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 8AFCAC433EF for ; Mon, 15 Nov 2021 22:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6ED6F60273 for ; Mon, 15 Nov 2021 22:58:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344382AbhKOXBg (ORCPT ); Mon, 15 Nov 2021 18:01:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:54768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242965AbhKOSwe (ORCPT ); Mon, 15 Nov 2021 13:52:34 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5DBDF63466; Mon, 15 Nov 2021 18:10:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636999800; bh=cYrOYS1+KIfaOEpww6W/hCePkj8cZjnxveBQ64QIXSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PNk19wkFWiYyrrhiFC88AJWoGDVYOlzig+1+lwZYLqEwpwsY1nyYMmksJVB/CYQh0 RpaI99a7hQ27zlUeA9vDS0GU5TW9kD05kXLQ+RSTVhy48Pjd/QGRINBFOvxxxhv3uN a30tVR9YERLzoZ59yV7QfE2aqsecde2K9YDVK5ts= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuan-Ying Lee , Will Deacon , Sami Tolvanen , Yee Lee , Sasha Levin Subject: [PATCH 5.14 396/849] scs: Release kasan vmalloc poison in scs_free process Date: Mon, 15 Nov 2021 17:57:59 +0100 Message-Id: <20211115165433.646650439@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165419.961798833@linuxfoundation.org> References: <20211115165419.961798833@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yee Lee [ Upstream commit 528a4ab45300fa6283556d9b48e26b45a8aa15c4 ] Since scs allocation is moved to vmalloc region, the shadow stack is protected by kasan_posion_vmalloc. However, the vfree_atomic operation needs to access its context for scs_free process and causes kasan error as the dump info below. This patch Adds kasan_unpoison_vmalloc() before vfree_atomic, which aligns to the prior flow as using kmem_cache. The vmalloc region will go back posioned in the following vumap() operations. ================================================================== BUG: KASAN: vmalloc-out-of-bounds in llist_add_batch+0x60/0xd4 Write of size 8 at addr ffff8000100b9000 by task kthreadd/2 CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.15.0-rc2-11681-g92477dd1faa6-dirty #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x43c show_stack+0x1c/0x2c dump_stack_lvl+0x68/0x84 print_address_description+0x80/0x394 kasan_report+0x180/0x1dc __asan_report_store8_noabort+0x48/0x58 llist_add_batch+0x60/0xd4 vfree_atomic+0x60/0xe0 scs_free+0x1dc/0x1fc scs_release+0xa4/0xd4 free_task+0x30/0xe4 __put_task_struct+0x1ec/0x2e0 delayed_put_task_struct+0x5c/0xa0 rcu_do_batch+0x62c/0x8a0 rcu_core+0x60c/0xc14 rcu_core_si+0x14/0x24 __do_softirq+0x19c/0x68c irq_exit+0x118/0x2dc handle_domain_irq+0xcc/0x134 gic_handle_irq+0x7c/0x1bc call_on_irq_stack+0x40/0x70 do_interrupt_handler+0x78/0x9c el1_interrupt+0x34/0x60 el1h_64_irq_handler+0x1c/0x2c el1h_64_irq+0x78/0x7c _raw_spin_unlock_irqrestore+0x40/0xcc sched_fork+0x4f0/0xb00 copy_process+0xacc/0x3648 kernel_clone+0x168/0x534 kernel_thread+0x13c/0x1b0 kthreadd+0x2bc/0x400 ret_from_fork+0x10/0x20 Memory state around the buggy address: ffff8000100b8f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff8000100b8f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffff8000100b9000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffff8000100b9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff8000100b9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== Suggested-by: Kuan-Ying Lee Acked-by: Will Deacon Tested-by: Will Deacon Reviewed-by: Sami Tolvanen Signed-off-by: Yee Lee Fixes: a2abe7cbd8fe ("scs: switch to vmapped shadow stacks") Link: https://lore.kernel.org/r/20210930081619.30091-1-yee.lee@mediatek.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- kernel/scs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/scs.c b/kernel/scs.c index e2a71fc82fa06..579841be88646 100644 --- a/kernel/scs.c +++ b/kernel/scs.c @@ -78,6 +78,7 @@ void scs_free(void *s) if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL) return; + kasan_unpoison_vmalloc(s, SCS_SIZE); vfree_atomic(s); } -- 2.33.0