| Message ID | 1589550415-99935-1-git-send-email-u9012063@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [ovs-dev,PATCHv2] ovsdb-idl: Fix NULL deref reported by Coverity. | expand |
Thanks William. Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com> On Fri, May 15, 2020 at 6:47 AM William Tu <u9012063@gmail.com> wrote: > When 'datum.values' or 'datum.keys' is NULL, some code path calling > into ovsdb_idl_txn_write__ triggers NULL deref. > > An example: > ovsrec_open_vswitch_set_cur_cfg(const struct ovsrec_open_vswitch > { > struct ovsdb_datum datum; > union ovsdb_atom key; > > datum.n = 1; > datum.keys = &key; > > key.integer = cur_cfg; > // 1. assign_zero: Assigning: datum.values = NULL. > datum.values = NULL; > // CID 1421356 (#1 of 1): Explicit null dereferenced (FORWARD_NULL) > // 2. var_deref_model: Passing &datum to ovsdb_idl_txn_write_clone,\ > // which dereferences null datum.values. > ovsdb_idl_txn_write_clone(&row->header_, &ovsrec_open_vswitch_col > } > > And with the following calls: > ovsdb_idl_txn_write_clone > ovsdb_idl_txn_write__ > 6. deref_parm_in_call: Function ovsdb_datum_destroy dereferences > datum->values > ovsdb_datum_destroy > > Signed-off-by: William Tu <u9012063@gmail.com> > --- > v2: > - I applied previous patch e398275024e815b52with yifeng's comments, > but accidently remove this chunk. With this fix, the Coverity > shows around 133 defects. (now it's around 300) > --- > lib/ovsdb-idl.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c > index 1535ad7b5197..6614ea1617ef 100644 > --- a/lib/ovsdb-idl.c > +++ b/lib/ovsdb-idl.c > @@ -4449,7 +4449,8 @@ ovsdb_idl_txn_write__(const struct ovsdb_idl_row > *row_, > * transaction only does writes of existing values, without making > any real > * changes, we will drop the whole transaction later in > * ovsdb_idl_txn_commit().) */ > - if (write_only && ovsdb_datum_equals(ovsdb_idl_read(row, column), > + if (datum->keys && datum->values && > + write_only && ovsdb_datum_equals(ovsdb_idl_read(row, column), > datum, &column->type)) { > goto discard_datum; > } > -- > 2.7.4 > >
On Mon, May 18, 2020 at 02:14:36PM -0700, Yifeng Sun wrote: > Thanks William. > > Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com> > Thanks, applied to master. William
diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c index 1535ad7b5197..6614ea1617ef 100644 --- a/lib/ovsdb-idl.c +++ b/lib/ovsdb-idl.c @@ -4449,7 +4449,8 @@ ovsdb_idl_txn_write__(const struct ovsdb_idl_row *row_, * transaction only does writes of existing values, without making any real * changes, we will drop the whole transaction later in * ovsdb_idl_txn_commit().) */ - if (write_only && ovsdb_datum_equals(ovsdb_idl_read(row, column), + if (datum->keys && datum->values && + write_only && ovsdb_datum_equals(ovsdb_idl_read(row, column), datum, &column->type)) { goto discard_datum; }
When 'datum.values' or 'datum.keys' is NULL, some code path calling into ovsdb_idl_txn_write__ triggers NULL deref. An example: ovsrec_open_vswitch_set_cur_cfg(const struct ovsrec_open_vswitch { struct ovsdb_datum datum; union ovsdb_atom key; datum.n = 1; datum.keys = &key; key.integer = cur_cfg; // 1. assign_zero: Assigning: datum.values = NULL. datum.values = NULL; // CID 1421356 (#1 of 1): Explicit null dereferenced (FORWARD_NULL) // 2. var_deref_model: Passing &datum to ovsdb_idl_txn_write_clone,\ // which dereferences null datum.values. ovsdb_idl_txn_write_clone(&row->header_, &ovsrec_open_vswitch_col } And with the following calls: ovsdb_idl_txn_write_clone ovsdb_idl_txn_write__ 6. deref_parm_in_call: Function ovsdb_datum_destroy dereferences datum->values ovsdb_datum_destroy Signed-off-by: William Tu <u9012063@gmail.com> --- v2: - I applied previous patch e398275024e815b52with yifeng's comments, but accidently remove this chunk. With this fix, the Coverity shows around 133 defects. (now it's around 300) --- lib/ovsdb-idl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)