diff options
| author | Yafang Shao <laoar.shao@gmail.com> | 2022-01-19 18:08:29 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-20 08:52:53 +0200 |
| commit | 95af469c4f609de011debc08e7a35b45201623a8 (patch) | |
| tree | 5acdead52139bdeee5eddc9a0d73e8ba0a04520f | |
| parent | 7b6397d7e5dfabf2ce1e77739d2a24af31b8a43f (diff) | |
fs/binfmt_elf: replace open-coded string copy with get_task_comm
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.
Link: https://lkml.kernel.org/r/20211120112738.45980-5-laoar.shao@gmail.com
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>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/binfmt_elf.c | 2 | ||||
| -rw-r--r-- | include/linux/elfcore-compat.h | 5 | ||||
| -rw-r--r-- | include/linux/elfcore.h | 5 |
3 files changed, 11 insertions, 1 deletions
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 */ }; |