From: Kees Cook <keescook@chromium.org>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: akpm@linux-foundation.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com,
pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk,
valentin.schneider@arm.com, qiang.zhang@windriver.com,
robdclark@chromium.org, christian@brauner.io,
dietmar.eggemann@arm.com, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
davem@davemloft.net, kuba@kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com,
mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com,
jgg@ziepe.ca, linux-rdma@vger.kernel.org, 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, Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Vladimir Zapolskiy <vzapolskiy@gmail.com>,
David Howells <dhowells@redhat.com>
Subject: Re: [PATCH v6 03/12] drivers/connector: make connector comm always nul ternimated
Date: Mon, 25 Oct 2021 14:14:36 -0700 [thread overview]
Message-ID: <202110251411.93B477676B@keescook> (raw)
In-Reply-To: <20211025083315.4752-4-laoar.shao@gmail.com>
On Mon, Oct 25, 2021 at 08:33:06AM +0000, Yafang Shao wrote:
> connector comm was introduced in commit
> f786ecba4158 ("connector: add comm change event report to proc connector").
> struct comm_proc_event was defined in include/linux/cn_proc.h first and
> then been moved into file include/uapi/linux/cn_proc.h in commit
> 607ca46e97a1 ("UAPI: (Scripted) Disintegrate include/linux").
>
> As this is the UAPI code, we can't change it without potentially breaking
> things (i.e. userspace binaries have this size built in, so we can't just
> change the size). To prepare for the followup change - extending task
> comm, we have to use __get_task_comm() to avoid the BUILD_BUG_ON() in
> proc_comm_connector().
I wonder, looking at this again, if it might make more sense to avoid
this cn_proc.c change, and instead, adjust get_task_comm() like so:
#define get_task_comm(buf, tsk)
__get_task_comm(buf, __must_be_array(buf) + sizeof(buf), tsk)
This would still enforce the original goal of making sure
get_task_comm() is being used on a char array, and now that
__get_task_comm() will truncate & pad, it's safe to use on both
too-small and too-big arrays.
--
Kees Cook
next prev parent reply other threads:[~2021-10-25 21:14 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-25 8:33 [PATCH v6 00/12] extend task comm from 16 to 24 Yafang Shao
2021-10-25 8:33 ` [PATCH v6 01/12] fs/exec: make __set_task_comm always set a nul ternimated string Yafang Shao
2021-10-25 21:07 ` Kees Cook
2021-10-26 1:48 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 02/12] fs/exec: make __get_task_comm always get a nul terminated string Yafang Shao
2021-10-25 21:08 ` Kees Cook
2021-10-26 1:49 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 03/12] drivers/connector: make connector comm always nul ternimated Yafang Shao
2021-10-25 21:14 ` Kees Cook [this message]
2021-10-26 1:50 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 04/12] drivers/infiniband: make setup_ctxt always get a nul terminated task comm Yafang Shao
2021-10-25 18:20 ` Dennis Dalessandro
2021-10-25 21:16 ` Kees Cook
2021-10-26 1:52 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 05/12] elfcore: make prpsinfo " Yafang Shao
2021-10-25 21:18 ` Kees Cook
2021-10-26 1:56 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 06/12] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Yafang Shao
2021-10-25 21:20 ` Kees Cook
2021-10-25 8:33 ` [PATCH v6 07/12] samples/bpf/offwaketime_kern: make sched_switch tracepoint args adopt to " Yafang Shao
2021-10-25 21:21 ` Kees Cook
2021-10-26 1:56 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 08/12] tools/bpf/bpftool/skeleton: make it adopt to task " Yafang Shao
2021-10-25 21:24 ` Kees Cook
2021-10-26 2:18 ` Yafang Shao
2021-10-26 13:12 ` Steven Rostedt
2021-10-26 13:55 ` Yafang Shao
2021-10-26 14:02 ` Yafang Shao
2021-10-26 16:09 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 09/12] tools/perf/test: make perf test " Yafang Shao
2021-10-25 21:26 ` Kees Cook
2021-10-25 8:33 ` [PATCH v6 10/12] tools/testing/selftests/bpf: make it " Yafang Shao
2021-10-25 21:29 ` Kees Cook
2021-10-26 2:21 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 11/12] sched.h: extend task comm from 16 to 24 Yafang Shao
2021-10-25 21:30 ` Kees Cook
2021-10-26 2:22 ` Yafang Shao
2021-10-25 8:33 ` [PATCH v6 12/12] kernel/kthread: show a warning if kthread's comm is truncated Yafang Shao
2021-10-25 21:35 ` Kees Cook
2021-10-26 2:23 ` Yafang Shao
2021-10-27 20:10 ` Petr Mladek
2021-10-28 1:42 ` Yafang Shao
2021-10-29 7:44 ` Yafang Shao
2021-10-25 18:10 ` [PATCH v6 00/12] extend task comm from 16 to 24 Alexei Starovoitov
2021-10-25 21:05 ` Steven Rostedt
2021-10-25 21:06 ` Kees Cook
2021-10-26 10:35 ` Petr Mladek
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