From 0e95414ab2705649cea323115a618b558c30397f Mon Sep 17 00:00:00 2001
From: Tomas Heinrich <theinric@redhat.com>
Date: Wed, 2 Jul 2014 17:01:09 +0200
Subject: [PATCH] bugfix: prevent division by zero

The result is set to 0 in that case. Might be better to do something
else in the future, but at least it'll stop crashing for now.
---
 grammar/rainerscript.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/grammar/rainerscript.c b/grammar/rainerscript.c
index 25d9c9a..c3365b1 100644
--- a/grammar/rainerscript.c
+++ b/grammar/rainerscript.c
@@ -1560,6 +1560,17 @@ evalStrArrayCmp(es_str_t *estr_l, struct cnfarray* ar, int cmpop)
 	ret->d.n = var2Number(&l, &convok_l) x var2Number(&r, &convok_r); \
 	FREE_BOTH_RET
 
+#define COMP_NUM_BINOP_DIV(x) \
+	cnfexprEval(expr->l, &l, usrptr); \
+	cnfexprEval(expr->r, &r, usrptr); \
+	ret->datatype = 'N'; \
+	if((ret->d.n = var2Number(&r, &convok_r)) == 0) { \
+		/* division by zero */ \
+	} else { \
+		ret->d.n = var2Number(&l, &convok_l) x ret->d.n; \
+	} \
+	FREE_BOTH_RET
+
 /* NOTE: array as right-hand argument MUST be handled by user */
 #define PREP_TWO_STRINGS \
 		cnfexprEval(expr->l, &l, usrptr); \
@@ -1965,10 +1976,10 @@ cnfexprEval(struct cnfexpr *expr, struct var *ret, void* usrptr)
 		COMP_NUM_BINOP(*);
 		break;
 	case '/':
-		COMP_NUM_BINOP(/);
+		COMP_NUM_BINOP_DIV(/);
 		break;
 	case '%':
-		COMP_NUM_BINOP(%);
+		COMP_NUM_BINOP_DIV(%);
 		break;
 	case 'M':
 		cnfexprEval(expr->r, &r, usrptr);
@@ -2907,13 +2918,23 @@ cnfexprOptimize(struct cnfexpr *expr)
 	case '/':
 		if(getConstNumber(expr, &ln, &rn))  {
 			expr->nodetype = 'N';
-			((struct cnfnumval*)expr)->val = ln / rn;
+			if(rn == 0) {
+				/* division by zero */
+				((struct cnfnumval*)expr)->val = 0;
+			} else {
+				((struct cnfnumval*)expr)->val = ln / rn;
+			}
 		}
 		break;
 	case '%':
 		if(getConstNumber(expr, &ln, &rn))  {
 			expr->nodetype = 'N';
-			((struct cnfnumval*)expr)->val = ln % rn;
+			if(rn == 0) {
+				/* division by zero */
+				((struct cnfnumval*)expr)->val = 0;
+			} else {
+				((struct cnfnumval*)expr)->val = ln % rn;
+			}
 		}
 		break;
 	case CMP_NE:
-- 
1.9.3