From 2add4235ef674988948155f9a8f60a8c7b09bcff Mon Sep 17 00:00:00 2001

From: Florian Weimer <fweimer@redhat.com>

Date: Thu, 16 Jul 2020 17:31:20 +0200

Subject: [PATCH 08/11] gshadow: Implement fgetsgent_r using __nss_fgetent_r

 (bug 20338)

Tested-by: Carlos O'Donell <carlos@redhat.com>

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

---

 gshadow/Makefile          |   2 +-

 gshadow/fgetsgent_r.c     |  41 ++--------

 gshadow/tst-fgetsgent_r.c | 191 ++++++++++++++++++++++++++++++++++++++++++++++

 3 files changed, 198 insertions(+), 36 deletions(-)

 create mode 100644 gshadow/tst-fgetsgent_r.c

diff -rupN a/gshadow/Makefile b/gshadow/Makefile

--- a/gshadow/Makefile	2018-08-01 01:10:47.000000000 -0400

+++ b/gshadow/Makefile	2020-09-14 18:00:57.167145887 -0400

@@ -26,7 +26,7 @@ headers		= gshadow.h

 routines	= getsgent getsgnam sgetsgent fgetsgent putsgent \

 		  getsgent_r getsgnam_r sgetsgent_r fgetsgent_r

-tests = tst-gshadow tst-putsgent

+tests = tst-gshadow tst-putsgent tst-fgetsgent_r

 CFLAGS-getsgent_r.c += -fexceptions

 CFLAGS-getsgent.c += -fexceptions

diff -rupN a/gshadow/fgetsgent_r.c b/gshadow/fgetsgent_r.c

--- a/gshadow/fgetsgent_r.c	2018-08-01 01:10:47.000000000 -0400

+++ b/gshadow/fgetsgent_r.c	2020-09-14 18:45:59.189353065 -0400

@@ -36,40 +36,11 @@ int

 __fgetsgent_r (FILE *stream, struct sgrp *resbuf, char *buffer, size_t buflen,

 	       struct sgrp **result)

 {

-  char *p;

-

-  _IO_flockfile (stream);

-  do

-    {

-      buffer[buflen - 1] = '\xff';

-      p = fgets_unlocked (buffer, buflen, stream);

-      if (p == NULL && feof_unlocked (stream))

-	{

-	  _IO_funlockfile (stream);

-	  *result = NULL;

-	  __set_errno (ENOENT);

-	  return errno;

-	}

-      if (p == NULL || buffer[buflen - 1] != '\xff')

-	{

-	  _IO_funlockfile (stream);

-	  *result = NULL;

-	  __set_errno (ERANGE);

-	  return errno;

-	}

-

-      /* Skip leading blanks.  */

-      while (isspace (*p))

-	++p;

-    } while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines.  */

-	     /* Parse the line.  If it is invalid, loop to

-		get the next line of the file to parse.  */

-	     ! parse_line (buffer, (void *) resbuf, (void *) buffer, buflen,

-			   &errno));

-

-  _IO_funlockfile (stream);

-

-  *result = resbuf;

-  return 0;

+  int ret = __nss_fgetent_r (stream, resbuf, buffer, buflen, parse_line);

+  if (ret == 0)

+    *result = resbuf;

+  else

+    *result = NULL;

+  return ret;

 }

 weak_alias (__fgetsgent_r, fgetsgent_r)

diff -rupN a/gshadow/tst-fgetsgent_r.c b/gshadow/tst-fgetsgent_r.c

--- a/gshadow/tst-fgetsgent_r.c	1969-12-31 19:00:00.000000000 -0500

+++ b/gshadow/tst-fgetsgent_r.c	2020-09-14 18:00:57.174146151 -0400

@@ -0,0 +1,191 @@

+/* Test for fgetsgent_r and buffer sizes.

+   Copyright (C) 2020 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library 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

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <https://www.gnu.org/licenses/>.  */

+

+#include <array_length.h>

+#include <errno.h>

+#include <gshadow.h>

+#include <stdbool.h>

+#include <stdlib.h>

+#include <support/check.h>

+#include <support/support.h>

+#include <support/temp_file.h>

+#include <support/xmemstream.h>

+#include <support/xstdio.h>

+

+/* Turn a parsed struct back into a line string.  The returned string

+   should be freed.  */

+static char *

+format_ent (const struct sgrp *e)

+{

+  struct xmemstream stream;

+  xopen_memstream (&stream);

+  TEST_COMPARE (putsgent (e, stream.out), 0);

+  xfclose_memstream (&stream);

+  return stream.buffer;

+}

+

+/* An entry in the input file along with the expected output.  */

+struct input

+{

+  const char *line;		/* Line in the file.  */

+  const char *expected;		/* Expected output.  NULL if skipped.  */

+};

+

+const struct input inputs[] =

+  {

+   /* Regular entries.  */

+   { "g1:x1::\n", "g1:x1::\n" },

+   { "g2:x2:a1:\n", "g2:x2:a1:\n" },

+   { "g3:x3:a2:u1\n", "g3:x3:a2:u1\n" },

+   { "g4:x4:a3,a4:u2,u3,u4\n", "g4:x4:a3,a4:u2,u3,u4\n" },

+

+   /* Comments and empty lines.  */

+   { "\n", NULL },

+   { " \n", NULL },

+   { "\t\n", NULL },

+   { "#g:x::\n", NULL },

+   { " #g:x::\n", NULL },

+   { "\t#g:x::\n", NULL },

+   { " \t#g:x::\n", NULL },

+

+   /* Marker for synchronization.  */

+   { "g5:x5::\n", "g5:x5::\n" },

+

+   /* Leading whitespace.  */

+   { " g6:x6::\n", "g6:x6::\n" },

+   { "\tg7:x7::\n", "g7:x7::\n" },

+

+   /* This is expected to trigger buffer exhaustion during parsing

+      (bug 20338).  */

+   {

+    "g8:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx:u5,u6,u7,u8,u9:\n",

+    "g8:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx:u5,u6,u7,u8,u9:\n",

+   },

+   {

+    "g9:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx::a5,a6,a7,a8,a9,a10\n",

+    "g9:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx::a5,a6,a7,a8,a9,a10\n",

+   },

+  };

+

+/* Writes the test data to a temporary file and returns its name.  The

+   returned pointer should be freed.  */

+static char *

+create_test_file (void)

+{

+  char *path;

+  int fd = create_temp_file ("tst-fgetsgent_r-", &path);

+  FILE *fp = fdopen (fd, "w");

+  TEST_VERIFY_EXIT (fp != NULL);

+

+  for (size_t i = 0; i < array_length (inputs); ++i)

+    fputs (inputs[i].line, fp);

+

+  xfclose (fp);

+  return path;

+}

+

+/* Read the test file with the indicated start buffer size.  Return

+   true if the buffer size had to be increased during reading.  */

+static bool

+run_test (const char *path, size_t buffer_size)

+{

+  bool resized = false;

+  FILE *fp = xfopen (path, "r");

+

+  /* This avoids repeated lseek system calls (bug 26257).  */

+  TEST_COMPARE (fseeko64 (fp, 0, SEEK_SET), 0);

+

+  size_t i = 0;

+  while (true)

+    {

+      /* Skip over unused expected entries.  */

+      while (i < array_length (inputs) && inputs[i].expected == NULL)

+	++i;

+

+      /* Store the data on the heap, to help valgrind to detect

+	 invalid accesses.  */

+      struct sgrp *result_storage = xmalloc (sizeof (*result_storage));

+      char *buffer = xmalloc (buffer_size);

+      struct sgrp **result_pointer_storage

+	= xmalloc (sizeof (*result_pointer_storage));

+

+      int ret = fgetsgent_r (fp, result_storage, buffer, buffer_size,

+			     result_pointer_storage);

+      if (ret == 0)

+	{

+	  TEST_VERIFY (*result_pointer_storage != NULL);

+	  TEST_VERIFY (i < array_length (inputs));

+	  if (*result_pointer_storage != NULL

+	      && i < array_length (inputs))

+	    {

+	      char * actual = format_ent (*result_pointer_storage);

+	      TEST_COMPARE_STRING (inputs[i].expected, actual);

+	      free (actual);

+	      ++i;

+	    }

+	  else

+	    break;

+	}

+      else

+	{

+	  TEST_VERIFY (*result_pointer_storage == NULL);

+	  TEST_COMPARE (ret, errno);

+

+	  if (ret == ENOENT)

+	    {

+	      TEST_COMPARE (i, array_length (inputs));

+	      free (result_pointer_storage);

+	      free (buffer);

+	      free (result_storage);

+	      break;

+	    }

+	  else if (ret == ERANGE)

+	    {

+	      resized = true;

+	      ++buffer_size;

+	    }

+	  else

+	    FAIL_EXIT1 ("read failure: %m");

+	}

+

+      free (result_pointer_storage);

+      free (buffer);

+      free (result_storage);

+    }

+

+  return resized;

+}

+

+static int

+do_test (void)

+{

+  char *path = create_test_file ();

+

+  for (size_t buffer_size = 3; ; ++buffer_size)

+    {

+      bool resized = run_test (path, buffer_size);

+      if (!resized)

+	break;

+    }

+

+  free (path);

+

+  return 0;

+}

+

+#include <support/test-driver.c>