[LTP] [PATCH v2] readdir: delete readdir02

[Li Wang]

Issue:
  On ppc64le and aarch64, when testing in NFS mountpoint, test
  process receives SIGSEGV when calling readdir on a DIR which
  has just been closed by closedir().

  Unfortunately, ltp/readdir02.c handles SIGSEGV. This makes it
  hits SIGSEGV again in its cleanup function. So readdir02 hangs
  there hitting SEGV endlessly.

That's because a DIR * is NOT a file descriptor. It's memory
allocated by opendir() that contains libc internal information
about the directory. closedir(test_dir) frees any memory associated
with the open directory pointer test_dir.

To then pass the freed dir pointer to readdir() is a use-after-free.
It probably won't return EBADF, it will dereference freed memory
and whatever happens after that is undefined.

And, considering LTP does cover the EBADF for getents() syscalls
getdents02 test already, here let's remove this readdir02 directly.

Reported-by: Xiong Zhou <xzhou@redhat.com>
Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Scott Mayhew <smayhew@redhat.com>
Cc: Cyril Hrubis <chrubis@suse.cz>
---
 testcases/kernel/syscalls/readdir/readdir02.c | 142 ------------------
 1 file changed, 142 deletions(-)
 delete mode 100644 testcases/kernel/syscalls/readdir/readdir02.c

diff --git a/testcases/kernel/syscalls/readdir/readdir02.c b/testcases/kernel/syscalls/readdir/readdir02.c
deleted file mode 100644
index 3f3151f6a..000000000
--- a/testcases/kernel/syscalls/readdir/readdir02.c
+++ /dev/null
@@ -1,142 +0,0 @@
-/*
- * Copyright (C) Bull S.A. 2001
- * Copyright (c) International Business Machines  Corp., 2001
- *
- * This program is free software;  you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY;  without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
- * the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program;  if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/*
- * DESCRIPTION
- *      Try to readdir with Invalid directory stream descriptor dir.
- *
- * ALGORITHM
- *      loop if that option was specified
- *      call readdir() with an invalid file descriptor
- *      check the errno value
- *        issue a PASS message if we get EBADF - errno 9
- *      otherwise, the tests fails
- *        issue a FAIL message
- *        call cleanup
- *
- * NOTE
- *	The POSIX standard says:
- *	  The readdir() function may fail if:
- *	  [EBADF] The dirp argument does not refer to an open directory stream.
- *	  (Note that readdir() is not _required_ to fail in this case.)
- *
- * HISTORY
- *      04/2002 - Written by Jacky Malcles
- *
- *      06/2003 - Added code to catch SIGSEGV and return TCONF.
- *		Robbie Williamson<robbiew@us.ibm.com>
- */
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <dirent.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <signal.h>
-
-#include "test.h"
-
-static void setup(void);
-static void cleanup(void);
-
-char *TCID = "readdir02";
-int TST_TOTAL = 1;
-
-int main(int ac, char **av)
-{
-	int lc;
-	DIR *test_dir;
-	struct dirent *dptr;
-
-	tst_parse_opts(ac, av, NULL, NULL);
-
-	setup();
-
-	for (lc = 0; TEST_LOOPING(lc); lc++) {
-
-		tst_count = 0;
-
-		if ((test_dir = opendir(".")) == NULL) {
-			tst_resm(TFAIL, "opendir(\".\") Failed, errno=%d : %s",
-				 errno, strerror(errno));
-		} else {
-			if (closedir(test_dir) < 0) {
-				tst_resm(TFAIL,
-					 "closedir(\".\") Failed, errno=%d : %s",
-					 errno, strerror(errno));
-			} else {
-				dptr = readdir(test_dir);
-				switch (errno) {
-				case EBADF:
-					tst_resm(TPASS,
-						 "expected failure - errno = %d : %s",
-						 errno, strerror(errno));
-					break;
-				default:
-					if (dptr != NULL) {
-						tst_brkm(TFAIL, cleanup,
-							 "call failed with an "
-							 "unexpected error - %d : %s",
-							 errno,
-							 strerror(errno));
-					} else {
-						tst_resm(TINFO,
-							 "readdir() is not _required_ to fail, "
-							 "errno = %d  ", errno);
-					}
-				}
-			}
-
-		}
-
-	}
-
-	cleanup();
-	tst_exit();
-}
-
-static void sigsegv_handler(int sig)
-{
-	tst_resm(TCONF,
-		 "This system's implementation of closedir() will not allow this test to execute properly.");
-	cleanup();
-}
-
-static void setup(void)
-{
-	struct sigaction act;
-
-	tst_sig(NOFORK, DEF_HANDLER, cleanup);
-
-	act.sa_handler = sigsegv_handler;
-	act.sa_flags = 0;
-	sigemptyset(&act.sa_mask);
-	sigaction(SIGSEGV, &act, NULL);
-
-	TEST_PAUSE;
-
-	tst_tmpdir();
-}
-
-static void cleanup(void)
-{
-	tst_rmdir();
-}
-- 
2.19.1