Disallow bless hackery around classes and instances

1 files changed, 5 insertions, 0 deletions

diff --git a/sv.c b/sv.c
index 8f11e9778f..800377ba0e 100644
--- a/sv.c
+++ b/sv.c
@@ -10772,10 +10772,15 @@ Perl_sv_bless(pTHX_ SV *const sv, HV *const stash)
     SvGETMAGIC(sv);
     if (!SvROK(sv))
         Perl_croak(aTHX_ "Can't bless non-reference value");
+    if (HvSTASH_IS_CLASS(stash))
+        Perl_croak(aTHX_ "Attempt to bless into a class");
+
     tmpRef = SvRV(sv);
     if (SvFLAGS(tmpRef) & (SVs_OBJECT|SVf_READONLY|SVf_PROTECT)) {
         if (SvREADONLY(tmpRef))
             Perl_croak_no_modify();
+        if (SvTYPE(tmpRef) == SVt_PVOBJ)
+            Perl_croak(aTHX_ "Can't bless an object reference");
         if (SvOBJECT(tmpRef)) {
             oldstash = SvSTASH(tmpRef);
         }