From 043ccc9781cc2e2914253c1c6f17923905c83a4e Mon Sep 17 00:00:00 2001 From: Stephen Douthit Date: Mon, 7 Aug 2017 17:11:00 -0400 Subject: [PATCH] i2c: ismt: Return EMSGSIZE for block reads with bogus length commit ba201c4f5ebe13d7819081756378777d8153f23e upstream. Compare the number of bytes actually seen on the wire to the byte count field returned by the slave device. Previously we just overwrote the byte count returned by the slave with the real byte count and let the caller figure out if the message was sane. Signed-off-by: Stephen Douthit Tested-by: Dan Priamo Acked-by: Neil Horman Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-ismt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c index f22b0e5778dd1..639d1a9c8793e 100644 --- a/drivers/i2c/busses/i2c-ismt.c +++ b/drivers/i2c/busses/i2c-ismt.c @@ -339,8 +339,10 @@ 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; -- 2.47.3