@@ -262,7 +262,7 @@ tests-static-normal := \
tst-array5-static \
tst-dl-iter-static \
tst-dst-static \
- tst-env-setuid \
+ tst-env-setuid-static \
tst-getauxval-static \
tst-linkall-static \
tst-single_threaded-pthread-static \
@@ -305,6 +305,7 @@ tests := \
tst-array5 \
tst-auxv \
tst-dl-hash \
+ tst-env-setuid \
tst-leaks1 \
tst-stringtable \
tst-tls9 \
@@ -2429,9 +2430,6 @@ $(objpfx)tst-nodelete-dlclose: $(objpfx)tst-nodelete-dlclose-dso.so
$(objpfx)tst-nodelete-dlclose.out: $(objpfx)tst-nodelete-dlclose-dso.so \
$(objpfx)tst-nodelete-dlclose-plugin.so
-tst-env-setuid-ENV = MALLOC_CHECK_=2 MALLOC_MMAP_THRESHOLD_=4096 \
- LD_HWCAP_MASK=0x1
-
$(objpfx)tst-debug1.out: $(objpfx)tst-debug1mod1.so
$(objpfx)tst-debug1mod1.so: $(objpfx)testobj1.so
@@ -2983,3 +2981,5 @@ LDFLAGS-tst-dlclose-lazy-mod1.so = -Wl,-z,lazy,--no-as-needed
$(objpfx)tst-dlclose-lazy-mod1.so: $(objpfx)tst-dlclose-lazy-mod2.so
$(objpfx)tst-dlclose-lazy.out: \
$(objpfx)tst-dlclose-lazy-mod1.so $(objpfx)tst-dlclose-lazy-mod2.so
+
+tst-env-setuid-ARGS = -- $(host-test-program-cmd)
new file mode 100644
@@ -0,0 +1 @@
+#include "tst-env-setuid.c"
@@ -15,18 +15,14 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-/* Verify that tunables correctly filter out unsafe environment variables like
- MALLOC_CHECK_ and MALLOC_MMAP_THRESHOLD_ but also retain
- MALLOC_MMAP_THRESHOLD_ in an unprivileged child. */
+/* Verify that correctly filter out unsafe environment variables defined
+ in unsecvars.h. */
-#include <errno.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <array_length.h>
+#include <gnu/lib-names.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
#include <unistd.h>
#include <support/check.h>
@@ -36,61 +32,72 @@
static char SETGID_CHILD[] = "setgid-child";
-#ifndef test_child
-static int
-test_child (void)
-{
- if (getenv ("MALLOC_CHECK_") != NULL)
- {
- printf ("MALLOC_CHECK_ is still set\n");
- return 1;
- }
-
- if (getenv ("MALLOC_MMAP_THRESHOLD_") == NULL)
- {
- printf ("MALLOC_MMAP_THRESHOLD_ lost\n");
- return 1;
- }
+#define FILTERED_VALUE "some-filtered-value"
+#define UNFILTERED_VALUE "some-unfiltered-value"
- if (getenv ("LD_HWCAP_MASK") != NULL)
- {
- printf ("LD_HWCAP_MASK still set\n");
- return 1;
- }
+struct envvar_t
+{
+ const char *env;
+ const char *value;
+};
- return 0;
-}
-#endif
+/* That is not an extensible list of all filtered out environment
+ variables. */
+static const struct envvar_t filtered_envvars[] =
+{
+ { "GLIBC_TUNABLES", FILTERED_VALUE },
+ { "LD_AUDIT", FILTERED_VALUE },
+ { "LD_HWCAP_MASK", FILTERED_VALUE },
+ { "LD_LIBRARY_PATH", FILTERED_VALUE },
+ { "LD_PRELOAD", FILTERED_VALUE },
+ { "LD_PROFILE", FILTERED_VALUE },
+ { "MALLOC_ARENA_MAX", FILTERED_VALUE },
+ { "MALLOC_PERTURB_", FILTERED_VALUE },
+ { "MALLOC_TRACE", FILTERED_VALUE },
+ { "MALLOC_TRIM_THRESHOLD_", FILTERED_VALUE },
+ { "RES_OPTIONS", FILTERED_VALUE },
+};
+
+static const struct envvar_t unfiltered_envvars[] =
+{
+ { "LD_BIND_NOW", "0" },
+ { "LD_BIND_NOT", "1" },
+ /* Non longer supported option. */
+ { "LD_ASSUME_KERNEL", UNFILTERED_VALUE },
+};
-#ifndef test_parent
static int
-test_parent (void)
+test_child (void)
{
- if (getenv ("MALLOC_CHECK_") == NULL)
- {
- printf ("MALLOC_CHECK_ lost\n");
- return 1;
- }
+ int ret = 0;
- if (getenv ("MALLOC_MMAP_THRESHOLD_") == NULL)
+ for (const struct envvar_t *e = filtered_envvars;
+ e != array_end (filtered_envvars);
+ e++)
{
- printf ("MALLOC_MMAP_THRESHOLD_ lost\n");
- return 1;
+ const char *env = getenv (e->env);
+ ret |= env != NULL;
}
- if (getenv ("LD_HWCAP_MASK") == NULL)
+ for (const struct envvar_t *e = unfiltered_envvars;
+ e != array_end (unfiltered_envvars);
+ e++)
{
- printf ("LD_HWCAP_MASK lost\n");
- return 1;
+ const char *env = getenv (e->env);
+ ret |= !(env != NULL && strcmp (env, e->value) == 0);
}
- return 0;
+ return ret;
}
-#endif
static int
do_test (int argc, char **argv)
{
+ /* For dynamic loader, the test requires --enable-hardcoded-path-in-tests so
+ the kernel sets the AT_SECURE on process initialization. */
+ if (argc >= 2 && strstr (argv[1], LD_SO) != 0)
+ FAIL_UNSUPPORTED ("dynamic test requires --enable-hardcoded-path-in-tests");
+
/* Setgid child process. */
if (argc == 2 && strcmp (argv[1], SETGID_CHILD) == 0)
{
@@ -104,20 +111,33 @@ do_test (int argc, char **argv)
if (ret != 0)
exit (1);
- exit (EXIT_SUCCESS);
+ /* Special return code to make sure that the child executed all the way
+ through. */
+ exit (42);
}
else
{
- if (test_parent () != 0)
- exit (1);
+ for (const struct envvar_t *e = filtered_envvars;
+ e != array_end (filtered_envvars);
+ e++)
+ setenv (e->env, e->value, 1);
+
+ for (const struct envvar_t *e = unfiltered_envvars;
+ e != array_end (unfiltered_envvars);
+ e++)
+ setenv (e->env, e->value, 1);
int status = support_capture_subprogram_self_sgid (SETGID_CHILD);
if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
- return EXIT_UNSUPPORTED;
-
- if (!WIFEXITED (status))
- FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status);
+ exit (EXIT_UNSUPPORTED);
+
+ if (WEXITSTATUS (status) != 42)
+ {
+ printf (" child failed with status %d\n",
+ WEXITSTATUS (status));
+ support_record_failure ();
+ }
return 0;
}
@@ -18,7 +18,14 @@
"LD_SHOW_AUXV\0" \
"LOCALDOMAIN\0" \
"LOCPATH\0" \
+ "MALLOC_ARENA_MAX\0" \
+ "MALLOC_ARENA_TEST\0" \
+ "MALLOC_MMAP_MAX_\0" \
+ "MALLOC_MMAP_THRESHOLD_\0" \
+ "MALLOC_PERTURB_\0" \
+ "MALLOC_TOP_PAD_\0" \
"MALLOC_TRACE\0" \
+ "MALLOC_TRIM_THRESHOLD_\0" \
"NIS_PATH\0" \
"NLSPATH\0" \
"RESOLV_HOST_CONF\0" \
Some environment variables allow alteration of allocator behavior across setuid boundaries, where a setuid program may ignore the tunable, but its non-setuid child can read it and adjust the memory allocator behavior accordingly. Most library behavior tunings is limited to the current process and does not bleed in scope; so it is unclear how pratical this misfeature is. If behavior change across privilege boundaries is desirable, it would be better done with a wrapper program around the non-setuid child that sets these envvars, instead of using the setuid process as the messenger. The patch as fixes tst-env-setuid, where it fail if any unsecvars is set. It also adds a dynamic test, although it requires --enable-hardcoded-path-in-tests so kernel correctly sets the setuid bit (using the loader command directly would require to set the setuid bit on the loader itself, which is not a usual deployment). Co-authored-by: Siddhesh Poyarekar <siddhesh@sourceware.org> Checked on x86_64-linux-gnu. Reviewed-by: DJ Delorie <dj@redhat.com> --- elf/Makefile | 8 +-- elf/tst-env-setuid-static.c | 1 + elf/tst-env-setuid.c | 128 +++++++++++++++++++++--------------- sysdeps/generic/unsecvars.h | 7 ++ 4 files changed, 86 insertions(+), 58 deletions(-) create mode 100644 elf/tst-env-setuid-static.c