From: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
To: Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Linux Kernel Mailing List
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Alexey Gladkov
<gladkov.alexey-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Kirill A. Shutemov"
<kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>,
Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>,
James Bottomley
<James.Bottomley-JuX6DAaQMKPCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>,
Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
Dongsu Park <dpark-VwIFZPTo/vqsTnJN9+BGXg@public.gmane.org>,
Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>,
Alexey Dobriyan
<adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"kernel-hardening-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org"
<kernel-hardening-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org>,
LSM List <linux-security-module-u79uwXL29TY@public.gmane.org>
Subject: Re: [PATCH RFC 3/4] proc: support mounting new procfs instances inside same pid namespace
Date: Thu, 30 Mar 2017 12:10:11 -0700 [thread overview]
Message-ID: <CALCETrUs12sywzFntjz69gkNLmCNwQyKGDHEFM9K5jh5GpT9eA@mail.gmail.com> (raw)
In-Reply-To: <1490887379-25880-4-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
On Thu, Mar 30, 2017 at 8:22 AM, Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> This patch adds support for 'unshare' mount option to have multiple
> separated procfs inside the same pid namespace. This allows to solve lot
> of problem for containers and their specific use cases.
It would be nice if we could make this work without 'unshare'. How about:
hidepid still sets pid_ns->hidepid. "this_mount_hidepid" (or whatever
you want to call it), if set, overrides pid_ns->hidepid.
--Andy
>
> Signed-off-by: Djalal Harouni <tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> fs/proc/generic.c | 10 +++++++++
> fs/proc/inode.c | 3 +++
> fs/proc/root.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++--
> include/linux/proc_fs.h | 12 ++++++++++
> 4 files changed, 82 insertions(+), 2 deletions(-)
>
> diff --git a/fs/proc/generic.c b/fs/proc/generic.c
> index 7e5e419..7ae5377 100644
> --- a/fs/proc/generic.c
> +++ b/fs/proc/generic.c
> @@ -52,6 +52,11 @@ void proc_fs_set_pid_gid(struct proc_fs_info *fs_info, kgid_t gid)
> fs_info->pid_gid = gid;
> }
>
> +void proc_fs_set_unshare(struct proc_fs_info *fs_info, int version)
> +{
> + fs_info->version = version;
> +}
> +
> int proc_fs_get_hide_pid(struct proc_fs_info *fs_info)
> {
> /* For backward compatibility */
> @@ -70,6 +75,11 @@ kgid_t proc_fs_get_pid_gid(struct proc_fs_info *fs_info)
> return fs_info->pid_gid;
> }
>
> +int proc_fs_get_unshare(struct proc_fs_info *fs_info)
> +{
> + return fs_info->version;
> +}
> +
> static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
> {
> if (len < de->namelen)
> diff --git a/fs/proc/inode.c b/fs/proc/inode.c
> index ca47a0a..5f7557d 100644
> --- a/fs/proc/inode.c
> +++ b/fs/proc/inode.c
> @@ -111,6 +111,9 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root)
> if (pid->hide_pid != HIDEPID_OFF)
> seq_printf(seq, ",hidepid=%u", pid->hide_pid);
>
> + if (proc_fs_get_unshare(fs_info) == PROC_FS_V2)
> + seq_printf(seq, ",unshare");
> +
> return 0;
> }
>
> diff --git a/fs/proc/root.c b/fs/proc/root.c
> index 6a96c02..7a8f425 100644
> --- a/fs/proc/root.c
> +++ b/fs/proc/root.c
> @@ -27,15 +27,52 @@
> #include "internal.h"
>
> enum {
> - Opt_gid, Opt_hidepid, Opt_err,
> + Opt_gid, Opt_hidepid, Opt_unshare, Opt_err,
> };
>
> static const match_table_t tokens = {
> {Opt_hidepid, "hidepid=%u"},
> {Opt_gid, "gid=%u"},
> + {Opt_unshare, "unshare"},
> {Opt_err, NULL},
> };
>
> +/* We only parse 'unshare' option here */
> +int proc_parse_early_options(char *options, struct proc_fs_info *fs_info)
> +{
> + char *p, *opts, *orig;
> + substring_t args[MAX_OPT_ARGS];
> +
> + if (!options)
> + return 0;
> +
> + opts = kstrdup(options, GFP_KERNEL);
> + if (!opts)
> + return -ENOMEM;
> +
> + orig = opts;
> +
> + while ((p = strsep(&opts, ",")) != NULL) {
> + int token;
> +
> + if (!*p)
> + continue;
> +
> + token = match_token(p, tokens, args);
> + switch (token) {
> + case Opt_unshare:
> + pr_info("proc: mounting a new procfs instance ");
> + proc_fs_set_unshare(fs_info, PROC_FS_V2);
> + break;
> + default:
> + break;
> + }
> + }
> +
> + kfree(orig);
> + return 0;
> +}
> +
> int proc_parse_options(char *options, struct proc_fs_info *fs_info)
> {
> char *p;
> @@ -70,6 +107,8 @@ int proc_parse_options(char *options, struct proc_fs_info *fs_info)
> }
> proc_fs_set_hide_pid(fs_info, option);
> break;
> + case Opt_unshare:
> + break;
> default:
> pr_err("proc: unrecognized mount option \"%s\" "
> "or missing value\n", p);
> @@ -82,9 +121,19 @@ int proc_parse_options(char *options, struct proc_fs_info *fs_info)
>
> int proc_remount(struct super_block *sb, int *flags, char *data)
> {
> + int error, version;
> struct proc_fs_info *fs_info = proc_sb(sb);
>
> + version = proc_fs_get_unshare(fs_info);
> +
> sync_filesystem(sb);
> +
> + if (version == PROC_FS_V2) {
> + error = proc_parse_early_options(data, fs_info);
> + if (error < 0)
> + return error;
> + }
> +
> return !proc_parse_options(data, fs_info);
> }
>
> @@ -122,15 +171,21 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
> if (!fs_info)
> return ERR_PTR(-ENOMEM);
>
> + /* Set it as early as possible */
> + proc_fs_set_unshare(fs_info, PROC_FS_V1);
> +
> if (flags & MS_KERNMOUNT) {
> ns = data;
> data = NULL;
> } else {
> + error = proc_parse_early_options(data, fs_info);
> + if (error < 0)
> + goto error_fs_info;
> +
> ns = task_active_pid_ns(current);
> }
>
> fs_info->pid_ns = ns;
> - fs_info->version = PROC_FS_V1;
> fs_info->hide_pid = HIDEPID_OFF;
> fs_info->pid_gid = GLOBAL_ROOT_GID;
> refcount_set(&fs_info->users, 1);
> diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
> index c23299d..e3a78a5 100644
> --- a/include/linux/proc_fs.h
> +++ b/include/linux/proc_fs.h
> @@ -31,8 +31,11 @@ extern void proc_fs_set_hide_pid(struct proc_fs_info *fs_info, int hide_pid);
>
> extern void proc_fs_set_pid_gid(struct proc_fs_info *fs_info, kgid_t gid);
>
> +extern void proc_fs_set_unshare(struct proc_fs_info *fs_info, int version);
> +
> extern int proc_fs_get_hide_pid(struct proc_fs_info *fs_info);
> extern kgid_t proc_fs_get_pid_gid(struct proc_fs_info *fs_info);
> +extern int proc_fs_get_unshare(struct proc_fs_info *fs_info);
>
> extern void proc_root_init(void);
> extern void proc_flush_task(struct task_struct *);
> @@ -84,6 +87,10 @@ static inline void proc_fs_set_hide_pid(struct proc_fs_info *fs_info, int hide_p
> {
> }
>
> +static inline void proc_fs_set_unshare(struct proc_fs_info *fs_info, int version)
> +{
> +}
> +
> static inline void proc_fs_set_pid_gid(struct proc_info_fs *fs_info, kgid_t gid)
> {
> }
> @@ -98,6 +105,11 @@ extern kgid_t proc_fs_get_pid_gid(struct proc_fs_info *fs_info)
> return GLOBAL_ROOT_GID;
> }
>
> +static inline int proc_fs_get_unshare(struct proc_fs_info *fs_info)
> +{
> + return PROC_FS_V1;
> +}
> +
> extern inline struct proc_fs_info *proc_sb(struct super_block *sb) { return NULL;}
> static inline struct proc_dir_entry *proc_symlink(const char *name,
> struct proc_dir_entry *parent,const char *dest) { return NULL;}
> --
> 2.10.2
>
--
Andy Lutomirski
AMA Capital Management, LLC
next prev parent reply other threads:[~2017-03-30 19:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-30 15:22 [PATCH RFC 0/4] proc: support multiple separate proc instances per pidnamespace Djalal Harouni
2017-03-30 15:22 ` [PATCH RFC 1/4] proc: add proc_fs_info struct to store proc options Djalal Harouni
[not found] ` <1490887379-25880-2-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-03-30 19:10 ` Andy Lutomirski
2017-03-31 10:49 ` Djalal Harouni
2017-03-30 15:22 ` [PATCH RFC 2/4] proc: add helpers to set/get hidepid and gid mount options Djalal Harouni
2017-03-30 15:22 ` [PATCH RFC 3/4] proc: support mounting new procfs instances inside same pid namespace Djalal Harouni
[not found] ` <1490887379-25880-4-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-03-30 19:10 ` Andy Lutomirski [this message]
2017-03-30 15:22 ` [PATCH RFC 4/4] proc: support flushing dcache entries of a task on multiple procfs mounts Djalal Harouni
[not found] ` <1490887379-25880-1-git-send-email-tixxdz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-03-30 19:12 ` [PATCH RFC 0/4] proc: support multiple separate proc instances per pidnamespace Andy Lutomirski
[not found] ` <CALCETrWooKTtViVh4ik9e-3nLs3NET9wptgxhjS9V499sfUJQA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-31 11:45 ` Djalal Harouni
2017-03-30 22:16 ` Alexey Gladkov
2017-03-31 11:26 ` Djalal Harouni
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