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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
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')
-rw-r--r--elf/Makefile21
-rw-r--r--elf/tst-execstack-mod.c30
-rw-r--r--elf/tst-execstack-needed.c36
-rw-r--r--elf/tst-execstack.c133
4 files changed, 217 insertions, 3 deletions
diff --git a/elf/Makefile b/elf/Makefile
index d5a1c3de34..36f205abb2 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -29,7 +29,8 @@ routines = $(dl-routines) dl-open dl-close dl-support dl-iteratephdr \
# profiled libraries.
dl-routines = $(addprefix dl-,load cache lookup object reloc deps \
runtime error init fini debug misc \
- version profile conflict tls origin)
+ version profile conflict tls origin \
+ execstack)
all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
# But they are absent from the shared libc, because that code is in ld.so.
elide-routines.os = $(all-dl-routines) dl-support enbl-secure \
@@ -80,6 +81,7 @@ distribute := rtld-Rules \
reldep9.c reldep9mod1.c reldep9mod2.c reldep9mod3.c \
tst-array1.exp tst-array2.exp tst-array4.exp \
tst-array2dep.c \
+ tst-execstack-mod.c \
check-textrel.c dl-sysdep.h
CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables
@@ -150,12 +152,14 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \
neededtest3 neededtest4 unload2 lateglobal initfirst global \
restest2 next dblload dblunload reldep5 reldep6 reldep7 reldep8 \
circleload1 tst-tls3 tst-tls4 tst-tls5 tst-tls6 tst-tls7 tst-tls8 \
- tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-align
+ tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-align \
+ $(tests-execstack-$(have-z-execstack))
# reldep9
test-srcs = tst-pathopt
tests-vis-yes = vismain
tests-nodelete-yes = nodelete nodelete2
tests-nodlopen-yes = nodlopen nodlopen2
+tests-execstack-yes = tst-execstack tst-execstack-needed
endif
modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
testobj1_1 failobj constload2 constload3 unloadmod \
@@ -178,7 +182,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
circlemod3 circlemod3a \
reldep8mod1 reldep8mod2 reldep8mod3 \
reldep9mod1 reldep9mod2 reldep9mod3 \
- tst-alignmod
+ tst-alignmod $(modules-execstack-$(have-z-execstack))
ifeq (yes,$(have-initfini-array))
modules-names += tst-array2dep
endif
@@ -186,6 +190,7 @@ modules-vis-yes = vismod1 vismod2 vismod3
modules-nodelete-yes = nodelmod1 nodelmod2 nodelmod3 nodelmod4 \
nodel2mod1 nodel2mod2 nodel2mod3
modules-nodlopen-yes = nodlopenmod nodlopenmod2
+modules-execstack-yes = tst-execstack-mod
extra-objs += $(addsuffix .os,$(strip $(modules-names)))
# We need this variable to be sure the test modules get the right CPPFLAGS.
test-extras += $(modules-names)
@@ -660,6 +665,16 @@ $(objpfx)tst-tls9-static: $(common-objpfx)dlfcn/libdl.a
$(objpfx)tst-tls9-static.out: $(objpfx)tst-tlsmod5.so $(objpfx)tst-tlsmod6.so
endif
+ifeq ($(have-z-execstack),yes)
+$(objpfx)tst-execstack: $(libdl)
+$(objpfx)tst-execstack.out: $(objpfx)tst-execstack-mod.so
+LDFLAGS-tst-execstack = -Wl,-z,noexecstack
+LDFLAGS-tst-execstack-mod = -Wl,-z,execstack
+
+$(objpfx)tst-execstack-needed: $(objpfx)tst-execstack-mod.so
+LDFLAGS-tst-execstack-needed = -Wl,-z,noexecstack
+endif
+
$(objpfx)tst-array1.out: $(objpfx)tst-array1
$(elf-objpfx)$(rtld-installed-name) \
--library-path $(rpath-link)$(patsubst %,:%,$(sysdep-library-path)) \
diff --git a/elf/tst-execstack-mod.c b/elf/tst-execstack-mod.c
new file mode 100644
index 0000000000..038e6550b5
--- /dev/null
+++ b/elf/tst-execstack-mod.c
@@ -0,0 +1,30 @@
+/* Test module for making nonexecutable stacks executable
+ on load of a DSO that requires executable stacks. */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void callme (void (*callback) (void));
+
+/* This is a function that makes use of executable stack by
+ using a local function trampoline. */
+void
+tryme (void)
+{
+ bool ok = false;
+ void callback (void) { ok = true; }
+
+ callme (&callback);
+
+ if (ok)
+ printf ("DSO called ok (local %p, trampoline %p)\n", &ok, &callback);
+ else
+ abort ();
+}
+
+void
+callme (void (*callback) (void))
+{
+ (*callback) ();
+}
diff --git a/elf/tst-execstack-needed.c b/elf/tst-execstack-needed.c
new file mode 100644
index 0000000000..03090f7dd6
--- /dev/null
+++ b/elf/tst-execstack-needed.c
@@ -0,0 +1,36 @@
+/* Test program for making nonexecutable stacks executable
+ on DT_NEEDED load of a DSO that requires executable stacks. */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <error.h>
+
+extern void tryme (void); /* from tst-execstack-mod.so */
+
+static void deeper (void (*f) (void));
+
+static int
+do_test (void)
+{
+ tryme ();
+
+ /* Test that growing the stack region gets new executable pages too. */
+ deeper (&tryme);
+
+ 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"
diff --git a/elf/tst-execstack.c b/elf/tst-execstack.c
new file mode 100644
index 0000000000..21eaa9bc90
--- /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"