perl:fix for CVE-2010-4777

Upstream-Status: Backport
    
The Perl_reg_numbered_buff_fetch function in Perl 5.10.0, 5.12.0,
5.14.0, and other versions, when running with debugging enabled,
allows context-dependent attackers to cause a denial of service
(assertion failure and application exit) via crafted input that
is not properly handled when using certain regular expressions,
as demonstrated by causing SpamAssassin and OCSInventory to
crash.

http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2010-4777

Signed-off-by: yanjun.zhu <yanjun.zhu@windriver.com>
--- a/regcomp.c
+++ b/regcomp.c
@@ -11868,8 +11868,25 @@ Perl_save_re_context(pTHX)
 
 		if (gvp) {
 		    GV * const gv = *gvp;
-		    if (SvTYPE(gv) == SVt_PVGV && GvSV(gv))
-			save_scalar(gv);
+		    if (SvTYPE(gv) == SVt_PVGV && GvSV(gv)) {
+			/* this is a copy of save_scalar() without the GETMAGIC call, RT#76538 */
+			SV ** const sptr = &GvSVn(gv);
+			SV * osv = *sptr;
+			SV * nsv = newSV(0);
+			save_pushptrptr(SvREFCNT_inc_simple(gv),
+			SvREFCNT_inc(osv), SAVEt_SV);
+			if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv) &&
+			    SvTYPE(osv) != SVt_PVGV) {
+			    if (SvGMAGICAL(osv)) {
+				const bool oldtainted = PL_tainted;
+				SvFLAGS(osv) |= (SvFLAGS(osv) &
+				    (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
+				PL_tainted = oldtainted;
+			    }
+			    mg_localize(osv, nsv, 1);
+			}
+			*sptr = nsv;
+		    }
 		}
 	    }
 	}
