Re: [PATCH 1/1] Char: ipmi_bt_sm, fix infinite loop

From: Corey Minyard
Date: Tue Feb 25 2014 - 16:50:40 EST


Looks right to me. Rocky, copying you in case there's an issue with this.

Thanks,

-corey

On 02/25/2014 04:14 AM, Jiri Slaby wrote:
> In read_all_bytes, we do
> unsigned char i;
> ...
> bt->read_data[0] = BMC2HOST;
> bt->read_count = bt->read_data[0];
> ...
> for (i = 1; i <= bt->read_count; i++)
> bt->read_data[i] = BMC2HOST;
>
> If bt->read_data[0] == bt->read_count == 255, we loop infinitely in
> the 'for' loop. Make 'i' an 'int' instead of 'char' to get rid of the
> overflow and finish the loop after 255 iterations every time.
>
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> Reported-and-debugged-by: Rui Hui Dian <rhdian@xxxxxxxxxx>
> Cc: Tomas Cech <tcech@xxxxxxx>
> Cc: Corey Minyard <minyard@xxxxxxx>
> Cc: <openipmi-developer@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/char/ipmi/ipmi_bt_sm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/ipmi/ipmi_bt_sm.c b/drivers/char/ipmi/ipmi_bt_sm.c
> index f5e4cd7617f6..61e71616689b 100644
> --- a/drivers/char/ipmi/ipmi_bt_sm.c
> +++ b/drivers/char/ipmi/ipmi_bt_sm.c
> @@ -352,7 +352,7 @@ static inline void write_all_bytes(struct si_sm_data *bt)
>
> static inline int read_all_bytes(struct si_sm_data *bt)
> {
> - unsigned char i;
> + unsigned int i;
>
> /*
> * length is "framing info", minimum = 4: NetFn, Seq, Cmd, cCode.

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