On Tue, Jun 04, 2019 at 05:58:59PM +0000, Trond Myklebust wrote:
> On Tue, 2019-06-04 at 11:46 -0400, J. Bruce Fields wrote:
> > On Mon, Jun 03, 2019 at 01:12:26PM -0400, Trond Myklebust wrote:
> > > When attempting to strip the root path, we should first
> > > canonicalise
> > > the root pathname.
> > >
> > > Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> > > ---
> > > support/misc/nfsd_path.c | 17 +++++++++++++----
> > > 1 file changed, 13 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/support/misc/nfsd_path.c b/support/misc/nfsd_path.c
> > > index 2f41a793c534..9b38dd96007f 100644
> > > --- a/support/misc/nfsd_path.c
> > > +++ b/support/misc/nfsd_path.c
> > > @@ -1,6 +1,7 @@
> > > #include <errno.h>
> > > #include <sys/types.h>
> > > #include <sys/stat.h>
> > > +#include <limits.h>
> > > #include <stdlib.h>
> > > #include <unistd.h>
> > >
> > > @@ -62,13 +63,21 @@ nfsd_path_nfsd_rootdir(void)
> > > char *
> > > nfsd_path_strip_root(char *pathname)
> > > {
> > > + char buffer[PATH_MAX];
> > > const char *dir = nfsd_path_nfsd_rootdir();
> > > char *ret;
> > >
> > > - ret = strstr(pathname, dir);
> > > - if (!ret || ret != pathname)
> > > - return pathname;
> > > - return pathname + strlen(dir);
> > > + if (!dir)
> > > + goto out;
> > > + if (realpath(dir, buffer)) {
> > > + ret = strstr(pathname, buffer);
> > > + if (ret == pathname)
> > > + return pathname + strlen(dir);
> > > + } else
> > > + xlog(D_GENERAL, "%s: failed to resolve path %s: %m",
> > > + __func__, dir);
> > > +out:
> > > + return pathname;
> >
> > I still don't get this.
> >
> > So in the case strstr doesn't find anything, it returns the path
> > unchanged.
> >
> > That means that if the next_mnt() caller asks whether there are any
> > mounts underneath /rootdir/a/b, and nextdir finds a mountpoint at
> > /a/b/c, it can return that, right?
> >
>
> Ack. Sending out a v2 of these patches.
Oh, good, thanks, I thought I was going crazy.
(Always a possibility, especially when I'm looking at code.)
--b.
