1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
index 9af2337eb17a..22ffcb73c185 100644
--- a/drivers/i2c/busses/i2c-ismt.c
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -341,8 +341,10 @@ static int ismt_process_desc(const struct ismt_desc *desc,
                         break;
                 case I2C_SMBUS_BLOCK_DATA:
                 case I2C_SMBUS_I2C_BLOCK_DATA:
+                        if (desc->rxbytes != dma_buffer[0] + 1)
+                                return -EMSGSIZE;
+
                         memcpy(data->block, dma_buffer, desc->rxbytes);
-                        data->block[0] = desc->rxbytes - 1;
                         break;
                 }
                 return 0;