This is a note to let you know that I've just added the patch titled
HID: cp2112: prevent a buffer overflow in cp2112_xfer()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hid-cp2112-prevent-a-buffer-overflow-in-cp2112_xfer.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 579d7a117cf7fae2be6b0731294dc6d8a06ed2c0
Author: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Date: Wed Jun 8 05:26:09 2022 -0700
HID: cp2112: prevent a buffer overflow in cp2112_xfer()
[ Upstream commit 381583845d19cb4bd21c8193449385f3fefa9caf ]
Smatch warnings:
drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy()
'data->block[1]' too small (33 vs 255)
drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'buf' too
small (64 vs 255)
The 'read_length' variable is provided by 'data->block[0]' which comes
from user and it(read_length) can take a value between 0-255. Add an
upper bound to 'read_length' variable to prevent a buffer overflow in
memcpy().
Fixes: 542134c0375b ("HID: cp2112: Fix I2C_BLOCK_DATA transactions")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index db1b55df0d13..340408f8c8ab 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -787,6 +787,11 @@ static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
data->word = le16_to_cpup((__le16 *)buf);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
+ if (read_length > I2C_SMBUS_BLOCK_MAX) {
+ ret = -EINVAL;
+ goto power_normal;
+ }
+
memcpy(data->block + 1, buf, read_length);
break;
case I2C_SMBUS_BLOCK_DATA:
