[binutils-gdb] PR22230, buffer overflow in display_debug_macro

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4f1881b94473f1034f950feb863b464435a8fb5f

commit 4f1881b94473f1034f950feb863b464435a8fb5f
Author: Alan Modra <amodra@gmail.com>
Date:   Sun Oct 1 12:07:07 2017 +1030

    PR22230, buffer overflow in display_debug_macro
    
    	PR 22230
    	* objdump.c (load_specific_debug_section): Allocate an extra byte
    	for a terminating NUL.

Diff:
---
 binutils/ChangeLog | 6 ++++++
 binutils/objdump.c | 9 +++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index d9f0899..d45eeaf 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-01  Alan Modra  <amodra@gmail.com>
+
+	PR 22230
+	* objdump.c (load_specific_debug_section): Allocate an extra byte
+	for a terminating NUL.
+
 2017-09-30  Alan Modra  <amodra@gmail.com>
 
 	PR 21978
diff --git a/binutils/objdump.c b/binutils/objdump.c
index 3b2c7a3..83b8b2a 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -2475,17 +2475,18 @@ load_specific_debug_section (enum dwarf_section_display_enum debug,
   section->num_relocs = 0;
   section->address = bfd_get_section_vma (abfd, sec);
   section->size = bfd_get_section_size (sec);
-  section->start = NULL;
+  section->start = malloc (section->size + 1);
   section->user_data = sec;
-  ret = bfd_get_full_section_contents (abfd, sec, &section->start);
-
-  if (! ret)
+  if (section->start == NULL
+      || !bfd_get_full_section_contents (abfd, sec, &section->start))
     {
       free_debug_section (debug);
       printf (_("\nCan't get contents for section '%s'.\n"),
 	      section->name);
       return 0;
     }
+  /* Ensure any string section has a terminating NUL.  */
+  section->start[section->size] = 0;
 
   if (is_relocatable && debug_displays [debug].relocate)
     {