From 4a3f20bceee7cef125f9a88bab32439f9fe4f773 Mon Sep 17 00:00:00 2001
From: Neven Sajko <nsajko@gmail.com>
Date: Thu, 22 Aug 2019 11:28:53 +0000
Subject: cmd/yacc: do not create an out of bounds pointer

An out of bounds pointer/array index being created is an error in
standard C.

Updates #313

Change-Id: I7108fcde1a8e03017e9ab852adb737940489c827
---
 src/cmd/yacc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/cmd/yacc.c')

diff --git a/src/cmd/yacc.c b/src/cmd/yacc.c
index 32990f62..5db36d04 100644
--- a/src/cmd/yacc.c
+++ b/src/cmd/yacc.c
@@ -2819,8 +2819,9 @@ stin(int i)
 	for(n = -maxoff; n < ACTSIZE; n++) {
 		flag = 0;
 		for(r = q1; r < q2; r += 2) {
-			if((s = *r + n + amem) < amem)
+			if(*r + n < 0)
 				goto nextn;
+			s = *r + n + amem;
 			if(*s == 0)
 				flag++;
 			else
-- 
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