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 19937C433EF for ; Thu, 11 Nov 2021 10:06:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBCAE61215 for ; Thu, 11 Nov 2021 10:06:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232764AbhKKKI6 (ORCPT ); Thu, 11 Nov 2021 05:08:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:28971 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232587AbhKKKI6 (ORCPT ); Thu, 11 Nov 2021 05:08:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636625168; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jl6i9Vg5MH/D47qfgpp1++mvVXS5mXYZyKefeF00ENM=; b=BYT7gpKl0ciEu7JZa8s2Gad2/zns9UCqsAF/DiwrKTa3Gc5aRZNuxMChC1N8AipDeVFmdG G3wmCrZ8Raa8rJTuPGsNjmBK9YtIoB2aytkPDV5jm48IWAK8+dUafYoXkaFTyvufdp5EOk GzGi1gAyTDozdR6UFTHpmLO15n/54F0= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-408-N3ASglBiOda7qNGh0VzhWA-1; Thu, 11 Nov 2021 05:06:07 -0500 X-MC-Unique: N3ASglBiOda7qNGh0VzhWA-1 Received: by mail-wr1-f69.google.com with SMTP id p17-20020adff211000000b0017b902a7701so918709wro.19 for ; Thu, 11 Nov 2021 02:06:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:from:to:cc:references:organization:in-reply-to :content-transfer-encoding; bh=jl6i9Vg5MH/D47qfgpp1++mvVXS5mXYZyKefeF00ENM=; b=6M9eWFYc5OwVv3Qo4ZW3RvfINvGSYAIRzuQfbvytoUBuVaKqg9WT1CrwVlkGQhhlxd XkPopRSDkA3Y1VU2aAZ3HQuZ6EBKh6xWO08MORAtcW1eJxvcXWsqwB8hm+zDNlG7/uWK 9Vr6uP2K3NiK06gB1DhJw6ipPd+mWW6dvXtFdRLXSMd2toW95euZeFH5TXQ6rsLDudFX UHT3pzbSGOuSZXvzIlis/5hYimZIk56cVwoinIsi5fnDWJ5IgONmtsxn18SQBmTC0t5V 9MQILXYrlHiX6zC1Hgj47UPv8iVBE6BfJWU1JRpCdkFPQ4XfeazbG1tEfSJT8M5VKUFB SJ5Q== X-Gm-Message-State: AOAM533IPZjmn1Q2lQZNQHJQhLPHFJoYx8TnZwn3UpisnopPYJp2UDmB VW8Omk/paZdKGzsaNGAcllVBIIMPqGutV1LrJF34UAtYkfhN4iZn8+9pqFkUDVBeaAT9wWZtSDC ma/3LUxc7Aj3KdKOHeNoT7dj9PD+oZg== X-Received: by 2002:adf:ef52:: with SMTP id c18mr7576520wrp.162.1636625166581; Thu, 11 Nov 2021 02:06:06 -0800 (PST) X-Google-Smtp-Source: ABdhPJzsepfx71+Xyqb2g2FyILt7HhfvGVM2Y27qZ2ME6eL9iigsTPlV6uU5mw6Ulj3j6sBKopzmZQ== X-Received: by 2002:adf:ef52:: with SMTP id c18mr7576497wrp.162.1636625166404; Thu, 11 Nov 2021 02:06:06 -0800 (PST) Received: from [192.168.3.132] (p4ff23ee8.dip0.t-ipconnect.de. [79.242.62.232]) by smtp.gmail.com with ESMTPSA id l15sm2324926wme.47.2021.11.11.02.06.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 02:06:05 -0800 (PST) Message-ID: Date: Thu, 11 Nov 2021 11:06:04 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH 4/7] fs/binfmt_elf: use get_task_comm instead of open-coded string copy Content-Language: en-US From: David Hildenbrand To: Yafang Shao , akpm@linux-foundation.org Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Kees Cook , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , Al Viro , Petr Mladek References: <20211108083840.4627-1-laoar.shao@gmail.com> <20211108083840.4627-5-laoar.shao@gmail.com> Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On 11.11.21 11:03, David Hildenbrand wrote: > On 08.11.21 09:38, Yafang Shao wrote: >> It is better to use get_task_comm() instead of the open coded string >> copy as we do in other places. >> >> struct elf_prpsinfo is used to dump the task information in userspace >> coredump or kernel vmcore. Below is the verfication of vmcore, >> >> crash> ps >> PID PPID CPU TASK ST %MEM VSZ RSS COMM >> 0 0 0 ffffffff9d21a940 RU 0.0 0 0 [swapper/0] >>> 0 0 1 ffffa09e40f85e80 RU 0.0 0 0 [swapper/1] >>> 0 0 2 ffffa09e40f81f80 RU 0.0 0 0 [swapper/2] >>> 0 0 3 ffffa09e40f83f00 RU 0.0 0 0 [swapper/3] >>> 0 0 4 ffffa09e40f80000 RU 0.0 0 0 [swapper/4] >>> 0 0 5 ffffa09e40f89f80 RU 0.0 0 0 [swapper/5] >> 0 0 6 ffffa09e40f8bf00 RU 0.0 0 0 [swapper/6] >>> 0 0 7 ffffa09e40f88000 RU 0.0 0 0 [swapper/7] >>> 0 0 8 ffffa09e40f8de80 RU 0.0 0 0 [swapper/8] >>> 0 0 9 ffffa09e40f95e80 RU 0.0 0 0 [swapper/9] >>> 0 0 10 ffffa09e40f91f80 RU 0.0 0 0 [swapper/10] >>> 0 0 11 ffffa09e40f93f00 RU 0.0 0 0 [swapper/11] >>> 0 0 12 ffffa09e40f90000 RU 0.0 0 0 [swapper/12] >>> 0 0 13 ffffa09e40f9bf00 RU 0.0 0 0 [swapper/13] >>> 0 0 14 ffffa09e40f98000 RU 0.0 0 0 [swapper/14] >>> 0 0 15 ffffa09e40f9de80 RU 0.0 0 0 [swapper/15] >> >> It works well as expected. >> >> Suggested-by: Kees Cook >> Signed-off-by: Yafang Shao >> Cc: Mathieu Desnoyers >> Cc: Arnaldo Carvalho de Melo >> Cc: Andrii Nakryiko >> Cc: Michal Miroslaw >> Cc: Peter Zijlstra >> Cc: Steven Rostedt >> Cc: Matthew Wilcox >> Cc: David Hildenbrand >> Cc: Al Viro >> Cc: Kees Cook >> Cc: Petr Mladek >> --- >> fs/binfmt_elf.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c >> index a813b70f594e..138956fd4a88 100644 >> --- a/fs/binfmt_elf.c >> +++ b/fs/binfmt_elf.c >> @@ -1572,7 +1572,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p, >> SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); >> SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); >> rcu_read_unlock(); >> - strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); >> + get_task_comm(psinfo->pr_fname, p); >> >> return 0; >> } >> > > We have a hard-coded "pr_fname[16]" as well, not sure if we want to > adjust that to use TASK_COMM_LEN? But if the intention is to chance TASK_COMM_LEN later, we might want to keep that unchanged. (replacing the 16 by a define might still be a good idea, similar to how it's done for ELF_PRARGSZ, but just a thought) -- Thanks, David / dhildenb