[PATCH 04/17] x86/cet: Check legacy shadow stack applications

H.J. Lu hjl.tools@gmail.com
Wed Dec 6 17:19:57 GMT 2023


Add tests to verify that legacy shadow stack applications run properly
when shadow stack is enabled in Linux kernel.
---
 sysdeps/x86/Makefile                     | 23 ++++++++++++++
 sysdeps/x86/tst-shstk-legacy-1-extra.S   | 35 ++++++++++++++++++++++
 sysdeps/x86/tst-shstk-legacy-1a-static.c |  1 +
 sysdeps/x86/tst-shstk-legacy-1a.c        | 32 ++++++++++++++++++++
 sysdeps/x86/tst-shstk-legacy-1b-static.c |  1 +
 sysdeps/x86/tst-shstk-legacy-1b.c        | 38 ++++++++++++++++++++++++
 6 files changed, 130 insertions(+)
 create mode 100644 sysdeps/x86/tst-shstk-legacy-1-extra.S
 create mode 100644 sysdeps/x86/tst-shstk-legacy-1a-static.c
 create mode 100644 sysdeps/x86/tst-shstk-legacy-1a.c
 create mode 100644 sysdeps/x86/tst-shstk-legacy-1b-static.c
 create mode 100644 sysdeps/x86/tst-shstk-legacy-1b.c

diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index ea45aad34c..dea14e343c 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -129,6 +129,21 @@ tests += tst-cet-legacy-1 tst-cet-legacy-1a tst-cet-legacy-2 \
 	 tst-cet-legacy-10 tst-cet-legacy-10-static
 tests-static += tst-cet-legacy-9-static tst-cet-legacy-10-static
 tst-cet-legacy-1a-ARGS = -- $(host-test-program-cmd)
+
+tests += \
+  tst-shstk-legacy-1a \
+  tst-shstk-legacy-1a-static \
+  tst-shstk-legacy-1b \
+  tst-shstk-legacy-1b-static \
+# tests
+tests-static += \
+  tst-shstk-legacy-1a-static \
+  tst-shstk-legacy-1b-static \
+# tests-static
+extra-objs += \
+  tst-shstk-legacy-1-extra.o \
+# extra-objs
+
 tests += tst-cet-legacy-4a tst-cet-legacy-4b tst-cet-legacy-4c \
 	 tst-cet-legacy-5b tst-cet-legacy-6b
 modules-names += tst-cet-legacy-mod-1 tst-cet-legacy-mod-2 \
@@ -168,6 +183,9 @@ CFLAGS-tst-cet-legacy-7.c += -fcf-protection=none
 CFLAGS-tst-cet-legacy-10.c += -mshstk
 CFLAGS-tst-cet-legacy-10-static.c += -mshstk
 
+CFLAGS-tst-shstk-legacy-1a.c += -fcf-protection=none
+CFLAGS-tst-shstk-legacy-1a-static.c += -fcf-protection=none
+
 $(objpfx)tst-cet-legacy-1: $(objpfx)tst-cet-legacy-mod-1.so \
 		       $(objpfx)tst-cet-legacy-mod-2.so
 $(objpfx)tst-cet-legacy-1a: $(objpfx)tst-cet-legacy-mod-1.so \
@@ -200,6 +218,11 @@ $(objpfx)tst-cet-legacy-6b.out: $(objpfx)tst-cet-legacy-mod-6a.so \
 tst-cet-legacy-6b-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
 tst-cet-legacy-9-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
 tst-cet-legacy-9-static-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
+
+$(objpfx)tst-shstk-legacy-1a: $(objpfx)tst-shstk-legacy-1-extra.o
+$(objpfx)tst-shstk-legacy-1a-static: $(objpfx)tst-shstk-legacy-1-extra.o
+$(objpfx)tst-shstk-legacy-1b: $(objpfx)tst-shstk-legacy-1-extra.o
+$(objpfx)tst-shstk-legacy-1b-static: $(objpfx)tst-shstk-legacy-1-extra.o
 endif
 
 # Add -fcf-protection to CFLAGS when CET is enabled.
diff --git a/sysdeps/x86/tst-shstk-legacy-1-extra.S b/sysdeps/x86/tst-shstk-legacy-1-extra.S
new file mode 100644
index 0000000000..f3adb9f639
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1-extra.S
@@ -0,0 +1,35 @@
+/* Legacy shadow stack code.
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+	.text
+	.globl	legacy
+	.type	legacy, @function
+legacy:
+	.cfi_startproc
+#ifdef __x86_64__
+	movq	(%rsp), %rax
+	addq	$8, %rsp
+	jmp	*%rax
+#else
+	movl	(%esp), %eax
+	addl	$4, %esp
+	jmp	*%eax
+#endif
+	.cfi_endproc
+	.size	legacy, .-legacy
+	.section	.note.GNU-stack,"",@progbits
diff --git a/sysdeps/x86/tst-shstk-legacy-1a-static.c b/sysdeps/x86/tst-shstk-legacy-1a-static.c
new file mode 100644
index 0000000000..dd549890a0
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1a-static.c
@@ -0,0 +1 @@
+#include "tst-shstk-legacy-1a.c"
diff --git a/sysdeps/x86/tst-shstk-legacy-1a.c b/sysdeps/x86/tst-shstk-legacy-1a.c
new file mode 100644
index 0000000000..c6f5810838
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1a.c
@@ -0,0 +1,32 @@
+/* Check that legacy shadow stack code won't trigger segfault.
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <support/test-driver.h>
+
+/* Check that legacy shadow stack code won't trigger segfault.  */
+extern void legacy (void);
+
+static int
+do_test (void)
+{
+  legacy ();
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86/tst-shstk-legacy-1b-static.c b/sysdeps/x86/tst-shstk-legacy-1b-static.c
new file mode 100644
index 0000000000..4945344675
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1b-static.c
@@ -0,0 +1 @@
+#include "tst-shstk-legacy-1b.c"
diff --git a/sysdeps/x86/tst-shstk-legacy-1b.c b/sysdeps/x86/tst-shstk-legacy-1b.c
new file mode 100644
index 0000000000..05231e60ae
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1b.c
@@ -0,0 +1,38 @@
+/* Check that legacy shadow stack code will trigger segfault.
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <sys/platform/x86.h>
+#include <support/test-driver.h>
+#include <support/xsignal.h>
+
+/* Check that legacy shadow stack code will trigger segfault.  */
+extern void legacy (void);
+
+static int
+do_test (void)
+{
+  if (!CPU_FEATURE_ACTIVE (SHSTK))
+    return EXIT_UNSUPPORTED;
+
+  legacy ();
+  return EXIT_FAILURE;
+}
+
+#define EXPECTED_SIGNAL (CPU_FEATURE_ACTIVE (SHSTK) ? SIGSEGV : 0)
+#include <support/test-driver.c>
-- 
2.43.0



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