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Message-Id: <1308163900-6006-1-git-send-email-segoon@openwall.com>
Date: Wed, 15 Jun 2011 22:51:39 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: linux-kernel@...r.kernel.org
Cc: kernel-hardening@...ts.openwall.com,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...e.de>,
"David S. Miller" <davem@...emloft.net>,
Arnd Bergmann <arnd@...db.de>,
"Eric W. Biederman" <ebiederm@...ssion.com> ,
Al Viro <viro@...iv.linux.org.uk> ,
Daniel Lezcano <daniel.lezcano@...e.fr> ,
Alexey Dobriyan <adobriyan@...il.com> ,
Stephen Wilson <wilsons@...rt.ca> ,
"Serge E. Hallyn" <serge@...lyn.com>
Subject: [RFC 1/5 v4] procfs: parse mount options
This patch adds support of procfs mount options.
Actual mount options are comming in the next patches.
Signed-off-by: Vasiliy Kulikov <segoon@...nwall.com>
---
fs/proc/inode.c | 10 +++++++++
fs/proc/internal.h | 1 +
fs/proc/root.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 65 insertions(+), 2 deletions(-)
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 74b48cf..b5f49eb 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -7,6 +7,7 @@
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/kernel.h>
+#include <linux/pid_namespace.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
@@ -17,7 +18,9 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sysctl.h>
+#include <linux/seq_file.h>
#include <linux/slab.h>
+#include <linux/mount.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -102,12 +105,19 @@ void __init proc_init_inodecache(void)
init_once);
}
+static int proc_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+ return 0;
+}
+
static const struct super_operations proc_sops = {
.alloc_inode = proc_alloc_inode,
.destroy_inode = proc_destroy_inode,
.drop_inode = generic_delete_inode,
.evict_inode = proc_evict_inode,
.statfs = simple_statfs,
+ .remount_fs = proc_remount,
+ .show_options = proc_show_options,
};
static void __pde_users_dec(struct proc_dir_entry *pde)
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 7838e5c..2925775 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -117,6 +117,7 @@ void pde_put(struct proc_dir_entry *pde);
int proc_fill_super(struct super_block *);
struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
+int proc_remount(struct super_block *sb, int *flags, char *data);
/*
* These are generic /proc routines that use the internal
diff --git a/fs/proc/root.c b/fs/proc/root.c
index a9000e9..b2571fe 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -18,6 +18,7 @@
#include <linux/bitops.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
+#include <linux/parser.h>
#include "internal.h"
@@ -35,6 +36,49 @@ static int proc_set_super(struct super_block *sb, void *data)
return set_anon_super(sb, NULL);
}
+enum {
+ Opt_err,
+};
+
+static const match_table_t tokens = {
+ {Opt_err, NULL},
+};
+
+static int proc_parse_options(char *options, struct pid_namespace *pid)
+{
+ char *p;
+ substring_t args[MAX_OPT_ARGS];
+ int option;
+
+ pr_debug("proc: options = %s\n", options);
+
+ if (!options)
+ return 1;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ args[0].to = args[0].from = 0;
+ token = match_token(p, tokens, args);
+ switch (token) {
+ default:
+ pr_err("proc: unrecognized mount option \"%s\" "
+ "or missing value", p);
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+int proc_remount(struct super_block *sb, int *flags, char *data)
+{
+ struct pid_namespace *pid = sb->s_fs_info;
+ return !proc_parse_options(data, pid);
+}
+
static struct dentry *proc_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
@@ -42,11 +86,15 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
struct super_block *sb;
struct pid_namespace *ns;
struct proc_inode *ei;
+ char *options;
- if (flags & MS_KERNMOUNT)
+ if (flags & MS_KERNMOUNT) {
ns = (struct pid_namespace *)data;
- else
+ options = NULL;
+ } else {
ns = current->nsproxy->pid_ns;
+ options = data;
+ }
sb = sget(fs_type, proc_test_super, proc_set_super, ns);
if (IS_ERR(sb))
@@ -54,6 +102,10 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
if (!sb->s_root) {
sb->s_flags = flags;
+ if (!proc_parse_options(options, ns)) {
+ deactivate_locked_super(sb);
+ return ERR_PTR(-EINVAL);
+ }
err = proc_fill_super(sb);
if (err) {
deactivate_locked_super(sb);
--
1.7.0.4
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