Re: [PATCH v5 2/2] KEYS: Avoid false positive ENOMEM error on key read

[Waiman Long]

On 3/19/20 3:46 PM, Jarkko Sakkinen wrote:
> On Wed, Mar 18, 2020 at 06:14:57PM -0400, Waiman Long wrote:
>> +			 * It is possible, though unlikely, that the key
>> +			 * changes in between the up_read->down_read period.
>> +			 * If the key becomes longer, we will have to
>> +			 * allocate a larger buffer and redo the key read
>> +			 * again.
>> +			 */
>> +			if (!tmpbuf || unlikely(ret > tmpbuflen)) {
> Shouldn't you check that tmpbuflen stays below buflen (why else
> you had made copy of buflen otherwise)?

The check above this thunk:

if ((ret > 0) && (ret <= buflen)) {

will make sure that ret will not be larger than buflen. So tmpbuflen
will never be bigger than buflen.

Cheers,
Longman