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Message-Id: <1493123038-30590-3-git-send-email-tixxdz@gmail.com>
Date: Tue, 25 Apr 2017 14:23:54 +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 2/6] proc: move /proc/{self|thread-self} dentries to proc_fs_info
This is a preparation patch that moves /proc/{self|thread-self} dentries
to be stored inside procfs fs_info struct instead of making them per pid
namespace. Since we want to support multiple procfs instances we need to
make sure that these dentries are also per-superblock instead of
per-pidns, unmounting a private procfs won't clash with other procfs
mounts.
Cc: Kees Cook <keescook@...omium.org>
Cc: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Djalal Harouni <tixxdz@...il.com>
---
fs/proc/base.c | 4 ++--
fs/proc/root.c | 8 ++++----
fs/proc/self.c | 3 +--
fs/proc/thread_self.c | 5 ++---
include/linux/pid_namespace.h | 4 +---
include/linux/proc_fs.h | 2 ++
6 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index fa7d725..c96a9c6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3214,13 +3214,13 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx)
return 0;
if (pos == TGID_OFFSET - 2) {
- struct inode *inode = d_inode(ns->proc_self);
+ struct inode *inode = d_inode(fs_info->proc_self);
if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
return 0;
ctx->pos = pos = pos + 1;
}
if (pos == TGID_OFFSET - 1) {
- struct inode *inode = d_inode(ns->proc_thread_self);
+ struct inode *inode = d_inode(fs_info->proc_thread_self);
if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
return 0;
ctx->pos = pos = pos + 1;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index a625361..f44b864 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -161,10 +161,10 @@ static void proc_kill_sb(struct super_block *sb)
struct proc_fs_info *fs_info = proc_sb(sb);
struct pid_namespace *ns = (struct pid_namespace *)fs_info->pid_ns;
- if (ns->proc_self)
- dput(ns->proc_self);
- if (ns->proc_thread_self)
- dput(ns->proc_thread_self);
+ if (fs_info->proc_self)
+ dput(fs_info->proc_self);
+ if (fs_info->proc_thread_self)
+ dput(fs_info->proc_thread_self);
kill_anon_super(sb);
put_pid_ns(ns);
kfree(fs_info);
diff --git a/fs/proc/self.c b/fs/proc/self.c
index 9f95174..d3aaf71 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -36,7 +36,6 @@ int proc_setup_self(struct super_block *s)
{
struct inode *root_inode = d_inode(s->s_root);
struct proc_fs_info *fs_info = proc_sb(s);
- struct pid_namespace *ns = fs_info->pid_ns;
struct dentry *self;
inode_lock(root_inode);
@@ -63,7 +62,7 @@ int proc_setup_self(struct super_block *s)
pr_err("proc_fill_super: can't allocate /proc/self\n");
return PTR_ERR(self);
}
- ns->proc_self = self;
+ fs_info->proc_self = self;
return 0;
}
diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
index 13d9aef..14ea8e6 100644
--- a/fs/proc/thread_self.c
+++ b/fs/proc/thread_self.c
@@ -36,7 +36,6 @@ static unsigned thread_self_inum;
int proc_setup_thread_self(struct super_block *s)
{
struct proc_fs_info *fs_info = proc_sb(s);
- struct pid_namespace *ns = fs_info->pid_ns;
struct inode *root_inode = d_inode(s->s_root);
struct dentry *thread_self;
@@ -61,10 +60,10 @@ int proc_setup_thread_self(struct super_block *s)
}
inode_unlock(root_inode);
if (IS_ERR(thread_self)) {
- pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
+ pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
return PTR_ERR(thread_self);
}
- ns->proc_thread_self = thread_self;
+ fs_info->proc_thread_self = thread_self;
return 0;
}
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index c2a989d..306bdc6 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -38,9 +38,7 @@ struct pid_namespace {
unsigned int level;
struct pid_namespace *parent;
#ifdef CONFIG_PROC_FS
- struct vfsmount *proc_mnt;
- struct dentry *proc_self;
- struct dentry *proc_thread_self;
+ struct vfsmount *proc_mnt; /* Internal proc mounted during each new pidns */
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
struct fs_pin *bacct;
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index dd1dadd..7ba8540 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -10,6 +10,8 @@
struct proc_fs_info {
struct pid_namespace *pid_ns;
+ struct dentry *proc_self; /* For /proc/self */
+ struct dentry *proc_thread_self; /* For /proc/thread-self/ */
};
struct proc_dir_entry;
--
2.10.2
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