[ovs-dev] [PATCH] ovsdb-idlc: Initialize nonnull string columns for inserted rows.

Ben Pfaff blp at ovn.org
Wed Dec 21 05:22:24 UTC 2016


On Tue, Dec 20, 2016 at 07:32:58PM -0500, Lance Richardson wrote:
> 
> 
> ----- Original Message -----
> > From: "Ben Pfaff" <blp at ovn.org>
> > To: dev at openvswitch.org
> > Cc: "Ben Pfaff" <blp at ovn.org>, "Lance Richardson" <lrichard at redhat.com>
> > Sent: Tuesday, December 20, 2016 7:17:31 PM
> > Subject: [PATCH] ovsdb-idlc: Initialize nonnull string columns for inserted rows.
> > 
> > When a schema column has type "exactly one string", the corresponding
> > struct member has type "char *" and the documented and expected behavior
> > is that the string should always be nonnull.  (The code generator even
> > adds a comment /* Always nonnull. */ in the struct definition.)  In the
> > case where a value is not available, the string is supposed to be
> > initialized to "" instead of to NULL.
> > 
> > However, the IDL code for inserting a new row did not properly initialize
> > the column to "", instead leaving it NULL.  This could cause null pointer
> > dereferences in corner cases.
> > 
> > This commit fixes the problem.
> > 
> > Reported-by: Lance Richardson <lrichard at redhat.com>
> > Reported-at:
> > https://mail.openvswitch.org/pipermail/ovs-dev/2016-December/326500.html
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > ---
> >  ovsdb/ovsdb-idlc.in | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/ovsdb/ovsdb-idlc.in b/ovsdb/ovsdb-idlc.in
> > index f1c7a35..721ab50 100755
> > --- a/ovsdb/ovsdb-idlc.in
> > +++ b/ovsdb/ovsdb-idlc.in
> > @@ -452,6 +452,11 @@ void
> >          for columnName, column in sorted_columns(table):
> >              if column.type.is_smap():
> >                  print "    smap_init(&row->%s);" % columnName
> > +            elif (column.type.n_min == 1 and
> > +                  column.type.n_max == 1 and
> > +                  column.type.key.type == ovs.db.types.StringType and
> > +                  not column.type.value):
> > +                print "    row->%s = \"\";" % columnName
> >          print "}"
> >  
> >          # First, next functions.
> > --
> > 2.10.2
> > 
> > 
> 
> Works for me, thanks! BTW, this was originally encountered for a CMS application
> using the Python IDL interface to execute transactions on the northbound DB.
> 
> Tested-by: Lance Richardson <lrichard at redhat.com>

Thanks, I applied this to master and branch-2.6.  This is a generic IDL
bug and so in theory it could crop up with older branches as well, in
non-OVN contexts, but I don't expect that and so I didn't bother to
backport it farther.


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