[Lynx-dev] ASAN/UBSAN issues

[Gisle Vanem]

I found some ASAN+UBSAN issues after building the
latest GitHub snapshot [1] of Lynx on Windows.

I used 'clang-cl -fsanitize=address -fsanitize-recover=address
                 -fsanitize=undefined'

First the ASAN issue:
  src/GridText.c:915:12: runtime error: applying zero offset to null pointer
  SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/GridText.c:915:12

Fixed by:
  --- a/src/GridText.c 2023-02-18 11:10:31
  +++ b/src/GridText.c 2023-06-30 10:08:49
  @@ -912,6 +912,7 @@
          result = a->lites.hl_info[count - 1].hl_text;
       else
          result = a->lites.hl_base.hl_text;
  +    if (result)
           result += LYAdjHiTextPos(a, count);
       return result;

then this UBSAN ("Undefined Behavior Sanitizer") issue:

  src/LYMainLoop.c:6809:27: runtime error: index -1 out of bounds for type 
'LinkInfo[1024]'
  SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
src/LYMainLoop.c:6809:27 in
  =================================================================
  ==12236==ERROR: AddressSanitizer: global-buffer-overflow on address 
0x7ff774780160 at
  pc 0x7ffc6cc271bb bp 0x005d7ab3d200 sp 0x005d7ab3c990
  READ of size 96 at 0x7ff774780160 thread T0
      #0 0x7ffc6cc271ba in __asan_memcpy 
D:\a\_work\1\s\src\vctools\asan\llvm\compiler-rt\lib\asan\asan_interceptors_memintrinsics.cpp:22
      #1 0x7ff77371e477 in mainloop 
F:\MinGW32\src\inet\Web\Lynx\src\LYMainLoop.c:6809
      #2 0x7ff77370d88c in main F:\MinGW32\src\inet\Web\Lynx\src\LYMain.c:2276
      #3 0x7ff773e23c67 in invoke_main 
D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
      #4 0x7ff773e23c67 in __scrt_common_main_seh 
D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
      #5 0x7ffcd7fe7613  (C:\Windows\System32\KERNEL32.DLL+0x180017613)
      #6 0x7ffcd88026f0  (C:\Windows\SYSTEM32\ntdll.dll+0x1800526f0)

Fixed by:
  --- a/src/LYMainLoop.c 2023-02-18 11:10:31
  +++ b/src/LYMainLoop.c 2023-06-30 10:14:17
  @@ -6774,7 +6774,7 @@
           * If help is not on the screen, then put a message on the screen to
           * tell the user other misc info.
           */
  -       if (!show_help) {
  +       if (!show_help && curdoc.link >= 0) {
              show_main_statusline(links[curdoc.link],
                                   ((curlink_is_editable &&
                                     textinput_activated)
----------------

(the line-numbers count be off since I've made other
unrelated patches locally).

I was sure I've posted this before somewhere. Apparently not.
So I was thinking of creating an issue for this on Github, but
there's no 'issue page' there! Why not Tom?

[1] https://github.com/ThomasDickey/lynx-snapshots.git

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--gv