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From:   Felix Fietkau <nbd@nbd.name>
To:     linux-wireless@vger.kernel.org
Cc:     stable@vger.kernel.org
Subject: [PATCH] mt76: round up length on mt76_wr_copy
Date:   Mon,  1 Jul 2019 13:27:34 +0200
Message-Id: <20190701112734.86552-1-nbd@nbd.name>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

When beacon length is not a multiple of 4, the beacon could be sent with
the last 1-3 bytes corrupted. The skb data is guaranteed to have enough
room for reading beyond the end, because it is always followed by
skb_shared_info, so rounding up is safe.
All other callers of mt76_wr_copy have multiple-of-4 length already.

Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mmio.c | 2 +-
 drivers/net/wireless/mediatek/mt76/usb.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mmio.c b/drivers/net/wireless/mediatek/mt76/mmio.c
index 38368d19aa6f..83c96a47914f 100644
--- a/drivers/net/wireless/mediatek/mt76/mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mmio.c
@@ -43,7 +43,7 @@ static u32 mt76_mmio_rmw(struct mt76_dev *dev, u32 offset, u32 mask, u32 val)
 static void mt76_mmio_copy(struct mt76_dev *dev, u32 offset, const void *data,
 			   int len)
 {
-	__iowrite32_copy(dev->mmio.regs + offset, data, len >> 2);
+	__iowrite32_copy(dev->mmio.regs + offset, data, DIV_ROUND_UP(len, 4));
 }
 
 static int mt76_mmio_wr_rp(struct mt76_dev *dev, u32 base,
diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 61b27f3ec6e4..87ecbe290f99 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -164,7 +164,7 @@ static void mt76u_copy(struct mt76_dev *dev, u32 offset,
 	int i, ret;
 
 	mutex_lock(&usb->usb_ctrl_mtx);
-	for (i = 0; i < (len / 4); i++) {
+	for (i = 0; i < DIV_ROUND_UP(len, 4); i++) {
 		put_unaligned_le32(val[i], usb->data);
 		ret = __mt76u_vendor_request(dev, MT_VEND_MULTI_WRITE,
 					     USB_DIR_OUT | USB_TYPE_VENDOR,
-- 
2.17.0