On Fri, Jan 29, 2016 at 4:50 PM, Corey Minyard <miny...@acm.org> wrote:
> On 01/28/2016 10:17 PM, Sergey Temerkhanov wrote:
>>
>> Fix NULL pointer dereference at the end of multi-part message send
>> process caused by the buffer pointer being set to NULL too early
>
>
> Dang, I know I tested this. Unfortunately, the fix you have won't work. It
> opens a race, msg_written_handler can be called again before ssif_i2c_send
> returns.
>
> Can you save the value of ssif_info->multi_data in a local then call it with
> that?
The actual struct ssif_info setup is performed in ssif_i2c_send() so
what if we just split it int 2 parts and issue the call to complete()
after we've made sure that nothing is gonna race?
Regards,
Sergey
>
> -corey
>
>
>> ---
>> drivers/char/ipmi/ipmi_ssif.c | 11 ++++++-----
>> 1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
>> index dc3491c..2b222bf 100644
>> --- a/drivers/char/ipmi/ipmi_ssif.c
>> +++ b/drivers/char/ipmi/ipmi_ssif.c
>> @@ -896,6 +896,12 @@ static void msg_written_handler(struct ssif_info
>> *ssif_info, int result,
>> /* Length byte. */
>> ssif_info->multi_data[ssif_info->multi_pos] = left;
>> ssif_info->multi_pos += left;
>> +
>> + rv = ssif_i2c_send(ssif_info, msg_written_handler,
>> + I2C_SMBUS_WRITE,
>> + SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
>> + ssif_info->multi_data +
>> ssif_info->multi_pos,
>> + I2C_SMBUS_BLOCK_DATA);
>> if (left < 32)
>> /*
>> * Write is finished. Note that we must end
>> @@ -905,11 +911,6 @@ static void msg_written_handler(struct ssif_info
>> *ssif_info, int result,
>> */
>> ssif_info->multi_data = NULL;
>> - rv = ssif_i2c_send(ssif_info, msg_written_handler,
>> - I2C_SMBUS_WRITE,
>> - SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
>> - ssif_info->multi_data +
>> ssif_info->multi_pos,
>> - I2C_SMBUS_BLOCK_DATA);
>> if (rv < 0) {
>> /* request failed, just return the error. */
>> ssif_inc_stat(ssif_info, send_errors);
>
>
------------------------------------------------------------------------------
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
_______________________________________________
Openipmi-developer mailing list
Openipmi-developer@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/openipmi-developer
