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From: David Hildenbrand <david@redhat.com>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	netdev <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	"linux-perf-use." <linux-perf-users@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kernel test robot <oliver.sang@intel.com>,
	kbuild test robot <lkp@intel.com>,
	Kees Cook <keescook@chromium.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Michal Miroslaw <mirq-linux@rere.qmqm.pl>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Matthew Wilcox <willy@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>, Petr Mladek <pmladek@suse.com>
Subject: Re: [PATCH 1/7] fs/exec: make __set_task_comm always set a nul terminated string
Date: Thu, 11 Nov 2021 10:58:13 +0100	[thread overview]
Message-ID: <3526ab88-afa3-e87b-d773-72807a27a88d@redhat.com> (raw)
In-Reply-To: <CALOAHbCexkBs7FCdmQcatQbc+RsGTSoJkNBop0khsZX=g8Ftkg@mail.gmail.com>

On 10.11.21 10:05, Yafang Shao wrote:
> On Wed, Nov 10, 2021 at 4:28 PM David Hildenbrand <david@redhat.com> wrote:
>>
>> 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?
>>
> 
> In a earlier version [1], the checkpatch.py found a warning:
> WARNING: Prefer strscpy over strlcpy - see:
> https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
> So I replaced strlcpy() with strscpy() to fix this warning.
> And then in v5[2], the strscpy() was replaced with strscpy_pad() to
> make sure there's no garbade data and also make get_task_comm() be
> consistent with get_task_comm().
> 
> This commit log didn't clearly describe the historical changes.  So I
> think we can update the commit log and subject with:
> 
> Subject: use strscpy_pad with strlcpy in __set_task_comm
> Commit log:
> strlcpy is not suggested to use by the checkpatch.pl, so we'd better
> recplace it with strscpy.
> To avoid leaving garbage data and be consistent with the usage in
> __get_task_comm(), the strscpy_pad is used here.
> 
> WDYT?

Yes, that makes it clearer what this patch actually does :)

With the subject+description changed

Reviewed-by: David Hildenbrand <david@redhat.com>

Thanks!

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2021-11-11  9:58 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-08  8:38 [PATCH 0/7] task comm cleanups Yafang Shao
2021-11-08  8:38 ` [PATCH 1/7] fs/exec: make __set_task_comm always set a nul terminated string Yafang Shao
2021-11-10  8:28   ` David Hildenbrand
2021-11-10  9:05     ` Yafang Shao
2021-11-11  9:58       ` David Hildenbrand [this message]
2021-11-10 20:17     ` Kees Cook
2021-11-08  8:38 ` [PATCH 2/7] fs/exec: make __get_task_comm always get " Yafang Shao
2021-11-11  9:59   ` David Hildenbrand
2021-11-08  8:38 ` [PATCH 3/7] drivers/infiniband: use get_task_comm instead of open-coded string copy Yafang Shao
2021-11-11 10:01   ` David Hildenbrand
2021-11-08  8:38 ` [PATCH 4/7] fs/binfmt_elf: " Yafang Shao
2021-11-11 10:03   ` David Hildenbrand
2021-11-11 10:06     ` David Hildenbrand
2021-11-11 11:34       ` Petr Mladek
2021-11-11 11:47         ` David Hildenbrand
2021-11-12  1:08           ` Yafang Shao
2021-11-12  1:03         ` Yafang Shao
2021-11-08  8:38 ` [PATCH 5/7] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Yafang Shao
2021-11-08 18:20   ` Andrii Nakryiko
2021-11-11 10:07   ` David Hildenbrand
2021-11-08  8:38 ` [PATCH 6/7] tools/bpf/bpftool/skeleton: use bpf_probe_read_kernel_str to get task comm Yafang Shao
2021-11-11 10:08   ` David Hildenbrand
2021-11-08  8:38 ` [PATCH 7/7] tools/testing/selftests/bpf: make it adopt to task comm size change Yafang Shao
2021-11-11 10:11   ` David Hildenbrand
2021-11-09 18:28 ` [PATCH 0/7] task comm cleanups Kees Cook

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