arc: Fix potential invalid pointer access when fixing got symbols.

When statically linking, it can arrive to an undefined weak symbol of
which its value cannot be determined. However, we are having pieces of
code which doesn't take this situation into account, leading to access
a structure which may not be initialized. Fix this situation and add a
test.

bfd/
xxxx-xx-xx  Cupertino Miranda  <cmiranda@synopsys.com>
            Claudiu Zissulescu  <claziss@synopsys.com>

	* arc-got.h (arc_static_sym_data): New structure.
	(get_static_sym_data): New function.
	(relocate_fix_got_relocs_for_got_info): Move the computation fo
	symbol value and section to above introduced function, and use
	this new function.

ld/testsuite/
xxxx-xx-xx  Claudiu Zissulescu  <claziss@synopsys.com>

	* ld-arc/got-weak.d: New file.
	* ld-arc/got-weak.s: Likewise.

Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>

fix

5 files changed, 90 insertions, 37 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index d878d05..a69b50c 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2021-09-014  Cupertino Miranda  <cmiranda@synopsys.com>
+           Claudiu Zissulescu  <claziss@synopsys.com>
+
+	* arc-got.h (arc_static_sym_data): New structure.
+	(get_static_sym_data): New function.
+	(relocate_fix_got_relocs_for_got_info): Move the computation fo
+	symbol value and section to above introduced function, and use
+	this new function.
+
 2021-09-07  Luis Machado  <luis.machado@linaro.org>
 
 	Revert: [AArch64] MTE corefile support
diff --git a/bfd/arc-got.h b/bfd/arc-got.h
index 76fc761..c45d981 100644
--- a/bfd/arc-got.h
+++ b/bfd/arc-got.h
@@ -262,6 +262,48 @@ arc_fill_got_info_for_reloc (enum tls_type_e type,
   return true;
 }
 
+struct arc_static_sym_data {
+  bfd_vma sym_value;
+  const char *symbol_name;
+};
+
+static struct arc_static_sym_data
+get_static_sym_data (unsigned long  r_symndx,
+		     Elf_Internal_Sym  *local_syms,
+		     asection **local_sections,
+		     struct elf_link_hash_entry *h,
+		     struct arc_relocation_data *reloc_data)
+{
+  static const char local_name[] = "(local)";
+  struct arc_static_sym_data ret = { 0, NULL };
+
+  if (h != NULL)
+    {
+      BFD_ASSERT (h->root.type != bfd_link_hash_undefweak
+		  && h->root.type != bfd_link_hash_undefined);
+      /* TODO: This should not be here.  */
+      reloc_data->sym_value = h->root.u.def.value;
+      reloc_data->sym_section = h->root.u.def.section;
+
+      ret.sym_value = h->root.u.def.value
+	+ h->root.u.def.section->output_section->vma
+	+ h->root.u.def.section->output_offset;
+
+      ret.symbol_name = h->root.root.string;
+    }
+  else
+  {
+    Elf_Internal_Sym *sym = local_syms + r_symndx;
+    asection *sec = local_sections[r_symndx];
+
+    ret.sym_value = sym->st_value
+      + sec->output_section->vma
+      + sec->output_offset;
+
+    ret.symbol_name = local_name;
+  }
+  return ret;
+}
 
 static bfd_vma
 relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
@@ -290,38 +332,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 	      && SYMBOL_REFERENCES_LOCAL (info, h))))
     {
       const char ATTRIBUTE_UNUSED *symbol_name;
-      static const char local_name[] = "(local)";
-      asection *tls_sec = NULL;
-      bfd_vma sym_value = 0;
-
-      if (h != NULL)
-	{
-	  /* TODO: This should not be here.  */
-	  reloc_data->sym_value = h->root.u.def.value;
-	  reloc_data->sym_section = h->root.u.def.section;
-
-	  sym_value = h->root.u.def.value
-	    + h->root.u.def.section->output_section->vma
-	    + h->root.u.def.section->output_offset;
-
-	  tls_sec = elf_hash_table (info)->tls_sec;
-
-	  symbol_name = h->root.root.string;
-	}
-      else
-	{
-	  Elf_Internal_Sym *sym = local_syms + r_symndx;
-	  asection *sec = local_sections[r_symndx];
-
-	  sym_value = sym->st_value
-	    + sec->output_section->vma
-	    + sec->output_offset;
-
-	  tls_sec = elf_hash_table (info)->tls_sec;
-
-	  symbol_name = local_name;
-	}
-
+      asection *tls_sec = elf_hash_table (info)->tls_sec;
 
       if (entry && !entry->processed)
 	{
@@ -335,8 +346,12 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 		if (h == NULL || h->forced_local
 		   || !elf_hash_table (info)->dynamic_sections_created)
 		  {
+		    struct arc_static_sym_data tmp =
+		      get_static_sym_data (r_symndx, local_syms, local_sections,
+					   h, reloc_data);
+
 		    bfd_put_32 (output_bfd,
-			    sym_value - sec_vma
+			    tmp.sym_value - sec_vma
 			    + (elf_hash_table (info)->dynamic_sections_created
 			       ? 0
 			       : (align_power (0,
@@ -355,7 +370,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			     + entry->offset
 			     + (entry->existing_entries == TLS_GOT_MOD_AND_OFF
 				? 4 : 0)),
-			  symbol_name);
+			  tmp.symbol_name);
 		  }
 	      }
 	      break;
@@ -366,8 +381,12 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 		bfd_vma ATTRIBUTE_UNUSED sec_vma
 		  = tls_sec->output_section->vma;
 
+		struct arc_static_sym_data tmp =
+		  get_static_sym_data (r_symndx, local_syms, local_sections,
+				       h, reloc_data);
+
 		bfd_put_32 (output_bfd,
-			    sym_value - sec_vma
+			    tmp.sym_value - sec_vma
 			    + (elf_hash_table (info)->dynamic_sections_created
 			       ? 0
 			       : (align_power (TCB_SIZE,
@@ -386,7 +405,7 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			      + entry->offset
 			      + (entry->existing_entries == TLS_GOT_MOD_AND_OFF
 				 ? 4 : 0)),
-			   symbol_name);
+			   tmp.symbol_name);
 	      }
 	      break;
 
@@ -415,7 +434,8 @@ relocate_fix_got_relocs_for_got_info (struct got_entry **	   list_p,
 			       "@ %#08lx for sym %s in got offset %#lx\n",
 			       (long) (reloc_data->sym_value + sec_vma),
 			       (long) (htab->sgot->output_section->vma
-				       + htab->sgot->output_offset + entry->offset),
+				       + htab->sgot->output_offset
+				       + entry->offset),
 			       symbol_name,
 			       (long) entry->offset);
 		  }
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 28deefc..ebcd4cd 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,8 @@
+2021-09-14  Claudiu Zissulescu  <claziss@synopsys.com>
+
+	* ld-arc/got-weak.d: New file.
+	* ld-arc/got-weak.s: Likewise.
+
 2021-07-26  Roland McGrath  <mcgrathr@google.com>
 
 	* testsuite/ld-x86-64/x86-64.exp (Build textrel-1): Use --warn-textrel.
diff --git a/ld/testsuite/ld-arc/got-weak.d b/ld/testsuite/ld-arc/got-weak.d
new file mode 100644
index 0000000..cf15069
--- /dev/null
+++ b/ld/testsuite/ld-arc/got-weak.d
@@ -0,0 +1,12 @@
+#source: got-weak.s
+#as:
+#ld: -Bstatic
+#objdump: -d
+
+[^:]*:     file format elf32-.*arc
+
+
+Disassembly of section \.text:
+
+00000100 <.*>:
+ 100:	2730 7f80 0000 2014 	ld	r0,\[pcl,0x2014\].*
diff --git a/ld/testsuite/ld-arc/got-weak.s b/ld/testsuite/ld-arc/got-weak.s
new file mode 100644
index 0000000..8ea18be
--- /dev/null
+++ b/ld/testsuite/ld-arc/got-weak.s
@@ -0,0 +1,7 @@
+	.cpu archs
+
+	.weak symb
+	.global __start
+	.text
+__start:
+	ld	r0,[pcl,@symb@gotpc]