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 <[email protected]> Cc: Andy Lutomirski <[email protected]> Signed-off-by: Djalal Harouni <[email protected]> --- 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
