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@amacapital.net>,
Balbir Singh <bsingharora@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.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>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [RFC PATCH v4 22/27] x86/cet/shstk: Handle thread shadow stack
Date: Fri, 21 Sep 2018 08:03:46 -0700 [thread overview]
Message-ID: <20180921150351.20898-23-yu-cheng.yu@intel.com> (raw)
Message-ID: <20180921150346.LZ4cs0P4mIVpBbvFvWsxrgxODpqKwF0v_w27qTVsI9w@z> (raw)
In-Reply-To: <20180921150351.20898-1-yu-cheng.yu@intel.com>
The shadow stack for clone/fork is handled as the following:
(1) If ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM),
the kernel allocates (and frees on thread exit) a new SHSTK
for the child.
It is possible for the kernel to complete the clone syscall
and set the child's SHSTK pointer to NULL and let the child
thread allocate a SHSTK for itself. There are two issues
in this approach: It is not compatible with existing code
that does inline syscall and it cannot handle signals before
the child can successfully allocate a SHSTK.
(2) For (clone_flags & CLONE_VFORK), the child uses the existing
SHSTK.
(3) For all other cases, the SHSTK is copied/reused whenever the
parent or the child does a call/ret.
This patch handles cases (1) & (2). Case (3) is handled in
the SHSTK page fault patches.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/include/asm/cet.h | 2 ++
arch/x86/include/asm/mmu_context.h | 3 +++
arch/x86/kernel/cet.c | 34 ++++++++++++++++++++++++++++++
arch/x86/kernel/process.c | 1 +
arch/x86/kernel/process_64.c | 7 ++++++
5 files changed, 47 insertions(+)
diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h
index d9ae3d86cdd7..b7b33e1026bb 100644
--- a/arch/x86/include/asm/cet.h
+++ b/arch/x86/include/asm/cet.h
@@ -17,12 +17,14 @@ struct cet_status {
#ifdef CONFIG_X86_INTEL_CET
int cet_setup_shstk(void);
+int cet_setup_thread_shstk(struct task_struct *p);
void cet_disable_shstk(void);
void cet_disable_free_shstk(struct task_struct *p);
int cet_restore_signal(unsigned long ssp);
int cet_setup_signal(bool ia32, unsigned long rstor, unsigned long *new_ssp);
#else
static inline int cet_setup_shstk(void) { return 0; }
+static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; }
static inline void cet_disable_shstk(void) {}
static inline void cet_disable_free_shstk(struct task_struct *p) {}
static inline int cet_restore_signal(unsigned long ssp) { return 0; }
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index eeeb9289c764..8da7c999b7ee 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
+#include <asm/cet.h>
extern atomic64_t last_mm_ctx_id;
@@ -223,6 +224,8 @@ do { \
#else
#define deactivate_mm(tsk, mm) \
do { \
+ if (!tsk->vfork_done) \
+ cet_disable_free_shstk(tsk); \
load_gs_index(0); \
loadsegment(fs, 0); \
} while (0)
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 5cc4be6e0982..ce0b3b7b1160 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -134,6 +134,40 @@ int cet_setup_shstk(void)
return 0;
}
+int cet_setup_thread_shstk(struct task_struct *tsk)
+{
+ unsigned long addr, size;
+ struct cet_user_state *state;
+
+ if (!current->thread.cet.shstk_enabled)
+ return 0;
+
+ state = get_xsave_addr(&tsk->thread.fpu.state.xsave,
+ XFEATURE_MASK_SHSTK_USER);
+
+ if (!state)
+ return -EINVAL;
+
+ size = tsk->thread.cet.shstk_size;
+ if (size == 0)
+ size = rlimit(RLIMIT_STACK);
+
+ addr = do_mmap_locked(0, size, PROT_READ,
+ MAP_ANONYMOUS | MAP_PRIVATE, VM_SHSTK);
+
+ if (addr >= TASK_SIZE_MAX) {
+ tsk->thread.cet.shstk_base = 0;
+ tsk->thread.cet.shstk_size = 0;
+ tsk->thread.cet.shstk_enabled = 0;
+ return -ENOMEM;
+ }
+
+ state->user_ssp = (u64)(addr + size - sizeof(u64));
+ tsk->thread.cet.shstk_base = addr;
+ tsk->thread.cet.shstk_size = size;
+ return 0;
+}
+
void cet_disable_shstk(void)
{
u64 r;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 4a776da4c28c..440f012ef925 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -125,6 +125,7 @@ void exit_thread(struct task_struct *tsk)
free_vm86(t);
+ cet_disable_free_shstk(tsk);
fpu__drop(fpu);
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ea5ea850348d..9cdbd87bb908 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -325,6 +325,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
if (sp)
childregs->sp = sp;
+ /* Allocate a new shadow stack for pthread */
+ if ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM) {
+ err = cet_setup_thread_shstk(p);
+ if (err)
+ goto out;
+ }
+
err = -ENOMEM;
if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
--
2.17.1
next prev parent reply other threads:[~2018-09-21 20:58 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 15:03 [RFC PATCH v4 00/27] Control Flow Enforcement: Shadow Stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 01/27] x86/cpufeatures: Add CPUIDs for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-25 16:27 ` Peter Zijlstra
2018-09-25 16:27 ` Peter Zijlstra
2018-09-25 16:29 ` Yu-cheng Yu
2018-09-25 16:29 ` Yu-cheng Yu
2018-09-28 16:51 ` Borislav Petkov
2018-09-28 16:51 ` Borislav Petkov
2018-09-28 16:56 ` Yu-cheng Yu
2018-09-28 16:56 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 02/27] x86/fpu/xstate: Change some names to separate XSAVES system and user states Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-25 16:37 ` Peter Zijlstra
2018-09-25 16:37 ` Peter Zijlstra
2018-10-02 15:29 ` Borislav Petkov
2018-10-02 15:29 ` Borislav Petkov
2018-10-02 16:21 ` Yu-cheng Yu
2018-10-02 16:21 ` Yu-cheng Yu
2018-10-02 16:30 ` Dave Hansen
2018-10-02 16:30 ` Dave Hansen
2018-10-02 16:37 ` Borislav Petkov
2018-10-02 16:37 ` Borislav Petkov
2018-10-02 16:39 ` Dave Hansen
2018-10-02 16:39 ` Dave Hansen
2018-10-02 16:43 ` Yu-cheng Yu
2018-10-02 16:43 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 03/27] x86/fpu/xstate: Enable XSAVES system states Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-25 17:03 ` Peter Zijlstra
2018-09-25 17:03 ` Peter Zijlstra
2018-09-25 17:23 ` Yu-cheng Yu
2018-09-25 17:23 ` Yu-cheng Yu
2018-10-02 17:15 ` Borislav Petkov
2018-10-02 17:15 ` Borislav Petkov
2018-10-04 15:47 ` Yu-cheng Yu
2018-10-04 15:47 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 04/27] x86/fpu/xstate: Add XSAVES system states for shadow stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 05/27] Documentation/x86: Add CET description Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 06/27] x86/cet: Control protection exception handler Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 10:39 ` Eugene Syromiatnikov
2018-10-03 10:39 ` Eugene Syromiatnikov
2018-10-03 16:11 ` Yu-cheng Yu
2018-10-03 16:11 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 07/27] x86/cet/shstk: Add Kconfig option for user-mode shadow stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 08/27] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 09/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 13:38 ` Matthew Wilcox
2018-10-03 13:38 ` Matthew Wilcox
2018-10-03 14:05 ` Dave Hansen
2018-10-03 14:05 ` Dave Hansen
2018-10-03 16:07 ` Yu-cheng Yu
2018-10-03 16:07 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 10/27] drm/i915/gvt: Update _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 13:19 ` Eugene Syromiatnikov
2018-10-03 13:19 ` Eugene Syromiatnikov
2018-09-21 15:03 ` [RFC PATCH v4 11/27] x86/mm: Introduce _PAGE_DIRTY_SW Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 12/27] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 13/27] x86/mm: Shadow stack page fault error checking Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 14/27] mm: Handle shadow stack page fault Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 15/27] mm: Handle THP/HugeTLB " Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 16/27] mm: Update can_follow_write_pte/pmd for shadow stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 17/27] mm: Introduce do_mmap_locked() Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 18/27] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 15:08 ` Eugene Syromiatnikov
2018-10-03 15:08 ` Eugene Syromiatnikov
2018-10-03 15:12 ` Yu-cheng Yu
2018-10-03 15:12 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 19/27] x86/cet/shstk: Introduce WRUSS instruction Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 4:15 ` Eugene Syromiatnikov
2018-10-03 4:15 ` Eugene Syromiatnikov
2018-09-21 15:03 ` [RFC PATCH v4 20/27] x86/cet/shstk: Signal handling for shadow stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 14:36 ` Eugene Syromiatnikov
2018-10-03 14:36 ` Eugene Syromiatnikov
2018-10-03 16:46 ` Jann Horn
2018-10-03 16:46 ` Jann Horn
2018-09-21 15:03 ` [RFC PATCH v4 21/27] x86/cet/shstk: ELF header parsing of Shadow Stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 23:27 ` Eugene Syromiatnikov
2018-10-03 23:27 ` Eugene Syromiatnikov
2018-10-09 21:15 ` Yu-cheng Yu
2018-10-09 21:15 ` Yu-cheng Yu
2018-10-15 23:40 ` Kees Cook
2018-10-15 23:40 ` Kees Cook
2018-10-16 17:23 ` Yu-cheng Yu
2018-10-16 17:23 ` Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu [this message]
2018-09-21 15:03 ` [RFC PATCH v4 22/27] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 23/27] mm/map: Add Shadow stack pages to memory accounting Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 16:55 ` Randy Dunlap
2018-09-21 16:55 ` Randy Dunlap
2018-09-21 17:21 ` Yu-cheng Yu
2018-09-21 17:21 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 24/27] mm/mmap: Create a guard area between VMAs Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 4:56 ` Eugene Syromiatnikov
2018-10-03 4:56 ` Eugene Syromiatnikov
2018-10-03 5:36 ` Andy Lutomirski
2018-10-03 5:36 ` Andy Lutomirski
2018-10-03 16:00 ` Yu-cheng Yu
2018-10-03 16:00 ` Yu-cheng Yu
2018-10-03 16:18 ` Andy Lutomirski
2018-10-03 16:18 ` Andy Lutomirski
2018-10-03 16:32 ` Eugene Syromiatnikov
2018-10-03 16:32 ` Eugene Syromiatnikov
2018-10-03 16:40 ` Yu-cheng Yu
2018-10-03 16:40 ` Yu-cheng Yu
2018-10-03 16:52 ` Jann Horn
2018-10-03 16:52 ` Jann Horn
2018-10-03 21:21 ` Eugene Syromiatnikov
2018-10-03 21:21 ` Eugene Syromiatnikov
2018-09-21 15:03 ` [RFC PATCH v4 25/27] mm/mmap: Prevent Shadow Stack VMA merges Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 15:03 ` [RFC PATCH v4 26/27] x86/cet/shstk: Add arch_prctl functions for Shadow Stack Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-10-03 17:57 ` Eugene Syromiatnikov
2018-10-03 17:57 ` Eugene Syromiatnikov
2018-09-21 15:03 ` [RFC PATCH v4 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map Yu-cheng Yu
2018-09-21 15:03 ` Yu-cheng Yu
2018-09-21 22:53 ` [RFC PATCH v4 00/27] Control Flow Enforcement: Shadow Stack Dave Hansen
2018-09-21 22:53 ` Dave Hansen
2018-09-24 15:25 ` Yu-cheng Yu
2018-09-24 15:25 ` Yu-cheng Yu
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