parser: fix leaking disconnected paths when merging

Valgrind showed that the disconnected paths variables were leaking
during the merge. That happened because flagvals did not implement a
destructor freeing the variables, so they leaked. flagvals cannot
implement a destructor, because that would make it a non-trivial union
member and parser_yacc.y would not compile. This patch implements a
"clear" function that is supposed to act as the destructor.

$ /usr/bin/valgrind --leak-check=full --error-exitcode=151 ../apparmor_parser -Q -I simple_tests/ -M ./features_files/features.all flags_ok_disconnected_ipc15.sd
...
==3708747== 5 bytes in 1 blocks are definitely lost in loss record 1 of 11
==3708747==    at 0x4846828: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==3708747==    by 0x492E35E: strdup (strdup.c:42)
==3708747==    by 0x14C74E: set_disconnected_path (profile.h:188)
==3708747==    by 0x14C74E: flagvals::init(char const*) (profile.h:223)
==3708747==    by 0x14859B: yyparse() (parser_yacc.y:592)
==3708747==    by 0x141A99: process_profile(int, aa_kernel_interface*, char const*, aa_policy_cache*) (parser_main.c:1187)
==3708747==    by 0x135421: main (parser_main.c:1771)
...

Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>

parser/parser_yacc.y

@@ -577,6 +577,7 @@ flags:	opt_flags TOK_OPENPAREN flagvals TOK_CLOSEPAREN
 flagvals:	flagvals flagval
 	{
 		$1.merge($2);
+		$2.clear();
 		$$ = $1;
 	};
 

parser/profile.cc

@@ -78,6 +78,7 @@ void ProfileList::dump_profile_names(bool children)
 Profile::~Profile()
 {
 	hat_table.clear();
+	flags.clear();
 	free_cod_entries(entries);
 	free_cond_entry_list(xattrs);
 
@@ -97,10 +98,6 @@ Profile::~Profile()
 		free(name);
 	if (attachment)
 		free(attachment);
-	if (flags.disconnected_path)
-		free(flags.disconnected_path);
-	if (flags.disconnected_ipc)
-		free(flags.disconnected_ipc);
 	if (ns)
 		free(ns);
 	for (int i = (AA_EXEC_LOCAL >> 10) + 1; i < AA_EXEC_COUNT; i++)

parser/profile.h

@@ -175,6 +175,12 @@ public:
 		signal = 0;
 		error = 0;
 	}
+
+	void clear(void) {
+		free(disconnected_path);
+		free(disconnected_ipc);
+	}
+
 	void init(const char *str)
 	{
 		init();
@@ -301,7 +307,7 @@ public:
 				}
 				// same ignore rhs.disconnect_path
 			} else {
-				disconnected_path = rhs.disconnected_path;
+				disconnected_path = strdup(rhs.disconnected_path);
 			}
 		}
 		if (rhs.disconnected_ipc) {
@@ -311,7 +317,7 @@ public:
 				}
 				// same so do nothing
 			} else {
-				disconnected_ipc = rhs.disconnected_ipc;
+				disconnected_ipc = strdup(rhs.disconnected_ipc);
 			}
 		}
 		if (rhs.signal) {