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[91.12.96.79]) by smtp.gmail.com with ESMTPSA id u23sm15854437wru.21.2021.11.10.00.28.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Nov 2021 00:28:14 -0800 (PST) Message-ID: Date: Wed, 10 Nov 2021 09:28:12 +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 1/7] fs/exec: make __set_task_comm always set a nul terminated string 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 , Alexei Starovoitov , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , Al Viro , Petr Mladek References: <20211108083840.4627-1-laoar.shao@gmail.com> <20211108083840.4627-2-laoar.shao@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20211108083840.4627-2-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: rspam05 X-Rspamd-Queue-Id: 43A8F104E710 X-Stat-Signature: ibg8qshc8pbhe9xnwwoyptyz5kuommxk Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=FsESyu9r; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf31.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com X-HE-Tag: 1636532886-248068 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: > Make sure the string set to task comm is always nul terminated. > strlcpy: "the result is always a valid NUL-terminated string that fits in the buffer" The only difference seems to be that strscpy_pad() pads the remainder with zeroes. Is this description correct and I am missing something important? > Signed-off-by: Yafang Shao > Reviewed-by: Kees Cook > Cc: Mathieu Desnoyers > Cc: Arnaldo Carvalho de Melo > Cc: Alexei Starovoitov > 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/exec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/exec.c b/fs/exec.c > index a098c133d8d7..404156b5b314 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1224,7 +1224,7 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) > { > task_lock(tsk); > trace_task_rename(tsk, buf); > - strlcpy(tsk->comm, buf, sizeof(tsk->comm)); > + strscpy_pad(tsk->comm, buf, sizeof(tsk->comm)); > task_unlock(tsk); > perf_event_comm(tsk, exec); > } > -- Thanks, David / dhildenb