checkpolicy: use YYerror only when available

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 <[email protected]> Acked-by: James Carter <[email protected]>
SELinuxProject · Mar 27, 2024 · ca77c59 · ca77c59
1 parent 6e2f703
commit ca77c59
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diff --git a/checkpolicy/policy_parse.y b/checkpolicy/policy_parse.y
@@ -153,6 +153,7 @@ 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/checkpolicy/policy_scan.l b/checkpolicy/policy_scan.l
@@ -308,7 +308,14 @@ 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)
 {