diff options
| author | Ian Kent <raven@themaw.net> | 2025-11-18 10:46:31 +0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-11-19 11:14:02 +0100 |
| commit | 922a6f34c1756d2b0c35d9b2d915b8af19e85965 (patch) | |
| tree | c3eb198458480d3de60abd556e21039fc5b988de /fs/autofs | |
| parent | 3a8660878839faadb4f1a6dd72c3179c1df56787 (diff) | |
autofs: dont trigger mount if it cant succeed
If a mount namespace contains autofs mounts, and they are propagation
private, and there is no namespace specific automount daemon to handle
possible automounting then attempted path resolution will loop until
MAXSYMLINKS is reached before failing causing quite a bit of noise in
the log.
Add a check for this in autofs ->d_automount() so that the VFS can
immediately return an error in this case. Since the mount is propagation
private an EPERM return seems most appropriate.
Suggested by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Ian Kent <raven@themaw.net>
Link: https://patch.msgid.link/20251118024631.10854-2-raven@themaw.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/autofs')
| -rw-r--r-- | fs/autofs/autofs_i.h | 5 | ||||
| -rw-r--r-- | fs/autofs/dev-ioctl.c | 1 | ||||
| -rw-r--r-- | fs/autofs/inode.c | 1 | ||||
| -rw-r--r-- | fs/autofs/root.c | 8 |
4 files changed, 15 insertions, 0 deletions
diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h index 23cea74f9933..4fd555528c5d 100644 --- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -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; diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c index d8dd150cbd74..ed2efe4e97b2 100644 --- a/fs/autofs/dev-ioctl.c +++ b/fs/autofs/dev-ioctl.c @@ -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: diff --git a/fs/autofs/inode.c b/fs/autofs/inode.c index f5c16ffba013..732aee76a24c 100644 --- a/fs/autofs/inode.c +++ b/fs/autofs/inode.c @@ -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); diff --git a/fs/autofs/root.c b/fs/autofs/root.c index 174c7205fee4..d10df9d89d1c 100644 --- a/fs/autofs/root.c +++ b/fs/autofs/root.c @@ -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 |