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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 032CBC433DF for ; Fri, 29 May 2020 00:10:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D321A206B6 for ; Fri, 29 May 2020 00:10:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438058AbgE2AKi (ORCPT ); Thu, 28 May 2020 20:10:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437671AbgE2AKZ (ORCPT ); Thu, 28 May 2020 20:10:25 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E3EEC08C5C7; Thu, 28 May 2020 17:10:25 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.93 #3 (Red Hat Linux)) id 1jeSbP-00HEZb-Lh; Fri, 29 May 2020 00:10:23 +0000 From: Al Viro To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 3/3] pcm_native: result of put_user() needs to be checked Date: Fri, 29 May 2020 01:10:23 +0100 Message-Id: <20200529001023.4107547-3-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200529001023.4107547-1-viro@ZenIV.linux.org.uk> References: <20200529000957.GW23230@ZenIV.linux.org.uk> <20200529001023.4107547-1-viro@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Al Viro ... and no, __put_user() doesn't help here - skipping access_ok() on the second call does not remove the possibility of page having become unmapped or r/o in the meanwhile Signed-off-by: Al Viro --- sound/core/pcm_native.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index aef860256278..47838f57a647 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -3093,7 +3093,8 @@ static int snd_pcm_xferi_frames_ioctl(struct snd_pcm_substream *substream, result = snd_pcm_lib_write(substream, xferi.buf, xferi.frames); else result = snd_pcm_lib_read(substream, xferi.buf, xferi.frames); - __put_user(result, &_xferi->result); + if (put_user(result, &_xferi->result)) + return -EFAULT; return result < 0 ? result : 0; } @@ -3122,7 +3123,8 @@ static int snd_pcm_xfern_frames_ioctl(struct snd_pcm_substream *substream, else result = snd_pcm_lib_readv(substream, bufs, xfern.frames); kfree(bufs); - __put_user(result, &_xfern->result); + if (put_user(result, &_xfern->result)) + return -EFAULT; return result < 0 ? result : 0; } @@ -3137,7 +3139,8 @@ static int snd_pcm_rewind_ioctl(struct snd_pcm_substream *substream, if (put_user(0, _frames)) return -EFAULT; result = snd_pcm_rewind(substream, frames); - __put_user(result, _frames); + if (put_user(result, _frames)) + return -EFAULT; return result < 0 ? result : 0; } @@ -3152,7 +3155,8 @@ static int snd_pcm_forward_ioctl(struct snd_pcm_substream *substream, if (put_user(0, _frames)) return -EFAULT; result = snd_pcm_forward(substream, frames); - __put_user(result, _frames); + if (put_user(result, _frames)) + return -EFAULT; return result < 0 ? result : 0; } -- 2.11.0