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List:       perl5-changes
Subject:    [Perl/perl5] 45f235: (perl #17844) don't update SvCUR until after we've...
From:       Tony Cook <noreply () github ! com>
Date:       2020-07-30 23:28:21
Message-ID: Perl/perl5/push/refs/heads/blead/cb3d73-45f235 () github ! com
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  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 45f235c116d4deab95c576aff77fe46d609f8553
      https://github.com/Perl/perl5/commit/45f235c116d4deab95c576aff77fe46d609f8553
  Author: Tony Cook <tony@develop-help.com>
  Date:   2020-07-30 (Thu, 30 Jul 2020)

  Changed paths:
    M doop.c
    M t/op/bop.t

  Log Message:
  -----------
  (perl #17844) don't update SvCUR until after we've done moving

SvCUR() before the SvGROW() calls could result in reading beyond the
end of a buffer.

It wasn't a problem in the normal case, since sv_grow() just calls
realloc() which has its own notion of how big the memory block is, but
if the SV is SvOOK() sv_backoff() tries to move SvCUR()+1 bytes, which
might be larger than the currently allocated size of the PV.
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