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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 96795C3F350 for ; Thu, 27 Feb 2020 13:51:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D1D720578 for ; Thu, 27 Feb 2020 13:51:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811465; bh=FOoqKnrn4qOTHfbpPkiMYn5/tbWYlDqVW6aM+YvjngA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Yc+8Qibv7knz3FpXzax1fPxb5UgF1I8i3pZzAu5ZbUvndhqPkGQJaRzBPgoMqofdV RMRBisEA8ecNMPHXP08aRIAvLmoU/HTiUcgYPyb5tUn5I9qtOfqPXRrWgReSGQBJ3k frNL/DVchvLzEx0SGRaQsE1ldLAgr59dlKkn/4vY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731333AbgB0NvD (ORCPT ); Thu, 27 Feb 2020 08:51:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:49578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730883AbgB0NvB (ORCPT ); Thu, 27 Feb 2020 08:51:01 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B030920801; Thu, 27 Feb 2020 13:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811461; bh=FOoqKnrn4qOTHfbpPkiMYn5/tbWYlDqVW6aM+YvjngA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YzfTcdDB+Upq9gxCGsp2VPGkefZxm0vZ4haC86LWFFgeeLsx/Pdbm8M3/qKpjBsMx WmHHP+lEE5d0rSbhsCCtdg2PFG/vJ2I3PzhAEI/0aSWl+/lZ/5IHN+sCGT0W4YJrnJ NCgoh4DXeUV1DGxrABJ31dExAOlL5zHpeyL/SWac= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Potapenko , Walter Wu , Dmitry Vyukov , Matthias Brugger , Thomas Gleixner , Josh Poimboeuf , Kate Stewart , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.9 142/165] lib/stackdepot.c: fix global out-of-bounds in stack_slabs Date: Thu, 27 Feb 2020 14:36:56 +0100 Message-Id: <20200227132251.709838993@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132230.840899170@linuxfoundation.org> References: <20200227132230.840899170@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexander Potapenko [ Upstream commit 305e519ce48e935702c32241f07d393c3c8fed3e ] Walter Wu has reported a potential case in which init_stack_slab() is called after stack_slabs[STACK_ALLOC_MAX_SLABS - 1] has already been initialized. In that case init_stack_slab() will overwrite stack_slabs[STACK_ALLOC_MAX_SLABS], which may result in a memory corruption. Link: http://lkml.kernel.org/r/20200218102950.260263-1-glider@google.com Fixes: cd11016e5f521 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB") Signed-off-by: Alexander Potapenko Reported-by: Walter Wu Cc: Dmitry Vyukov Cc: Matthias Brugger Cc: Thomas Gleixner Cc: Josh Poimboeuf Cc: Kate Stewart Cc: Greg Kroah-Hartman Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- lib/stackdepot.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 1724cb0d6283f..54fe55b6bbc0a 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -92,15 +92,19 @@ static bool init_stack_slab(void **prealloc) return true; if (stack_slabs[depot_index] == NULL) { stack_slabs[depot_index] = *prealloc; + *prealloc = NULL; } else { - stack_slabs[depot_index + 1] = *prealloc; + /* If this is the last depot slab, do not touch the next one. */ + if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) { + stack_slabs[depot_index + 1] = *prealloc; + *prealloc = NULL; + } /* * This smp_store_release pairs with smp_load_acquire() from * |next_slab_inited| above and in stack_depot_save(). */ smp_store_release(&next_slab_inited, 1); } - *prealloc = NULL; return true; } -- 2.20.1