* The nios2*-*-linux-gnu configurations are no longer supported.
+* dlopen and dlmopen no longer make the stack executable if a shared
+ library requires it, either implicitly because of a missing GNU_STACK ELF
+ header (and default ABI permission having the executable bit set) or
+ explicitly because of the executable bit in GNU_STACK, and the stack is
+ not already executable. Instead, loading such objects will fail.
+
Changes to build and runtime requirements:
* On recent Linux kernels with vDSO getrandom support, getrandom does not
if (__glibc_unlikely ((stack_flags &~ GL(dl_stack_flags)) & PF_X))
{
/* The stack is presently not executable, but this module
- requires that it be executable. */
-#if PTHREAD_IN_LIBC
- errval = _dl_make_stacks_executable (stack_endp);
-#else
- errval = (*GL(dl_make_stack_executable_hook)) (stack_endp);
-#endif
+ requires that it be executable. Only tries to change the
+ stack protection during process startup. */
+ if ((mode & __RTLD_DLOPEN) == 0)
+ errval = _dl_make_stack_executable (stack_endp);
+ else
+ errval = EINVAL;
+
if (errval)
{
errstring = N_("\
uintptr_t _dl_in_flight_stack;
int _dl_stack_cache_lock;
#else
-/* If loading a shared object requires that we make the stack executable
- when it was not, we do it by calling this function.
- It returns an errno code or zero on success. */
-int (*_dl_make_stack_executable_hook) (void **) = _dl_make_stack_executable;
void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
#endif
struct dl_scope_free_list *_dl_scope_free_list;
__tls_pre_init_tp ();
-#if !PTHREAD_IN_LIBC
- /* The explicit initialization here is cheaper than processing the reloc
- in the _rtld_local definition's initializer. */
- GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
-#endif
-
/* Process the environment variable which control the behaviour. */
skip_env = process_envvars (&state);
#include <stackinfo.h>
#include <stdbool.h>
#include <string.h>
+#include <stdlib.h>
#include <support/xdlfcn.h>
#include <support/xthread.h>
#include <support/check.h>
#include <support/xstdio.h>
-static void deeper (void (*f) (void));
+/* The DEFAULT_RWX_STACK controls whether the toolchain enables an executable
+ stack for the testcase (which does not contain features that might require
+ an executable stack, such as nested function).
+ Some ABIs do require an executable stack, even if the toolchain supports
+ non-executable stack. In this cases the DEFAULT_RWX_STACK can be
+ overridden. */
+#ifndef DEFAULT_RWX_STACK
+# define DEFAULT_RWX_STACK 0
+#else
+static void
+deeper (void (*f) (void))
+{
+ char stack[1100 * 1024];
+ explicit_bzero (stack, sizeof stack);
+ (*f) ();
+ memfrob (stack, sizeof stack);
+}
+#endif
#if USE_PTHREADS
-# include <pthread.h>
-
+# if DEFAULT_RWX_STACK
static void *
tryme_thread (void *f)
{
return 0;
}
+# endif
static pthread_barrier_t startup_barrier, go_barrier;
static void *
waiter_thread (void *arg)
{
- void **f = arg;
xpthread_barrier_wait (&startup_barrier);
xpthread_barrier_wait (&go_barrier);
+# if DEFAULT_RWX_STACK
+ void **f = arg;
(*((void (*) (void)) *f)) ();
+# else
+ abort ();
+# endif
return 0;
}
printf ("executable stacks %sallowed\n", allow_execstack ? "" : "not ");
+#if USE_PTHREADS || DEFAULT_RWX_STACK
static void *f; /* Address of this is used in other threads. */
+#endif
#if USE_PTHREADS
/* Create some threads while stacks are nonexecutable. */
puts ("threads waiting");
#endif
-#if USE_PTHREADS
+#if USE_PTHREADS && DEFAULT_RWX_STACK
void *old_stack_addr, *new_stack_addr;
size_t stack_size;
pthread_t me = pthread_self ();
const char *soname = "tst-execstack-mod.so";
#endif
void *h = dlopen (soname, RTLD_LAZY);
- if (h == NULL)
- {
- printf ("cannot load: %s\n", dlerror ());
- return allow_execstack;
- }
+#if !DEFAULT_RWX_STACK
+ TEST_VERIFY_EXIT (h == NULL);
+#else
+ TEST_VERIFY_EXIT (h != NULL);
f = xdlsym (h, "tryme");
# if _STACK_GROWS_DOWN
new_stack_addr += stack_size;
-# else
+# else
new_stack_addr -= stack_size;
-# endif
+# endif
/* It is possible that the dlopen'd module may have been mmapped just below
the stack. The stack size is taken as MIN(stack rlimit size, end of last
should remain the same, which is computed as stackaddr + stacksize. */
TEST_VERIFY_EXIT (old_stack_addr == new_stack_addr);
printf ("Stack address remains the same: %p\n", old_stack_addr);
-#endif
+# endif
/* Test that growing the stack region gets new executable pages too. */
deeper ((void (*) (void)) f);
-#if USE_PTHREADS
+# if USE_PTHREADS
/* Test that a fresh thread now gets an executable stack. */
xpthread_create (NULL, &tryme_thread, f);
xpthread_barrier_wait (&go_barrier);
pthread_exit ((void *) (long int) (! allow_execstack));
+# endif
#endif
return ! allow_execstack;
}
-static void
-deeper (void (*f) (void))
-{
- char stack[1100 * 1024];
- explicit_bzero (stack, sizeof stack);
- (*f) ();
- memfrob (stack, sizeof stack);
-}
-
-
#include <support/test-driver.c>
lll_unlock (GL (dl_stack_cache_lock), LLL_PRIVATE);
-
- /* There might have been a race. Another thread might have
- caused the stacks to get exec permission while this new
- stack was prepared. Detect if this was possible and
- change the permission if necessary. */
- if (__builtin_expect ((GL(dl_stack_flags) & PF_X) != 0
- && (prot & PROT_EXEC) == 0, 0))
- {
- int err = __nptl_change_stack_perm (pd);
- if (err != 0)
- {
- /* Free the stack memory we just allocated. */
- (void) __munmap (mem, size);
-
- return err;
- }
- }
-
-
/* Note that all of the stack and the thread descriptor is
zeroed. This means we do not have to initialize fields
with initial value zero. This is specifically true for
#endif
#include <dl-procruntime.c>
-#if !PTHREAD_IN_LIBC
- /* If loading a shared object requires that we make the stack executable
- when it was not, we do it by calling this function.
- It returns an errno code or zero on success. */
- EXTERN int (*_dl_make_stack_executable_hook) (void **);
-#endif
-
/* Prevailing state of the stack, PF_X indicating it's executable. */
EXTERN ElfW(Word) _dl_stack_flags;
extern size_t _dl_phnum;
#endif
-#if PTHREAD_IN_LIBC
-/* This function changes the permissions of all stacks (not just those
- of the main stack). */
-int _dl_make_stacks_executable (void **stack_endp) attribute_hidden;
-#else
-/* This is the initial value of GL(dl_make_stack_executable_hook).
- A threads library can change it. The ld.so implementation changes
- the permissions of the main stack only. */
-extern int _dl_make_stack_executable (void **stack_endp);
-rtld_hidden_proto (_dl_make_stack_executable)
-#endif
+/* This function changes the permission of the memory region pointed
+ by STACK_ENDP to executable and update the internal memory protection
+ flags for future thread stack creation. */
+int _dl_make_stack_executable (void **stack_endp) attribute_hidden;
/* Variable pointing to the end of the stack (or close to it). This value
must be constant over the runtime of the application. Some programs
check-execstack-xfail += ld.so libc.so libpthread.so
# We always create a thread for signals
test-xfail-tst-single_threaded-pthread-static = yes
+
+CFLAGS-tst-execstack.c += -DDEFAULT_RWX_STACK=1
endif
# For bug 30166
return ENOSYS;
#endif
}
-rtld_hidden_def (_dl_make_stack_executable)
extern void __nptl_free_tcb (struct pthread *pd);
libc_hidden_proto (__nptl_free_tcb)
-/* Change the permissions of a thread stack. Called from
- _dl_make_stacks_executable and pthread_create. */
-int
-__nptl_change_stack_perm (struct pthread *pd);
-rtld_hidden_proto (__nptl_change_stack_perm)
-
/* longjmp handling. */
extern void __pthread_cleanup_upto (__jmp_buf target, char *targetframe);
libc_hidden_proto (__pthread_cleanup_upto)
__rseq_offset;
__rseq_size;
}
- GLIBC_PRIVATE {
- __nptl_change_stack_perm;
- }
}
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <errno.h>
#include <ldsodefs.h>
-#include <libintl.h>
-#include <list.h>
-#include <pthreadP.h>
-#include <stackinfo.h>
-#include <stdbool.h>
-#include <sys/mman.h>
-#include <sysdep.h>
-#include <unistd.h>
-static int
-make_main_stack_executable (void **stack_endp)
+int
+_dl_make_stack_executable (void **stack_endp)
{
/* This gives us the highest/lowest page that needs to be changed. */
uintptr_t page = ((uintptr_t) *stack_endp
return 0;
}
-
-int
-_dl_make_stacks_executable (void **stack_endp)
-{
- /* First the main thread's stack. */
- int err = make_main_stack_executable (stack_endp);
- if (err != 0)
- return err;
-
- lll_lock (GL (dl_stack_cache_lock), LLL_PRIVATE);
-
- list_t *runp;
- list_for_each (runp, &GL (dl_stack_used))
- {
- err = __nptl_change_stack_perm (list_entry (runp, struct pthread, list));
- if (err != 0)
- break;
- }
-
- /* Also change the permission for the currently unused stacks. This
- might be wasted time but better spend it here than adding a check
- in the fast path. */
- if (err == 0)
- list_for_each (runp, &GL (dl_stack_cache))
- {
- err = __nptl_change_stack_perm (list_entry (runp, struct pthread,
- list));
- if (err != 0)
- break;
- }
-
- lll_unlock (GL (dl_stack_cache_lock), LLL_PRIVATE);
-
- return err;
-}
-
-int
-__nptl_change_stack_perm (struct pthread *pd)
-{
-#if _STACK_GROWS_DOWN
- void *stack = pd->stackblock + pd->guardsize;
- size_t len = pd->stackblock_size - pd->guardsize;
-#elif _STACK_GROWS_UP
- void *stack = pd->stackblock;
- size_t len = (uintptr_t) pd - pd->guardsize - (uintptr_t) pd->stackblock;
-#else
-# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
-#endif
- if (__mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
- return errno;
-
- return 0;
-}
-rtld_hidden_def (__nptl_change_stack_perm)
# this test is expected to fail.
ifneq ($(mips-has-gnustack),yes)
test-xfail-check-execstack = yes
+CFLAGS-tst-execstack.c += -DDEFAULT_RWX_STACK=1
endif
endif
gen-as-const-headers += ucontext_i.sym
endif
+ifeq ($(subdir),nptl)
+ifeq ($(mips-force-execstack),yes)
+CFLAGS-tst-execstack-threads.c += -DDEFAULT_RWX_STACK=1
+endif
+endif
+
ifeq ($(mips-force-execstack),yes)
CFLAGS-.o += -Wa,-execstack
CFLAGS-.os += -Wa,-execstack
projects / thirdparty / glibc.git / commitdiff
