Subject: [PATCH 6.1 027/118] net: ethernet: mtk_eth_soc: Avoid truncating allocation

From: Greg Kroah-Hartman <[email-masked]>
Date: Mon, 20 Feb 2023 14:35:43 +0100

From: Kees Cook <[email-masked]>

[ Upstream commit f3eceaed9edd7c0e0d9fb057613131f92973626f ]

There doesn't appear to be a reason to truncate the allocation used for
flow_info, so do a full allocation and remove the unused empty struct.
GCC does not like having a reference to an object that has been
partially allocated, as bounds checking may become impossible when
such an object is passed to other code. Seen with GCC 13:

../drivers/net/ethernet/mediatek/mtk_ppe.c: In function 'mtk_foe_entry_commit_subflow':
../drivers/net/ethernet/mediatek/mtk_ppe.c:623:18: warning: array subscript 'struct mtk_flow_entry[0]' is partly outside array bounds of 'unsigned char[48]' [-Warray-bounds=]
  623 |         flow_info->l2_data.base_flow = entry;
      |                  ^~

Cc: Felix Fietkau <[email-masked]>
Cc: John Crispin <[email-masked]>
Cc: Sean Wang <[email-masked]>
Cc: Mark Lee <[email-masked]>
Cc: Lorenzo Bianconi <[email-masked]>
Cc: "David S. Miller" <[email-masked]>
Cc: Eric Dumazet <[email-masked]>
Cc: Jakub Kicinski <[email-masked]>
Cc: Paolo Abeni <[email-masked]>
Cc: Matthias Brugger <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Cc: [email-masked]
Signed-off-by: Kees Cook <[email-masked]>
Reviewed-by: Simon Horman <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Paolo Abeni <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/ethernet/mediatek/mtk_ppe.c | 3 +--
 drivers/net/ethernet/mediatek/mtk_ppe.h | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_ppe.c b/drivers/net/ethernet/mediatek/mtk_ppe.c
index 784ecb2dc9fbd..34ea8af48c3d0 100644
--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -595,8 +595,7 @@ mtk_foe_entry_commit_subflow(struct mtk_ppe *ppe, struct mtk_flow_entry *entry,
 	u32 ib1_mask = mtk_get_ib1_pkt_type_mask(ppe->eth) | MTK_FOE_IB1_UDP;
 	int type;
 
-	flow_info = kzalloc(offsetof(struct mtk_flow_entry, l2_data.end),
-			    GFP_ATOMIC);
+	flow_info = kzalloc(sizeof(*flow_info), GFP_ATOMIC);
 	if (!flow_info)
 		return;
 
diff --git a/drivers/net/ethernet/mediatek/mtk_ppe.h b/drivers/net/ethernet/mediatek/mtk_ppe.h
index a09c32539bcc9..e66283b1bc79e 100644
--- a/drivers/net/ethernet/mediatek/mtk_ppe.h
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.h
@@ -277,7 +277,6 @@ struct mtk_flow_entry {
 		struct {
 			struct mtk_flow_entry *base_flow;
 			struct hlist_node list;
-			struct {} end;
 		} l2_data;
 	};
 	struct rhash_head node;
-- 
2.39.0