[PATCH AUTOSEL for 3.18 07/53] wil6210: fix memory access violation in wil_memcpy_from/toio_32

[Sasha Levin]

From: Dedy Lansky <qca_dlan...@qca.qualcomm.com>

[ 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_dlan...@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_me...@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kv...@qca.qualcomm.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 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 c5676841fd12..e27dd5017218 100644
--- a/drivers/net/wireless/ath/wil6210/main.c
+++ b/drivers/net/wireless/ath/wil6210/main.c
@@ -59,9 +59,15 @@ 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,
@@ -70,8 +76,16 @@ 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