From: "zhangyi (F)" <yi.zhang@huawei.com>
To: <gregkh@linuxfoundation.org>
Cc: <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
<luto@kernel.org>, <adobriyan@gmail.com>,
<akpm@linux-foundation.org>, <vbabka@suse.cz>,
<peterz@infradead.org>, <bigeasy@linutronix.de>,
<mhocko@suse.com>, <john.ogness@linutronix.de>,
<yi.zhang@huawei.com>, <nixiaoming@huawei.com>
Subject: [PATCH 4.4 4/7] fs/proc: Stop reporting eip and esp in /proc/PID/stat
Date: Mon, 2 Dec 2019 16:35:16 +0800 [thread overview]
Message-ID: <20191202083519.23138-5-yi.zhang@huawei.com> (raw)
In-Reply-To: <20191202083519.23138-1-yi.zhang@huawei.com>
From: Andy Lutomirski <luto@kernel.org>
commit 0a1eb2d474edfe75466be6b4677ad84e5e8ca3f5 upstream.
Reporting these fields on a non-current task is dangerous. If the
task is in any state other than normal kernel code, they may contain
garbage or even kernel addresses on some architectures. (x86_64
used to do this. I bet lots of architectures still do.) With
CONFIG_THREAD_INFO_IN_TASK=y, it can OOPS, too.
As far as I know, there are no use programs that make any material
use of these fields, so just get rid of them.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/a5fed4c3f4e33ed25d4bb03567e329bc5a712bcc.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
---
fs/proc/array.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 60cbaa821164..618c83f1866d 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -425,10 +425,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
mm = get_task_mm(task);
if (mm) {
vsize = task_vsize(mm);
- if (permitted) {
- eip = KSTK_EIP(task);
- esp = KSTK_ESP(task);
- }
+ /*
+ * esp and eip are intentionally zeroed out. There is no
+ * non-racy way to read them without freezing the task.
+ * Programs that need reliable values can use ptrace(2).
+ */
}
get_task_comm(tcomm, task);
--
2.17.2
next prev parent reply other threads:[~2019-12-02 8:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-02 8:35 [PATCH 4.4 0/7] fs/proc: Stop reporting eip and esp in zhangyi (F)
2019-12-02 8:35 ` [PATCH 4.4 1/7] sched/core: Allow putting thread_info into task_struct zhangyi (F)
2019-12-02 8:35 ` [PATCH 4.4 2/7] sched/core: Add try_get_task_stack() and put_task_stack() zhangyi (F)
2019-12-02 8:35 ` [PATCH 4.4 3/7] sched/core, x86: Make struct thread_info arch specific again zhangyi (F)
2019-12-02 8:35 ` zhangyi (F) [this message]
2019-12-02 8:35 ` [PATCH 4.4 5/7] fs/proc: Report eip/esp in /prod/PID/stat for coredumping zhangyi (F)
2019-12-02 8:35 ` [PATCH 4.4 6/7] proc: fix coredump vs read /proc/*/stat race zhangyi (F)
2019-12-02 8:35 ` [PATCH 4.4 7/7] fs/proc/array.c: allow reporting eip/esp for all coredumping threads zhangyi (F)
2019-12-12 17:15 ` [PATCH 4.4 0/7] fs/proc: Stop reporting eip and esp in Greg KH
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191202083519.23138-5-yi.zhang@huawei.com \
--to=yi.zhang@huawei.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=bigeasy@linutronix.de \
--cc=gregkh@linuxfoundation.org \
--cc=john.ogness@linutronix.de \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=nixiaoming@huawei.com \
--cc=peterz@infradead.org \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).