summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorH.J. Lu <hjl.tools@gmail.com>2018-07-25 08:40:39 -0700
committerH.J. Lu <hjl.tools@gmail.com>2018-07-25 08:40:50 -0700
commit08ac6bed146c0546d63163ac0d42c9a35880412d (patch)
treea3e3a44aea93c41afdfadfc25b9733b2b2468aa2
parent9faaf9385034ac71f308643de1afc91b5dd731aa (diff)
x86/CET: Add a setcontext test for CET
Verify that setcontext works with gaps above and below the newly allocated shadow stack. * sysdeps/unix/sysv/linux/x86/Makefile (tests): Add tst-cet-setcontext-1 if CET is enabled. (CFLAGS-tst-cet-setcontext-1.c): Add -mshstk. * sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c: New file.
-rw-r--r--ChangeLog7
-rw-r--r--sysdeps/unix/sysv/linux/x86/Makefile7
-rw-r--r--sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c127
3 files changed, 141 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index f6aa73550b..0694ff3f24 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-07-25 H.J. Lu <hongjiu.lu@intel.com>
+
+ * sysdeps/unix/sysv/linux/x86/Makefile (tests): Add
+ tst-cet-setcontext-1 if CET is enabled.
+ (CFLAGS-tst-cet-setcontext-1.c): Add -mshstk.
+ * sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c: New file.
+
2018-07-25 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* include/threads.h: Move to ...
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index 111ff9ff58..a30fdb1dc1 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -23,3 +23,10 @@ endif
ifeq ($(subdir),setjmp)
tests += tst-saved_mask-1
endif
+
+ifeq ($(enable-cet),yes)
+ifeq ($(subdir),stdlib)
+tests += tst-cet-setcontext-1
+CFLAGS-tst-cet-setcontext-1.c += -mshstk
+endif
+endif
diff --git a/sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c b/sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c
new file mode 100644
index 0000000000..ecf86a9e16
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/tst-cet-setcontext-1.c
@@ -0,0 +1,127 @@
+/* Check getcontext and setcontext on the context from makecontext
+ with shadow stack.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <ucontext.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <stdatomic.h>
+#include <x86intrin.h>
+
+static ucontext_t ctx[5];
+static atomic_int done;
+
+static void
+__attribute__((noinline, noclone))
+f2 (void)
+{
+ printf ("start f2\n");
+ done++;
+ if (setcontext (&ctx[2]) != 0)
+ {
+ printf ("%s: setcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+}
+
+static void
+f1 (void)
+{
+ printf ("start f1\n");
+ if (getcontext (&ctx[2]) != 0)
+ {
+ printf ("%s: getcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ if (done)
+ exit (EXIT_SUCCESS);
+ f2 ();
+}
+
+static int
+do_test (void)
+{
+ char st1[32768];
+ puts ("making contexts");
+ if (getcontext (&ctx[0]) != 0)
+ {
+ printf ("%s: getcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ if (getcontext (&ctx[1]) != 0)
+ {
+ printf ("%s: getcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+
+ ctx[3].uc_stack.ss_sp = st1;
+ ctx[3].uc_stack.ss_size = sizeof st1;
+ ctx[3].uc_link = &ctx[0];
+ makecontext (&ctx[3], (void (*) (void)) f1, 0);
+
+ ctx[1].uc_stack.ss_sp = st1;
+ ctx[1].uc_stack.ss_size = sizeof st1;
+ ctx[1].uc_link = &ctx[0];
+ makecontext (&ctx[1], (void (*) (void)) f1, 0);
+
+ ctx[4].uc_stack.ss_sp = st1;
+ ctx[4].uc_stack.ss_size = sizeof st1;
+ ctx[4].uc_link = &ctx[0];
+ makecontext (&ctx[4], (void (*) (void)) f1, 0);
+
+ /* NB: When shadow stack is enabled, makecontext calls arch_prctl
+ with ARCH_CET_ALLOC_SHSTK to allocate a new shadow stack which
+ can be unmapped. The base address and size of the new shadow
+ stack are returned in __ssp[1] and __ssp[2]. makecontext is
+ called for CTX1, CTX3 and CTX4. But only CTX1 is used. New
+ shadow stacks are allocated in the order of CTX3, CTX1, CTX4.
+ It is very likely that CTX1's shadow stack is placed between
+ CTX3 and CTX4. We munmap CTX3's and CTX4's shadow stacks to
+ create gaps above and below CTX1's shadow stack. We check
+ that setcontext CTX1 works correctly in this case. */
+ if (_get_ssp () != 0)
+ {
+ if (ctx[3].__ssp[1] != 0
+ && munmap ((void *) (uintptr_t) ctx[3].__ssp[1],
+ (size_t) ctx[3].__ssp[2]) != 0)
+ {
+ printf ("%s: munmap: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+
+ if (ctx[4].__ssp[1] != 0
+ && munmap ((void *) (uintptr_t) ctx[4].__ssp[1],
+ (size_t) ctx[4].__ssp[2]) != 0)
+ {
+ printf ("%s: munmap: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ if (setcontext (&ctx[1]) != 0)
+ {
+ printf ("%s: setcontext: %m\n", __FUNCTION__);
+ exit (EXIT_FAILURE);
+ }
+ exit (EXIT_FAILURE);
+}
+
+#include <support/test-driver.c>