[PATCH v2] overflow: Change DEFINE_FLEX to take __counted_by member

From: Kees Cook
Date: Wed Mar 06 2024 - 18:51:56 EST


The norm should be flexible array structures with __counted_by
annotations, so DEFINE_FLEX() is updated to expect that. Rename
the non-annotated version to DEFINE_RAW_FLEX(), and update the
few existing users.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Cc: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>
Cc: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
Cc: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
Cc: intel-wired-lan@xxxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-hardening@xxxxxxxxxxxxxxx
v2: swap member/counter args
v1: https://lore.kernel.org/lkml/20240306010746.work.678-kees@xxxxxxxxxx/
---
drivers/net/ethernet/intel/ice/ice_common.c | 4 +--
drivers/net/ethernet/intel/ice/ice_ddp.c | 8 +++---
drivers/net/ethernet/intel/ice/ice_lag.c | 6 ++---
drivers/net/ethernet/intel/ice/ice_lib.c | 4 +--
drivers/net/ethernet/intel/ice/ice_sched.c | 4 +--
drivers/net/ethernet/intel/ice/ice_switch.c | 10 ++++----
drivers/net/ethernet/intel/ice/ice_xsk.c | 2 +-
include/linux/overflow.h | 27 +++++++++++++++++----
lib/overflow_kunit.c | 19 +++++++++++++++
9 files changed, 60 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c
index 10c32cd80fff..ce50a322daa9 100644
--- a/drivers/net/ethernet/intel/ice/ice_common.c
+++ b/drivers/net/ethernet/intel/ice/ice_common.c
@@ -4700,7 +4700,7 @@ ice_dis_vsi_txq(struct ice_port_info *pi, u16 vsi_handle, u8 tc, u8 num_queues,
enum ice_disq_rst_src rst_src, u16 vmvf_num,
struct ice_sq_cd *cd)
{
- DEFINE_FLEX(struct ice_aqc_dis_txq_item, qg_list, q_id, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_dis_txq_item, qg_list, q_id, 1);
u16 i, buf_size = __struct_size(qg_list);
struct ice_q_ctx *q_ctx;
int status = -ENOENT;
@@ -4922,7 +4922,7 @@ int
ice_dis_vsi_rdma_qset(struct ice_port_info *pi, u16 count, u32 *qset_teid,
u16 *q_id)
{
- DEFINE_FLEX(struct ice_aqc_dis_txq_item, qg_list, q_id, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_dis_txq_item, qg_list, q_id, 1);
u16 qg_size = __struct_size(qg_list);
struct ice_hw *hw;
int status = 0;
diff --git a/drivers/net/ethernet/intel/ice/ice_ddp.c b/drivers/net/ethernet/intel/ice/ice_ddp.c
index 8b7504a9df31..03efb2521ca7 100644
--- a/drivers/net/ethernet/intel/ice/ice_ddp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ddp.c
@@ -1934,8 +1934,8 @@ static enum ice_ddp_state ice_init_pkg_info(struct ice_hw *hw,
*/
static enum ice_ddp_state ice_get_pkg_info(struct ice_hw *hw)
{
- DEFINE_FLEX(struct ice_aqc_get_pkg_info_resp, pkg_info, pkg_info,
- ICE_PKG_CNT);
+ DEFINE_RAW_FLEX(struct ice_aqc_get_pkg_info_resp, pkg_info, pkg_info,
+ ICE_PKG_CNT);
u16 size = __struct_size(pkg_info);
u32 i;

@@ -1986,8 +1986,8 @@ static enum ice_ddp_state ice_chk_pkg_compat(struct ice_hw *hw,
struct ice_pkg_hdr *ospkg,
struct ice_seg **seg)
{
- DEFINE_FLEX(struct ice_aqc_get_pkg_info_resp, pkg, pkg_info,
- ICE_PKG_CNT);
+ DEFINE_RAW_FLEX(struct ice_aqc_get_pkg_info_resp, pkg, pkg_info,
+ ICE_PKG_CNT);
u16 size = __struct_size(pkg);
enum ice_ddp_state state;
u32 i;
diff --git a/drivers/net/ethernet/intel/ice/ice_lag.c b/drivers/net/ethernet/intel/ice/ice_lag.c
index 2a25323105e5..da38edac1c42 100644
--- a/drivers/net/ethernet/intel/ice/ice_lag.c
+++ b/drivers/net/ethernet/intel/ice/ice_lag.c
@@ -470,7 +470,7 @@ static void
ice_lag_move_vf_node_tc(struct ice_lag *lag, u8 oldport, u8 newport,
u16 vsi_num, u8 tc)
{
- DEFINE_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
struct device *dev = ice_pf_to_dev(lag->pf);
u16 numq, valq, num_moved, qbuf_size;
u16 buf_size = __struct_size(buf);
@@ -828,7 +828,7 @@ static void
ice_lag_reclaim_vf_tc(struct ice_lag *lag, struct ice_hw *src_hw, u16 vsi_num,
u8 tc)
{
- DEFINE_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
struct device *dev = ice_pf_to_dev(lag->pf);
u16 numq, valq, num_moved, qbuf_size;
u16 buf_size = __struct_size(buf);
@@ -1852,7 +1852,7 @@ static void
ice_lag_move_vf_nodes_tc_sync(struct ice_lag *lag, struct ice_hw *dest_hw,
u16 vsi_num, u8 tc)
{
- DEFINE_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
struct device *dev = ice_pf_to_dev(lag->pf);
u16 numq, valq, num_moved, qbuf_size;
u16 buf_size = __struct_size(buf);
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 9be724291ef8..6819e95cec32 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -1805,7 +1805,7 @@ int ice_vsi_cfg_single_rxq(struct ice_vsi *vsi, u16 q_idx)

int ice_vsi_cfg_single_txq(struct ice_vsi *vsi, struct ice_tx_ring **tx_rings, u16 q_idx)
{
- DEFINE_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);

if (q_idx >= vsi->alloc_txq || !tx_rings || !tx_rings[q_idx])
return -EINVAL;
@@ -1854,7 +1854,7 @@ int ice_vsi_cfg_rxqs(struct ice_vsi *vsi)
static int
ice_vsi_cfg_txqs(struct ice_vsi *vsi, struct ice_tx_ring **rings, u16 count)
{
- DEFINE_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);
int err = 0;
u16 q_idx;

diff --git a/drivers/net/ethernet/intel/ice/ice_sched.c b/drivers/net/ethernet/intel/ice/ice_sched.c
index d174a4eeb899..a1525992d14b 100644
--- a/drivers/net/ethernet/intel/ice/ice_sched.c
+++ b/drivers/net/ethernet/intel/ice/ice_sched.c
@@ -237,7 +237,7 @@ static int
ice_sched_remove_elems(struct ice_hw *hw, struct ice_sched_node *parent,
u32 node_teid)
{
- DEFINE_FLEX(struct ice_aqc_delete_elem, buf, teid, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_delete_elem, buf, teid, 1);
u16 buf_size = __struct_size(buf);
u16 num_groups_removed = 0;
int status;
@@ -2219,7 +2219,7 @@ int
ice_sched_move_nodes(struct ice_port_info *pi, struct ice_sched_node *parent,
u16 num_items, u32 *list)
{
- DEFINE_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_move_elem, buf, teid, 1);
u16 buf_len = __struct_size(buf);
struct ice_sched_node *node;
u16 i, grps_movd = 0;
diff --git a/drivers/net/ethernet/intel/ice/ice_switch.c b/drivers/net/ethernet/intel/ice/ice_switch.c
index f84bab80ca42..d4baae8c3b72 100644
--- a/drivers/net/ethernet/intel/ice/ice_switch.c
+++ b/drivers/net/ethernet/intel/ice/ice_switch.c
@@ -1812,7 +1812,7 @@ ice_aq_alloc_free_vsi_list(struct ice_hw *hw, u16 *vsi_list_id,
enum ice_sw_lkup_type lkup_type,
enum ice_adminq_opc opc)
{
- DEFINE_FLEX(struct ice_aqc_alloc_free_res_elem, sw_buf, elem, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_alloc_free_res_elem, sw_buf, elem, 1);
u16 buf_len = __struct_size(sw_buf);
struct ice_aqc_res_elem *vsi_ele;
int status;
@@ -2081,7 +2081,7 @@ ice_aq_get_recipe_to_profile(struct ice_hw *hw, u32 profile_id, u8 *r_bitmap,
*/
int ice_alloc_recipe(struct ice_hw *hw, u16 *rid)
{
- DEFINE_FLEX(struct ice_aqc_alloc_free_res_elem, sw_buf, elem, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_alloc_free_res_elem, sw_buf, elem, 1);
u16 buf_len = __struct_size(sw_buf);
int status;

@@ -4418,7 +4418,7 @@ int
ice_alloc_res_cntr(struct ice_hw *hw, u8 type, u8 alloc_shared, u16 num_items,
u16 *counter_id)
{
- DEFINE_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
u16 buf_len = __struct_size(buf);
int status;

@@ -4446,7 +4446,7 @@ int
ice_free_res_cntr(struct ice_hw *hw, u8 type, u8 alloc_shared, u16 num_items,
u16 counter_id)
{
- DEFINE_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
u16 buf_len = __struct_size(buf);
int status;

@@ -4476,7 +4476,7 @@ ice_free_res_cntr(struct ice_hw *hw, u8 type, u8 alloc_shared, u16 num_items,
*/
int ice_share_res(struct ice_hw *hw, u16 type, u8 shared, u16 res_id)
{
- DEFINE_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_alloc_free_res_elem, buf, elem, 1);
u16 buf_len = __struct_size(buf);
u16 res_type;
int status;
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 8b81a1677045..92ffa8de5171 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -217,7 +217,7 @@ static int ice_qp_dis(struct ice_vsi *vsi, u16 q_idx)
*/
static int ice_qp_ena(struct ice_vsi *vsi, u16 q_idx)
{
- DEFINE_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);
+ DEFINE_RAW_FLEX(struct ice_aqc_add_tx_qgrp, qg_buf, txqs, 1);
u16 size = __struct_size(qg_buf);
struct ice_q_vector *q_vector;
struct ice_tx_ring *tx_ring;
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index aa691f2119b0..677b03c4c84f 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -396,9 +396,9 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
* @name: Name for a variable to define.
* @member: Name of the array member.
* @count: Number of elements in the array; must be compile-time const.
- * @initializer: initializer expression (could be empty for no init).
+ * @initializer...: initializer expression (could be empty for no init).
*/
-#define _DEFINE_FLEX(type, name, member, count, initializer) \
+#define _DEFINE_FLEX(type, name, member, count, initializer...) \
_Static_assert(__builtin_constant_p(count), \
"onstack flex array members require compile-time const count"); \
union { \
@@ -408,8 +408,8 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
type *name = (type *)&name##_u

/**
- * DEFINE_FLEX() - Define an on-stack instance of structure with a trailing
- * flexible array member.
+ * DEFINE_RAW_FLEX() - Define an on-stack instance of structure with a trailing
+ * flexible array member, when it does not have a __counted_by annotation.
*
* @type: structure type name, including "struct" keyword.
* @name: Name for a variable to define.
@@ -420,7 +420,24 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
* flexible array member.
* Use __struct_size(@name) to get compile-time size of it afterwards.
*/
-#define DEFINE_FLEX(type, name, member, count) \
+#define DEFINE_RAW_FLEX(type, name, member, count) \
_DEFINE_FLEX(type, name, member, count, = {})

+/**
+ * DEFINE_FLEX() - Define an on-stack instance of structure with a trailing
+ * flexible array member.
+ *
+ * @TYPE: structure type name, including "struct" keyword.
+ * @NAME: Name for a variable to define.
+ * @MEMBER: Name of the array member.
+ * @COUNTER: Name of the __counted_by member.
+ * @COUNT: Number of elements in the array; must be compile-time const.
+ *
+ * Define a zeroed, on-stack, instance of @TYPE structure with a trailing
+ * flexible array member.
+ * Use __struct_size(@NAME) to get compile-time size of it afterwards.
+ */
+#define DEFINE_FLEX(TYPE, NAME, MEMBER, COUNTER, COUNT) \
+ _DEFINE_FLEX(TYPE, NAME, MEMBER, COUNT, = { .obj.COUNTER = COUNT, })
+
#endif /* __LINUX_OVERFLOW_H */
diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c
index 65e8a72a83bf..4ef31b0bb74d 100644
--- a/lib/overflow_kunit.c
+++ b/lib/overflow_kunit.c
@@ -1172,6 +1172,24 @@ static void castable_to_type_test(struct kunit *test)
#undef TEST_CASTABLE_TO_TYPE
}

+struct foo {
+ int a;
+ u32 counter;
+ s16 array[] __counted_by(counter);
+};
+
+static void DEFINE_FLEX_test(struct kunit *test)
+{
+ DEFINE_RAW_FLEX(struct foo, two, array, 2);
+ DEFINE_FLEX(struct foo, eight, array, counter, 8);
+ DEFINE_FLEX(struct foo, empty, array, counter, 0);
+
+ KUNIT_EXPECT_EQ(test, __struct_size(two),
+ sizeof(struct foo) + sizeof(s16) + sizeof(s16));
+ KUNIT_EXPECT_EQ(test, __struct_size(eight), 24);
+ KUNIT_EXPECT_EQ(test, __struct_size(empty), sizeof(struct foo));
+}
+
static struct kunit_case overflow_test_cases[] = {
KUNIT_CASE(u8_u8__u8_overflow_test),
KUNIT_CASE(s8_s8__s8_overflow_test),
@@ -1194,6 +1212,7 @@ static struct kunit_case overflow_test_cases[] = {
KUNIT_CASE(overflows_type_test),
KUNIT_CASE(same_type_test),
KUNIT_CASE(castable_to_type_test),
+ KUNIT_CASE(DEFINE_FLEX_test),
{}
};

--
2.34.1