| Message ID | 1588440525-71022-4-git-send-email-u9012063@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | ovsdb-idl: Fix memory leak and NULL deref | expand |
Thanks William, this patch looks good to me.
Maybe code will be a little neater with the fixes below:
@@ -1017,6 +1017,9 @@ static void
free_data(enum ovsdb_atomic_type type,
union ovsdb_atom *atoms, size_t n_atoms)
{
+ if (!atoms) {
+ return;
+ }
if (ovsdb_atom_needs_destruction(type)) {
Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com>
Yifeng
On Sat, May 2, 2020 at 10:29 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 is below:
>
> 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
>
> And another possible NULL deref is at ovsdb_datum_equals(). Fix the
> two by adding additional checks.
>
> Signed-off-by: William Tu <u9012063@gmail.com>
> ---
> lib/ovsdb-data.c | 8 ++++++--
> lib/ovsdb-idl.c | 3 ++-
> 2 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/lib/ovsdb-data.c b/lib/ovsdb-data.c
> index 4828624f658d..9ce3cdeca28a 100644
> --- a/lib/ovsdb-data.c
> +++ b/lib/ovsdb-data.c
> @@ -1033,8 +1033,12 @@ free_data(enum ovsdb_atomic_type type,
> void
> ovsdb_datum_destroy(struct ovsdb_datum *datum, const struct ovsdb_type
> *type)
> {
> - free_data(type->key.type, datum->keys, datum->n);
> - free_data(type->value.type, datum->values, datum->n);
> + if (datum->keys) {
> + free_data(type->key.type, datum->keys, datum->n);
> + }
> + if (datum->values) {
> + free_data(type->value.type, datum->values, datum->n);
> + }
> }
>
> /* Swaps the contents of 'a' and 'b', which need not have the same type.
> */
> 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
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
On Sat, May 9, 2020 at 11:02 AM Yifeng Sun <pkusunyifeng@gmail.com> wrote: > > Thanks William, this patch looks good to me. > Maybe code will be a little neater with the fixes below: > > @@ -1017,6 +1017,9 @@ static void > free_data(enum ovsdb_atomic_type type, > union ovsdb_atom *atoms, size_t n_atoms) > { > + if (!atoms) { > + return; > + } > if (ovsdb_atom_needs_destruction(type)) { > > > > Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com> > Thank you. I applied the series to master. William
diff --git a/lib/ovsdb-data.c b/lib/ovsdb-data.c index 4828624f658d..9ce3cdeca28a 100644 --- a/lib/ovsdb-data.c +++ b/lib/ovsdb-data.c @@ -1033,8 +1033,12 @@ free_data(enum ovsdb_atomic_type type, void ovsdb_datum_destroy(struct ovsdb_datum *datum, const struct ovsdb_type *type) { - free_data(type->key.type, datum->keys, datum->n); - free_data(type->value.type, datum->values, datum->n); + if (datum->keys) { + free_data(type->key.type, datum->keys, datum->n); + } + if (datum->values) { + free_data(type->value.type, datum->values, datum->n); + } } /* Swaps the contents of 'a' and 'b', which need not have the same type. */ 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 is below: 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 And another possible NULL deref is at ovsdb_datum_equals(). Fix the two by adding additional checks. Signed-off-by: William Tu <u9012063@gmail.com> --- lib/ovsdb-data.c | 8 ++++++-- lib/ovsdb-idl.c | 3 ++- 2 files changed, 8 insertions(+), 3 deletions(-)