libdw: Make sure that address_size and offset_size are 4 or 8 bytes.

When interning a CU make sure that address_size and offset_size are
either 4 or 8 bytes. We really don't (want to) handle any other size.

Signed-off-by: Mark Wielaard <mark@klomp.org>

2 files changed, 17 insertions, 2 deletions

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index b5693930..9d0b4849 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,9 @@
+2018-06-07  Mark Wielaard  <mark@klomp.org>
+
+	* libdw_findcu.c (__libdw_intern_next_unit): Report DWARF_E_VERSION,
+	not DWARF_E_INVALID_DWARF on unknown version. Set address_size and
+	offset_size to 8 when unknown.
+
 2018-06-06  Mark Wielaard  <mark@klomp.org>
 
 	* libdwP.h (__libdw_dieabbrev): Check DIE addr falls in cu.
diff --git a/libdw/libdw_findcu.c b/libdw/libdw_findcu.c
index 2f5c6c42..ed744231 100644
--- a/libdw/libdw_findcu.c
+++ b/libdw/libdw_findcu.c
@@ -120,14 +120,23 @@ __libdw_intern_next_unit (Dwarf *dbg, bool debug_types)
     return NULL;
 
   /* We only know how to handle the DWARF version 2 through 5 formats.
-     For v4 debug types we only handle version 4. */
+     For v4 debug types we only handle version 4.  */
   if (unlikely (version < 2) || unlikely (version > 5)
       || (debug_types && unlikely (version != 4)))
     {
-      __libdw_seterrno (DWARF_E_INVALID_DWARF);
+      __libdw_seterrno (DWARF_E_VERSION);
       return NULL;
     }
 
+  /* We only handle 32 or 64 bit (4 or 8 byte) addresses and offsets.
+     Just assume we are dealing with 64bit in case the size is "unknown".
+     Too much code assumes if it isn't 4 then it is 8 (or the other way
+     around).  */
+  if (unlikely (address_size != 4 && address_size != 8))
+    address_size = 8;
+  if (unlikely (offset_size != 4 && offset_size != 8))
+    offset_size = 8;
+
   /* Invalid or truncated debug section data?  */
   size_t sec_idx = debug_types ? IDX_debug_types : IDX_debug_info;
   Elf_Data *data = dbg->sectiondata[sec_idx];