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[79.242.62.232]) by smtp.gmail.com with ESMTPSA id h3sm2362194wrv.69.2021.11.11.02.03.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Nov 2021 02:03:54 -0800 (PST) Message-ID: Date: Thu, 11 Nov 2021 11:03:53 +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 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> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20211108083840.4627-5-laoar.shao@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 78D2AE00199D X-Stat-Signature: e3s4nrjgjpjnaxscpo9uakn7n7b69obz Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=hmSeQgN1; spf=none (imf30.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1636625019-142561 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: 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? Anyhow Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb