net: stmmac: fix out-of-bounds access in a selftest

[ Upstream commit fe5c5fc145edcf98a759b895f52b646730eeb7be ]

GCC 12 points out that struct tc_action is smaller than
struct tcf_action:

drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c: In function ‘stmmac_test_rxp’:
drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c:1132:21: warning: array subscript ‘struct tcf_gact[0]’ is partly outside array bounds of ‘unsigned char[272]’ [-Warray-bounds]
 1132 |                 gact->tcf_action = TC_ACT_SHOT;
      |                     ^~

Fixes: ccfc639a94f2 ("net: stmmac: selftests: Add a selftest for Flexible RX Parser")
Link: https://lore.kernel.org/r/20220519004305.2109708-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
index e649a3e..dd5c4ef 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
@@ -1084,8 +1084,9 @@ static int stmmac_test_rxp(struct stmmac_priv *priv)
        unsigned char addr[ETH_ALEN] = {0xde, 0xad, 0xbe, 0xef, 0x00, 0x00};
        struct tc_cls_u32_offload cls_u32 = { };
        struct stmmac_packet_attrs attr = { };
-       struct tc_action **actions, *act;
+       struct tc_action **actions;
        struct tc_u32_sel *sel;
+       struct tcf_gact *gact;
        struct tcf_exts *exts;
        int ret, i, nk = 1;
 
@@ -1110,8 +1111,8 @@ static int stmmac_test_rxp(struct stmmac_priv *priv)
                goto cleanup_exts;
        }
 
-       act = kcalloc(nk, sizeof(*act), GFP_KERNEL);
-       if (!act) {
+       gact = kcalloc(nk, sizeof(*gact), GFP_KERNEL);
+       if (!gact) {
                ret = -ENOMEM;
                goto cleanup_actions;
        }
@@ -1126,9 +1127,7 @@ static int stmmac_test_rxp(struct stmmac_priv *priv)
        exts->nr_actions = nk;
        exts->actions = actions;
        for (i = 0; i < nk; i++) {
-               struct tcf_gact *gact = to_gact(&act[i]);
-
-               actions[i] = &act[i];
+               actions[i] = (struct tc_action *)&gact[i];
                gact->tcf_action = TC_ACT_SHOT;
        }
 
@@ -1152,7 +1151,7 @@ static int stmmac_test_rxp(struct stmmac_priv *priv)
        stmmac_tc_setup_cls_u32(priv, priv, &cls_u32);
 
 cleanup_act:
-       kfree(act);
+       kfree(gact);
 cleanup_actions:
        kfree(actions);
 cleanup_exts: