[PATCH AUTOSEL for 4.4 083/115] wil6210: fix memory access violation in wil_memcpy_from/toio_32

[Sasha Levin]

From: Dedy Lansky <qca_dlansky@xxxxxxxxxxxxxxxx>

[ Upstream commit 0f6edfe2bbbb59d161580cb4870fcc46f5490f85 ]

In case count is not multiple of 4, there is a read access in
wil_memcpy_toio_32() from outside src buffer boundary.
In wil_memcpy_fromio_32(), in case count is not multiple of 4, there is
a write access to outside dst io memory boundary.

Fix these issues with proper handling of the last 1 to 4 copied bytes.

Signed-off-by: Dedy Lansky <qca_dlansky@xxxxxxxxxxxxxxxx>
Signed-off-by: Maya Erez <qca_merez@xxxxxxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/net/wireless/ath/wil6210/main.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/main.c b/drivers/net/wireless/ath/wil6210/main.c
index 85bca557a339..f09fafaaaf1a 100644
--- a/drivers/net/wireless/ath/wil6210/main.c
+++ b/drivers/net/wireless/ath/wil6210/main.c
@@ -125,9 +125,15 @@ void wil_memcpy_fromio_32(void *dst, const volatile void __iomem *src,
 	u32 *d = dst;
 	const volatile u32 __iomem *s = src;
 
-	/* size_t is unsigned, if (count%4 != 0) it will wrap */
-	for (count += 4; count > 4; count -= 4)
+	for (; count >= 4; count -= 4)
 		*d++ = __raw_readl(s++);
+
+	if (unlikely(count)) {
+		/* count can be 1..3 */
+		u32 tmp = __raw_readl(s);
+
+		memcpy(d, &tmp, count);
+	}
 }
 
 void wil_memcpy_toio_32(volatile void __iomem *dst, const void *src,
@@ -136,8 +142,16 @@ void wil_memcpy_toio_32(volatile void __iomem *dst, const void *src,
 	volatile u32 __iomem *d = dst;
 	const u32 *s = src;
 
-	for (count += 4; count > 4; count -= 4)
+	for (; count >= 4; count -= 4)
 		__raw_writel(*s++, d++);
+
+	if (unlikely(count)) {
+		/* count can be 1..3 */
+		u32 tmp = 0;
+
+		memcpy(&tmp, s, count);
+		__raw_writel(tmp, d);
+	}
 }
 
 static void wil_disconnect_cid(struct wil6210_priv *wil, int cid,
-- 
2.14.1