From: David Hildenbrand <david@redhat.com>
To: Yafang Shao <laoar.shao@gmail.com>, 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 <keescook@chromium.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Arnaldo Carvalho de Melo <arnaldo.melo@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 4/7] fs/binfmt_elf: use get_task_comm instead of open-coded string copy
Date: Thu, 11 Nov 2021 11:03:53 +0100 [thread overview]
Message-ID: <a13c0541-59a3-6561-6d42-b51fef9f7c8b@redhat.com> (raw)
In-Reply-To: <20211108083840.4627-5-laoar.shao@gmail.com>
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 <keescook@chromium.org>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Petr Mladek <pmladek@suse.com>
> ---
> 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 <david@redhat.com>
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-11-11 10:04 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
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 [this message]
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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