From dcfcb1b208cd94847807492eee74059f0943b975 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date: Tue, 16 Mar 2021 12:37:54 +0530
Subject: [PATCH] Enhance setuid-tunables test

Instead of passing GLIBC_TUNABLES via the environment, pass the
environment variable from parent to child.  This allows us to test
multiple variables to ensure better coverage.

The test list currently only includes the case that's already being
tested.  More tests will be added later.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

(cherry picked from commit 061fe3f8add46a89b7453e87eabb9c4695005ced)
---
 elf/Makefile                  |  2 -
 elf/tst-env-setuid-tunables.c | 86 +++++++++++++++++++++++++++--------
 2 files changed, 67 insertions(+), 21 deletions(-)

diff --git a/elf/Makefile b/elf/Makefile
index 70b9d368e3..ea3a160024 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1465,8 +1465,6 @@ $(objpfx)tst-nodelete-dlclose.out: $(objpfx)tst-nodelete-dlclose-dso.so \
 
 tst-env-setuid-ENV = MALLOC_CHECK_=2 MALLOC_MMAP_THRESHOLD_=4096 \
 		     LD_HWCAP_MASK=0x1
-tst-env-setuid-tunables-ENV = \
-	GLIBC_TUNABLES=glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096
 
 $(objpfx)tst-debug1: $(libdl)
 $(objpfx)tst-debug1.out: $(objpfx)tst-debug1mod1.so
diff --git a/elf/tst-env-setuid-tunables.c b/elf/tst-env-setuid-tunables.c
index e92e9f5fbf..4681a60494 100644
--- a/elf/tst-env-setuid-tunables.c
+++ b/elf/tst-env-setuid-tunables.c
@@ -25,35 +25,50 @@
 #include "config.h"
 #undef _LIBC
 
-#define test_parent test_parent_tunables
-#define test_child test_child_tunables
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <intprops.h>
+#include <array_length.h>
 
-static int test_child_tunables (void);
-static int test_parent_tunables (void);
+#include <support/check.h>
+#include <support/support.h>
+#include <support/test-driver.h>
+#include <support/capture_subprocess.h>
 
-#include "tst-env-setuid.c"
+const char *teststrings[] =
+{
+  "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096",
+};
 
-#define CHILD_VALSTRING_VALUE "glibc.malloc.mmap_threshold=4096"
-#define PARENT_VALSTRING_VALUE \
-  "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096"
+const char *resultstrings[] =
+{
+  "glibc.malloc.mmap_threshold=4096",
+};
 
 static int
-test_child_tunables (void)
+test_child (int off)
 {
   const char *val = getenv ("GLIBC_TUNABLES");
 
 #if HAVE_TUNABLES
-  if (val != NULL && strcmp (val, CHILD_VALSTRING_VALUE) == 0)
+  if (val != NULL && strcmp (val, resultstrings[off]) == 0)
     return 0;
 
   if (val != NULL)
-    printf ("Unexpected GLIBC_TUNABLES VALUE %s\n", val);
+    printf ("[%d] Unexpected GLIBC_TUNABLES VALUE %s\n", off, val);
 
   return 1;
 #else
   if (val != NULL)
     {
-      printf ("GLIBC_TUNABLES not cleared\n");
+      printf ("[%d] GLIBC_TUNABLES not cleared\n", off);
       return 1;
     }
   return 0;
@@ -61,15 +76,48 @@ test_child_tunables (void)
 }
 
 static int
-test_parent_tunables (void)
+do_test (int argc, char **argv)
 {
-  const char *val = getenv ("GLIBC_TUNABLES");
+  /* Setgid child process.  */
+  if (argc == 2)
+    {
+      if (getgid () == getegid ())
+	/* This can happen if the file system is mounted nosuid.  */
+	FAIL_UNSUPPORTED ("SGID failed: GID and EGID match (%jd)\n",
+			  (intmax_t) getgid ());
 
-  if (val != NULL && strcmp (val, PARENT_VALSTRING_VALUE) == 0)
-    return 0;
+      int ret = test_child (atoi (argv[1]));
 
-  if (val != NULL)
-    printf ("Unexpected GLIBC_TUNABLES VALUE %s\n", val);
+      if (ret != 0)
+	exit (1);
 
-  return 1;
+      exit (EXIT_SUCCESS);
+    }
+  else
+    {
+      int ret = 0;
+
+      /* Spawn tests.  */
+      for (int i = 0; i < array_length (teststrings); i++)
+	{
+	  char buf[INT_BUFSIZE_BOUND (int)];
+
+	  printf ("Spawned test for %s (%d)\n", teststrings[i], i);
+	  snprintf (buf, sizeof (buf), "%d\n", i);
+	  if (setenv ("GLIBC_TUNABLES", teststrings[i], 1) != 0)
+	    exit (1);
+
+	  int status = support_capture_subprogram_self_sgid (buf);
+
+	  /* Bail out early if unsupported.  */
+	  if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
+	    return EXIT_UNSUPPORTED;
+
+	  ret |= status;
+	}
+      return ret;
+    }
 }
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>