[PATCH v3 06/24] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf

John Keeping
2017-01-29T13:24:26Z

As a side-effect of this, encode the endianness explicitly rather than
casting a u16.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Chris Zhong <zyw@rock-chips.com>
---
v3:
- Add Chris' Reviewed-by
Unchanged in v2

drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index 4be1ff3a42bb..2e6ad4591ebf 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -572,8 +572,13 @@ static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
const struct mipi_dsi_msg *msg)
{
- const u16 *tx_buf = msg->tx_buf;
- u32 val = GEN_HDATA(*tx_buf) | GEN_HTYPE(msg->type);
+ const u8 *tx_buf = msg->tx_buf;
+ u32 val = GEN_HTYPE(msg->type);
+
+ if (msg->tx_len > 0)
+ val |= GEN_HDATA(tx_buf[0]);
+ if (msg->tx_len > 1)
+ val |= GEN_HDATA(tx_buf[1] << 8);

if (msg->tx_len > 2) {
dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
--
2.11.0.197.gb556de5.dirty