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>,
Pengfei Xu <pengfei.xu@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v13 8/8] x86/vsyscall/64: Fixup Shadow Stack and Indirect Branch Tracking for vsyscall emulation
Date: Fri, 25 Sep 2020 07:58:04 -0700 [thread overview]
Message-ID: <20200925145804.5821-9-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20200925145804.5821-1-yu-cheng.yu@intel.com>
Vsyscall entry points are effectively branch targets. Mark them with
ENDBR64 opcodes. When emulating the RET instruction, unwind shadow stack
and reset IBT state machine.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
v13:
- Check shadow stack address is canonical.
- Change from writing to MSRs to writing to CET xstate.
arch/x86/entry/vsyscall/vsyscall_64.c | 34 +++++++++++++++++++++++
arch/x86/entry/vsyscall/vsyscall_emu_64.S | 9 ++++++
arch/x86/entry/vsyscall/vsyscall_trace.h | 1 +
3 files changed, 44 insertions(+)
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 44c33103a955..315ee3572664 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -38,6 +38,9 @@
#include <asm/fixmap.h>
#include <asm/traps.h>
#include <asm/paravirt.h>
+#include <asm/fpu/xstate.h>
+#include <asm/fpu/types.h>
+#include <asm/fpu/internal.h>
#define CREATE_TRACE_POINTS
#include "vsyscall_trace.h"
@@ -286,6 +289,37 @@ bool emulate_vsyscall(unsigned long error_code,
/* Emulate a ret instruction. */
regs->ip = caller;
regs->sp += 8;
+
+#ifdef CONFIG_X86_CET
+ if (tsk->thread.cet.shstk_size || tsk->thread.cet.ibt_enabled) {
+ struct cet_user_state *cet;
+ struct fpu *fpu;
+
+ fpu = &tsk->thread.fpu;
+ fpregs_lock();
+
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ copy_fpregs_to_fpstate(fpu);
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+ }
+
+ cet = get_xsave_addr(&fpu->state.xsave, XFEATURE_CET_USER);
+ if (!cet) {
+ fpregs_unlock();
+ goto sigsegv;
+ }
+
+ if (cet->user_ssp && ((cet->user_ssp + 8) < TASK_SIZE_MAX))
+ cet->user_ssp += 8;
+
+ if (cet->user_cet & CET_ENDBR_EN)
+ cet->user_cet &= ~CET_WAIT_ENDBR;
+
+ __fpu_invalidate_fpregs_state(fpu);
+ fpregs_unlock();
+ }
+#endif
+
return true;
sigsegv:
diff --git a/arch/x86/entry/vsyscall/vsyscall_emu_64.S b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
index 2e203f3a25a7..b2fa92104cdb 100644
--- a/arch/x86/entry/vsyscall/vsyscall_emu_64.S
+++ b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
@@ -17,16 +17,25 @@ __PAGE_ALIGNED_DATA
.type __vsyscall_page, @object
__vsyscall_page:
+#ifdef CONFIG_X86_BRANCH_TRACKING_USER
+ endbr64
+#endif
mov $__NR_gettimeofday, %rax
syscall
ret
.balign 1024, 0xcc
+#ifdef CONFIG_X86_BRANCH_TRACKING_USER
+ endbr64
+#endif
mov $__NR_time, %rax
syscall
ret
.balign 1024, 0xcc
+#ifdef CONFIG_X86_BRANCH_TRACKING_USER
+ endbr64
+#endif
mov $__NR_getcpu, %rax
syscall
ret
diff --git a/arch/x86/entry/vsyscall/vsyscall_trace.h b/arch/x86/entry/vsyscall/vsyscall_trace.h
index 3c3f9765a85c..7aa2101ada44 100644
--- a/arch/x86/entry/vsyscall/vsyscall_trace.h
+++ b/arch/x86/entry/vsyscall/vsyscall_trace.h
@@ -25,6 +25,7 @@ TRACE_EVENT(emulate_vsyscall,
#endif
#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
#define TRACE_INCLUDE_PATH ../../arch/x86/entry/vsyscall/
#define TRACE_INCLUDE_FILE vsyscall_trace
#include <trace/define_trace.h>
--
2.21.0
next prev parent reply other threads:[~2020-09-25 14:58 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 14:57 [PATCH v13 0/8] Control-flow Enforcement: Indirect Branch Tracking Yu-cheng Yu
2020-09-25 14:57 ` [PATCH v13 1/8] x86/cet/ibt: Add Kconfig option for user-mode " Yu-cheng Yu
2020-09-25 14:57 ` [PATCH v13 2/8] x86/cet/ibt: User-mode Indirect Branch Tracking support Yu-cheng Yu
2020-09-25 14:57 ` [PATCH v13 3/8] x86/cet/ibt: Handle signals for Indirect Branch Tracking Yu-cheng Yu
2020-09-25 14:58 ` [PATCH v13 4/8] x86/cet/ibt: ELF header parsing " Yu-cheng Yu
2020-09-25 14:58 ` [PATCH v13 5/8] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2020-09-25 14:58 ` [PATCH v13 6/8] x86/vdso/32: Add ENDBR32 to __kernel_vsyscall entry point Yu-cheng Yu
2020-09-25 14:58 ` [PATCH v13 7/8] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2020-09-25 16:18 ` Andy Lutomirski
2020-09-25 16:24 ` Yu, Yu-cheng
2020-09-25 14:58 ` Yu-cheng Yu [this message]
2020-09-25 16:31 ` [PATCH v13 8/8] x86/vsyscall/64: Fixup Shadow Stack and Indirect Branch Tracking for vsyscall emulation Andy Lutomirski
2020-09-25 16:47 ` Yu, Yu-cheng
2020-09-25 16:51 ` Andy Lutomirski
2020-09-28 16:59 ` Yu-cheng Yu
2020-09-28 17:37 ` Andy Lutomirski
2020-09-28 19:04 ` Yu, Yu-cheng
2020-09-29 18:37 ` Yu, Yu-cheng
2020-09-29 19:57 ` Andy Lutomirski
2020-09-29 20:00 ` Andy Lutomirski
2020-09-30 22:33 ` Yu, Yu-cheng
2020-09-30 23:44 ` Andy Lutomirski
2020-10-01 1:00 ` H.J. Lu
2020-10-01 1:10 ` Andy Lutomirski
2020-10-01 1:21 ` H.J. Lu
2020-10-01 16:51 ` Yu, Yu-cheng
2020-10-01 17:26 ` Andy Lutomirski
2020-10-06 19:09 ` Yu, Yu-cheng
2020-10-09 17:42 ` Andy Lutomirski
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