Commit ffbf700d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'vfs-6.19-rc1.autofs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 

Pull autofs update from Christian Brauner:
 "Prevent futile mount triggers in private mount namespaces.

  Fix a problematic loop in autofs when a mount namespace contains
  autofs mounts that are propagation private and there is no
  namespace-specific automount daemon to handle possible automounting.

  Previously, attempted path resolution would loop until MAXSYMLINKS was
  reached before failing, causing significant noise in the log.

 The fix adds a check in autofs ->d_automount() so that the VFS can
 immediately return EPERM in this case. Since the mount is propagation
 private, EPERM is the most appropriate error code"

* tag 'vfs-6.19-rc1.autofs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  autofs: dont trigger mount if it cant succeed
parents d0deeb80 922a6f34

fs/autofs/autofs_i.h

+5 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/wait.h>

#include <linux/sched.h>

#include <linux/sched/signal.h>

#include <uapi/linux/mount.h>

#include <linux/mount.h>

#include <linux/namei.h>

#include <linux/uaccess.h>
@@ -27,6 +28,9 @@ 
#include <linux/magic.h>

#include <linux/fs_context.h>

#include <linux/fs_parser.h>

#include "../mount.h"

#include <linux/ns_common.h>





/* This is the range of ioctl() numbers we claim as ours */

#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
@@ -114,6 +118,7 @@ struct autofs_sb_info { 
	int pipefd;

	struct file *pipe;

	struct pid *oz_pgrp;

	u64 mnt_ns_id;

	int version;

	int sub_version;

	int min_proto;

fs/autofs/dev-ioctl.c

+1 −0
Original line number Diff line number Diff line
@@ -381,6 +381,7 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp, 
		swap(sbi->oz_pgrp, new_pid);

		sbi->pipefd = pipefd;

		sbi->pipe = pipe;

		sbi->mnt_ns_id = to_ns_common(current->nsproxy->mnt_ns)->ns_id;

		sbi->flags &= ~AUTOFS_SBI_CATATONIC;

	}

out:

fs/autofs/inode.c

+1 −0
Original line number Diff line number Diff line
@@ -251,6 +251,7 @@ static struct autofs_sb_info *autofs_alloc_sbi(void) 
	sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;

	sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;

	sbi->pipefd = -1;

	sbi->mnt_ns_id = to_ns_common(current->nsproxy->mnt_ns)->ns_id;



	set_autofs_type_indirect(&sbi->type);

	mutex_init(&sbi->wq_mutex);

fs/autofs/root.c

+8 −0
Original line number Diff line number Diff line
@@ -341,6 +341,14 @@ static struct vfsmount *autofs_d_automount(struct path *path) 
	if (autofs_oz_mode(sbi))

		return NULL;



	/* Refuse to trigger mount if current namespace is not the owner

	 * and the mount is propagation private.

	 */

	if (sbi->mnt_ns_id != to_ns_common(current->nsproxy->mnt_ns)->ns_id) {

		if (vfsmount_to_propagation_flags(path->mnt) & MS_PRIVATE)

			return ERR_PTR(-EPERM);

	}



	/*

	 * If an expire request is pending everyone must wait.

	 * If the expire fails we're still mounted so continue

fs/namespace.c

+6 −0
Original line number Diff line number Diff line
@@ -5148,6 +5148,12 @@ static u64 mnt_to_propagation_flags(struct mount *m) 
	return propagation;

}



u64 vfsmount_to_propagation_flags(struct vfsmount *mnt)

{

	return mnt_to_propagation_flags(real_mount(mnt));

}

EXPORT_SYMBOL_GPL(vfsmount_to_propagation_flags);



static void statmount_sb_basic(struct kstatmount *s)

{

	struct super_block *sb = s->mnt->mnt_sb;