[PATCH] lib/ldb minor fixes

[Kamen Mazdrashki]

Hi Andrew,

On Tue, Nov 11, 2014 at 3:32 AM, Andrew Bartlett <abartlet at samba.org> wrote:

> G'Day Kamen,
>
> I'll push the rest of these shortly, but the last patch I'm not
> comfortable with.  The code should be written such that this cannot
> fail, and we should be able to print out the structure as LDIF even if
> we don't fully understand it - otherwise debugging is going to get
> really hard.
>
> What was the situation you hit this on?
>
> Pretty rookie actually - I have created message elements like
  m = Message()
  m[attr] = MessageElement(value)
and it segfault because there is no name for the attribute.
First it is going to segfault because of this:

https://github.com/kamenim/samba/commit/f69a5f6618f64d6c6b584d90bfe1d61a62970deb
and then in 'ldb_ldif_write_trace' because now 'ldb_schema_attribute_by_name'
doesn't segfault
but fail gracefully.

Cheers,
Kamen



> Thanks,
>
> Andrew Bartlett
>
> On Tue, 2014-11-11 at 03:20 +0100, Kamen Mazdrashki wrote:
> > From: Kamen Mazdrashki <kamenim at samba.org>
> > Date: Tue, 11 Nov 2014 02:57:50 +0100
> > Subject: [PATCH 5/5] lib-ldb_ldif: Stop processing if we can't resolve
> >  ldb_message element name
> >
> > This also prevent a segfault when using Python binding
> >
> > Signed-off-by: Kamen Mazdrashki <kamenim at samba.org>
> > ---
> >  lib/ldb/common/ldb_ldif.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/lib/ldb/common/ldb_ldif.c b/lib/ldb/common/ldb_ldif.c
> > index a2e4488..eb8179a 100644
> > --- a/lib/ldb/common/ldb_ldif.c
> > +++ b/lib/ldb/common/ldb_ldif.c
> > @@ -313,6 +313,13 @@ static int ldb_ldif_write_trace(struct
> > ldb_context *ldb,
> >                 const struct ldb_schema_attribute *a;
> >
> >                 a = ldb_schema_attribute_by_name(ldb,
> > msg->elements[i].name);
> > +               if (a == NULL || a->name == NULL) {
> > +                       ldb_debug(ldb, LDB_DEBUG_ERROR, "Error:
> > ldb_schema_attribute_by_name() "
> > +                                       "failed for Message element at
> > %d with name %s.",
> > +                                       i, msg->elements[i].name);
> > +                       talloc_free(mem_ctx);
> > +                       return -1;
> > +               }
> >
> >                 if (ldif->changetype == LDB_CHANGETYPE_MODIFY) {
> >                         switch (msg->elements[i].flags &
> > LDB_FLAG_MOD_MASK) {
>
> --
> Andrew Bartlett
> http://samba.org/~abartlet/
> Authentication Developer, Samba Team  http://samba.org
> Samba Developer, Catalyst IT
> http://catalyst.net.nz/services/samba
>
>
>
>
>