From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [RFC PATCH 3/5] selftest/x86: Fix sigreturn_64 test.
Date: Thu, 21 May 2020 14:17:18 -0700 [thread overview]
Message-ID: <20200521211720.20236-4-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20200521211720.20236-1-yu-cheng.yu@intel.com>
When shadow stack is enabled, selftests/x86/sigreturn_64 triggers a fault
when doing sigreturn to 32-bit context but the task's shadow stack pointer
is above 32-bit address range. Fix it by:
- Allocate a small shadow stack below 32-bit address,
- Switch to the new shadow stack,
- Run tests,
- Switch back to the original 64-bit shadow stack.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
tools/testing/selftests/x86/sigreturn.c | 28 +++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c
index 57c4f67f16ef..5bcd74d416ff 100644
--- a/tools/testing/selftests/x86/sigreturn.c
+++ b/tools/testing/selftests/x86/sigreturn.c
@@ -45,6 +45,14 @@
#include <stdbool.h>
#include <sys/ptrace.h>
#include <sys/user.h>
+#include <x86intrin.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+
+#ifdef __x86_64__
+int arch_prctl(int code, unsigned long *addr);
+#define ARCH_CET_ALLOC_SHSTK 0x3004
+#endif
/* Pull in AR_xyz defines. */
typedef unsigned int u32;
@@ -766,6 +774,20 @@ int main()
int total_nerrs = 0;
unsigned short my_cs, my_ss;
+#ifdef __x86_64__
+ /* Alloc a shadow stack within 32-bit address range */
+ unsigned long arg, ssp_64, ssp_32;
+ ssp_64 = _get_ssp();
+
+ if (ssp_64 != 0) {
+ arg = 0x1001;
+ arch_prctl(ARCH_CET_ALLOC_SHSTK, &arg);
+ ssp_32 = arg + 0x1000 - 8;
+ asm volatile("RSTORSSP (%0)\n":: "r" (ssp_32));
+ asm volatile("SAVEPREVSSP");
+ }
+#endif
+
asm volatile ("mov %%cs,%0" : "=r" (my_cs));
asm volatile ("mov %%ss,%0" : "=r" (my_ss));
setup_ldt();
@@ -870,6 +892,12 @@ int main()
#ifdef __x86_64__
total_nerrs += test_nonstrict_ss();
+
+ if (ssp_64 != 0) {
+ ssp_64 -= 8;
+ asm volatile("RSTORSSP (%0)\n":: "r" (ssp_64));
+ asm volatile("SAVEPREVSSP");
+ }
#endif
return total_nerrs ? 1 : 0;
--
2.21.0
next prev parent reply other threads:[~2020-05-21 21:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 21:17 [RFC PATCH 0/5] Update selftests/x86 for CET Yu-cheng Yu
2020-05-21 21:17 ` [RFC PATCH 1/5] x86/cet/shstk: Modify ARCH_X86_CET_ALLOC_SHSTK for 32-bit address range Yu-cheng Yu
2020-05-21 22:43 ` Kees Cook
2020-05-21 21:17 ` [RFC PATCH 2/5] selftest/x86: Enable CET for selftests/x86 Yu-cheng Yu
2020-05-21 22:44 ` Kees Cook
2020-05-21 22:58 ` Yu-cheng Yu
2020-05-21 21:17 ` Yu-cheng Yu [this message]
2020-05-21 22:47 ` [RFC PATCH 3/5] selftest/x86: Fix sigreturn_64 test Kees Cook
2020-05-21 22:48 ` Kees Cook
2020-05-21 21:17 ` [RFC PATCH 4/5] selftest/x86: Fix sysret_rip with ENDBR Yu-cheng Yu
2020-05-21 21:34 ` Thomas Gleixner
2020-05-21 22:59 ` Yu-cheng Yu
2020-05-21 21:17 ` [RFC PATCH 5/5] selftest/x86: Add CET quick test Yu-cheng Yu
2020-05-21 23:02 ` Kees Cook
2020-05-21 23:23 ` Yu-cheng Yu
2020-05-22 9:28 ` Peter Zijlstra
2020-05-22 15:10 ` Yu-cheng Yu
2020-05-22 17:22 ` Kees Cook
2020-05-22 17:27 ` Peter Zijlstra
2020-05-22 17:36 ` Kees Cook
2020-05-22 18:07 ` Yu-cheng Yu
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