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=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS 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 61724C43381 for ; Thu, 21 Feb 2019 00:21:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 18F012089F for ; Thu, 21 Feb 2019 00:21:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550708464; bh=kdFDe1h/LxsYUxxUCyEQ7rDuL5vpfwk/tzF6NmlEan8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=K1FfIgRR6feiPsKNqpdAOhJ3WNMMKLsqUHgwqoxQKikXKyg7hKqrK41dD6D5uJacn sxxK+wLEXWObHDwdEl/KdJP3Pk4yJZFZyXTOMn+vigRwgzwZkuQ8zML5gzanqw1rzg 0DDnJjLgTJIP/5YpZed/QA4BUCP5xZqrE+XDEANM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726224AbfBUAVC (ORCPT ); Wed, 20 Feb 2019 19:21:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:44888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbfBUAVC (ORCPT ); Wed, 20 Feb 2019 19:21:02 -0500 Received: from devnote (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 81BE120855; Thu, 21 Feb 2019 00:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550708461; bh=kdFDe1h/LxsYUxxUCyEQ7rDuL5vpfwk/tzF6NmlEan8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ZqJehPOrVXLGasi+2K0691rjrJV4sAtLY77TJx0LdBQMIkZkDD+3TOssL51EWK4qT 1E1LyK+rzJNezHO6dF1DPrKOnfoGQTGQqRl4MtmX3eQId6jRxwbPb+Ph4Piy7BwO92 GAXAYcsvqtxh/TtnougYnIpoFECBlPu44WNMEgB4= Date: Thu, 21 Feb 2019 09:20:57 +0900 From: Masami Hiramatsu To: Jann Horn Cc: Ingo Molnar , Steven Rostedt , linux-kernel@vger.kernel.org, Song Liu , Masami Hiramatsu Subject: Re: [PATCH v2] perf/core: use strndup_user() instead of buggy open-coded version Message-Id: <20190221092057.8c56fa4db9eb39b7b14cd0fe@kernel.org> In-Reply-To: <20190220165443.152385-1-jannh@google.com> References: <20190220165443.152385-1-jannh@google.com> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jann, On Wed, 20 Feb 2019 17:54:43 +0100 Jann Horn wrote: > The first version of this method was missing the check for > `ret == PATH_MAX`; then such a check was added, but it didn't call kfree() > on error, so there was still a small memory leak in the error case. > Fix it by using strndup_user() instead of open-coding it. > This looks good to me. Reviewed-by: Masami Hiramatsu BTW, for stable, this is good. For the long term, I think we should fix strndup_user() to return -E2BUG when the user string is longer than max. Thank you, > Fixes: 0eadcc7a7bc0 ("perf/core: Fix perf_uprobe_init()") > Signed-off-by: Jann Horn > --- > v2: > - be compatible with existing error codes (Masami Hiramatsu) > > kernel/trace/trace_event_perf.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c > index 76217bbef815..4629a6104474 100644 > --- a/kernel/trace/trace_event_perf.c > +++ b/kernel/trace/trace_event_perf.c > @@ -299,15 +299,13 @@ int perf_uprobe_init(struct perf_event *p_event, > > if (!p_event->attr.uprobe_path) > return -EINVAL; > - path = kzalloc(PATH_MAX, GFP_KERNEL); > - if (!path) > - return -ENOMEM; > - ret = strncpy_from_user( > - path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX); > - if (ret == PATH_MAX) > - return -E2BIG; > - if (ret < 0) > - goto out; > + > + path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path), > + PATH_MAX); > + if (IS_ERR(path)) { > + ret = PTR_ERR(path); > + return (ret == -EINVAL) ? -E2BIG : ret; > + } > if (path[0] == '\0') { > ret = -EINVAL; > goto out; > -- > 2.21.0.rc0.258.g878e2cd30e-goog > -- Masami Hiramatsu