From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Gladkov Subject: [PATCH v5 5/7] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option Date: Fri, 11 May 2018 11:36:14 +0200 Message-ID: <20180511093613.GA1330@comp-core-i7-2640m-0182e6> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Kees Cook , Andy Lutomirski , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org Cc: Greg Kroah-Hartman , Alexander Viro , Akinobu Mita , Oleg Nesterov , Jeff Layton , Ingo Molnar , Alexey Dobriyan , "Eric W. Biederman" , Linus Torvalds , aniel Micay , Jonathan Corbet , bfields@fieldses.org, Stephen Rothwell , solar@openwall.com, "Dmitry V. Levin" , Djalal Harouni List-Id: linux-api@vger.kernel.org From: Djalal Harouni 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 Cc: Andy Lutomirski Signed-off-by: Djalal Harouni --- fs/proc/base.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/proc/base.c b/fs/proc/base.c index 6f084344..31baeef 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3187,6 +3187,7 @@ 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) @@ -3200,7 +3201,15 @@ 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); -- 2.10.5