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authorRoland McGrath <roland@gnu.org>2003-09-23 12:07:26 +0000
committerRoland McGrath <roland@gnu.org>2003-09-23 12:07:26 +0000
commit2abf9ff11384a47dc456c138a8faf6b1469aac2b (patch)
treed0ccba6b9bf3096c8d1d2d209984bf4d28597408 /elf/tst-execstack.c
parentecdeaac05f73c29eca92eecd55ad4fb8513c7771 (diff)
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* sysdeps/i386/dl-machine.h (RTLD_START): Set __libc_stack_end before
calling _dl_start, using GOTOFF access. * configure.in (libc_cv_z_execstack): New check. * configure: Regenerated. * config.make.in (have-z-execstack): New variable set by it. * elf/tst-execstack.c: New file. * elf/tst-execstack-mod.c: New file. * elf/tst-execstack-needed.c: New file. * elf/Makefile (tests-execstack-yes, modules-execstack-yes): New variables. (tests, modules-names): Conditionally include them. (distribute): Add tst-execstack-mod.c here. ($(objpfx)tst-execstack, $(objpfx)tst-execstack.out): New targets. (LDFLAGS-tst-execstack, LDFLAGS-tst-execstack-mod): New variables. ($(objpfx)tst-execstack-needed): New target. (LDFLAGS-tst-execstack-needed): New variable. * sysdeps/generic/ldsodefs.h (struct rtld_global): Add _dl_stack_flags and _dl_make_stack_executable_hook. Declare _dl_make_stack_executable. * elf/rtld.c (_rtld_global): Add initializer for _dl_stack_flags. (dl_main): Reset _dl_stack_flags according to PT_GNU_STACK phdr. Initialize _dl_make_stack_executable_hook. * elf/dl-support.c: Define those new variables. (_dl_non_dynamic_init): Scan phdrs for PT_GNU_STACK. (_dl_phdr): Fix type. * elf/dl-load.c (_dl_map_object_from_fd): Grok PT_GNU_STACK phdr and enable execute permission for the stack if necessary. * sysdeps/generic/dl-execstack.c: New file. * elf/Makefile (dl-routines): Add it. * elf/Versions (ld: GLIBC_PRIVATE): Add _dl_make_stack_executable. * sysdeps/unix/sysv/linux/dl-execstack.c: New file.
Diffstat (limited to 'elf/tst-execstack.c')
-rw-r--r--elf/tst-execstack.c133
1 files changed, 133 insertions, 0 deletions
diff --git a/elf/tst-execstack.c b/elf/tst-execstack.c
new file mode 100644
index 0000000..21eaa9b
--- /dev/null
+++ b/elf/tst-execstack.c
@@ -0,0 +1,133 @@
+/* Test program for making nonexecutable stacks executable
+ on load of a DSO that requires executable stacks. */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <error.h>
+
+static void
+print_maps (void)
+{
+#if 0
+ char *cmd = NULL;
+ asprintf (&cmd, "cat /proc/%d/maps", getpid ());
+ system (cmd);
+ free (cmd);
+#endif
+}
+
+static void deeper (void (*f) (void));
+
+#if USE_PTHREADS
+# include <pthread.h>
+
+static void *
+tryme_thread (void *f)
+{
+ (*((void (*) (void)) f)) ();
+
+ return 0;
+}
+
+static pthread_barrier_t startup_barrier, go_barrier;
+static void *
+waiter_thread (void *arg)
+{
+ void **f = arg;
+ pthread_barrier_wait (&startup_barrier);
+ pthread_barrier_wait (&go_barrier);
+
+ (*((void (*) (void)) *f)) ();
+
+ return 0;
+}
+#endif
+
+static int
+do_test (void)
+{
+ void *f;
+
+#if USE_PTHREADS
+ /* Create some threads while stacks are nonexecutable. */
+ #define N 5
+ pthread_t thr[N];
+
+ pthread_barrier_init (&startup_barrier, NULL, N + 1);
+ pthread_barrier_init (&go_barrier, NULL, N + 1);
+
+ for (int i = 0; i < N; ++i)
+ {
+ int rc = pthread_create (&thr[i], NULL, &waiter_thread, &f);
+ if (rc)
+ error (1, rc, "pthread_create");
+ }
+
+ /* Make sure they are all there using their stacks. */
+ pthread_barrier_wait (&startup_barrier);
+ puts ("threads waiting");
+#endif
+
+ print_maps ();
+
+ /* Loading this module should force stacks to become executable. */
+ void *h = dlopen ("tst-execstack-mod.so", RTLD_LAZY);
+ if (h == NULL)
+ {
+ printf ("cannot load: %s\n", dlerror ());
+ return 1;
+ }
+
+ f = dlsym (h, "tryme");
+ if (f == NULL)
+ {
+ printf ("symbol not found: %s\n", dlerror ());
+ return 1;
+ }
+
+ /* Test if that really made our stack executable.
+ The `tryme' function should crash if not. */
+
+ (*((void (*) (void)) f)) ();
+
+ print_maps ();
+
+ /* Test that growing the stack region gets new executable pages too. */
+ deeper ((void (*) (void)) f);
+
+ print_maps ();
+
+#if USE_PTHREADS
+ /* Test that a fresh thread now gets an executable stack. */
+ {
+ pthread_t th;
+ int rc = pthread_create (&th, NULL, &tryme_thread, f);
+ if (rc)
+ error (1, rc, "pthread_create");
+ }
+
+ puts ("threads go");
+ /* The existing threads' stacks should have been changed.
+ Let them run to test it. */
+ pthread_barrier_wait (&go_barrier);
+
+ pthread_exit (0);
+#endif
+
+ return 0;
+}
+
+static void
+deeper (void (*f) (void))
+{
+ char stack[1100 * 1024];
+ memfrob (stack, sizeof stack);
+ (*f) ();
+ memfrob (stack, sizeof stack);
+}
+
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"