Fix a potential illegal memory access when testing for a special LTO symbol name.

bfd	* linker.c (_bfd_generic_link_add_one_symbol): Test for a NULL
	name before checking to see if the symbol is __gnu_lto_slim.
	* archive.c (_bfd_compute_and_write_armap): Likewise.
binutils
	* nm.c (filter_symbols): Test for a NULL name before checking to
	see if the symbol is __gnu_lto_slim.
	* objcopy.c (filter_symbols): Likewise.

bfd/ChangeLog

@@ -1,3 +1,9 @@
+2021-10-19  Nick Clifton  <nickc@redhat.com>
+
+	* linker.c (_bfd_generic_link_add_one_symbol): Test for a NULL
+	name before checking to see if the symbol is __gnu_lto_slim.
+	* archive.c (_bfd_compute_and_write_armap): Likewise.
+
 2021-09-27  Nick Alcock  <nick.alcock@oracle.com>
 
 	* configure: Regenerate.

bfd/archive.c

@@ -2357,7 +2357,8 @@ _bfd_compute_and_write_armap (bfd *arch, unsigned int elength)
 			  map = new_map;
 			}
 
-		      if (syms[src_count]->name[0] == '_'
+		      if (syms[src_count]->name != NULL
+			  && syms[src_count]->name[0] == '_'
 			  && syms[src_count]->name[1] == '_'
 			  && strcmp (syms[src_count]->name
 				     + (syms[src_count]->name[2] == '_'),

bfd/linker.c

@@ -1420,6 +1420,7 @@ _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
     {
       row = COMMON_ROW;
       if (!bfd_link_relocatable (info)
+	  && name != NULL
 	  && name[0] == '_'
 	  && name[1] == '_'
 	  && strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0)

binutils/ChangeLog

@@ -1,3 +1,9 @@
+2021-10-19  Nick Clifton  <nickc@redhat.com>
+
+	* nm.c (filter_symbols): Test for a NULL name before checking to
+	see if the symbol is __gnu_lto_slim.
+	* objcopy.c (filter_symbols): Likewise.
+
 2021-09-30  Nick Clifton  <nickc@redhat.com>
 
 	* objcopy.c (filter_symbols): Fail if attempting to dredefine

binutils/nm.c

@@ -544,7 +544,8 @@ filter_symbols (bfd *abfd, bool is_dynamic, void *minisyms,
       if (sym == NULL)
 	bfd_fatal (bfd_get_filename (abfd));
 
-      if (sym->name[0] == '_'
+      if (sym->name != NULL
+	  && sym->name[0] == '_'
 	  && sym->name[1] == '_'
 	  && strcmp (sym->name + (sym->name[2] == '_'), "__gnu_lto_slim") == 0
 	  && report_plugin_err)

binutils/objcopy.c

@@ -1542,7 +1542,8 @@ filter_symbols (bfd *abfd, bfd *obfd, asymbol **osyms,
 	{
 	  char *new_name;
 
-	  if (name[0] == '_'
+	  if (name != NULL
+	      && name[0] == '_'
 	      && name[1] == '_'
 	      && strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0)
 	    {