read_unitinfo_dwarf2 DW_FORM_ref_addr is address size in DWARF version 2.

Bug #305513 contained a patch for some extra robustness checks. But
the real cause of crashing in the read_unitinfo_dwarf2 DWARF reader
seemed to have been this issue where DWARF version 2 DWZ partial_units
were read and DW_FORM_ref_addr had an unexpected size. This combination
is rare. DWARF version 4 is the current default version of GCC.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13367

diff --git a/coregrind/m_debuginfo/readdwarf.c b/coregrind/m_debuginfo/readdwarf.c
index ce34bc767bc295c6a4c40f875b21acf1f4f5af92..52a90993706607bf4b978a6129a977ad22efd50b 100644 (file)
--- a/coregrind/m_debuginfo/readdwarf.c
+++ b/coregrind/m_debuginfo/readdwarf.c
@@ -991,7 +991,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
    UInt   acode, abcode;
    ULong  atoffs, blklen;
    Int    level;
-   /* UShort ver; */
+   UShort ver;
 
    UChar addr_size;
    UChar* p = unitblock_img;
@@ -1008,7 +1008,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
    p += ui->dw64 ? 12 : 4;
 
    /* version should be 2, 3 or 4 */
-   /* ver = ML_(read_UShort)(p); */
+   ver = ML_(read_UShort)(p);
    p += 2;
 
    /* get offset in abbrev */
@@ -1122,7 +1122,7 @@ void read_unitinfo_dwarf2( /*OUT*/UnitInfo* ui,
             case 0x0c: /* FORM_flag */      p++; break;
             case 0x0d: /* FORM_sdata */     read_leb128S( &p ); break;
             case 0x0f: /* FORM_udata */     read_leb128U( &p ); break;
-            case 0x10: /* FORM_ref_addr */  p += ui->dw64 ? 8 : 4; break;
+            case 0x10: /* FORM_ref_addr */  p += (ver == 2) ? addr_size : (ui->dw64 ? 8 : 4); break;
             case 0x11: /* FORM_ref1 */      p++; break;
             case 0x12: /* FORM_ref2 */      p += 2; break;
             case 0x13: /* FORM_ref4 */      p += 4; break;