[PATCH 6.12 118/337] accel/qaic: use sizeof(*trans_hdr) for transaction length check

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Muhammad Bilal <[email protected]>

[ Upstream commit d6c075f797a672a6e3bd2fd44aee713801698ec2 ]

In encode_message() the per-transaction lower-bound check compares
trans_hdr->len against sizeof(trans_hdr), i.e. the size of the pointer,
instead of sizeof(*trans_hdr), the size of struct qaic_manage_trans_hdr.

Every other length check in this file (encode_message() at the loop
guard, decode_message(), etc.) correctly uses sizeof(*trans_hdr), so
this is an inconsistency. On 64-bit builds the pointer and the struct
are both 8 bytes, so the check is correct by coincidence and there is
no behavioural change. On 32-bit builds the pointer is 4 bytes, which
weakens the minimum-length check below the 8-byte header size.

Use sizeof(*trans_hdr) so the check validates against the actual
transaction header size on all builds.

Fixes: ea33cb6fc278 ("accel/qaic: tighten bounds checking in encode_message()")
Signed-off-by: Muhammad Bilal <[email protected]>
Reviewed-by: Jeff Hugo <[email protected]>
Signed-off-by: Jeff Hugo <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/accel/qaic/qaic_control.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index 8eae30fe14f98..8759b53ba38eb 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -782,7 +782,7 @@ static int encode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
 			break;
 		}
 		trans_hdr = (struct qaic_manage_trans_hdr *)(user_msg->data + user_len);
-		if (trans_hdr->len < sizeof(trans_hdr) ||
+		if (trans_hdr->len < sizeof(*trans_hdr) ||
 		    size_add(user_len, trans_hdr->len) > user_msg->len) {
 			ret = -EINVAL;
 			break;
-- 
2.53.0