[PATCH v4 06/23] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf
From: John Keeping
Date: Fri Feb 24 2017 - 07:58:02 EST
As a side-effect of this, encode the endianness explicitly rather than
casting a u16.
Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
---
v4:
- Introduce "data" variable to avoid confusion around the masking in
GEN_HDATA()
v3:
- Add Chris' Reviewed-by
Unchanged in v2
---
drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 11 +++++++++--
1 file changed, 9 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..f55010312f25 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -572,8 +572,14 @@ 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;
+ u16 data = 0;
+ u32 val;
+
+ if (msg->tx_len > 0)
+ data |= tx_buf[0];
+ if (msg->tx_len > 1)
+ data |= tx_buf[1] << 8;
if (msg->tx_len > 2) {
dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
@@ -581,6 +587,7 @@ static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
return -EINVAL;
}
+ val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
}
--
2.12.0.rc0.230.gf625d4cdb9.dirty