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2abf9ff113
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.
134 lines
2.5 KiB
C
134 lines
2.5 KiB
C
/* Test program for making nonexecutable stacks executable
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on load of a DSO that requires executable stacks. */
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#include <dlfcn.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <error.h>
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static void
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print_maps (void)
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{
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#if 0
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char *cmd = NULL;
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asprintf (&cmd, "cat /proc/%d/maps", getpid ());
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system (cmd);
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free (cmd);
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#endif
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}
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static void deeper (void (*f) (void));
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#if USE_PTHREADS
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# include <pthread.h>
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static void *
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tryme_thread (void *f)
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{
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(*((void (*) (void)) f)) ();
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return 0;
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}
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static pthread_barrier_t startup_barrier, go_barrier;
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static void *
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waiter_thread (void *arg)
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{
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void **f = arg;
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pthread_barrier_wait (&startup_barrier);
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pthread_barrier_wait (&go_barrier);
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(*((void (*) (void)) *f)) ();
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return 0;
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}
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#endif
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static int
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do_test (void)
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{
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void *f;
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#if USE_PTHREADS
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/* Create some threads while stacks are nonexecutable. */
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#define N 5
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pthread_t thr[N];
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pthread_barrier_init (&startup_barrier, NULL, N + 1);
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pthread_barrier_init (&go_barrier, NULL, N + 1);
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for (int i = 0; i < N; ++i)
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{
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int rc = pthread_create (&thr[i], NULL, &waiter_thread, &f);
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if (rc)
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error (1, rc, "pthread_create");
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}
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/* Make sure they are all there using their stacks. */
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pthread_barrier_wait (&startup_barrier);
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puts ("threads waiting");
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#endif
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print_maps ();
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/* Loading this module should force stacks to become executable. */
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void *h = dlopen ("tst-execstack-mod.so", RTLD_LAZY);
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if (h == NULL)
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{
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printf ("cannot load: %s\n", dlerror ());
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return 1;
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}
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f = dlsym (h, "tryme");
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if (f == NULL)
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{
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printf ("symbol not found: %s\n", dlerror ());
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return 1;
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}
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/* Test if that really made our stack executable.
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The `tryme' function should crash if not. */
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(*((void (*) (void)) f)) ();
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print_maps ();
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/* Test that growing the stack region gets new executable pages too. */
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deeper ((void (*) (void)) f);
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print_maps ();
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#if USE_PTHREADS
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/* Test that a fresh thread now gets an executable stack. */
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{
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pthread_t th;
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int rc = pthread_create (&th, NULL, &tryme_thread, f);
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if (rc)
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error (1, rc, "pthread_create");
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}
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puts ("threads go");
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/* The existing threads' stacks should have been changed.
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Let them run to test it. */
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pthread_barrier_wait (&go_barrier);
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pthread_exit (0);
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#endif
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return 0;
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}
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static void
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deeper (void (*f) (void))
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{
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char stack[1100 * 1024];
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memfrob (stack, sizeof stack);
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(*f) ();
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memfrob (stack, sizeof stack);
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}
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#define TEST_FUNCTION do_test ()
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#include "../test-skeleton.c"
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