endless loop in probable_prime

Ronny Meeus ronny.meeus at gmail.com
Fri Jun 19 05:44:57 UTC 2020


Replying again since it looks like the final mail has not been
delivered to the newsgroup archive.
The issue has been found. It was a bug in buildroot passing the wrong target.

Op do 18 jun. 2020 om 20:33 schreef Ronny Meeus <ronny.meeus at gmail.com>:
>
> Op do 18 jun. 2020 om 20:01 schreef Matt Caswell <matt at openssl.org>:
> >
> >
> >
> > On 18/06/2020 17:27, Ronny Meeus wrote:
> > > Op do 18 jun. 2020 om 18:13 schreef Salz, Rich <rsalz at akamai.com>:
> > >>
> > >>>    BN_bin2bn assumes that the size of a BN_ULONG (the type of a bn->d) is
> > >>     BN_BYTES. You have already told us that sizeof(*d) is 4. So BN_BYTES
> > >>     should also be 4. If BN_BYTES is being incorrectly set to 8 on your
> > >>     platform then that would explain the discrepancy. Can you check?
> > >>
> > >> This seems HIGHLY likely since Ronny said earlier that the same config/toolchain is used for 32bit userspace and 64bit kernel, right?
> > >>
> > >
> > > I used the following print statement so the sizeof is actual of the *d
> > > and not of the pointer :-).
> > > printf("BN_num data (size=%d top=%d neg=%d flags=%d, sizeof(*d)=%d)
> > > BN_BYTES=%d: ", rnd->dmax, rnd->top, rnd->neg, rnd->flags,
> > > sizeof(*rnd->d), BN_BYTES);
> > >
> > > The output clearly shows that BN_BYTES is 8:
> > >
> > > BN_num data (size=24 top=24 neg=0 flags=13, sizeof(*d)=4) BN_BYTES=8:
> > > efe838eb2cf627a7cf1944d5969e17602474f949d4e04f33263e49cdc9917b5f4f71f4f27eb06b2f41930dbac791ded7fae69fa604ec65686b412ef048e91cfd8c976e74ff237112406371b6cb2770588328f8db400718366665b6bca733a19c
> > >
> > > I think we are getting close to the root-cause here ...
> >
> > Ok, this is clearly why you're getting strange results. The question is
> > why is sizeof(*d) different to the value of BN_BYTES?
> >
> > What Configure target did you use to build for this platform?
>
> We have identified the issue.
> We use BR to compile our projects and it is a bug in the buildroot scripts.
> This was the code before the patch
>         default "linux-generic64 no-asm"        if BR2_ARCH_IS_64
>         default "linux-generic32 no-asm"
> resulting in the usage of the "linux-generic64 no-asm" target.
>
> When change the above line in:
>         default "linux-generic64 no-asm"        if BR2_ARCH_IS_64 &&
> !BR2_MIPS_NABI32
>         default "linux-generic32 no-asm"
> the target becomes "linux-generic32 no-asm".
>
> Compiling openssl with this solves the issue. We will deliver this
> correction to the buildroot community.
> Thanks all for the great support!
>
>
> > Also, take a look at the end of the file include/openssl/opensslconf.h
> >
> > You should see a section at the end that looks like this:
> >
> > /* Only one for the following should be defined */
> > # define SIXTY_FOUR_BIT_LONG
> > # undef SIXTY_FOUR_BIT
> > # undef THIRTY_TWO_BIT
>
> For completeness, this was the section in the file:
>
> /* Only one for the following should be defined */
> # define SIXTY_FOUR_BIT_LONG
> # undef SIXTY_FOUR_BIT
> # undef THIRTY_TWO_BIT
>
> > This file is generated, and depending on what Configure has decided is
> > appropriate for your platform one of the above 3 should be defined, and
> > the other 2 undef'd. What does it show for your platform?
> >
> > Matt
> >


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