Ensure that trailing characters aren't included in PECOFF section names

[fjricci]

Summary

If a section name is exactly 8 characters (the maximum section name length),
and the next item in the section header struct contains a non-zero value,
we would append garbage data to the end of the section name string due to the
lack of null-termination. Ensure that we don't construct the section name
with more than sizeof(sect.name) characters.

[wallace]

good catch

[labath]

Is it possible to test this? Is it possible to make yaml2obj generate a file that would trigger this?

[zturner]

Just compile something with /Z7 and you'll get a section called .debug$S in the object file, which is exactly 8 characters. Then teach lldb-test to dump an object file's sections.

[clayborg]

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

511

This is storing any extra NULL characters in sect_name. Might be better to do:

sect_name = std::string(sect.name, strnlen(sect.name, sizeof(sect.name)));

[clayborg]

Add test as well.

[clayborg]

Will we have the same problem with coff_symbol?

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

if (sect.name[0] == '/') {
     const char *name = m_data.GetCStr(&string_file_offset);
     if (name) {
       sect_name = name;
       return true;
     }
 
     return false;
   }
-  sect_name = sect.name;
+
+  // The section name has a max length of 8 characters, but isn't
+  // necessarily null-terminated
+  sect_name = std::string(sect.name, sizeof(sect.name));
   return true;
 }
 
 //----------------------------------------------------------------------
 // GetNListSymtab
 //----------------------------------------------------------------------
 Symtab *ObjectFilePECOFF::GetSymtab() {
   ModuleSP module_sp(GetModule());