Avoid insecure usage of tmpnam in tests.

Various glibc testcases use tmpnam in ways subject to race conditions
(generate a temporary file name, then later open that file without
O_EXCL).

This patch fixes those tests to use mkstemp - generally a minimal
local fix to use mkstemp instead of tmpnam, rather than a larger fix
to use other testsuite infrastructure for temporary files.  The
unchanged use of tmpnam in posix/wordexp-test.c would fail safe in the
event of a race (it's generating a name for use with mkdir rather than
for a file to be opened for writing).

Tested for x86_64.

	* grp/tst_fgetgrent.c: Include <unistd.h>.
	(main): Use mkstemp instead of tmpnam.
	* io/test-utime.c (main): Likewise.
	* posix/annexc.c (macrofile): Change to modifiable array.
	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
	macrofile here.
	* posix/bug-getopt1.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt2.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt3.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt4.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt5.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* stdio-common/bug7.c: Include <stdlib.h> and <unistd.h>.
	(main): Use mkstemp instead of tmpnam.
	* stdio-common/tst-fdopen.c: Include <stdlib.h>.
	(main): Use mkstemp instead of tmpnam.
	* stdio-common/tst-ungetc.c: Include <stdlib.h>.
	(main): use mkstemp instead of tmpnam.
	* stdlib/isomac.c (macrofile): Change to modifiable array.
	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
	macrofile here.

ChangeLog

@@ -1,3 +1,35 @@
+2018-07-18  Joseph Myers  <joseph@codesourcery.com>
+
+	* grp/tst_fgetgrent.c: Include <unistd.h>.
+	(main): Use mkstemp instead of tmpnam.
+	* io/test-utime.c (main): Likewise.
+	* posix/annexc.c (macrofile): Change to modifiable array.
+	(main): Remove macrofile here.
+	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
+	macrofile here.
+	(check_header): Do not remove macrofile here.
+	* posix/bug-getopt1.c: Include <stdlib.h>.
+	(do_test): Use mkstemp instead of tmpnam.
+	* posix/bug-getopt2.c: Include <stdlib.h>.
+	(do_test): Use mkstemp instead of tmpnam.
+	* posix/bug-getopt3.c: Include <stdlib.h>.
+	(do_test): Use mkstemp instead of tmpnam.
+	* posix/bug-getopt4.c: Include <stdlib.h>.
+	(do_test): Use mkstemp instead of tmpnam.
+	* posix/bug-getopt5.c: Include <stdlib.h>.
+	(do_test): Use mkstemp instead of tmpnam.
+	* stdio-common/bug7.c: Include <stdlib.h> and <unistd.h>.
+	(main): Use mkstemp instead of tmpnam.
+	* stdio-common/tst-fdopen.c: Include <stdlib.h>.
+	(main): Use mkstemp instead of tmpnam.
+	* stdio-common/tst-ungetc.c: Include <stdlib.h>.
+	(main): use mkstemp instead of tmpnam.
+	* stdlib/isomac.c (macrofile): Change to modifiable array.
+	(main): Remove macrofile here.
+	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
+	macrofile here.
+	(check_header): Do not remove macrofile here.
+
 2018-07-18  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* manual/tunables.texi: Document glibc.tune.x86_ibt and

grp/tst_fgetgrent.c

@@ -21,6 +21,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
+#include <unistd.h>
 
 static int errors;
 
@@ -99,7 +100,14 @@ test_fgetgrent (const char *filename)
 int
 main (int argc, char *argv[])
 {
-  char *file = tmpnam (NULL);
+  char file[] = "/tmp/tst_fgetgrent.XXXXXX";
+  int fd = mkstemp (file);
+  if (fd == -1)
+    {
+      printf ("mkstemp failed: %m\n");
+      return 1;
+    }
+  close (fd);
   int i = 0;
 
   if (argc > 1)

io/test-utime.c

@@ -27,23 +27,17 @@
 int
 main (int argc, char *argv[])
 {
-  char file[L_tmpnam];
+  char file[] = "/tmp/test-utime.XXXXXX";
   struct utimbuf ut;
   struct stat st;
   struct stat stnow;
   time_t now1, now2;
   int fd;
 
-  if (tmpnam (file) == 0)
+  fd = mkstemp (file);
-    {
-      perror ("tmpnam");
-      return 1;
-    }
-
-  fd = creat (file, 0666);
   if (fd < 0)
     {
-      perror ("creat");
+      perror ("mkstemp");
       return 1;
     }
   close (fd);

posix/annexc.c

@@ -26,7 +26,7 @@
 
 #define HEADER_MAX          256
 
-static const char *macrofile;
+static char macrofile[] = "/tmp/annexc.XXXXXX";
 
 /* <aio.h>.  */
 static const char *const aio_syms[] =
@@ -657,6 +657,8 @@ main (int argc, char *argv[])
   for (h = 0; h < NUMBER_OF_HEADERS; ++h)
     result |= check_header (&headers[h], ignore_list);
 
+  remove (macrofile);
+
   /* The test suite should return errors but for now this is not
      practical.  Give a warning and ask the user to correct the bugs.  */
   return result;
@@ -712,7 +714,13 @@ get_null_defines (void)
   FILE *input;
   int first = 1;
 
-  macrofile = tmpnam (NULL);
+  int fd = mkstemp (macrofile);
+  if (fd == -1)
+    {
+      printf ("mkstemp failed: %m\n");
+      exit (1);
+    }
+  close (fd);
 
   command = malloc (sizeof fmt + sizeof "/dev/null" + 2 * strlen (CC)
 		    + strlen (INC) + strlen (macrofile));
@@ -784,7 +792,6 @@ get_null_defines (void)
     }
   result[result_len] = NULL;
   fclose (input);
-  remove (macrofile);
 
   return (const char **) result;
 }
@@ -879,7 +886,6 @@ check_header (const struct header *header, const char **except)
       result |= 1;
     }
   fclose (input);
-  remove (macrofile);
 
   for (i = 0; i < header->nsyms; ++i)
     if (found[i] == 0)

posix/bug-getopt1.c

@@ -1,6 +1,7 @@
 /* BZ 11039 */
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static int
 one_test (const char *fmt, int argc, char *argv[], int expected[argc - 1])
@@ -39,12 +40,14 @@ one_test (const char *fmt, int argc, char *argv[], int expected[argc - 1])
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
+  char fname[] = "/tmp/bug-getopt1.XXXXXX";
-  if (fname == NULL)
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {

posix/bug-getopt2.c

@@ -1,6 +1,7 @@
 /* BZ 11039 */
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static int
 one_test (const char *fmt, int argc, char *argv[], int expected[argc - 1])
@@ -37,12 +38,14 @@ one_test (const char *fmt, int argc, char *argv[], int expected[argc - 1])
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
+  char fname[] = "/tmp/bug-getopt2.XXXXXX";
-  if (fname == NULL)
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {

posix/bug-getopt3.c

@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static const struct option opts[] =
   {
@@ -48,12 +49,14 @@ one_test (const char *fmt, int argc, char *argv[], int n, int expected[n],
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
+  char fname[] = "/tmp/bug-getopt3.XXXXXX";
-  if (fname == NULL)
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {

posix/bug-getopt4.c

@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static const struct option opts[] =
   {
@@ -52,12 +53,14 @@ one_test (const char *fmt, int argc, char *argv[], int n, int expected[n])
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
+  char fname[] = "/tmp/bug-getopt4.XXXXXX";
-  if (fname == NULL)
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {

posix/bug-getopt5.c

@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static const struct option opts[] =
   {
@@ -47,12 +48,14 @@ one_test (const char *fmt, int argc, char *argv[], int n, int expected[n])
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
+  char fname[] = "/tmp/bug-getopt5.XXXXXX";
-  if (fname == NULL)
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {

stdio-common/bug7.c

@@ -1,21 +1,25 @@
 /* Regression test for fseek and freopen bugs.  */
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
 
 int
 main (int argc, char *argv[])
 {
   int lose = 0;
-  char filename[L_tmpnam];
+  char filename[] = "/tmp/bug7.XXXXXX";
   FILE *fp;
 
-  if (tmpnam (filename) == NULL)
+  int fd = mkstemp (filename);
+  if (fd == -1)
     {
-      printf ("tmpnam failed\n");
+      printf ("mkstemp failed\n");
       lose = 1;
     }
   else
     {
+      close (fd);
       fp = fopen (filename, "w+");
       fprintf (fp, "Hello world!\n");
       fflush (fp);
@@ -32,17 +36,21 @@ main (int argc, char *argv[])
   {
     FILE *file1;
     FILE *file2;
-    char filename1[L_tmpnam];
+    char filename1[] = "/tmp/bug7.XXXXXX";
-    char filename2[L_tmpnam];
+    char filename2[] = "/tmp/bug7.XXXXXX";
     int ch;
 
-    if (tmpnam (filename1) == NULL || tmpnam (filename2) == NULL)
+    int fd1 = mkstemp (filename1);
+    int fd2 = mkstemp (filename2);
+    if (fd1 == -1 || fd2 == -1)
       {
-	printf ("tmpnam failed\n");
+	printf ("mkstemp failed\n");
 	lose = 1;
       }
     else
       {
+	close (fd1);
+	close (fd2);
 
 	file1 = fopen (filename1, "w");
 	fclose (file1);

stdio-common/tst-fdopen.c

@@ -1,6 +1,7 @@
 /* Test for fdopen bugs.  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 
@@ -18,12 +19,18 @@ char buffer[256];
 int
 main (int argc, char *argv[])
 {
-  char *name;
+  char name[] = "/tmp/tst-fdopen.XXXXXX";
   FILE *fp = NULL;
   int retval = 0;
   int fd;
 
-  name = tmpnam (NULL);
+  fd = mkstemp (name);
+  if (fd == -1)
+    {
+      printf ("mkstemp failed: %m\n");
+      return 1;
+    }
+  close (fd);
   fp = fopen (name, "w");
   assert (fp != NULL)
   fputs ("foobar and baz", fp);

stdio-common/tst-ungetc.c

@@ -1,6 +1,7 @@
 /* Test for ungetc bugs.  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #undef assert
@@ -15,13 +16,19 @@
 int
 main (int argc, char *argv[])
 {
-  char *name;
+  char name[] = "/tmp/tst-ungetc.XXXXXX";
   FILE *fp = NULL;
   int retval = 0;
   int c;
   char buffer[64];
 
-  name = tmpnam (NULL);
+  int fd = mkstemp (name);
+  if (fd == -1)
+    {
+      printf ("mkstemp failed: %m\n");
+      return 1;
+    }
+  close (fd);
   fp = fopen (name, "w");
   assert (fp != NULL)
   fputs ("bla", fp);

stdlib/isomac.c

@@ -77,7 +77,7 @@
 
 #define HEADER_MAX          256
 
-static const char *macrofile;
+static char macrofile[] = "/tmp/isomac.XXXXXX";
 
 /* ISO C header names including Amendment 1 (without ".h" suffix).  */
 static char *header[] =
@@ -219,6 +219,8 @@ main (int argc, char *argv[])
       result |= check_header (file_name, ignore_list);
     }
 
+  remove (macrofile);
+
   /* The test suite should return errors but for now this is not
      practical.  Give a warning and ask the user to correct the bugs.  */
   return result;
@@ -249,7 +251,13 @@ get_null_defines (void)
   FILE *input;
   int first = 1;
 
-  macrofile = tmpnam (NULL);
+  int fd = mkstemp (macrofile);
+  if (fd == -1)
+    {
+      printf ("mkstemp failed: %m\n");
+      exit (1);
+    }
+  close (fd);
 
   command = malloc (sizeof fmt + sizeof "/dev/null" + 2 * strlen (CC)
 		    + strlen (INC) + strlen (macrofile));
@@ -330,7 +338,6 @@ get_null_defines (void)
     }
   result[result_len] = NULL;
   fclose (input);
-  remove (macrofile);
 
   return (const char **) result;
 }
@@ -439,7 +446,6 @@ check_header (const char *file_name, const char **except)
 	}
     }
   fclose (input);
-  remove (macrofile);
 
   return result;
 }