1 files changed, 81 insertions, 76 deletions

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 5fe34c355e85..5c555db68aa2 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
  *
@@ -10,45 +11,49 @@
 #include <linux/nsproxy.h>
 #include <linux/security.h>
 #include <linux/fs_struct.h>
+#include <linux/sched/task.h>
+
 #include "proc/internal.h" /* only for get_proc_task() in ->open() */
 
 #include "pnode.h"
 #include "internal.h"
 
-static unsigned mounts_poll(struct file *file, poll_table *wait)
+static __poll_t mounts_poll(struct file *file, poll_table *wait)
 {
-	struct proc_mounts *p = proc_mounts(file->private_data);
+	struct seq_file *m = file->private_data;
+	struct proc_mounts *p = m->private;
 	struct mnt_namespace *ns = p->ns;
-	unsigned res = POLLIN | POLLRDNORM;
+	__poll_t res = EPOLLIN | EPOLLRDNORM;
+	int event;
 
 	poll_wait(file, &p->ns->poll, wait);
 
-	br_read_lock(&vfsmount_lock);
-	if (p->m.poll_event != ns->event) {
-		p->m.poll_event = ns->event;
-		res |= POLLERR | POLLPRI;
+	event = READ_ONCE(ns->event);
+	if (m->poll_event != event) {
+		m->poll_event = event;
+		res |= EPOLLERR | EPOLLPRI;
 	}
-	br_read_unlock(&vfsmount_lock);
 
 	return res;
 }
 
-struct proc_fs_info {
+struct proc_fs_opts {
 	int flag;
 	const char *str;
 };
 
 static int show_sb_opts(struct seq_file *m, struct super_block *sb)
 {
-	static const struct proc_fs_info fs_info[] = {
-		{ MS_SYNCHRONOUS, ",sync" },
-		{ MS_DIRSYNC, ",dirsync" },
-		{ MS_MANDLOCK, ",mand" },
+	static const struct proc_fs_opts fs_opts[] = {
+		{ SB_SYNCHRONOUS, ",sync" },
+		{ SB_DIRSYNC, ",dirsync" },
+		{ SB_MANDLOCK, ",mand" },
+		{ SB_LAZYTIME, ",lazytime" },
 		{ 0, NULL }
 	};
-	const struct proc_fs_info *fs_infop;
+	const struct proc_fs_opts *fs_infop;
 
-	for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
+	for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
 		if (sb->s_flags & fs_infop->flag)
 			seq_puts(m, fs_infop->str);
 	}
@@ -56,34 +61,38 @@ static int show_sb_opts(struct seq_file *m, struct super_block *sb)
 	return security_sb_show_options(m, sb);
 }
 
-static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
+static void show_vfsmnt_opts(struct seq_file *m, struct vfsmount *mnt)
 {
-	static const struct proc_fs_info mnt_info[] = {
+	static const struct proc_fs_opts mnt_opts[] = {
 		{ MNT_NOSUID, ",nosuid" },
 		{ MNT_NODEV, ",nodev" },
 		{ MNT_NOEXEC, ",noexec" },
 		{ MNT_NOATIME, ",noatime" },
 		{ MNT_NODIRATIME, ",nodiratime" },
 		{ MNT_RELATIME, ",relatime" },
+		{ MNT_NOSYMFOLLOW, ",nosymfollow" },
 		{ 0, NULL }
 	};
-	const struct proc_fs_info *fs_infop;
+	const struct proc_fs_opts *fs_infop;
 
-	for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
+	for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
 		if (mnt->mnt_flags & fs_infop->flag)
 			seq_puts(m, fs_infop->str);
 	}
+
+	if (is_idmapped_mnt(mnt))
+		seq_puts(m, ",idmapped");
 }
 
 static inline void mangle(struct seq_file *m, const char *s)
 {
-	seq_escape(m, s, " \t\n\\");
+	seq_escape(m, s, " \t\n\\#");
 }
 
 static void show_type(struct seq_file *m, struct super_block *sb)
 {
 	mangle(m, sb->s_type->name);
-	if (sb->s_subtype && sb->s_subtype[0]) {
+	if (sb->s_subtype) {
 		seq_putc(m, '.');
 		mangle(m, sb->s_subtype);
 	}
@@ -91,27 +100,31 @@ static void show_type(struct seq_file *m, struct super_block *sb)
 
 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
 {
+	struct proc_mounts *p = m->private;
 	struct mount *r = real_mount(mnt);
-	int err = 0;
 	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
 	struct super_block *sb = mnt_path.dentry->d_sb;
+	int err;
 
 	if (sb->s_op->show_devname) {
 		err = sb->s_op->show_devname(m, mnt_path.dentry);
 		if (err)
 			goto out;
 	} else {
-		mangle(m, r->mnt_devname ? r->mnt_devname : "none");
+		mangle(m, r->mnt_devname);
 	}
 	seq_putc(m, ' ');
-	seq_path(m, &mnt_path, " \t\n\\");
+	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
+	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
+	if (err)
+		goto out;
 	seq_putc(m, ' ');
 	show_type(m, sb);
 	seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
 	err = show_sb_opts(m, sb);
 	if (err)
 		goto out;
-	show_mnt_opts(m, mnt);
+	show_vfsmnt_opts(m, mnt);
 	if (sb->s_op->show_options)
 		err = sb->s_op->show_options(m, mnt_path.dentry);
 	seq_puts(m, " 0 0\n");
@@ -121,30 +134,26 @@ out:
 
 static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
 {
-	struct proc_mounts *p = proc_mounts(m);
+	struct proc_mounts *p = m->private;
 	struct mount *r = real_mount(mnt);
 	struct super_block *sb = mnt->mnt_sb;
 	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
-	struct path root = p->root;
-	int err = 0;
+	int err;
 
 	seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
 		   MAJOR(sb->s_dev), MINOR(sb->s_dev));
-	if (sb->s_op->show_path)
-		err = sb->s_op->show_path(m, mnt->mnt_root);
-	else
-		seq_dentry(m, mnt->mnt_root, " \t\n\\");
+	err = show_path(m, mnt->mnt_root);
 	if (err)
 		goto out;
 	seq_putc(m, ' ');
 
 	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
-	err = seq_path_root(m, &mnt_path, &root, " \t\n\\");
+	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
 	if (err)
 		goto out;
 
 	seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
-	show_mnt_opts(m, mnt);
+	show_vfsmnt_opts(m, mnt);
 
 	/* Tagged fields ("foo:X" or "bar") */
 	if (IS_MNT_SHARED(r))
@@ -163,13 +172,14 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
 	seq_puts(m, " - ");
 	show_type(m, sb);
 	seq_putc(m, ' ');
-	if (sb->s_op->show_devname)
+	if (sb->s_op->show_devname) {
 		err = sb->s_op->show_devname(m, mnt->mnt_root);
-	else
-		mangle(m, r->mnt_devname ? r->mnt_devname : "none");
-	if (err)
-		goto out;
-	seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
+		if (err)
+			goto out;
+	} else {
+		mangle(m, r->mnt_devname);
+	}
+	seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
 	err = show_sb_opts(m, sb);
 	if (err)
 		goto out;
@@ -182,26 +192,28 @@ out:
 
 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
 {
+	struct proc_mounts *p = m->private;
 	struct mount *r = real_mount(mnt);
 	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
 	struct super_block *sb = mnt_path.dentry->d_sb;
-	int err = 0;
+	int err;
 
 	/* device */
+	seq_puts(m, "device ");
 	if (sb->s_op->show_devname) {
-		seq_puts(m, "device ");
 		err = sb->s_op->show_devname(m, mnt_path.dentry);
+		if (err)
+			goto out;
 	} else {
-		if (r->mnt_devname) {
-			seq_puts(m, "device ");
-			mangle(m, r->mnt_devname);
-		} else
-			seq_puts(m, "no device");
+		mangle(m, r->mnt_devname);
 	}
 
 	/* mount point */
 	seq_puts(m, " mounted on ");
-	seq_path(m, &mnt_path, " \t\n\\");
+	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
+	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
+	if (err)
+		goto out;
 	seq_putc(m, ' ');
 
 	/* file system type */
@@ -211,11 +223,11 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
 	/* optional statistics */
 	if (sb->s_op->show_stats) {
 		seq_putc(m, ' ');
-		if (!err)
-			err = sb->s_op->show_stats(m, mnt_path.dentry);
+		err = sb->s_op->show_stats(m, mnt_path.dentry);
 	}
 
 	seq_putc(m, '\n');
+out:
 	return err;
 }
 
@@ -227,27 +239,21 @@ static int mounts_open_common(struct inode *inode, struct file *file,
 	struct mnt_namespace *ns = NULL;
 	struct path root;
 	struct proc_mounts *p;
+	struct seq_file *m;
 	int ret = -EINVAL;
 
 	if (!task)
 		goto err;
 
-	rcu_read_lock();
-	nsp = task_nsproxy(task);
-	if (!nsp) {
-		rcu_read_unlock();
+	task_lock(task);
+	nsp = task->nsproxy;
+	if (!nsp || !nsp->mnt_ns) {
+		task_unlock(task);
 		put_task_struct(task);
 		goto err;
 	}
 	ns = nsp->mnt_ns;
-	if (!ns) {
-		rcu_read_unlock();
-		put_task_struct(task);
-		goto err;
-	}
 	get_mnt_ns(ns);
-	rcu_read_unlock();
-	task_lock(task);
 	if (!task->fs) {
 		task_unlock(task);
 		put_task_struct(task);
@@ -258,25 +264,20 @@ static int mounts_open_common(struct inode *inode, struct file *file,
 	task_unlock(task);
 	put_task_struct(task);
 
-	ret = -ENOMEM;
-	p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
-	if (!p)
+	ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
+	if (ret)
 		goto err_put_path;
 
-	file->private_data = &p->m;
-	ret = seq_open(file, &mounts_op);
-	if (ret)
-		goto err_free;
+	m = file->private_data;
+	m->poll_event = ns->event;
 
+	p = m->private;
 	p->ns = ns;
 	p->root = root;
-	p->m.poll_event = ns->event;
 	p->show = show;
 
 	return 0;
 
- err_free:
-	kfree(p);
  err_put_path:
 	path_put(&root);
  err_put_ns:
@@ -287,10 +288,11 @@ static int mounts_open_common(struct inode *inode, struct file *file,
 
 static int mounts_release(struct inode *inode, struct file *file)
 {
-	struct proc_mounts *p = proc_mounts(file->private_data);
+	struct seq_file *m = file->private_data;
+	struct proc_mounts *p = m->private;
 	path_put(&p->root);
 	put_mnt_ns(p->ns);
-	return seq_release(inode, file);
+	return seq_release_private(inode, file);
 }
 
 static int mounts_open(struct inode *inode, struct file *file)
@@ -310,7 +312,8 @@ static int mountstats_open(struct inode *inode, struct file *file)
 
 const struct file_operations proc_mounts_operations = {
 	.open		= mounts_open,
-	.read		= seq_read,
+	.read_iter	= seq_read_iter,
+	.splice_read	= copy_splice_read,
 	.llseek		= seq_lseek,
 	.release	= mounts_release,
 	.poll		= mounts_poll,
@@ -318,7 +321,8 @@ const struct file_operations proc_mounts_operations = {
 
 const struct file_operations proc_mountinfo_operations = {
 	.open		= mountinfo_open,
-	.read		= seq_read,
+	.read_iter	= seq_read_iter,
+	.splice_read	= copy_splice_read,
 	.llseek		= seq_lseek,
 	.release	= mounts_release,
 	.poll		= mounts_poll,
@@ -326,7 +330,8 @@ const struct file_operations proc_mountinfo_operations = {
 
 const struct file_operations proc_mountstats_operations = {
 	.open		= mountstats_open,
-	.read		= seq_read,
+	.read_iter	= seq_read_iter,
+	.splice_read	= copy_splice_read,
 	.llseek		= seq_lseek,
 	.release	= mounts_release,
 };