On 18/06/2020 08:46, Ronny Meeus wrote:
> Hello
>
> we are in the process of upgrading our openssl to version 1.1.1g.
> On one of our architectures (Cavium MIPS, running kernel 4.9) we have
> an issue in the ssh-keygen tool. It keeps on consuming 100% CPU of 1
> core.
> On other architectures we do not see the issue at all.
>
> I instrumented the openssl library with some traces and observed that
> it keeps on looping in the "probable prime" function.
> At the end of the function the "BN_num_bits" check is done and if the
> return value is not equal to "bits" it basically starts all over
> again.
>
> }
> if (!BN_add_word(rnd, delta))
> return 0;
> if (BN_num_bits(rnd) != bits) {
> printf("%s BN_num_bits %d %d\n", __FUNCTION__, BN_num_bits(rnd), bits);
> goto again;
> }
> bn_check_top(rnd);
> return 1;
> }
>
> I added the print function and the result of the print is as follows:
> probable_prime BN_num_bits 1473 1536
Hmm. That is very suspicious. I wonder if the generated number in `rnd`
is actually different each time? Can you check?
Matt
> This trace keeps on going forever and the values never change.
>
> Any idea what could be the underlying root-cause?
>
> Many thanks and best regards,
> Ronny
>
