Re: [PATCH] i2c: i801: Fix memory corruption in i801_isr_byte_done()

[Wolfram Sang]

On Tue, Jan 14, 2020 at 10:34:06AM +0300, Dan Carpenter wrote:
> Assigning "priv->data[-1] = priv->len;" obviously doesn't make sense.
> What it does is it ends up corrupting the last byte of priv->len so
> priv->len becomes a very high number.
> 
> Reported-by: syzbot+ed71512d469895b5b34e@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: d3ff6ce40031 ("i2c-i801: Enable IRQ for byte_by_byte transactions")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---

Daniel, Jean: what do you think?
Also, adding Jarkko to CC who works a lot with this driver...

> Untested.
> 
>  drivers/i2c/busses/i2c-i801.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index f5e69fe56532..420d8025901e 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -584,7 +584,6 @@ static void i801_isr_byte_done(struct i801_priv *priv)
>  					"SMBus block read size is %d\n",
>  					priv->len);
>  			}
> -			priv->data[-1] = priv->len;
>  		}
>  
>  		/* Read next byte */
> -- 
> 2.11.0
>

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