[Rpm-maint] [Rpm-announce] RPM 4.14.0 release candidate 2 is out

[Thierry Vignaud]

On 3 October 2017 at 07:34, Panu Matilainen <pmatilai at redhat.com> wrote:
>>> Also this new rpm introduced segfault regressions in both RPM4 & urpmi
>>> testsuites
>>> See attached gdb traces in BUG*.txt
>>> valgrind seems to hint about invalid writes/reads
>>> See you
>>
>>
>> The urpmi issue is when checking bogus pkgs.
>> The RPM4 issue is when traversing the transaction (not the rpmdb)
>> Attached are the valgrind outputs
>>
>
> So we have stuff like
>
> ==14087== Invalid write of size 4
> ==14087==    at 0x103AA6DD: headerUnlink (header.c:188)
> ==14087==    by 0x103AA6DD: headerFree (header.c:194)
> ==14087==    by 0xFF69314: XS_RPM4__Header_DESTROY (RPM4.xs:890)
> ==14087==    by 0x3F512E2C40: Perl_pp_entersub (pp_hot.c:4231)
> ==14087==    by 0x3F5125551E: Perl_call_sv (perl.c:2848)
> ==14087==    by 0x3F512E7C09: S_curse (sv.c:6987)
> ==14087==    by 0x3F512E84F7: Perl_sv_clear (sv.c:6591)
> ==14087==    by 0x3F512E898D: Perl_sv_free2 (sv.c:7088)
> ==14087==    by 0x3F513182E6: UnknownInlinedFun (inline.h:200)
> ==14087==    by 0x3F513182E6: Perl_free_tmps (scope.c:212)
> ==14087==    by 0x3F512DAD74: Perl_pp_nextstate (pp_hot.c:52)
> ==14087==    by 0x3F512DAA55: Perl_runops_standard (run.c:41)
> ==14087==    by 0x3F5125D236: S_run_body (perl.c:2524)
> ==14087==    by 0x3F5125D236: perl_run (perl.c:2447)
> ==14087==    by 0x400C79: main (perlmain.c:123)
> ==14087==  Address 0xffeffef8c is on thread 1's stack
> ==14087==  396 bytes below stack pointer
>
> ...and all the failures are around headerFree(), but none of the traces go
> into rpm itself, so I dont really know what does "traversing the
> transaction" actually mean.

in both URPM & RPM4 bindings, there's a family of traverse functions
that enable to execute a callback on each package of either:
- rpmdb
- the current transaction,
- pkgs header from an hdlist file
- synthetic metadata from a synthesis file
calling the callback on the currrent header

See:
- Db_traverse*() & Trans_traverse() in perl-URPM/URPM.xs
- Ts_traverse() in RPM4-0.36/src/RPM4.xs

It's loosely documented at
http://search.cpan.org/~tvignaud/URPM-5.12/URPM.pm or
http://search.cpan.org/~tvignaud/RPM4-0.36/lib/RPM4/Transaction.pm#Hdlist::Db-%3Etraverse_headers(sub)
(RPM4's doc is very incomplete -- I'm only maintaining this b/c other
tools depend on that and I cannot break them when upgrading rpm)

> But the problem is simply with perl-RPM4 and
> urpmi passing uninitialized variables to headerFree().
>
> What changed in rpm is that rpmReadPackageFile() no longer does this as the
> first thing:
>
>     if (hdrp)
>         *hdrp = NULL;
>
> Ie if you pass an uninitialized pointer as hdrp, it remains uninitialized
> unless rpmReadPackageFile() returns with a success code.
> Which is how I think it should be, but it does deserve a release note on the
> changed API.
>
> So the moral of the story is basically: if you depend on your variables
> being initialized, initialize them by yourself. It's a good practise anyway.

I'll check for uninitialized variables later today