The branch stable/13 has been updated by dfr: URL: https://cgit.FreeBSD.org/src/commit/?id=d373650a53977de4aba1da737525bd37eeba72ca
commit d373650a53977de4aba1da737525bd37eeba72ca Author: Doug Rabson <[email protected]> AuthorDate: 2022-11-23 14:51:13 +0000 Commit: Doug Rabson <[email protected]> CommitDate: 2023-01-06 07:57:57 +0000 Add support for mounting single files in nullfs The main use-case for this is to support mounting config files and secrets into OCI containers. My current workaround copies the files into the container which is messy and risks secrets leaking into container images if the cleanup fails. This adds a VFCF flag to indicate whether the filesystem supports file mounts and allows fspath to be either a directory or a file if the flag is set. Test Plan: $ sudo mkdir -p /mnt $ sudo touch /mnt/foo $ sudo mount -t nullfs /COPYRIGHT /mnt/foo Reviewed by: mjg, kib Tested by: pho (cherry picked from commit 521fbb722c33663cf00a83bca70ad7cb790687b3) --- sys/fs/nullfs/null_vfsops.c | 13 ++++++++++++- sys/kern/vfs_lookup.c | 4 ++-- sys/kern/vfs_mount.c | 32 ++++++++++++++++++++++++++------ sys/sys/mount.h | 1 + 4 files changed, 41 insertions(+), 9 deletions(-) diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c index 0bb98072edf4..1a83973313b1 100644 --- a/sys/fs/nullfs/null_vfsops.c +++ b/sys/fs/nullfs/null_vfsops.c @@ -156,6 +156,17 @@ nullfs_mount(struct mount *mp) } } + /* + * Lower vnode must be the same type as the covered vnode - we + * don't allow mounting directories to files or vice versa. + */ + if ((lowerrootvp->v_type != VDIR && lowerrootvp->v_type != VREG) || + lowerrootvp->v_type != mp->mnt_vnodecovered->v_type) { + NULLFSDEBUG("nullfs_mount: target must be same type as fspath"); + vput(lowerrootvp); + return (EINVAL); + } + xmp = (struct null_mount *) malloc(sizeof(struct null_mount), M_NULLFSMNT, M_WAITOK | M_ZERO); @@ -467,4 +478,4 @@ static struct vfsops null_vfsops = { .vfs_unlink_lowervp = nullfs_unlink_lowervp, }; -VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL); +VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL | VFCF_FILEMOUNT); diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c index bbceced68e50..3ded2180ac82 100644 --- a/sys/kern/vfs_lookup.c +++ b/sys/kern/vfs_lookup.c @@ -1154,8 +1154,8 @@ good: * Check to see if the vnode has been mounted on; * if so find the root of the mounted filesystem. */ - while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && - (cnp->cn_flags & NOCROSSMOUNT) == 0) { + while ((dp->v_type == VDIR || dp->v_type == VREG) && + (mp = dp->v_mountedhere) && (cnp->cn_flags & NOCROSSMOUNT) == 0) { if (vfs_busy(mp, 0)) continue; vput(dp); diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c index d17e1c7fbbd7..038ace288729 100644 --- a/sys/kern/vfs_mount.c +++ b/sys/kern/vfs_mount.c @@ -962,8 +962,13 @@ vfs_domount_first( error = priv_check_cred(td->td_ucred, PRIV_VFS_ADMIN); if (error == 0) error = vinvalbuf(vp, V_SAVE, 0, 0); - if (error == 0 && vp->v_type != VDIR) - error = ENOTDIR; + if (vfsp->vfc_flags & VFCF_FILEMOUNT) { + if (error == 0 && vp->v_type != VDIR && vp->v_type != VREG) + error = EINVAL; + } else { + if (error == 0 && vp->v_type != VDIR) + error = ENOTDIR; + } if (error == 0 && (fsflags & MNT_EMPTYDIR) != 0) error = vfs_emptydir(vp); if (error == 0) { @@ -1376,22 +1381,33 @@ vfs_domount( /* * Get vnode to be covered or mount point's vnode in case of MNT_UPDATE. */ - NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1, + NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1 | WANTPARENT, UIO_SYSSPACE, fspath, td); error = namei(&nd); if (error != 0) return (error); - NDFREE(&nd, NDF_ONLY_PNBUF); vp = nd.ni_vp; if ((fsflags & MNT_UPDATE) == 0) { if ((vp->v_vflag & VV_ROOT) != 0 && (fsflags & MNT_NOCOVER) != 0) { vput(vp); - return (EBUSY); + error = EBUSY; + goto out; } pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK); strcpy(pathbuf, fspath); - error = vn_path_to_global_path(td, vp, pathbuf, MNAMELEN); + /* + * Note: we allow any vnode type here. If the path sanity check + * succeeds, the type will be validated in vfs_domount_first + * above. + */ + if (vp->v_type == VDIR) + error = vn_path_to_global_path(td, vp, pathbuf, + MNAMELEN); + else + error = vn_path_to_global_path_hardlink(td, vp, + nd.ni_dvp, pathbuf, MNAMELEN, + nd.ni_cnd.cn_nameptr, nd.ni_cnd.cn_namelen); if (error == 0) { error = vfs_domount_first(td, vfsp, pathbuf, vp, fsflags, optlist); @@ -1400,6 +1416,10 @@ vfs_domount( } else error = vfs_domount_update(td, vp, fsflags, optlist); +out: + NDFREE(&nd, NDF_ONLY_PNBUF); + vrele(nd.ni_dvp); + return (error); } diff --git a/sys/sys/mount.h b/sys/sys/mount.h index 0e7ecd646964..6e988a48922e 100644 --- a/sys/sys/mount.h +++ b/sys/sys/mount.h @@ -648,6 +648,7 @@ struct ovfsconf { #define VFCF_DELEGADMIN 0x00800000 /* supports delegated administration */ #define VFCF_SBDRY 0x01000000 /* Stop at Boundary: defer stop requests to kernel->user (AST) transition */ +#define VFCF_FILEMOUNT 0x02000000 /* allow mounting files */ typedef uint32_t fsctlop_t;
