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

From	John Keeping <john@metanate.com>
Newsgroups	linux.kernel
Subject	[PATCH v3 06/24] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf
Date	2017-01-29 15:10 +0100
Message-ID	<t4Yl4-811-19@gated-at.bofh.it> (permalink)
References	<t4Yl3-811-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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

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[PATCH v3 06/24] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds read on tx_buf John Keeping <john@metanate.com> - 2017-01-29 15:10 +0100
  Re: [PATCH v3 06/24] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds  read on tx_buf Sean Paul <seanpaul@chromium.org> - 2017-01-30 19:10 +0100
    Re: [PATCH v3 06/24] drm/rockchip: dw-mipi-dsi: avoid out-of-bounds  read on tx_buf John Keeping <john@metanate.com> - 2017-01-30 19:20 +0100

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