On Thu, 23 Dec 2021, Ken Brown wrote:
> > - for (ULONG j = 0; j < phi->NumberOfHandles; j++)
> > + for (ULONG j = 0; j < min(phi->NumberOfHandles, n_handle); j++)
>
> Reading the preceding code, I don't see how n_handle could be less than
> phi->NumberOfHandles. Can you explain?
>
Not really. I saw this stack trace:
...
#3 0x0000000180062f13 in exception::handle (e=0x14cc4f0, frame=<optimized
out>, in=<optimized out>, dispatch=<optimized out>) at
/c/S/msys2-runtime/src/msys2-runtime/winsup/cygwin/exceptions.cc:835
#4 0x00007ff8abd320cf in ntdll!.chkstk () from /c/Windows/SYSTEM32/ntdll.dll
#5 0x00007ff8abce1454 in ntdll!RtlRaiseException () from
/c/Windows/SYSTEM32/ntdll.dll
#6 0x00007ff8abd30bfe in ntdll!KiUserExceptionDispatcher () from
/c/Windows/SYSTEM32/ntdll.dll
#7 0x0000000180092687 in fhandler_pipe::get_query_hdl_per_process
(this=this@entry=0x1803700f8, name=name@entry=0x14cc820
L"\\Device\\NamedPipe\\dd50a72ab4668b33-10348-pipe-nt-0x6E6",
ntfn=ntfn@entry=0x8000c2ce0) at
/c/S/msys2-runtime/src/msys2-runtime/winsup/cygwin/fhandler_pipe.cc:1281
#8 0x0000000180092bdb in fhandler_pipe::temporary_query_hdl
(this=this@entry=0x1803700f8) at
/c/S/msys2-runtime/src/msys2-runtime/winsup/cygwin/fhandler_pipe.cc:1190
...
Line 1281 of fhandler_pipe.cc was
if (phi->Handles[j].GrantedAccess != access)
The only way I could see that causing an exception was if it was reading
past the end of the allocated memory, if j was greater than (or equal to)
n_handle. Unfortunately, I haven't been able to catch it in a debugger
again, so I can't confirm this. I took a core with 'dumper' but gdb
doesn't want to load it (it says Core file format not supported, maybe
something with msys2's gdb?).
