i2c: ismt: prevent memory corruption in ismt_access()

The "data->block[0]" variable comes from the user and is a number
between 0-255.  It needs to be capped to prevent writing beyond the end
of dma_buffer[].

Fixes: 5e9a97b1f4 ("i2c: ismt: Adding support for I2C_SMBUS_BLOCK_PROC_CALL")
Reported-and-tested-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Carpenter 2022-06-02 14:02:18 +03:00 committed by Linus Torvalds
parent d1dc87763f
commit 690b2549b1

View File

@ -528,6 +528,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
case I2C_SMBUS_BLOCK_PROC_CALL:
dev_dbg(dev, "I2C_SMBUS_BLOCK_PROC_CALL\n");
if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
return -EINVAL;
dma_size = I2C_SMBUS_BLOCK_MAX;
desc->tgtaddr_rw = ISMT_DESC_ADDR_RW(addr, 1);
desc->wr_len_cmd = data->block[0] + 1;