readelf: fix out of range subtraction, seg fault from a NULL pointer and memory exhaustion, all from parsing corrupt binaries.

	PR binutils/21379
	* readelf.c (process_dynamic_section): Detect over large section
	offsets in the DT_SYMTAB entry.

	PR binutils/21345
	* readelf.c (process_mips_specific): Catch an unfeasible memory
	allocation before it happens and print a suitable error message.

2 files changed, 33 insertions, 5 deletions

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index ae734c4..5f75c17 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,5 +1,17 @@
 2017-04-13  Nick Clifton  <nickc@redhat.com>
 
+	PR binutils/21379
+	* readelf.c (process_dynamic_section): Detect over large section
+	offsets in the DT_SYMTAB entry.
+
+2017-04-13  Nick Clifton  <nickc@redhat.com>
+
+	PR binutils/21345
+	* readelf.c (process_mips_specific): Catch an unfeasible memory
+	allocation before it happens and print a suitable error message.
+
+2017-04-13  Nick Clifton  <nickc@redhat.com>
+
 	* objcopy.c: Add --no-merge-notes option to disable note merging.
 	Add --[no-]merge-notes option to strip, and enable it by default.
 	(num_bytes): New function.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 93b9402..ab53473 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -9436,6 +9436,12 @@ process_dynamic_section (FILE * file)
 	     processing that.  This is overkill, I know, but it
 	     should work.  */
 	  section.sh_offset = offset_from_vma (file, entry->d_un.d_val, 0);
+	  if ((bfd_size_type) section.sh_offset > current_file_size)
+	    {
+	      /* See PR 21379 for a reproducer.  */
+	      error (_("Invalid DT_SYMTAB entry: %lx"), (long) section.sh_offset);
+	      return FALSE;
+	    }
 
 	  if (archive_file_offset != 0)
 	    section.sh_size = archive_file_size - section.sh_offset;
@@ -15370,6 +15376,15 @@ process_mips_specific (FILE * file)
 	  return FALSE;
 	}
 
+      /* PR 21345 - print a slightly more helpful error message
+	 if we are sure that the cmalloc will fail.  */
+      if (conflictsno * sizeof (* iconf) > current_file_size)
+	{
+	  error (_("Overlarge number of conflicts detected: %lx\n"),
+		 (long) conflictsno);
+	  return FALSE;
+	}
+
       iconf = (Elf32_Conflict *) cmalloc (conflictsno, sizeof (* iconf));
       if (iconf == NULL)
 	{
@@ -16656,10 +16671,11 @@ print_symbol_for_build_attribute (FILE *         file,
   static unsigned long      strtablen;
   static Elf_Internal_Sym * symtab;
   static unsigned long      nsyms;
-  Elf_Internal_Sym *  saved_sym = NULL;
-  Elf_Internal_Sym *  sym;
+  Elf_Internal_Sym *        saved_sym = NULL;
+  Elf_Internal_Sym *        sym;
 
-  if (saved_file == NULL || file != saved_file)
+  if (section_headers != NULL
+      && (saved_file == NULL || file != saved_file))
     {
       Elf_Internal_Shdr * symsec;
 
@@ -16822,7 +16838,7 @@ print_gnu_build_attribute_name (Elf_Internal_Note * pnote)
   if (name == NULL || pnote->namesz < 2)
     {
       error (_("corrupt name field in GNU build attribute note: size = %ld\n"), pnote->namesz);
-      print_symbol (-20, _("  <corrupt name field>"));
+      print_symbol (-20, _("  <corrupt name>"));
       return FALSE;
     }
 
@@ -17452,7 +17468,7 @@ process_arch_specific (FILE * file)
       return process_mips_specific (file);
 
     case EM_MSP430:
-      return process_attributes (file, "mspabi", SHT_MSP430_ATTRIBUTES,
+     return process_attributes (file, "mspabi", SHT_MSP430_ATTRIBUTES,
 				 display_msp430x_attribute,
 				 display_generic_attribute);