From:   Wei Chen <harperchen1110@gmail.com>
To:     andi.shyti@kernel.org
Cc:     linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Wei Chen <harperchen1110@gmail.com>
Subject: [PATCH v4] i2c: xgene-slimpro: Fix out-of-bounds bug in xgene_slimpro_i2c_xfer()
Date:   Tue, 14 Mar 2023 16:54:21 +0000
Message-Id: <20230314165421.2823691-1-harperchen1110@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The data->block[0] variable comes from user and is a number between
0-255. Without proper check, the variable may be very large to cause
an out-of-bounds when performing memcpy in slimpro_i2c_blkwr.

Fix this bug by checking the value of writelen.

Fixes: f6505fbabc42 ("i2c: add SLIMpro I2C device driver on APM X-Gene platform")
Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Cc: stable@vger.kernel.org
---
Changes in v2:
 - Put length check inside slimpro_i2c_blkwr
Changes in v3:
 - Correct the format of patch
Changes in v4:
 - CC stable email address

 drivers/i2c/busses/i2c-xgene-slimpro.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-xgene-slimpro.c b/drivers/i2c/busses/i2c-xgene-slimpro.c
index bc9a3e7e0c96..0f7263e2276a 100644
--- a/drivers/i2c/busses/i2c-xgene-slimpro.c
+++ b/drivers/i2c/busses/i2c-xgene-slimpro.c
@@ -308,6 +308,9 @@ static int slimpro_i2c_blkwr(struct slimpro_i2c_dev *ctx, u32 chip,
 	u32 msg[3];
 	int rc;
 
+	if (writelen > I2C_SMBUS_BLOCK_MAX)
+		return -EINVAL;
+
 	memcpy(ctx->dma_buffer, data, writelen);
 	paddr = dma_map_single(ctx->dev, ctx->dma_buffer, writelen,
 			       DMA_TO_DEVICE);
-- 
2.25.1