Re: kern/40634: dostatvfs() broken when chroot to /

[enami tsugutomo <enami%sm.sony.co.jp@localhost>]

The following reply was made to PR kern/40634; it has been noted by GNATS.

From: enami tsugutomo <enami%sm.sony.co.jp@localhost>
To: bad%bsd.de@localhost
Cc: gnats-bugs%NetBSD.org@localhost
Subject: Re: kern/40634: dostatvfs() broken when chroot to /
Date: Sat, 14 Feb 2009 15:43:04 +0900 (JST)

 > >Fix:
 > Apply the following change to dostatvfs():
 > 
 >               * data.
 >               */
 >              if (strncmp(bp, sp->f_mntonname, len) == 0 &&
 > -                ((c = sp->f_mntonname[len]) == '/' || c == '\0')) {
 > +                (len <= 1 || (c = sp->f_mntonname[len]) == '/' || c == 
 > '\0')) {
 >                      (void)strlcpy(sp->f_mntonname, &sp->f_mntonname[len],
 >                          sizeof(sp->f_mntonname));
 >                      if (sp->f_mntonname[0] == '\0')
 > 
 > when the chroot dir is / len is 1 and bp is "/" f_mnttonname[1] is uneqal
 > to '/' and '\0' for all mount points other than /.
 
 Your change removes / in front of mount point, doesn't it?
 
 enami.
 
 Index: vfs_syscalls.c
 ===================================================================
 RCS file: /cvsroot/src/sys/kern/vfs_syscalls.c,v
 retrieving revision 1.385
 diff -u -r1.385 vfs_syscalls.c
 --- vfs_syscalls.c     5 Feb 2009 13:37:24 -0000       1.385
 +++ vfs_syscalls.c     14 Feb 2009 06:38:43 -0000
 @@ -888,7 +888,9 @@
                 * rest we cannot see, so we don't allow viewing the
                 * data.
                 */
 -              if (strncmp(bp, sp->f_mntonname, len) == 0 &&
 +              if (len == 1)
 +                      /* our root is / */;
 +              else if (strncmp(bp, sp->f_mntonname, len) == 0 &&
                    ((c = sp->f_mntonname[len]) == '/' || c == '\0')) {
                        (void)strlcpy(sp->f_mntonname, &sp->f_mntonname[len],
                            sizeof(sp->f_mntonname));