[Bug 1580348] [NEW] mksh 52c bi_errorf(Tbadsubst) format string is not a string literal

[Thorsten Glaser]

Chih-Hung Hsieh dixit:

>Lastest mksh/histrap.c (R52c) has a warning from clang/llvm compiler.
>It is a tricky use of pointer to the middle of string literals,
>which is recognized by gcc but not clang/llvm.

Arrgh, stupid compilers, trying to be too smart and utterly failing.
I’ve recently had “fun” with newer GCC versions and those string
pooling macros, TWICE. I already decided to remove them, but for
now I’ve added GCC workarounds… turns out Clang is just as bad.

Yes, I’ll tackle this for the next release, thank you for the report.

bye,
//mirabilos
-- 
22:20⎜<asarch> The crazy that persists in his craziness becomes a master
22:21⎜<asarch> And the distance between the craziness and geniality is
only measured by the success 18:35⎜<asarch> "Psychotics are consistently
inconsistent. The essence of sanity is to be inconsistently inconsistent

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https://bugs.launchpad.net/bugs/1580348

Title:
  mksh 52c bi_errorf(Tbadsubst) format string is not a string literal

Status in mksh package in Ubuntu:
  New

Bug description:
  Lastest mksh/histrap.c (R52c) has a warning from clang/llvm compiler.
  It is a tricky use of pointer to the middle of string literals,
  which is recognized by gcc but not clang/llvm.

  This warning now blocks mksh upgrade in Android open source.
  Could you fix the following warning and other places that use
  bi_errorf(Tbadsubst) or internal_errorf(Tbadsubst)?

  histrap.c:220:15: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
                                  bi_errorf(Tbadsubst);
                                            ^~~~~~~~~
  sh.h:891:19: note: expanded from macro 'Tbadsubst'
  #define Tbadsubst       (Tfg_badsubst + 10)     /* "bad substitution" */
                          ^~~~~~~~~~~~~~~~~~

  
  The warning can be fixed by changing
     bi_errorf(Tbadsubst);
  to
     bi_errorf("%s", Tbadsubst);

  If adding a few bytes is not acceptable, could you change
     bi_errorf(Tbadsubst);
  to
     bi_errorf0(Tbadsubst);
  where bi_errorf0 is declared as
     void bi_errorf0(const char *);  // without format check
  and implemented as a weak alias:
     void bi_errorf0(const char *s) __attribute__((weak, alias("bi_errorf")));

  
  Attached file is a suggested patch to compile with Android.

  Thanks.

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