[Bug c++/87350] NULL-Pointer problem in cplus-dem.c when executing program c++filt

[bernhard.kaindl at thalesgroup dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87350

Bernhard Kaindl <bernhard.kaindl at thalesgroup dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |bernhard.kaindl@thalesgroup
                   |                            |.com

--- Comment #5 from Bernhard Kaindl <bernhard.kaindl at thalesgroup dot com> ---
Simple observation from the asan traces, the source and a quick test:

iterate_demangle_function (struct work_stuff *work, ...
{
   [only cases for early returns here]

   work_stuff_copy_to_from (&work_init, work); <- SEGV on a member of work here

work_stuff_copy_to_from () is a dumb copy function which assumes that the
vectors it shall copy have been allocated:

void work_stuff_copy_to_from (struct work_stuff *to, struct work_stuff *from)

  [nothing relevant here]
  for... {
      int len = strlen (from->ktypevec[i]) + 1; <- SIGSEGV happens here bc
NULL.

I verified that function remember_Ktype() which does the all allocation of
work_stuff->ktypevec is never called by these POCs, hence ktypevec is still
NULL, causing the SIGSEGV.

iterate_demangle_function() itself is called from a rather complex function.

The only safe fix: Before copying work_stuff, check the work_stuff vectors to
be already. If not, return 0 -> no demangle.