From ca77c5929905216fb1c0f70ed632664aa3ec85a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Fri, 22 Mar 2024 15:50:48 +0100
Subject: [PATCH] checkpolicy: use YYerror only when available
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The special error value YYerror is only available since bison 3.6
(released 2020).  For example the version used by oss-fuzz does not
support it.

Use a special token in case YYerror is not available.  Only downside is
a duplicate error message, one from the manual yyerror() call and one
from within bison for the unexpected special token (which would be
omitted by using YYerror).

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
---
 policy_parse.y | 1 +
 policy_scan.l  | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/policy_parse.y b/policy_parse.y
index e0103502..1b275ebc 100644
--- a/policy_parse.y
+++ b/policy_parse.y
@@ -155,6 +155,7 @@ typedef int (* require_func_t)(int pass);
 %token FILESYSTEM
 %token DEFAULT_USER DEFAULT_ROLE DEFAULT_TYPE DEFAULT_RANGE
 %token LOW_HIGH LOW HIGH GLBLUB
+%token INVALID_CHAR
 
 %left OR
 %left XOR
diff --git a/policy_scan.l b/policy_scan.l
index 1926129c..c4d8e937 100644
--- a/policy_scan.l
+++ b/policy_scan.l
@@ -310,7 +310,14 @@ GLBLUB				{ return(GLBLUB); }
 "]" |
 "~" |
 "*"				{ return(yytext[0]); } 
-.                               { yyerror("unrecognized character"); return YYerror; }
+.                               { yyerror("unrecognized character");
+/* Available since bison 3.6, avoids duplicate error message */
+#ifdef YYerror
+				  return YYerror;
+#else
+				  return INVALID_CHAR;
+#endif
+				}
 %%
 int yyerror(const char *msg)
 {
-- 
2.33.0