asan: NULL deref in alpha_ecoff_get_relocated_section_contents

[Alan Modra]

This fixes some holes found by fuzzers, and removes aborts that can be
triggered by user input to objdump.  Abort should only be used within
bfd to show programming errors in bfd.

	* coff-alpha.c (alpha_ecoff_get_relocated_section_contents): Handle
	NULL howto.  Don't abort on stack errors or on unexpected relocs.
	Show more bfd reloc status messages.

diff --git a/bfd/coff-alpha.c b/bfd/coff-alpha.c
index 59476b57237..884073a3484 100644
--- a/bfd/coff-alpha.c
+++ b/bfd/coff-alpha.c
@@ -815,10 +815,20 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
       arelent *rel;
       bfd_reloc_status_type r;
       char *err;
+      unsigned int r_type;
 
       rel = *relp;
-      r = bfd_reloc_ok;
-      switch (rel->howto->type)
+      if (rel->howto == NULL)
+	{
+	  r = bfd_reloc_notsupported;
+	  r_type = ALPHA_R_IGNORE;
+	}
+      else
+	{
+	  r = bfd_reloc_ok;
+	  r_type = rel->howto->type;
+	}
+      switch (r_type)
 	{
 	case ALPHA_R_IGNORE:
 	  rel->address += input_section->output_offset;
@@ -985,7 +995,10 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 	    relocation += rel->addend;
 
 	    if (tos >= RELOC_STACKSIZE)
-	      abort ();
+	      {
+		r = bfd_reloc_notsupported;
+		break;
+	      }
 
 	    stack[tos++] = relocation;
 	  }
@@ -1004,7 +1017,10 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 	      }
 
 	    if (tos == 0)
-	      abort ();
+	      {
+		r = bfd_reloc_notsupported;
+		break;
+	      }
 
 	    /* The offset and size for this reloc are encoded into the
 	       addend field by alpha_adjust_reloc_in.  */
@@ -1045,7 +1061,10 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 	    relocation += rel->addend;
 
 	    if (tos == 0)
-	      abort ();
+	      {
+		r = bfd_reloc_notsupported;
+		break;
+	      }
 
 	    stack[tos - 1] -= relocation;
 	  }
@@ -1078,7 +1097,10 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 	    relocation += rel->addend;
 
 	    if (tos == 0)
-	      abort ();
+	      {
+		r = bfd_reloc_notsupported;
+		break;
+	      }
 
 	    stack[tos - 1] >>= relocation;
 	  }
@@ -1091,7 +1113,8 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 	  break;
 
 	default:
-	  abort ();
+	  r = bfd_reloc_notsupported;
+	  break;
 	}
 
       if (relocatable)
@@ -1123,15 +1146,30 @@ alpha_ecoff_get_relocated_section_contents (bfd *abfd,
 		 input_section, rel->address);
 	      break;
 	    case bfd_reloc_outofrange:
+	      (*link_info->callbacks->einfo)
+		/* xgettext:c-format */
+		(_("%X%P: %pB(%pA): relocation \"%pR\" goes out of range\n"),
+		 abfd, input_section, rel);
+	      goto error_return;
+	    case bfd_reloc_notsupported:
+	      (*link_info->callbacks->einfo)
+		/* xgettext:c-format */
+		(_("%X%P: %pB(%pA): relocation \"%pR\" is not supported\n"),
+		 abfd, input_section, rel);
+	      goto error_return;
 	    default:
-	      abort ();
+	      (*link_info->callbacks->einfo)
+		/* xgettext:c-format */
+		(_("%X%P: %pB(%pA): relocation \"%pR\""
+		   " returns an unrecognized value %x\n"),
+		 abfd, input_section, rel, r);
 	      break;
 	    }
 	}
     }
 
   if (tos != 0)
-    abort ();
+    goto error_return;
 
  successful_return:
   free (reloc_vector);

-- 
Alan Modra
Australia Development Lab, IBM