@@ -665,7 +665,7 @@ inline static int comp_str(int op, str* left, int rtype, union exp_op* r, struct

 			      * janakj: AVPs are zero terminated too so this is not problem either

 			      */

 			backup=left->s[left->len];

-			left->s[left->len]='\0';

+			if (backup) left->s[left->len]='\0';

 			if (rtype == AVP_ST || rtype == SELECT_ST) {

 				     /* For AVPs we need to compile the RE on the fly */

 				re=(regex_t*)pkg_malloc(sizeof(regex_t));

@@ -686,7 +686,7 @@ inline static int comp_str(int op, str* left, int rtype, union exp_op* r, struct

 			} else {

 				ret=(regexec(r->re, left->s, 0, 0, 0)==0);

 			}

-			left->s[left->len] = backup;

+			if (backup) left->s[left->len] = backup;

 			break;

 		default:

 			LOG(L_CRIT, "BUG: comp_str: unknown op %d\n", op);

@@ -814,9 +814,10 @@ inline static int comp_select(int op, select_t* sel, int rtype, union exp_op* r,

 	ret = run_select(&val, sel, msg);

 	if (ret < 0) return -1;

 	if (ret > 0) return 0;

+	if (val.len==0) return 0;

 	switch(op) {

-	case NO_OP: return (val.len>0);

+	case NO_OP: return 1;

 	case BINOR_OP:

 	case BINAND_OP:

 		ERR("Binary operators cannot be used with string selects\n");