From: Yafang Shao <laoar.shao@gmail.com>
To: 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,
Yafang Shao <laoar.shao@gmail.com>,
Kees Cook <keescook@chromium.org>,
David Hildenbrand <david@redhat.com>,
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: [PATCH v2 4/7] fs/binfmt_elf: replace open-coded string copy with get_task_comm
Date: Sat, 20 Nov 2021 11:27:35 +0000 [thread overview]
Message-ID: <20211120112738.45980-5-laoar.shao@gmail.com> (raw)
In-Reply-To: <20211120112738.45980-1-laoar.shao@gmail.com>
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 verification 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.
Some comments are added to explain why we use the hard-coded 16.
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.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 +-
include/linux/elfcore-compat.h | 5 +++++
include/linux/elfcore.h | 5 +++++
3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f8c7f26f1fbb..b9a33cc34d6b 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1585,7 +1585,7 @@ 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;
}
diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
index e272c3d452ce..54feb64e9b5d 100644
--- a/include/linux/elfcore-compat.h
+++ b/include/linux/elfcore-compat.h
@@ -43,6 +43,11 @@ struct compat_elf_prpsinfo
__compat_uid_t pr_uid;
__compat_gid_t pr_gid;
compat_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
+ /*
+ * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be
+ * changed as it is exposed to userspace. We'd better make it hard-coded
+ * here.
+ */
char pr_fname[16];
char pr_psargs[ELF_PRARGSZ];
};
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index 957ebec35aad..746e081879a5 100644
--- a/include/linux/elfcore.h
+++ b/include/linux/elfcore.h
@@ -65,6 +65,11 @@ struct elf_prpsinfo
__kernel_gid_t pr_gid;
pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
/* Lots missing */
+ /*
+ * The hard-coded 16 is derived from TASK_COMM_LEN, but it can't be
+ * changed as it is exposed to userspace. We'd better make it hard-coded
+ * here.
+ */
char pr_fname[16]; /* filename of executable */
char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
};
--
2.17.1
next prev parent reply other threads:[~2021-11-20 11:28 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-20 11:27 [PATCH v2 0/7] task comm cleanups Yafang Shao
2021-11-20 11:27 ` [PATCH v2 1/7] fs/exec: replace strlcpy with strscpy_pad in __set_task_comm Yafang Shao
2021-11-20 11:27 ` [PATCH v2 2/7] fs/exec: replace strncpy with strscpy_pad in __get_task_comm Yafang Shao
2021-11-20 11:27 ` [PATCH v2 3/7] drivers/infiniband: replace open-coded string copy with get_task_comm Yafang Shao
2021-11-20 11:27 ` Yafang Shao [this message]
2021-11-29 16:01 ` [PATCH v2 4/7] fs/binfmt_elf: " Steven Rostedt
2021-11-30 3:01 ` Yafang Shao
2021-11-30 14:22 ` Steven Rostedt
2021-11-30 15:53 ` Yafang Shao
2021-11-20 11:27 ` [PATCH v2 5/7] samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm Yafang Shao
2021-11-20 11:27 ` [PATCH v2 6/7] tools/bpf/bpftool/skeleton: " Yafang Shao
2021-11-20 11:27 ` [PATCH v2 7/7] tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN Yafang Shao
2021-11-29 10:13 ` Sven Schnelle
2021-11-29 13:41 ` Yafang Shao
2021-11-29 14:21 ` Sven Schnelle
2021-11-29 14:32 ` David Hildenbrand
2021-11-29 14:38 ` Sven Schnelle
2021-11-29 15:33 ` Yafang Shao
2021-11-29 16:07 ` Steven Rostedt
2021-11-29 16:08 ` Steven Rostedt
2021-11-29 15:28 ` Yafang Shao
2021-11-29 17:30 ` Steven Rostedt
2021-11-29 17:56 ` Sven Schnelle
2021-11-30 3:03 ` Yafang Shao
2021-11-30 14:23 ` Steven Rostedt
2021-11-30 15:46 ` Yafang Shao
2023-02-08 21:55 ` John Stultz
2023-02-09 0:10 ` Alexei Starovoitov
2023-02-09 0:54 ` John Stultz
2023-02-09 2:06 ` Mathieu Desnoyers
2023-02-09 6:20 ` Yafang Shao
2023-02-09 14:27 ` Kajetan Puchalski
2023-02-09 15:37 ` Yafang Shao
2023-02-10 18:09 ` Kajetan Puchalski
2023-02-11 16:51 ` Qais Yousef
2023-02-12 3:19 ` Yafang Shao
2023-02-09 2:28 ` Steven Rostedt
2023-02-09 2:33 ` Steven Rostedt
2023-02-11 19:00 ` Steven Rostedt
2023-02-12 3:38 ` Yafang Shao
2023-02-12 3:44 ` Steven Rostedt
2023-02-13 17:43 ` Namhyung Kim
2023-02-13 17:46 ` Mathieu Desnoyers
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