Re: [PATCH 12/29] tools/xenlogd: add 9pfs stat request support

[Juergen Gross <jgross@xxxxxxxx>]

On 07.11.23 15:04, Jason Andryuk wrote:
> On Wed, Nov 1, 2023 at 5:34 AM Juergen Gross <jgross@xxxxxxxx> wrote:
> > Add the stat request of the 9pfs protocol.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > ---
> >   tools/xenlogd/io.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 89 insertions(+)
> >
> > diff --git a/tools/xenlogd/io.c b/tools/xenlogd/io.c
> > index 34f137be1b..6e92667fab 100644
> > --- a/tools/xenlogd/io.c
> > +++ b/tools/xenlogd/io.c
> > @@ -33,6 +33,7 @@
> > +static void fill_p9_stat(struct p9_stat *p9s, struct stat *st, const char 
> > *name)
> > +{
> > +    memset(p9s, 0, sizeof(*p9s));
> > +    fill_qid(NULL, &p9s->qid, st);
> > +    p9s->mode = st->st_mode & 0777;
> > +    if ( S_ISDIR(st->st_mode) )
> > +        p9s->mode |= P9_CREATE_PERM_DIR;
> > +    p9s->atime = st->st_atime;
> > +    p9s->mtime = st->st_mtime;
> > +    p9s->length = st->st_size;
> > +    p9s->name = name;
> > +    p9s->uid = "";
> > +    p9s->gid = "";
> > +    p9s->muid = "";
> > +    p9s->extension = "";
> > +    p9s->n_uid = 0;
> > +    p9s->n_gid = 0;
> If the daemon is running as root and managing the directories, these
> probably match.  Still, do we want uid & gid to be populated from the
> stat struct?
I wouldn't want to do that. In the end the permissions of the daemon are
relevant for being able to access the files. There is no need to leak any
uids and gids from the host to the guests.

> > +    p9s->n_muid = 0;
> > +
> > +    /*
> > +     * Size of individual fields without the size field, including 5 2-byte
> > +     * string length fields.
> > +     */
> > +    p9s->size = 71 + strlen(p9s->name);
> > +}
> > +
> > +static void p9_stat(device *device, struct p9_header *hdr)
> > +{
> > +    uint32_t fid;
> > +    struct p9_fid *fidp;
> > +    struct p9_stat p9s;
> > +    struct stat st;
> > +    uint16_t total_length;
> total_length = 0;
>
> Otherwise it is used uninitialized.
I don't think so. There is a single user just after setting the variable.


Juergen

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