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Message-Id: <1493123038-30590-6-git-send-email-tixxdz@gmail.com> Date: Tue, 25 Apr 2017 14:23:57 +0200 From: Djalal Harouni <tixxdz@...il.com> To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Andy Lutomirski <luto@...nel.org>, Kees Cook <keescook@...omium.org>, Andrew Morton <akpm@...ux-foundation.org>, linux-fsdevel@...r.kernel.org, kernel-hardening@...ts.openwall.com, linux-security-module@...r.kernel.org Cc: Linux API <linux-api@...r.kernel.org>, Dongsu Park <dpark@...teo.net>, Casey Schaufler <casey@...aufler-ca.com>, James Morris <james.l.morris@...cle.com>, <serge@...lyn.com>, Jeff Layton <jlayton@...chiereds.net>, <bfields@...ldses.org>, Alexander Viro <viro@...iv.linux.org.uk>, Alexey Dobriyan <adobriyan@...il.com>, Ingo Molnar <mingo@...nel.org>, <ebiederm@...ssion.com>, Oleg Nesterov <oleg@...hat.com>, Michal Hocko <mhocko@...e.com>, Jonathan Corbet <corbet@....net>, Djalal Harouni <tixxdz@...il.com> Subject: [PATCH RFC v2 5/6] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option 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@...omium.org> Cc: Andy Lutomirski <luto@...nel.org> Signed-off-by: Djalal Harouni <tixxdz@...il.com> --- 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
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