From d07aad41e323fd36a1504809d1f9b89c0504f76c Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Wed, 27 May 2026 11:12:17 +0200 Subject: [PATCH 07/12] libmount: ignore X-mount.nocanonicalize for restricted users Paths must always be canonicalized in restricted (non-root) mode to ensure safe target resolution before fd pinning. Signed-off-by: Karel Zak --- libmount/src/context.c | 3 +++ sys-utils/mount.8.adoc | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) Index: util-linux-2.40.4/libmount/src/context.c =================================================================== --- util-linux-2.40.4.orig/libmount/src/context.c +++ util-linux-2.40.4/libmount/src/context.c @@ -1943,6 +1943,9 @@ int mnt_context_prepare_srcpath(struct l if (!path) path = src; + if (mnt_context_is_restricted(cxt)) + return 0; + ol = mnt_context_get_optlist(cxt); if (!ol) return -ENOMEM; Index: util-linux-2.40.4/sys-utils/mount.8.adoc =================================================================== --- util-linux-2.40.4.orig/sys-utils/mount.8.adoc +++ util-linux-2.40.4/sys-utils/mount.8.adoc @@ -319,7 +319,9 @@ Remount a subtree somewhere else (so tha *-c*, *--no-canonicalize*:: Don't canonicalize paths. The *mount* command canonicalizes all paths (from the command line or _fstab_) by default. This option can be used together with the *-f* flag for already canonicalized absolute paths. The option is designed for mount helpers which call *mount -i*. It is strongly recommended to not use this command-line option for normal mount operations. + -Note that *mount* does not pass this option to the **/sbin/mount.**__type__ helpers. +Note that *mount* does not pass this option to the **/sbin/mount.**__type__ helpers. ++ +Note that *mount* ignores this option for unprivileged (non-root) users. Paths are always canonicalized in restricted mode to ensure safe target resolution. *-F*, *--fork*:: (Used in conjunction with *-a*.) Fork off a new incarnation of *mount* for each device. This will do the mounts on different devices or different NFS servers in parallel. This has the advantage that it is faster; also NFS timeouts proceed in parallel. A disadvantage is that the order of the mount operations is undefined. Thus, you cannot use this option if you want to mount both _/usr_ and _/usr/spool_.