From: Vasiliy Kulikov <segoon@openwall.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Stephen Wilson <wilsons@start.ca>,
Alexey Dobriyan <adobriyan@gmail.com>,
security@kernel.org
Subject: Re: [PATCH] proc: restrict access to /proc/$PID/{sched,schedstat}
Date: Tue, 8 Nov 2011 15:59:00 +0400 [thread overview]
Message-ID: <20111108115900.GA14587@albatros> (raw)
In-Reply-To: <20111105104828.GA3489@albatros>
(CC'ed l-k)
On Sat, Nov 05, 2011 at 14:48 +0400, Vasiliy Kulikov wrote:
> /proc/$PID/{sched,schedstat} contain debugging scheduler counters, which
> should not be world readable. They may be used to gather private information
> about processes' activity. E.g. it can be used to count the number of
> characters typed in gksu dialog:
>
> http://www.openwall.com/lists/oss-security/2011/11/05/3
>
> This infoleak is similar to io (1d1221f375c) and stat's eip/esp (f83ce3e6b02d)
> infoleaks. Probably other 0644/0444 procfs files are vulnerable to
> similar infoleaks.
>
> Cc: <stable@kernel.org>
> Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
> ---
> fs/proc/base.c | 32 ++++++++++++++++++++++----------
> 1 files changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 6278ef1..8b67eec 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -410,10 +410,16 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
> */
> static int proc_pid_schedstat(struct task_struct *task, char *buffer)
> {
> - return sprintf(buffer, "%llu %llu %lu\n",
> - (unsigned long long)task->se.sum_exec_runtime,
> - (unsigned long long)task->sched_info.run_delay,
> - task->sched_info.pcount);
> + int ret;
> + ret = lock_trace(task);
> + if (!ret) {
> + ret = sprintf(buffer, "%llu %llu %lu\n",
> + (unsigned long long)task->se.sum_exec_runtime,
> + (unsigned long long)task->sched_info.run_delay,
> + task->sched_info.pcount);
> + unlock_trace(task);
> + }
> + return ret;
> }
> #endif
>
> @@ -1390,15 +1396,21 @@ static int sched_show(struct seq_file *m, void *v)
> {
> struct inode *inode = m->private;
> struct task_struct *p;
> + int ret;
>
> p = get_proc_task(inode);
> if (!p)
> return -ESRCH;
> - proc_sched_show_task(p, m);
> + ret = lock_trace(p);
> + if (!ret) {
> + proc_sched_show_task(p, m);
> + ret = 0;
> + unlock_trace(p);
> + }
>
> put_task_struct(p);
>
> - return 0;
> + return ret;
> }
>
> static ssize_t
> @@ -2813,7 +2825,7 @@ static const struct pid_entry tgid_base_stuff[] = {
> ONE("personality", S_IRUGO, proc_pid_personality),
> INF("limits", S_IRUGO, proc_pid_limits),
> #ifdef CONFIG_SCHED_DEBUG
> - REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations),
> + REG("sched", S_IRUSR|S_IWUSR, proc_pid_sched_operations),
> #endif
> #ifdef CONFIG_SCHED_AUTOGROUP
> REG("autogroup", S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
> @@ -2851,7 +2863,7 @@ static const struct pid_entry tgid_base_stuff[] = {
> ONE("stack", S_IRUGO, proc_pid_stack),
> #endif
> #ifdef CONFIG_SCHEDSTATS
> - INF("schedstat", S_IRUGO, proc_pid_schedstat),
> + INF("schedstat", S_IRUSR, proc_pid_schedstat),
> #endif
> #ifdef CONFIG_LATENCYTOP
> REG("latency", S_IRUGO, proc_lstats_operations),
> @@ -3162,7 +3174,7 @@ static const struct pid_entry tid_base_stuff[] = {
> ONE("personality", S_IRUGO, proc_pid_personality),
> INF("limits", S_IRUGO, proc_pid_limits),
> #ifdef CONFIG_SCHED_DEBUG
> - REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations),
> + REG("sched", S_IRUSR|S_IWUSR, proc_pid_sched_operations),
> #endif
> REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
> #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
> @@ -3196,7 +3208,7 @@ static const struct pid_entry tid_base_stuff[] = {
> ONE("stack", S_IRUGO, proc_pid_stack),
> #endif
> #ifdef CONFIG_SCHEDSTATS
> - INF("schedstat", S_IRUGO, proc_pid_schedstat),
> + INF("schedstat", S_IRUSR, proc_pid_schedstat),
> #endif
> #ifdef CONFIG_LATENCYTOP
> REG("latency", S_IRUGO, proc_lstats_operations),
> --
> 1.7.0.4
>
--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
next parent reply other threads:[~2011-11-08 12:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111105104828.GA3489@albatros>
2011-11-08 11:59 ` Vasiliy Kulikov [this message]
2011-11-08 23:17 ` [PATCH] proc: restrict access to /proc/$PID/{sched,schedstat} Andrew Morton
2011-11-09 9:06 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-09 9:06 ` Vasiliy Kulikov
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=20111108115900.GA14587@albatros \
--to=segoon@openwall.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=security@kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=wilsons@start.ca \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.