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From: Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Linux Kernel Mailing List
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	kernel-hardening-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org,
	linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Dongsu Park <dpark-VwIFZPTo/vqsTnJN9+BGXg@public.gmane.org>,
	Casey Schaufler <casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>,
	James Morris
	<james.l.morris-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
	serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org,
	Jeff Layton <jlayton-vpEMnDpepFuMZCB2o+C8xQ@public.gmane.org>,
	bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org,
	Alexander Viro
	<viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	Alexey Dobriyan
	<adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org,
	Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>,
	Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>,
	Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: [PATCH RFC v2 5/6] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option
Date: Tue, 25 Apr 2017 14:23:57 +0200	[thread overview]
Message-ID: <1493123038-30590-6-git-send-email-tixxdz@gmail.com> (raw)
In-Reply-To: <1493123038-30590-1-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

If "limit_pids=1" mount option is set then do not instantiate pids that
we can not ptrace. "limit_pids=1" means that procfs should only contain
pids that the caller can ptrace.

Cc: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 fs/proc/base.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 2e0f661..a663284 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3149,6 +3149,7 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign
 	unsigned tgid;
 	struct proc_fs_info *fs_info = proc_sb(dir->i_sb);
 	struct pid_namespace *ns = fs_info->pid_ns;
+	int limit_pids = proc_fs_limit_pids(fs_info);
 
 	tgid = name_to_int(&dentry->d_name);
 	if (tgid == ~0U)
@@ -3162,7 +3163,15 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign
 	if (!task)
 		goto out;
 
+	/* Limit procfs to only ptracable tasks */
+	if (limit_pids == PROC_LIMIT_PIDS_PTRACE) {
+		cond_resched();
+		if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
+			goto out_put_task;
+	}
+
 	result = proc_pid_instantiate(dir, dentry, task, NULL);
+out_put_task:
 	put_task_struct(task);
 out:
 	return ERR_PTR(result);
-- 
2.10.2

  parent reply	other threads:[~2017-04-25 12:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-25 12:23 [PATCH RFC v2 0/6] proc: support private proc instances per pidnamespace Djalal Harouni
2017-04-25 12:23 ` [PATCH RFC v2 1/6] proc: add proc_fs_info struct to store proc information Djalal Harouni
2017-04-25 12:23 ` [PATCH RFC v2 2/6] proc: move /proc/{self|thread-self} dentries to proc_fs_info Djalal Harouni
2017-04-25 12:23 ` [PATCH RFC v2 3/6] proc: add helpers to set and get proc hidepid and gid mount options Djalal Harouni
2017-04-25 12:23 ` [PATCH RFC v2 4/6] proc: support mounting private procfs instances inside same pid namespace Djalal Harouni
2017-04-26 22:13   ` Andy Lutomirski
2017-05-02 14:29     ` Djalal Harouni
2017-05-02 16:33       ` Andy Lutomirski
     [not found]         ` <CALCETrV4SjQE_NM4=j0JgRGBjOVY4o=iu0=ruuvzSuGRUPgNbg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-03 15:18           ` Djalal Harouni
     [not found] ` <1493123038-30590-1-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-04-25 12:23   ` Djalal Harouni [this message]
2017-04-26 22:09     ` [PATCH RFC v2 5/6] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option Andy Lutomirski
     [not found]       ` <CALCETrXM7-NBnBcXbuuhDJZyUFLT7iRfcGGvaqUhDJBGkYJgcQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-02 14:00         ` Djalal Harouni
2017-04-25 12:23 ` [PATCH RFC v2 6/6] proc: flush task dcache entries from all procfs instances Djalal Harouni

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