mount user option
ibotty
bsd at ibotty.net
Thu Sep 25 16:36:27 PDT 2003
> somehow, for now, DO NOT APPLY THIS PATCH to your checkout!!!
> i could not mount any fs with this patch (+some
> recent changes) now, so beware!
i do no know, what has caused this...
the patch is actually ok, something else must have caused this, now it is
fine though.
anyways, i attached a new cvs diff.
this patch finally handles the sysctl vfs.usermount.
you must set vfs.usermount to 1, to usermount any fs with 'user' option.
i also commented vfs-syscalls.c on every place, where security checks are
done (and not done).
so the only things missing are:
- checking, if the user is a local user
(i have no real idea on how to get the users console (utmp maybe?))
- manpage (i will write it at a journey by train tomorrow)
somehow i seem to have blown up mount_procfs, i have no idea how though, it
bails out with a BUS_ERROR. (maybe 'it wasnt me'(tm).)
so do not try the patch if you badly need procfs.
btw: i shortened the diff by excluding dirs, which i only ansi-ized
(declarations). take the usermount.tar.gz from ../..
~ibottyIndex: sys/kern/vfs_syscalls.c
===================================================================
RCS file: /home/src/dcvs/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.17
diff -u -3 -p -r1.17 vfs_syscalls.c
--- sys/kern/vfs_syscalls.c 23 Sep 2003 05:03:51 -0000 1.17
+++ sys/kern/vfs_syscalls.c 25 Sep 2003 22:56:43 -0000
@@ -114,20 +114,31 @@ mount(struct mount_args *uap)
struct nameidata nd;
char fstypename[MFSNAMELEN];
- if (usermount == 0 && (error = suser(td)))
+ /* this is a dropin replacement for suser in mount(2)
+ this macro cannot be used outside of mount(2):
+ it needs a valid proc *p and struct mount_args *uap. */
+#define SUSER(_thread) \
+ ( (suser(_thread) || \
+ (p->p_ucred->cr_ruid != 0 && \
+ SCARG(uap, flags) & MNT_USER )) \
+ ? EPERM : 0 )
+
+
+ if (usermount == 0 && (error = SUSER(td)))
return (error);
+
/*
* Do not allow NFS export by non-root users.
*/
if (SCARG(uap, flags) & MNT_EXPORTED) {
- error = suser(td);
+ error = SUSER(td);
if (error)
return (error);
}
/*
* Silently enforce MNT_NOSUID and MNT_NODEV for non-root users
*/
- if (suser(td))
+ if (SUSER(td))
SCARG(uap, flags) |= MNT_NOSUID | MNT_NODEV;
/*
* Get vnode to be covered
@@ -158,9 +169,11 @@ mount(struct mount_args *uap)
/*
* Only root, or the user that did the original mount is
* permitted to update it.
+ * If the filesystem was mounted with the MNT_USER option,
+ * noone is permitted to update it.
*/
if (mp->mnt_stat.f_owner != p->p_ucred->cr_uid &&
- (error = suser(td))) {
+ suser(td) && (SCARG(uap, flags) & MNT_USER)) {
vput(vp);
return (error);
}
@@ -186,6 +199,8 @@ mount(struct mount_args *uap)
/*
* If the user is not root, ensure that they own the directory
* onto which we are attempting to mount.
+ * Does no extra checks for MNT_USER mounts, because they are
+ * always done with euid = 0
*/
if ((error = VOP_GETATTR(vp, &va, td)) ||
(va.va_uid != p->p_ucred->cr_uid &&
@@ -280,7 +295,11 @@ mount(struct mount_args *uap)
mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
mp->mnt_vnodecovered = vp;
- mp->mnt_stat.f_owner = p->p_ucred->cr_uid;
+ /* if user-mounted fs, set owner */
+ if (SCARG(uap, flags) & MNT_USER)
+ mp->mnt_stat.f_owner = p->p_ucred->cr_ruid;
+ else
+ mp->mnt_stat.f_owner = p->p_ucred->cr_uid;
mp->mnt_iosize_max = DFLTPHYS;
VOP_UNLOCK(vp, 0, td);
update:
@@ -430,6 +449,8 @@ unmount(struct unmount_args *uap)
/*
* Only root, or the user that did the original mount is
* permitted to unmount this filesystem.
+ * Because MNT_USER mounts are owned by non-root,
+ * this non-root user can unmount this fs.
*/
if ((mp->mnt_stat.f_owner != p->p_ucred->cr_uid) &&
(error = suser(td))) {
Index: sbin/mount/extern.h
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/extern.h,v
retrieving revision 1.2
diff -u -3 -p -r1.2 extern.h
--- sbin/mount/extern.h 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/extern.h 25 Sep 2003 20:52:58 -0000
@@ -28,8 +28,8 @@
*/
/* vfslist.c */
-int checkvfsname __P((const char *, const char **));
-const char **makevfslist __P((char *));
+int checkvfsname (const char *, const char **);
+const char **makevfslist (char *);
/* mount_ufs.c */
-int mount_ufs __P((int, char *const *));
+int mount_ufs (int, char *const *);
Index: sbin/mount/getmntopts.c
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/getmntopts.c,v
retrieving revision 1.2
diff -u -3 -p -r1.2 getmntopts.c
--- sbin/mount/getmntopts.c 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/getmntopts.c 25 Sep 2003 20:52:58 -0000
@@ -49,11 +49,10 @@
int getmnt_silent = 0;
void
-getmntopts(options, m0, flagp, altflagp)
- const char *options;
- const struct mntopt *m0;
- int *flagp;
- int *altflagp;
+getmntopts(const char *options,
+ const struct mntopt *m0,
+ int *flagp,
+ int *altflagp)
{
const struct mntopt *m;
int negative, len;
@@ -106,9 +105,7 @@ getmntopts(options, m0, flagp, altflagp)
}
void
-rmslashes(rrpin, rrpout)
- char *rrpin;
- char *rrpout;
+rmslashes(char *rrpin, char *rrpout)
{
char *rrpoutstart;
@@ -128,9 +125,7 @@ rmslashes(rrpin, rrpout)
}
void
-checkpath(path, resolved)
- const char *path;
- char *resolved;
+checkpath(const char *path, char *resolved)
{
struct stat sb;
Index: sbin/mount/mntopts.h
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/mntopts.h,v
retrieving revision 1.2
diff -u -3 -p -r1.2 mntopts.h
--- sbin/mount/mntopts.h 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/mntopts.h 25 Sep 2003 21:40:56 -0000
@@ -57,6 +57,7 @@ struct mntopt {
#define MOPT_NOCLUSTERR { "clusterr", 1, MNT_NOCLUSTERR, 0 }
#define MOPT_NOCLUSTERW { "clusterw", 1, MNT_NOCLUSTERW, 0 }
#define MOPT_SUIDDIR { "suiddir", 0, MNT_SUIDDIR, 0 }
+#define MOPT_USER { "user", 0, MNT_USER, 0 }
/* Control flags. */
#define MOPT_FORCE { "force", 0, MNT_FORCE, 0 }
@@ -70,7 +71,8 @@ struct mntopt {
#define MOPT_FSTAB_COMPAT \
MOPT_RO, \
MOPT_RW, \
- MOPT_AUTO
+ MOPT_AUTO, \
+ MOPT_USER
/* Standard options which all mounts can understand. */
#define MOPT_STDOPTS \
@@ -86,9 +88,10 @@ struct mntopt {
MOPT_RDONLY, \
MOPT_UNION, \
MOPT_NOCLUSTERR, \
- MOPT_NOCLUSTERW
+ MOPT_NOCLUSTERW, \
+ MOPT_USER
-void getmntopts __P((const char *, const struct mntopt *, int *, int *));
-void rmslashes __P((char *, char *));
-void checkpath __P((const char *, char resolved_path[]));
+void getmntopts (const char *, const struct mntopt *, int *, int *);
+void rmslashes (char *, char *);
+void checkpath (const char *, char resolved_path[]);
extern int getmnt_silent;
Index: sbin/mount/mount.8
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/mount.8,v
retrieving revision 1.2
diff -u -3 -p -r1.2 mount.8
--- sbin/mount/mount.8 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/mount.8 25 Sep 2003 20:52:58 -0000
@@ -213,6 +213,8 @@ Lookups will be done in the mounted file
If those operations fail due to a non-existent file the underlying
directory is then accessed.
All creates are done in the mounted filesystem.
+.It Cm user
+Allow any user to mount this filesystem.
.El
.Pp
Any additional options specific to a filesystem type that is not
Index: sbin/mount/mount.c
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/mount.c,v
retrieving revision 1.2
diff -u -3 -p -r1.2 mount.c
--- sbin/mount/mount.c 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/mount.c 25 Sep 2003 20:52:58 -0000
@@ -61,21 +61,21 @@
int debug, fstab_style, verbose;
-char *catopt __P((char *, const char *));
+char *catopt (char *, const char *);
struct statfs
- *getmntpt __P((const char *));
-int hasopt __P((const char *, const char *));
-int ismounted __P((struct fstab *, struct statfs *, int));
-int isremountable __P((const char *));
-void mangle __P((char *, int *, const char **));
-char *update_options __P((char *, char *, int));
-int mountfs __P((const char *, const char *, const char *,
- int, const char *, const char *));
-void remopt __P((char *, const char *));
-void prmount __P((struct statfs *));
-void putfsent __P((const struct statfs *));
-void usage __P((void));
-char *flags2opts __P((int));
+ *getmntpt (const char *);
+int hasopt (const char *, const char *);
+int ismounted (struct fstab *, struct statfs *, int);
+int isremountable (const char *);
+void mangle (char *, int *, const char **);
+char *update_options (char *, char *, int);
+int mountfs (const char *, const char *, const char *,
+ int, const char *, const char *);
+void remopt (char *, const char *);
+void prmount (struct statfs *);
+void putfsent (const struct statfs *);
+void usage (void);
+char *flags2opts (int);
/* Map from mount options to printable formats. */
static struct opt {
@@ -113,9 +113,7 @@ remountable_fs_names[] = {
};
int
-main(argc, argv)
- int argc;
- char * const argv[];
+main(int argc, char * const argv[])
{
const char *mntfromname, **vfslist, *vfstype;
struct fstab *fs;
@@ -129,6 +127,8 @@ main(argc, argv)
options = NULL;
vfslist = NULL;
vfstype = "ufs";
+
+ /* iterate over options */
while ((ch = getopt(argc, argv, "adfo:prwt:uv")) != -1)
switch (ch) {
case 'a':
@@ -176,7 +176,8 @@ main(argc, argv)
#define BADTYPE(type) \
(strcmp(type, FSTAB_RO) && \
- strcmp(type, FSTAB_RW) && strcmp(type, FSTAB_RQ))
+ strcmp(type, FSTAB_RW) && \
+ strcmp(type, FSTAB_RQ))
rval = 0;
switch (argc) {
@@ -194,18 +195,21 @@ main(argc, argv)
if (!(init_flags & MNT_UPDATE) &&
ismounted(fs, mntbuf, mntsize))
continue;
+
if (mountfs(fs->fs_vfstype, fs->fs_spec,
fs->fs_file, init_flags, options,
fs->fs_mntops))
rval = 1;
}
- } else if (fstab_style) {
+ } else if (fstab_style) /* only print */
+ {
for (i = 0; i < mntsize; i++) {
if (checkvfsname(mntbuf[i].f_fstypename, vfslist))
continue;
putfsent(&mntbuf[i]);
}
- } else {
+ } else /* print currently mounted filesystems */
+ {
for (i = 0; i < mntsize; i++) {
if (checkvfsname(mntbuf[i].f_fstypename,
vfslist))
@@ -219,6 +223,7 @@ main(argc, argv)
usage();
if (init_flags & MNT_UPDATE) {
+
mntfromname = NULL;
have_fstab = 0;
if ((mntbuf = getmntpt(*argv)) == NULL)
@@ -253,7 +258,7 @@ main(argc, argv)
mntbuf->f_flags);
}
rval = mountfs(mntbuf->f_fstypename, mntfromname,
- mntbuf->f_mntonname, init_flags, options, 0);
+ mntbuf->f_mntonname, init_flags, options, NULL);
break;
}
rmslashes(*argv, *argv);
@@ -264,6 +269,7 @@ main(argc, argv)
if (BADTYPE(fs->fs_type))
errx(1, "%s has unknown file system type",
*argv);
+
rval = mountfs(fs->fs_vfstype, fs->fs_spec, fs->fs_file,
init_flags, options, fs->fs_mntops);
break;
@@ -287,7 +293,8 @@ main(argc, argv)
/*
* If the mount was successfully, and done by root, tell mountd the
- * good news. Pid checks are probably unnecessary, but don't hurt.
+ * good news.
+ * Do not tell mountd, if mounted by non-root user.
*/
if (rval == 0 && getuid() == 0 &&
(mountdfp = fopen(_PATH_MOUNTDPID, "r")) != NULL) {
@@ -301,10 +308,7 @@ main(argc, argv)
}
int
-ismounted(fs, mntbuf, mntsize)
- struct fstab *fs;
- struct statfs *mntbuf;
- int mntsize;
+ismounted(struct fstab *fs, struct statfs *mntbuf, int mntsize)
{
int i;
@@ -321,8 +325,8 @@ ismounted(fs, mntbuf, mntsize)
}
int
-isremountable(vfsname)
- const char *vfsname;
+isremountable(const char *vfsname)
+
{
const char **cp;
@@ -333,8 +337,7 @@ isremountable(vfsname)
}
int
-hasopt(mntopts, option)
- const char *mntopts, *option;
+hasopt(const char *mntopts, const char *option)
{
int negative, found;
char *opt, *optbuf;
@@ -357,10 +360,17 @@ hasopt(mntopts, option)
return (found);
}
+
+/*
+ * Mount the filesystem using mount_<type>.
+ */
int
-mountfs(vfstype, spec, name, flags, options, mntopts)
- const char *vfstype, *spec, *name, *options, *mntopts;
- int flags;
+mountfs(const char *vfstype,
+ const char *spec,
+ const char *name,
+ int flags,
+ const char *options,
+ const char *mntopts )
{
/* List of directories containing mount_xxx subcommands. */
static const char *edirs[] = {
@@ -379,6 +389,7 @@ mountfs(vfstype, spec, name, flags, opti
(void)&name;
#endif
+
/* resolve the mountpoint with realpath(3) */
(void)checkpath(name, mntpath);
name = mntpath;
@@ -490,8 +501,7 @@ mountfs(vfstype, spec, name, flags, opti
}
void
-prmount(sfp)
- struct statfs *sfp;
+prmount(struct statfs *sfp)
{
int flags;
struct opt *o;
@@ -525,8 +535,7 @@ prmount(sfp)
}
struct statfs *
-getmntpt(name)
- const char *name;
+getmntpt(const char *name)
{
struct statfs *mntbuf;
int i, mntsize;
@@ -541,9 +550,7 @@ getmntpt(name)
}
char *
-catopt(s0, s1)
- char *s0;
- const char *s1;
+catopt(char *s0, const char *s1)
{
size_t i;
char *cp;
@@ -565,10 +572,7 @@ catopt(s0, s1)
}
void
-mangle(options, argcp, argv)
- char *options;
- int *argcp;
- const char **argv;
+mangle(char *options, int *argcp, const char **argv)
{
char *p, *s;
int argc;
@@ -594,10 +598,7 @@ mangle(options, argcp, argv)
char *
-update_options(opts, fstab, curflags)
- char *opts;
- char *fstab;
- int curflags;
+update_options(char *opts, char *fstab, int curflags)
{
char *o, *p;
char *cur;
@@ -652,9 +653,7 @@ update_options(opts, fstab, curflags)
}
void
-remopt(string, opt)
- char *string;
- const char *opt;
+remopt(char *string, const char *opt)
{
char *o, *p, *r;
@@ -687,8 +686,7 @@ usage()
}
void
-putfsent(ent)
- const struct statfs *ent;
+putfsent(const struct statfs *ent)
{
struct fstab *fst;
char *opts;
@@ -713,8 +711,7 @@ putfsent(ent)
char *
-flags2opts(flags)
- int flags;
+flags2opts(int flags)
{
char *res;
Index: sbin/mount/vfslist.c
===================================================================
RCS file: /home/src/dcvs/src/sbin/mount/vfslist.c,v
retrieving revision 1.2
diff -u -3 -p -r1.2 vfslist.c
--- sbin/mount/vfslist.c 17 Jun 2003 04:27:33 -0000 1.2
+++ sbin/mount/vfslist.c 25 Sep 2003 21:19:30 -0000
@@ -44,9 +44,7 @@
static int skipvfs;
int
-checkvfsname(vfsname, vfslist)
- const char *vfsname;
- const char **vfslist;
+checkvfsname(const char *vfsname, const char **vfslist)
{
if (vfslist == NULL)
@@ -60,8 +58,7 @@ checkvfsname(vfsname, vfslist)
}
const char **
-makevfslist(fslist)
- char *fslist;
+makevfslist(char *fslist)
{
const char **av;
int i;
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