This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH] x86/CET: Add a setcontext test for CET
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Carlos O'Donell <carlos at redhat dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 25 Jul 2018 05:22:55 -0700
- Subject: [PATCH] x86/CET: Add a setcontext test for CET
Verify that setcontext works with gaps above and below the newly
allocated shadow stack.
OK for master?
H.J.
---
* sysdeps/x86/Makefile (tests): Add tst-cet-setcontext-1 if
CET is enabled.
(CFLAGS-tst-cet-setcontext-1.c): Add -mshstk.
* sysdeps/x86/tst-cet-setcontext-1.c: New file.
---
sysdeps/x86/Makefile | 5 ++
sysdeps/x86/tst-cet-setcontext-1.c | 119 +++++++++++++++++++++++++++++
2 files changed, 124 insertions(+)
create mode 100644 sysdeps/x86/tst-cet-setcontext-1.c
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 672bb19489..761d396108 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -92,4 +92,9 @@ $(objpfx)check-cet.out: $(..)sysdeps/x86/check-cet.awk \
$(evaluate-test)
generated += check-cet.out
endif
+
+ifeq ($(subdir),stdlib)
+tests += tst-cet-setcontext-1
+CFLAGS-tst-cet-setcontext-1.c += -mshstk
+endif
endif
diff --git a/sysdeps/x86/tst-cet-setcontext-1.c b/sysdeps/x86/tst-cet-setcontext-1.c
new file mode 100644
index 0000000000..08b7f6378e
--- /dev/null
+++ b/sysdeps/x86/tst-cet-setcontext-1.c
@@ -0,0 +1,119 @@
+/* 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);
+
+ /* Free the unused shadow stacks to create gaps above and below the
+ shadow stack of CTX1. */
+ 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>
--
2.17.1