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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 35829C433E0 for ; Thu, 4 Jun 2020 23:50:14 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E20AD20872 for ; Thu, 4 Jun 2020 23:50:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZQLjehVx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E20AD20872 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 87F9A28004C; Thu, 4 Jun 2020 19:50:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 809A8280005; Thu, 4 Jun 2020 19:50:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6AAD428004C; Thu, 4 Jun 2020 19:50:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0104.hostedemail.com [216.40.44.104]) by kanga.kvack.org (Postfix) with ESMTP id 447B1280005 for ; Thu, 4 Jun 2020 19:50:13 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 12D1D3749 for ; Thu, 4 Jun 2020 23:50:13 +0000 (UTC) X-FDA: 76893175506.13.sound45_3403fb626d9b Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin13.hostedemail.com (Postfix) with ESMTP id E95F418140B60 for ; Thu, 4 Jun 2020 23:50:12 +0000 (UTC) X-HE-Tag: sound45_3403fb626d9b X-Filterd-Recvd-Size: 2637 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Jun 2020 23:50:12 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 958FF2087D; Thu, 4 Jun 2020 23:50:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591314611; bh=v1+t/4D+mZtMPYyEFDRUgl/VA+MW8ZmkYQm8xnsdz8U=; h=Date:From:To:Subject:In-Reply-To:From; b=ZQLjehVxtO2ZFd4aydaWFzLisVgiLZEWVU+Peri64cS7MpR82lJYBUx8AHi28nqy+ EuhX+xqt5rwutAy6kyy+D7Rlio1lBsOzS7UeQpIhokkVuEeZ3BglFKNsaCBelVaTLN RaCLH2HDfIDVm2fEH5zqdk3hI3jERxCwFCLlCMR0= Date: Thu, 04 Jun 2020 16:50:11 -0700 From: Andrew Morton To: akpm@linux-foundation.org, christophe.leroy@c-s.fr, jannh@google.com, kpsingh@chromium.org, kpsingh@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, peterz@infradead.org, torvalds@linux-foundation.org Subject: [patch 076/127] lib: Add might_fault() to strncpy_from_user. Message-ID: <20200604235011.CzzlOlAbI%akpm@linux-foundation.org> In-Reply-To: <20200604164523.e15f3177f4b69dcb4f2534a1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: E95F418140B60 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: KP Singh Subject: lib: Add might_fault() to strncpy_from_user. From: KP Singh When updating a piece of broken logic from using get_user to strncpy_from_user, we noticed that a warning which is expected when calling a function that might fault from an atomic context with pagefaults enabled disappeared. Not having this warning in place can lead to calling strncpy_from_user from an atomic context and eventually kernel crashes/stack corruption. Link: http://lkml.kernel.org/r/20200414225705.255711-1-kpsingh@chromium.org Signed-off-by: KP Singh Reviewed-by: Andrew Morton Cc: Jann Horn Cc: Christophe Leroy Cc: Peter Zijlstra Signed-off-by: Andrew Morton --- lib/strncpy_from_user.c | 1 + 1 file changed, 1 insertion(+) --- a/lib/strncpy_from_user.c~lib-add-might_fault-to-strncpy_from_user +++ a/lib/strncpy_from_user.c @@ -98,6 +98,7 @@ long strncpy_from_user(char *dst, const { unsigned long max_addr, src_addr; + might_fault(); if (unlikely(count <= 0)) return 0; _