readelf: Make sure there is enough room for reading .debug_line unit_length.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
diff --git a/src/ChangeLog b/src/ChangeLog
index e36bb91..eaf60f0 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,7 +1,8 @@
 2014-12-15  Mark Wielaard  <mjw@redhat.com>
 
 	* readelf.c (print_debug_line_section): Check there is enough room
-	for DW_LNE_set_address argument.
+	for DW_LNE_set_address argument. Make sure there is enough room
+	for the the initial unit_length.
 
 2014-12-14  Mark Wielaard  <mjw@redhat.com>
 
diff --git a/src/readelf.c b/src/readelf.c
index faaa6d1..cd8ba86 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -6333,6 +6333,8 @@
 
       printf (gettext ("\nTable at offset %Zu:\n"), start_offset);
 
+      if (unlikely (linep + 4 > lineendp))
+	goto invalid_data;
       Dwarf_Word unit_length = read_4ubyte_unaligned_inc (dbg, linep);
       unsigned int length = 4;
       if (unlikely (unit_length == 0xffffffff))