--HcAYCG3uE/tztfnV
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Hi all,
attached patch changes getfsstat to only show filesystems
under the current chroot() path (or the jail root, if jailed, but
not chrooted).
A side effect is that the following works:
mkdir /mnt/test
mount -t procfs proc /mnt/test
mv /mnt /mnt2
umount /mnt2/test
This doesn't even work on Linux :)
Joerg
--HcAYCG3uE/tztfnV
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Content-Disposition: attachment; filename="getfsstat_visibility.patch"
Index: vfs_syscalls.c
===================================================================
RCS file: /home/joerg/wd/repository/dragonflybsd/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.57
diff -u -r1.57 vfs_syscalls.c
--- vfs_syscalls.c 1 Feb 2005 21:52:11 -0000 1.57
+++ vfs_syscalls.c 1 Feb 2005 23:46:32 -0000
@@ -892,6 +892,37 @@
return (error);
}
+static int
+chroot_visible_mnt(struct mount *mp, struct proc *p)
+{
+ struct namecache *ncp;
+ /*
+ * First check if this file system is below
+ * the chroot path.
+ */
+ ncp = mp->mnt_ncp;
+ while (ncp != NULL && ncp != p->p_fd->fd_nrdir)
+ ncp = ncp->nc_parent;
+ if (ncp == NULL) {
+ /*
+ * This is not below the chroot path.
+ *
+ * Check if the chroot path is on the same filesystem,
+ * by determing if we have to cross a mount point
+ * before reaching mp->mnt_ncp.
+ */
+ ncp = p->p_fd->fd_nrdir;
+ while (ncp != NULL && ncp != mp->mnt_ncp) {
+ if (ncp->nc_flag & NCF_MOUNTPT) {
+ ncp = NULL;
+ break;
+ }
+ ncp = ncp->nc_parent;
+ }
+ }
+ return(ncp != NULL);
+}
+
/*
* getfsstat_args(struct statfs *buf, long bufsize, int flags)
*
@@ -902,10 +933,18 @@
getfsstat(struct getfsstat_args *uap)
{
struct thread *td = curthread;
+ struct proc *p = td->td_proc;
struct mount *mp, *nmp;
struct statfs *sp, *sfsp;
lwkt_tokref ilock;
long count, maxcount, error;
+ int is_chrooted;
+ char *freepath, *fullpath;
+
+ if (p != NULL && (p->p_fd->fd_nrdir->nc_flag & NCF_ROOT) == 0)
+ is_chrooted = 1;
+ else
+ is_chrooted = 0;
maxcount = uap->bufsize / sizeof(struct statfs);
sfsp = uap->buf;
@@ -917,6 +956,12 @@
continue;
}
if (sfsp && count < maxcount) {
+ if (is_chrooted && !chroot_visible_mnt(mp, p)) {
+ lwkt_gettokref(&ilock);
+ nmp = TAILQ_NEXT(mp, mnt_list);
+ vfs_unbusy(mp, td);
+ continue;
+ }
sp = &mp->mnt_stat;
/*
* If MNT_NOWAIT or MNT_LAZY is specified, do not
@@ -932,6 +977,15 @@
continue;
}
sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
+
+ error = cache_fullpath(p, mp->mnt_ncp, &fullpath, &freepath);
+ if (error)
+ return(error);
+ bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
+ strlcpy(sp->f_mntonname, fullpath,
+ sizeof(sp->f_mntonname));
+ free(freepath, M_TEMP);
+
error = copyout(sp, sfsp, sizeof(*sp));
if (error) {
vfs_unbusy(mp, td);
--HcAYCG3uE/tztfnV--