v4.19.13 snapshot.
diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
new file mode 100644
index 0000000..e16fb8f
--- /dev/null
+++ b/fs/proc_namespace.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
+ *
+ * In fact, that's a piece of procfs; it's *almost* isolated from
+ * the rest of fs/proc, but has rather close relationships with
+ * fs/namespace.c, thus here instead of fs/proc
+ *
+ */
+#include <linux/mnt_namespace.h>
+#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 __poll_t mounts_poll(struct file *file, poll_table *wait)
+{
+ struct seq_file *m = file->private_data;
+ struct proc_mounts *p = m->private;
+ struct mnt_namespace *ns = p->ns;
+ __poll_t res = EPOLLIN | EPOLLRDNORM;
+ int event;
+
+ poll_wait(file, &p->ns->poll, wait);
+
+ event = READ_ONCE(ns->event);
+ if (m->poll_event != event) {
+ m->poll_event = event;
+ res |= EPOLLERR | EPOLLPRI;
+ }
+
+ return res;
+}
+
+struct proc_fs_info {
+ 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[] = {
+ { SB_SYNCHRONOUS, ",sync" },
+ { SB_DIRSYNC, ",dirsync" },
+ { SB_MANDLOCK, ",mand" },
+ { SB_LAZYTIME, ",lazytime" },
+ { 0, NULL }
+ };
+ const struct proc_fs_info *fs_infop;
+
+ for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
+ if (sb->s_flags & fs_infop->flag)
+ seq_puts(m, fs_infop->str);
+ }
+
+ return security_sb_show_options(m, sb);
+}
+
+static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
+{
+ static const struct proc_fs_info mnt_info[] = {
+ { MNT_NOSUID, ",nosuid" },
+ { MNT_NODEV, ",nodev" },
+ { MNT_NOEXEC, ",noexec" },
+ { MNT_NOATIME, ",noatime" },
+ { MNT_NODIRATIME, ",nodiratime" },
+ { MNT_RELATIME, ",relatime" },
+ { 0, NULL }
+ };
+ const struct proc_fs_info *fs_infop;
+
+ for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
+ if (mnt->mnt_flags & fs_infop->flag)
+ seq_puts(m, fs_infop->str);
+ }
+}
+
+static inline void mangle(struct seq_file *m, const char *s)
+{
+ 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]) {
+ seq_putc(m, '.');
+ mangle(m, sb->s_subtype);
+ }
+}
+
+static int show_vfsmnt(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;
+
+ 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");
+ }
+ seq_putc(m, ' ');
+ /* 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);
+ if (sb->s_op->show_options)
+ err = sb->s_op->show_options(m, mnt_path.dentry);
+ seq_puts(m, " 0 0\n");
+out:
+ return err;
+}
+
+static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
+{
+ 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 };
+ 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);
+ if (err)
+ goto out;
+ } else {
+ seq_dentry(m, mnt->mnt_root, " \t\n\\");
+ }
+ seq_putc(m, ' ');
+
+ /* 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_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
+ show_mnt_opts(m, mnt);
+
+ /* Tagged fields ("foo:X" or "bar") */
+ if (IS_MNT_SHARED(r))
+ seq_printf(m, " shared:%i", r->mnt_group_id);
+ if (IS_MNT_SLAVE(r)) {
+ int master = r->mnt_master->mnt_group_id;
+ int dom = get_dominating_id(r, &p->root);
+ seq_printf(m, " master:%i", master);
+ if (dom && dom != master)
+ seq_printf(m, " propagate_from:%i", dom);
+ }
+ if (IS_MNT_UNBINDABLE(r))
+ seq_puts(m, " unbindable");
+
+ /* Filesystem specific data */
+ seq_puts(m, " - ");
+ show_type(m, sb);
+ seq_putc(m, ' ');
+ if (sb->s_op->show_devname) {
+ err = sb->s_op->show_devname(m, mnt->mnt_root);
+ if (err)
+ goto out;
+ } else {
+ mangle(m, r->mnt_devname ? r->mnt_devname : "none");
+ }
+ seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
+ err = show_sb_opts(m, sb);
+ if (err)
+ goto out;
+ if (sb->s_op->show_options)
+ err = sb->s_op->show_options(m, mnt->mnt_root);
+ seq_putc(m, '\n');
+out:
+ return err;
+}
+
+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;
+
+ /* 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");
+ }
+
+ /* mount point */
+ seq_puts(m, " mounted on ");
+ /* 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 */
+ seq_puts(m, "with fstype ");
+ show_type(m, sb);
+
+ /* optional statistics */
+ if (sb->s_op->show_stats) {
+ seq_putc(m, ' ');
+ err = sb->s_op->show_stats(m, mnt_path.dentry);
+ }
+
+ seq_putc(m, '\n');
+out:
+ return err;
+}
+
+static int mounts_open_common(struct inode *inode, struct file *file,
+ int (*show)(struct seq_file *, struct vfsmount *))
+{
+ struct task_struct *task = get_proc_task(inode);
+ struct nsproxy *nsp;
+ struct mnt_namespace *ns = NULL;
+ struct path root;
+ struct proc_mounts *p;
+ struct seq_file *m;
+ int ret = -EINVAL;
+
+ if (!task)
+ goto err;
+
+ task_lock(task);
+ nsp = task->nsproxy;
+ if (!nsp || !nsp->mnt_ns) {
+ task_unlock(task);
+ put_task_struct(task);
+ goto err;
+ }
+ ns = nsp->mnt_ns;
+ get_mnt_ns(ns);
+ if (!task->fs) {
+ task_unlock(task);
+ put_task_struct(task);
+ ret = -ENOENT;
+ goto err_put_ns;
+ }
+ get_fs_root(task->fs, &root);
+ task_unlock(task);
+ put_task_struct(task);
+
+ ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
+ if (ret)
+ goto err_put_path;
+
+ m = file->private_data;
+ m->poll_event = ns->event;
+
+ p = m->private;
+ p->ns = ns;
+ p->root = root;
+ p->show = show;
+ p->cached_event = ~0ULL;
+
+ return 0;
+
+ err_put_path:
+ path_put(&root);
+ err_put_ns:
+ put_mnt_ns(ns);
+ err:
+ return ret;
+}
+
+static int mounts_release(struct inode *inode, struct file *file)
+{
+ 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_private(inode, file);
+}
+
+static int mounts_open(struct inode *inode, struct file *file)
+{
+ return mounts_open_common(inode, file, show_vfsmnt);
+}
+
+static int mountinfo_open(struct inode *inode, struct file *file)
+{
+ return mounts_open_common(inode, file, show_mountinfo);
+}
+
+static int mountstats_open(struct inode *inode, struct file *file)
+{
+ return mounts_open_common(inode, file, show_vfsstat);
+}
+
+const struct file_operations proc_mounts_operations = {
+ .open = mounts_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = mounts_release,
+ .poll = mounts_poll,
+};
+
+const struct file_operations proc_mountinfo_operations = {
+ .open = mountinfo_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = mounts_release,
+ .poll = mounts_poll,
+};
+
+const struct file_operations proc_mountstats_operations = {
+ .open = mountstats_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = mounts_release,
+};