ecpg: fix more minor mishandling of bad input in preprocessor.

tglsfdc · tglsfdc · commit 1fed234f9faf · 2024-10-17T15:28:32.000-04:00
Don't get confused by an unmatched right brace in the input. (Previously, this led to discarding information about file-level variables and then possibly crashing.) Detect, rather than crash on, an attempt to index into a non-array variable. As before, in the absence of field complaints I'm not too excited about back-patching these. Per valgrind testing by Alexander Lakhin. Discussion: https://postgr.es/m/a239aec2-6c79-5fc9-9272-cea41158a360@gmail.com
diff --git a/src/interfaces/ecpg/preproc/ecpg.trailer b/src/interfaces/ecpg/preproc/ecpg.trailer
@@ -43,12 +43,15 @@ statement: ecpgstart at toplevel_stmt ';'
 	}
 	| '}'
 	{
-		remove_typedefs(braces_open);
-		remove_variables(braces_open--);
-		if (braces_open == 0)
+		if (braces_open > 0)
 		{
-			free(current_function);
-			current_function = NULL;
+			remove_typedefs(braces_open);
+			remove_variables(braces_open);
+			if (--braces_open == 0)
+			{
+				free(current_function);
+				current_function = NULL;
+			}
 		}
 		fputs("}", base_yyout);
 	}
diff --git a/src/interfaces/ecpg/preproc/variable.c b/src/interfaces/ecpg/preproc/variable.c
@@ -233,7 +233,8 @@ find_variable(const char *name)
 				p = find_simple(name);
 				if (p == NULL)
 					mmfatal(PARSE_ERROR, "variable \"%s\" is not declared", name);
-
+				if (p->type->type != ECPGt_array)
+					mmfatal(PARSE_ERROR, "variable \"%s\" is not a pointer", name);
 				*next = c;
 				switch (p->type->u.element->type)
 				{

Original file line number	Diff line number	Diff line change
`@@ -43,12 +43,15 @@ statement: ecpgstart at toplevel_stmt ';'`
`43`	`43`	`}`
`44`	`44`	`\| '}'`
`45`	`45`	`{`
`46`		`- remove_typedefs(braces_open);`
`47`		`- remove_variables(braces_open--);`
`48`		`- if (braces_open == 0)`
	`46`	`+ if (braces_open > 0)`
`49`	`47`	`{`
`50`		`- free(current_function);`
`51`		`- current_function = NULL;`
	`48`	`+ remove_typedefs(braces_open);`
	`49`	`+ remove_variables(braces_open);`
	`50`	`+ if (--braces_open == 0)`
	`51`	`+ {`
	`52`	`+ free(current_function);`
	`53`	`+ current_function = NULL;`
	`54`	`+ }`
`52`	`55`	`}`
`53`	`56`	`fputs("}", base_yyout);`
`54`	`57`	`}`