libcsupport: Avoid TOCTOU and format errors

cpukit/libcsupport/src/pwdgrp.c

@@ -39,40 +39,42 @@
 
 static pthread_once_t pwdgrp_once = PTHREAD_ONCE_INIT;
 
+static void init_file(const char *name, const char *content)
+{
+  FILE *fp = fopen(name, "wx");
+
+  if (fp != NULL) {
+    fputs(content, fp);
+    fclose(fp);
+  }
+}
+
 /**
  *  Initialize useable but dummy databases
  */
 static void pwdgrp_init(void)
 {
-  FILE *fp;
-
   mkdir("/etc", 0777);
 
   /*
    *  Initialize /etc/passwd
    */
-  if ((fp = fopen("/etc/passwd", "r")) != NULL) {
-    fclose(fp);
-  }
-  else if ((fp = fopen("/etc/passwd", "w")) != NULL) {
-    fprintf(fp, "root:*:0:0:root::/:/bin/sh\n"
-                 "rtems:*:1:1:RTEMS Application::/:/bin/sh\n"
-                 "tty:!:2:2:tty owner::/:/bin/false\n" );
-    fclose(fp);
-  }
+  init_file(
+    "/etc/passwd",
+    "root:*:0:0:root::/:/bin/sh\n"
+      "rtems:*:1:1:RTEMS Application::/:/bin/sh\n"
+      "tty:!:2:2:tty owner::/:/bin/false\n"
+  );
 
   /*
    *  Initialize /etc/group
    */
-  if ((fp = fopen("/etc/group", "r")) != NULL) {
-    fclose(fp);
-  }
-  else if ((fp = fopen("/etc/group", "w")) != NULL) {
-    fprintf( fp, "root:x:0:root\n"
-                 "rtems:x:1:rtems\n"
-                 "tty:x:2:tty\n" );
-    fclose(fp);
-  }
+  init_file(
+    "/etc/group",
+    "root:x:0:root\n"
+      "rtems:x:1:rtems\n"
+      "tty:x:2:tty\n"
+  );
 }
 
 void _libcsupport_pwdgrp_init(void)

testsuites/libtests/Makefile.am

@@ -1,6 +1,7 @@
 ACLOCAL_AMFLAGS = -I ../aclocal
 
 _SUBDIRS = POSIX
+_SUBDIRS += pwdgrp01
 _SUBDIRS += crypt01
 _SUBDIRS += sha
 _SUBDIRS += i2c01

testsuites/libtests/configure.ac

@@ -66,6 +66,7 @@ AS_IF([test x"$HAVE_LIBDL" = x"yes"],[
 
 # Explicitly list all Makefiles here
 AC_CONFIG_FILES([Makefile
+pwdgrp01/Makefile
 crypt01/Makefile
 sha/Makefile
 i2c01/Makefile

testsuites/libtests/pwdgrp01/Makefile.am

@@ -0,0 +1,19 @@
+rtems_tests_PROGRAMS = pwdgrp01
+pwdgrp01_SOURCES = init.c
+
+dist_rtems_tests_DATA = pwdgrp01.scn pwdgrp01.doc
+
+include $(RTEMS_ROOT)/make/custom/@RTEMS_BSP@.cfg
+include $(top_srcdir)/../automake/compile.am
+include $(top_srcdir)/../automake/leaf.am
+
+AM_CPPFLAGS += -I$(top_srcdir)/../support/include
+
+LINK_OBJS = $(pwdgrp01_OBJECTS)
+LINK_LIBS = $(pwdgrp01_LDLIBS)
+
+pwdgrp01$(EXEEXT): $(pwdgrp01_OBJECTS) $(pwdgrp01_DEPENDENCIES)
+	@rm -f pwdgrp01$(EXEEXT)
+	$(make-exe)
+
+include $(top_srcdir)/../automake/local.am

testsuites/libtests/pwdgrp01/init.c

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <sys/stat.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+
+#include "tmacros.h"
+
+const char rtems_test_name[] = "PWDGRP 1";
+
+static void create_file(const char *name, const char *content)
+{
+  FILE *fp;
+  int rv;
+
+  fp = fopen(name, "wx");
+  rtems_test_assert(fp != NULL);
+
+  rv = fputs(content, fp);
+  rtems_test_assert(rv == 0);
+
+  rv = fclose(fp);
+  rtems_test_assert(rv == 0);
+}
+
+static void assert_pwd(struct passwd *pwd)
+{
+  rtems_test_assert(strcmp(pwd->pw_name, "moop") == 0);
+  rtems_test_assert(strcmp(pwd->pw_passwd, "foo") == 0);
+  rtems_test_assert(pwd->pw_uid == 1);
+  rtems_test_assert(pwd->pw_gid == 3);
+  rtems_test_assert(strcmp(pwd->pw_comment, "blob") == 0);
+  rtems_test_assert(strcmp(pwd->pw_gecos, "a") == 0);
+  rtems_test_assert(strcmp(pwd->pw_dir, "b") == 0);
+  rtems_test_assert(strcmp(pwd->pw_shell, "c") == 0);
+}
+
+static void assert_grp(struct group *grp)
+{
+  rtems_test_assert(strcmp(grp->gr_name, "blub") == 0);
+  rtems_test_assert(strcmp(grp->gr_passwd, "bar") == 0);
+  rtems_test_assert(grp->gr_gid == 3);
+  rtems_test_assert(strcmp(grp->gr_mem[0], "moop") == 0);
+  rtems_test_assert(grp->gr_mem[1] == NULL);
+}
+
+static void test(void)
+{
+  int rv;
+  struct passwd pwd;
+  struct group grp;
+  struct passwd *pwd_res;
+  struct group *grp_res;
+  char buf[256];
+
+  rv = mkdir("/etc", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+  rtems_test_assert(rv == 0);
+
+  create_file(
+    "/etc/passwd",
+    "moop:foo:1:3:blob:a:b:c\n"
+  );
+
+  create_file(
+    "/etc/group",
+    "blub:bar:3:moop\n"
+  );
+
+  memset(&pwd, 0xff, sizeof(pwd));
+  rv = getpwnam_r("moop", &pwd, &buf[0], sizeof(buf), &pwd_res);
+  rtems_test_assert(rv == 0);
+  rtems_test_assert(&pwd == pwd_res);
+  assert_pwd(pwd_res);
+
+  memset(&pwd, 0xff, sizeof(pwd));
+  rv = getpwuid_r(1, &pwd, &buf[0], sizeof(buf), &pwd_res);
+  rtems_test_assert(rv == 0);
+  rtems_test_assert(&pwd == pwd_res);
+  assert_pwd(pwd_res);
+
+  memset(&grp, 0xff, sizeof(grp));
+  rv = getgrnam_r("blub", &grp, &buf[0], sizeof(buf), &grp_res);
+  rtems_test_assert(rv == 0);
+  rtems_test_assert(&grp == grp_res);
+  assert_grp(grp_res);
+
+  memset(&grp, 0xff, sizeof(grp));
+  rv = getgrgid_r(3, &grp, &buf[0], sizeof(buf), &grp_res);
+  rtems_test_assert(rv == 0);
+  rtems_test_assert(&grp == grp_res);
+  assert_grp(grp_res);
+}
+
+static void Init(rtems_task_argument arg)
+{
+  TEST_BEGIN();
+
+  test();
+
+  TEST_END();
+  rtems_test_exit(0);
+}
+
+#define CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+
+#define CONFIGURE_USE_IMFS_AS_BASE_FILESYSTEM
+
+#define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 4
+
+#define CONFIGURE_MAXIMUM_TASKS 1
+
+#define CONFIGURE_INITIAL_EXTENSIONS RTEMS_TEST_INITIAL_EXTENSION
+
+#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
+
+#define CONFIGURE_INIT
+
+#include <rtems/confdefs.h>

testsuites/libtests/pwdgrp01/pwdgrp01.doc

@@ -0,0 +1,19 @@
+This file describes the directives and concepts tested by this test set.
+
+test set name: pwdgrp01
+
+directives:
+
+  - _libcsupport_pwdgrp_init
+  - getpwnam_r
+  - getpwuid_r
+  - getgrnam_r
+  - getgrgid_r
+
+concepts:
+
+  - Ensure that _libcsupport_pwdgrp_init() doesn't overwrite existing files.
+  - Ensure that getpwnam_r() and getpwuid_r() return the values specified by
+    custom /etc/passwd.
+  - Ensure that getgrnam_r() and getgrgid_r() return the values specified by
+    custom /etc/group.

testsuites/libtests/pwdgrp01/pwdgrp01.scn

@@ -0,0 +1,2 @@
+*** BEGIN OF TEST PWDGRP 1 ***
+*** END OF TEST PWDGRP 1 ***