[binutils-gdb] or1k: Fix messages for relocations in shared libraries

[Stafford Horne <shorne at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2c1801f6255a3f9f483ae2f07c7d7da0ddae4af

commit f2c1801f6255a3f9f483ae2f07c7d7da0ddae4af
Author: Stafford Horne <shorne@gmail.com>
Date:   Fri Oct 5 11:41:41 2018 +0900

    or1k: Fix messages for relocations in shared libraries
    
    Added checks include:
    
     - Do not allow relocations to global symbols using relocations which are
       meant for local symbol relocations.
     - Require the use of -fpic when compiling shared libraries.
     - Require zero addend for plt relocations.
    
    bfd/ChangeLog:
    
    yyyy-mm-dd  Richard Henderson  <rth@twiddle.net>
    
    	* elf32-or1k.c (or1k_elf_relocate_section): Add error for unknown
    	relocations.  Add error for non zero addend with plt and got
    	relocations.  Add error for got and plt references against dynamic, non
    	local, symbols.  Add error when linking non shared liraries with
    	flag_pic.

Diff:
---
 bfd/ChangeLog    |   8 +++
 bfd/elf32-or1k.c | 148 +++++++++++++++++++++++++++++++++----------------------
 2 files changed, 98 insertions(+), 58 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index e0b26df..d8f0949 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,4 +1,12 @@
 2018-10-05  Richard Henderson  <rth@twiddle.net>
+
+	* elf32-or1k.c (or1k_elf_relocate_section): Add error for unknown
+	relocations.  Add error for non zero addend with plt and got
+	relocations.  Add error for got and plt references against dynamic, non
+	local, symbols.  Add error when linking non shared liraries with
+	flag_pic.
+
+2018-10-05  Richard Henderson  <rth@twiddle.net>
 	    Stafford Horne  <shorne@gmail.com>
 
 	* bfd-in2.h: Regenerated.
diff --git a/bfd/elf32-or1k.c b/bfd/elf32-or1k.c
index d888c9f..451253d 100644
--- a/bfd/elf32-or1k.c
+++ b/bfd/elf32-or1k.c
@@ -1038,7 +1038,9 @@ or1k_elf_relocate_section (bfd *output_bfd,
   bfd *dynobj;
   asection *sreloc;
   bfd_vma *local_got_offsets;
-  asection *sgot;
+  asection *sgot, *splt;
+  bfd_vma plt_base, got_base;
+  bfd_boolean ret_val = TRUE;
 
   if (htab == NULL)
     return FALSE;
@@ -1048,7 +1050,15 @@ or1k_elf_relocate_section (bfd *output_bfd,
 
   sreloc = elf_section_data (input_section)->sreloc;
 
+  splt = htab->root.splt;
+  plt_base = 0;
+  if (splt != NULL)
+    plt_base = splt->output_section->vma + splt->output_offset;
+
   sgot = htab->root.sgot;
+  got_base = 0;
+  if (sgot != NULL)
+    got_base = sgot->output_section->vma + sgot->output_offset;
 
   symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
   sym_hashes = elf_sym_hashes (input_bfd);
@@ -1075,8 +1085,12 @@ or1k_elf_relocate_section (bfd *output_bfd,
 
       if (r_type < 0 || r_type >= (int) R_OR1K_max)
 	{
+	  _bfd_error_handler
+	    (_("%pB: unknown relocation type %d"),
+	     input_bfd, (int) r_type);
 	  bfd_set_error (bfd_error_bad_value);
-	  return FALSE;
+	  ret_val = FALSE;
+	  continue;
 	}
 
       howto = or1k_elf_howto_table + ELF32_R_TYPE (rel->r_info);
@@ -1102,6 +1116,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
 				   r_symndx, symtab_hdr, sym_hashes,
 				   h, sec, relocation,
 				   unresolved_reloc, warned, ignored);
+	  name = h->root.root.string;
 	}
 
       if (sec != NULL && discarded_section (sec))
@@ -1114,16 +1129,24 @@ or1k_elf_relocate_section (bfd *output_bfd,
       switch (howto->type)
 	{
 	case R_OR1K_PLT26:
-	  {
-	    if (htab->root.splt != NULL && h != NULL
-		&& h->plt.offset != (bfd_vma) -1)
-	      {
-		relocation = (htab->root.splt->output_section->vma
-			      + htab->root.splt->output_offset
-			      + h->plt.offset);
-	      }
-	    break;
-	  }
+	  /* If the call is not local, redirect the branch to the PLT.
+	     Otherwise do nothing to send the branch to the symbol direct.  */
+	  if (!SYMBOL_CALLS_LOCAL (info, h))
+	    {
+	      BFD_ASSERT (h->plt.offset != (bfd_vma) -1);
+	      relocation = plt_base + h->plt.offset;
+	    }
+
+	  /* Addend should be zero.  */
+	  if (rel->r_addend != 0)
+	    {
+	      _bfd_error_handler
+		(_("%pB: addend should be zero for plt relocations"),
+		 input_bfd);
+	      bfd_set_error (bfd_error_bad_value);
+	      ret_val = FALSE;
+	    }
+	  break;
 
 	case R_OR1K_GOT16:
 	  /* Relocation is to the entry for this symbol in the global
@@ -1200,9 +1223,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
 		      srelgot = htab->root.srelgot;
 		      BFD_ASSERT (srelgot != NULL);
 
-		      outrel.r_offset = (sgot->output_section->vma
-					 + sgot->output_offset
-					 + off);
+		      outrel.r_offset = got_base + off;
 		      outrel.r_info = ELF32_R_INFO (0, R_OR1K_RELATIVE);
 		      outrel.r_addend = relocation;
 		      loc = srelgot->contents;
@@ -1218,10 +1239,13 @@ or1k_elf_relocate_section (bfd *output_bfd,
 
 	  /* Addend should be zero.  */
 	  if (rel->r_addend != 0)
-	    _bfd_error_handler
-	      (_("internal error: addend should be zero for %s"),
-	       "R_OR1K_GOT16");
-
+	    {
+	      _bfd_error_handler
+		(_("%pB: addend should be zero for got relocations"),
+		 input_bfd);
+	      bfd_set_error (bfd_error_bad_value);
+	      ret_val = FALSE;
+	    }
 	  break;
 
 	case R_OR1K_GOTOFF_LO16:
@@ -1230,17 +1254,44 @@ or1k_elf_relocate_section (bfd *output_bfd,
 	case R_OR1K_GOTOFF_SLO16:
 	  /* Relocation is offset from GOT.  */
 	  BFD_ASSERT (sgot != NULL);
-	  relocation
-	    -= (htab->root.hgot->root.u.def.value
-		+ htab->root.hgot->root.u.def.section->output_offset
-		+ htab->root.hgot->root.u.def.section->output_section->vma);
+	  if (!SYMBOL_REFERENCES_LOCAL (info, h))
+	    {
+	      _bfd_error_handler
+		(_("%pB: gotoff relocation against dynamic symbol %s"),
+		 input_bfd, h->root.root.string);
+	      ret_val = FALSE;
+	      bfd_set_error (bfd_error_bad_value);
+	    }
+	  relocation -= got_base;
 	  break;
 
 	case R_OR1K_INSN_REL_26:
+	  /* For a non-shared link, these will reference either the plt
+	     or a .dynbss copy of the symbol.  */
+	  if (bfd_link_pic (info) && !SYMBOL_REFERENCES_LOCAL (info, h))
+	    {
+	      _bfd_error_handler
+		(_("%pB: pc-relative relocation against dynamic symbol %s"),
+		 input_bfd, name);
+	      ret_val = FALSE;
+	      bfd_set_error (bfd_error_bad_value);
+	    }
+	  break;
+
 	case R_OR1K_HI_16_IN_INSN:
 	case R_OR1K_LO_16_IN_INSN:
 	case R_OR1K_AHI16:
 	case R_OR1K_SLO16:
+	  if (bfd_link_pic (info))
+	    {
+	      _bfd_error_handler
+		(_("%pB: non-pic relocation against symbol %s"),
+		 input_bfd, name);
+	      ret_val = FALSE;
+	      bfd_set_error (bfd_error_bad_value);
+	    }
+	  break;
+
 	case R_OR1K_32:
 	  /* R_OR1K_16? */
 	  {
@@ -1251,18 +1302,17 @@ or1k_elf_relocate_section (bfd *output_bfd,
 		|| (input_section->flags & SEC_ALLOC) == 0)
 	      break;
 
-	    if ((bfd_link_pic (info)
-		 && (h == NULL
+	    /* Emit a direct relocation if the symbol is dynamic,
+	       or a RELATIVE reloc for shared objects.  We can omit
+	       RELATIVE relocs to local undefweak symbols.  */
+	    if (bfd_link_pic (info)
+		? (h == NULL
 		     || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
 		     || h->root.type != bfd_link_hash_undefweak)
-		 && (howto->type != R_OR1K_INSN_REL_26
-		     || !SYMBOL_CALLS_LOCAL (info, h)))
-		|| (!bfd_link_pic (info)
-		    && h != NULL
+		: (h != NULL
 		    && h->dynindx != -1
 		    && !h->non_got_ref
-		    && ((h->def_dynamic
-			 && !h->def_regular)
+		   && ((h->def_dynamic && !h->def_regular)
 			|| h->root.type == bfd_link_hash_undefweak
 			|| h->root.type == bfd_link_hash_undefined)))
 	      {
@@ -1290,32 +1340,16 @@ or1k_elf_relocate_section (bfd *output_bfd,
 
 		if (skip)
 		  memset (&outrel, 0, sizeof outrel);
-		/* h->dynindx may be -1 if the symbol was marked to
-		   become local.  */
-		else if (h != NULL
-			 && ((! info->symbolic && h->dynindx != -1)
-			     || !h->def_regular))
+		else if (SYMBOL_REFERENCES_LOCAL (info, h))
 		  {
-		    BFD_ASSERT (h->dynindx != -1);
-		    outrel.r_info = ELF32_R_INFO (h->dynindx, r_type);
-		    outrel.r_addend = rel->r_addend;
+		    outrel.r_info = ELF32_R_INFO (0, R_OR1K_RELATIVE);
+		    outrel.r_addend = relocation + rel->r_addend;
 		  }
 		else
 		  {
-		    if (r_type == R_OR1K_32)
-		      {
-			outrel.r_info = ELF32_R_INFO (0, R_OR1K_RELATIVE);
-			outrel.r_addend = relocation + rel->r_addend;
-		      }
-		    else
-		      {
-			BFD_FAIL ();
-			_bfd_error_handler
-			  (_("%pB: probably compiled without -fPIC?"),
-			   input_bfd);
-			bfd_set_error (bfd_error_bad_value);
-			return FALSE;
-		      }
+		    BFD_ASSERT (h->dynindx != -1);
+		    outrel.r_info = ELF32_R_INFO (h->dynindx, r_type);
+		    outrel.r_addend = rel->r_addend;
 		  }
 
 		loc = sreloc->contents;
@@ -1391,8 +1425,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
 		/* Add DTPMOD and DTPOFF GOT and rela entries.  */
 		for (i = 0; i < 2; ++i)
 		  {
-		    rela.r_offset = sgot->output_section->vma +
-		      sgot->output_offset + gotoff + i*4;
+		    rela.r_offset = got_base + gotoff + i*4;
 		    if (h != NULL && h->dynindx != -1)
 		      {
 			rela.r_info = ELF32_R_INFO (h->dynindx,
@@ -1426,8 +1459,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
 	    else if (dynamic)
 	      {
 		/* Add TPOFF GOT and rela entries.  */
-		rela.r_offset = sgot->output_section->vma +
-		  sgot->output_offset + gotoff;
+		rela.r_offset = got_base + gotoff;
 		if (h != NULL && h->dynindx != -1)
 		  {
 		    rela.r_info = ELF32_R_INFO (h->dynindx, R_OR1K_TLS_TPOFF);
@@ -1522,7 +1554,7 @@ or1k_elf_relocate_section (bfd *output_bfd,
 	}
     }
 
-  return TRUE;
+  return ret_val;
 }
 
 /* Return the section that should be marked against GC for a given