From nobody Fri Oct 17 08:49:29 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 570D4C43219 for ; Wed, 19 Oct 2022 09:31:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233741AbiJSJbw (ORCPT ); Wed, 19 Oct 2022 05:31:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233631AbiJSJ2K (ORCPT ); Wed, 19 Oct 2022 05:28:10 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F3C0E8A88; Wed, 19 Oct 2022 02:12:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 44A8261889; Wed, 19 Oct 2022 09:10:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A631C433C1; Wed, 19 Oct 2022 09:10:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666170655; bh=yxGkSTZYL1lOGJSNqH0ReJY84nBjcJY52M5+93fYZ7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1t+M6rieGlgqNzMfkuAo2HC1GTFnX2QBRcgP09FPssHpVGSJFebjDxw1+5jTDbXP0 7FQ9kTYS/WLaCwHhbTD8hK3V/4ofe7ws/55BVganxyrUMTE9U2Ltkx7Mz/8X/8rnij OtEt5MmZlx3EQ4qy0b6AhHhuyQlQEUNMRi41l4wo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+c80e9ef5d8bb45894db0@syzkaller.appspotmail.com, Gerd Hoffmann , Vivek Kasireddy , Sasha Levin Subject: [PATCH 6.0 736/862] udmabuf: Set ubuf->sg = NULL if the creation of sg table fails Date: Wed, 19 Oct 2022 10:33:43 +0200 Message-Id: <20221019083322.474096571@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Vivek Kasireddy [ Upstream commit d9c04a1b7a15b5e74b2977461d9511e497f05d8f ] When userspace tries to map the dmabuf and if for some reason (e.g. OOM) the creation of the sg table fails, ubuf->sg needs to be set to NULL. Otherwise, when the userspace subsequently closes the dmabuf fd, we'd try to erroneously free the invalid sg table from release_udmabuf resulting in the following crash reported by syzbot: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 3609 Comm: syz-executor487 Not tainted 5.19.0-syzkaller-13930-g7ebfc85e2cd7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 RIP: 0010:dma_unmap_sgtable include/linux/dma-mapping.h:378 [inline] RIP: 0010:put_sg_table drivers/dma-buf/udmabuf.c:89 [inline] RIP: 0010:release_udmabuf+0xcb/0x4f0 drivers/dma-buf/udmabuf.c:114 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 04 00 00 48 8d 7d 0c 4c 8b 63 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 e2 RSP: 0018:ffffc900037efd30 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffffffff8cb67800 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff84ad27e0 RDI: 0000000000000000 RBP: fffffffffffffff4 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000008c07c R12: ffff88801fa05000 R13: ffff888073db07e8 R14: ffff888025c25440 R15: 0000000000000000 FS: 0000555555fc4300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc1c0ce06e4 CR3: 00000000715e6000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dma_buf_release+0x157/0x2d0 drivers/dma-buf/dma-buf.c:78 __dentry_kill+0x42b/0x640 fs/dcache.c:612 dentry_kill fs/dcache.c:733 [inline] dput+0x806/0xdb0 fs/dcache.c:913 __fput+0x39c/0x9d0 fs/file_table.c:333 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 ptrace_notify+0x114/0x140 kernel/signal.c:2353 ptrace_report_syscall include/linux/ptrace.h:420 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:482 [inline] syscall_exit_work kernel/entry/common.c:249 [inline] syscall_exit_to_user_mode_prepare+0x129/0x280 kernel/entry/common.c:276 __syscall_exit_to_user_mode_work kernel/entry/common.c:281 [inline] syscall_exit_to_user_mode+0x9/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fc1c0c35b6b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffd78a06090 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007fc1c0c35b6b RDX: 0000000020000280 RSI: 0000000040086200 RDI: 0000000000000006 RBP: 0000000000000007 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000c R13: 0000000000000003 R14: 00007fc1c0cfe4a0 R15: 00007ffd78a06140 Modules linked in: Reported-by: syzbot+c80e9ef5d8bb45894db0@syzkaller.appspotmail.com ---[ end trace 0000000000000000 ]--- RIP: 0010:dma_unmap_sgtable include/linux/dma-mapping.h:378 [inline] RIP: 0010:put_sg_table drivers/dma-buf/udmabuf.c:89 [inline] RIP: 0010:release_udmabuf+0xcb/0x4f0 drivers/dma-buf/udmabuf.c:114 Reported-by: syzbot+c80e9ef5d8bb45894db0@syzkaller.appspotmail.com Cc: Gerd Hoffmann Signed-off-by: Vivek Kasireddy Link: http://patchwork.freedesktop.org/patch/msgid/20220825063522.801264-1-= vivek.kasireddy@intel.com Signed-off-by: Gerd Hoffmann Signed-off-by: Sasha Levin --- drivers/dma-buf/udmabuf.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 38e8767ec371..bf11d32205f3 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -124,17 +124,20 @@ static int begin_cpu_udmabuf(struct dma_buf *buf, { struct udmabuf *ubuf =3D buf->priv; struct device *dev =3D ubuf->device->this_device; + int ret =3D 0; =20 if (!ubuf->sg) { ubuf->sg =3D get_sg_table(dev, buf, direction); - if (IS_ERR(ubuf->sg)) - return PTR_ERR(ubuf->sg); + if (IS_ERR(ubuf->sg)) { + ret =3D PTR_ERR(ubuf->sg); + ubuf->sg =3D NULL; + } } else { dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents, direction); } =20 - return 0; + return ret; } =20 static int end_cpu_udmabuf(struct dma_buf *buf, --=20 2.35.1