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From: Hangyu Hua <hbh25y@gmail.com>
To: andrzej.hajda@intel.com, narmstrong@baylibre.com,
	robert.foss@linaro.org, Laurent.pinchart@ideasonboard.com,
	jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@linux.ie,
	daniel@ffwll.ch, architt@codeaurora.org
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Hangyu Hua <hbh25y@gmail.com>
Subject: [PATCH] drm: bridge: sii8620: fix possible off-by-one
Date: Wed, 18 May 2022 14:58:56 +0800	[thread overview]
Message-ID: <20220518065856.18936-1-hbh25y@gmail.com> (raw)

The next call to sii8620_burst_get_tx_buf will result in off-by-one
When ctx->burst.tx_count + size == ARRAY_SIZE(ctx->burst.tx_buf). The same
thing happens in sii8620_burst_get_rx_buf.

This patch also change tx_count and tx_buf to rx_count and rx_buf in
sii8620_burst_get_rx_buf. It is unreasonable to check tx_buf's size and
use rx_buf.

Fixes: e19e9c692f81 ("drm/bridge/sii8620: add support for burst eMSC transmissions")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
 drivers/gpu/drm/bridge/sil-sii8620.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
index ec7745c31da0..ab0bce4a988c 100644
--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -605,7 +605,7 @@ static void *sii8620_burst_get_tx_buf(struct sii8620 *ctx, int len)
 	u8 *buf = &ctx->burst.tx_buf[ctx->burst.tx_count];
 	int size = len + 2;
 
-	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
+	if (ctx->burst.tx_count + size >= ARRAY_SIZE(ctx->burst.tx_buf)) {
 		dev_err(ctx->dev, "TX-BLK buffer exhausted\n");
 		ctx->error = -EINVAL;
 		return NULL;
@@ -622,7 +622,7 @@ static u8 *sii8620_burst_get_rx_buf(struct sii8620 *ctx, int len)
 	u8 *buf = &ctx->burst.rx_buf[ctx->burst.rx_count];
 	int size = len + 1;
 
-	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
+	if (ctx->burst.rx_count + size >= ARRAY_SIZE(ctx->burst.rx_buf)) {
 		dev_err(ctx->dev, "RX-BLK buffer exhausted\n");
 		ctx->error = -EINVAL;
 		return NULL;
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Hangyu Hua <hbh25y@gmail.com>
To: andrzej.hajda@intel.com, narmstrong@baylibre.com,
	robert.foss@linaro.org, Laurent.pinchart@ideasonboard.com,
	jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@linux.ie,
	daniel@ffwll.ch, architt@codeaurora.org
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Hangyu Hua <hbh25y@gmail.com>
Subject: [PATCH] drm: bridge: sii8620: fix possible off-by-one
Date: Wed, 18 May 2022 14:58:56 +0800	[thread overview]
Message-ID: <20220518065856.18936-1-hbh25y@gmail.com> (raw)

The next call to sii8620_burst_get_tx_buf will result in off-by-one
When ctx->burst.tx_count + size == ARRAY_SIZE(ctx->burst.tx_buf). The same
thing happens in sii8620_burst_get_rx_buf.

This patch also change tx_count and tx_buf to rx_count and rx_buf in
sii8620_burst_get_rx_buf. It is unreasonable to check tx_buf's size and
use rx_buf.

Fixes: e19e9c692f81 ("drm/bridge/sii8620: add support for burst eMSC transmissions")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
 drivers/gpu/drm/bridge/sil-sii8620.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
index ec7745c31da0..ab0bce4a988c 100644
--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -605,7 +605,7 @@ static void *sii8620_burst_get_tx_buf(struct sii8620 *ctx, int len)
 	u8 *buf = &ctx->burst.tx_buf[ctx->burst.tx_count];
 	int size = len + 2;
 
-	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
+	if (ctx->burst.tx_count + size >= ARRAY_SIZE(ctx->burst.tx_buf)) {
 		dev_err(ctx->dev, "TX-BLK buffer exhausted\n");
 		ctx->error = -EINVAL;
 		return NULL;
@@ -622,7 +622,7 @@ static u8 *sii8620_burst_get_rx_buf(struct sii8620 *ctx, int len)
 	u8 *buf = &ctx->burst.rx_buf[ctx->burst.rx_count];
 	int size = len + 1;
 
-	if (ctx->burst.tx_count + size > ARRAY_SIZE(ctx->burst.tx_buf)) {
+	if (ctx->burst.rx_count + size >= ARRAY_SIZE(ctx->burst.rx_buf)) {
 		dev_err(ctx->dev, "RX-BLK buffer exhausted\n");
 		ctx->error = -EINVAL;
 		return NULL;
-- 
2.25.1


             reply	other threads:[~2022-05-18  6:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-18  6:58 Hangyu Hua [this message]
2022-05-18  6:58 ` [PATCH] drm: bridge: sii8620: fix possible off-by-one Hangyu Hua
2022-05-18  7:57 ` Andrzej Hajda
2022-05-18  7:57   ` Andrzej Hajda
2022-06-23  2:55   ` Hangyu Hua
2022-06-23  2:55     ` Hangyu Hua
2022-07-04 18:40     ` Robert Foss
2022-07-04 18:40       ` Robert Foss

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