Fix an access through a null pointer when parsing a corrupt SOM format fle.

PR 27793
	* som.c (som_slurp_symbol_table): Assign symbols without any scope
	to the undefined section.
	(som_decode_symclass): Check for a missing symbol section.
	* syms.c (bfd_decode_symclass): Likewise.

bfd/ChangeLog

@@ -1,3 +1,11 @@
+2021-04-29  Nick Clifton  <nickc@redhat.com>
+
+	PR 27793
+	* som.c (som_slurp_symbol_table): Assign symbols without any scope
+	to the undefined section.
+	(som_decode_symclass): Check for a missing symbol section.
+	* syms.c (bfd_decode_symclass): Likewise.
+
 2021-04-29  Nick Clifton  <nickc@redhat.com>
 
 	PR 27792

bfd/som.c

@@ -4740,7 +4740,7 @@ som_slurp_symbol_table (bfd *abfd)
 	  goto error_return;
 	}
       sym->symbol.value = bfd_getb32 (bufp->symbol_value);
-      sym->symbol.section = 0;
+      sym->symbol.section = NULL;
       sym->symbol.flags = 0;
 
       switch (symbol_type)
@@ -4800,6 +4800,10 @@ som_slurp_symbol_table (bfd *abfd)
 	  sym->symbol.section = bfd_section_from_som_symbol (abfd, bufp);
 	  sym->symbol.value -= sym->symbol.section->vma;
 	  break;
+
+	default:
+	  sym->symbol.section = bfd_und_section_ptr;
+	  break;
 	}
 
       /* Check for a weak symbol.  */
@@ -5848,6 +5852,11 @@ som_decode_symclass (asymbol *symbol)
 {
   char c;
 
+  /* If the symbol did not have a scope specified,
+     then it will not have associated section.  */
+  if (symbol == NULL || symbol->section == NULL)
+    return '?';
+
   if (bfd_is_com_section (symbol->section))
     return 'C';
   if (bfd_is_und_section (symbol->section))

bfd/syms.c

@@ -654,6 +654,10 @@ bfd_decode_symclass (asymbol *symbol)
 {
   char c;
 
+  /* Paranoia...  */
+  if (symbol == NULL || symbol->section == NULL)
+    return '?';
+
   if (symbol->section && bfd_is_com_section (symbol->section))
     {
       if (symbol->section->flags & SEC_SMALL_DATA)