1-guangming.cao@mediatek.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <169957a7-302b-1de9-39b0-415c4675743a@amd.com> References: <169957a7-302b-1de9-39b0-415c4675743a@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guangming Cao > Am 08.10.21 um 09:54 schrieb guangming.cao@mediatek.com: > > From: Guangming Cao > > > > Because dma-buf.name can be freed in func: "dma_buf_set_name", > > so, we need to acquire lock first before we read/write dma_buf.name > > to prevent Use After Free(UAF) issue. > > > > Signed-off-by: Guangming Cao > > Reviewed-by: Christian König > > Going to push that upstream if nobody else objects. > > Thanks, > Christian. I'm sorry to disturb you, actually I need this patch to solve our issues. Is there any question about it? seems it hasn't been merged into mainline. Thanks, Guangming. > > > --- > > drivers/dma-buf/dma-buf.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > index 511fe0d217a0..a7f6fd13a635 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -1372,6 +1372,8 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) > > if (ret) > > goto error_unlock; > > > > + > > + spin_lock(&buf_obj->name_lock); > > seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", > > buf_obj->size, > > buf_obj->file->f_flags, buf_obj->file->f_mode, > > @@ -1379,6 +1381,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) > > buf_obj->exp_name, > > file_inode(buf_obj->file)->i_ino, > > buf_obj->name ?: ""); > > + spin_unlock(&buf_obj->name_lock); > > > > robj = buf_obj->resv; > > fence = dma_resv_excl_fence(robj);