[SRU][N:gke][PATCH 2/5] i2c: tegra: check msg length in SMBUS block read

[Tim Whisonant]

From: Akhil R <akhilrajeev at nvidia.com>

BugLink: https://bugs.launchpad.net/bugs/2126453

For SMBUS block read, do not continue to read if the message length
passed from the device is '0' or greater than the maximum allowed bytes.

Signed-off-by: Akhil R <akhilrajeev at nvidia.com>
Acked-by: Thierry Reding <treding at nvidia.com>
Link: https://lore.kernel.org/r/20250424053320.19211-1-akhilrajeev@nvidia.com
Signed-off-by: Andi Shyti <andi.shyti at kernel.org>
(cherry picked from commit a6e04f05ce0b070ab39d5775580e65c7d943da0b)
Signed-off-by: Tim Whisonant <tim.whisonant at canonical.com>
---
 drivers/i2c/busses/i2c-tegra.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 91be04b534fe6..08a81daedc115 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1397,6 +1397,11 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 			ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], MSG_END_CONTINUE);
 			if (ret)
 				break;
+
+			/* Validate message length before proceeding */
+			if (msgs[i].buf[0] == 0 || msgs[i].buf[0] > I2C_SMBUS_BLOCK_MAX)
+				break;
+
 			/* Set the msg length from first byte */
 			msgs[i].len += msgs[i].buf[0];
 			dev_dbg(i2c_dev->dev, "reading %d bytes\n", msgs[i].len);
-- 
2.43.0