From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H.J. Lu" <hjl.tools@gmail.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Jonathan Corbet <corbet@lwn.net>, Oleg Nesterov <oleg@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
Mike Kravetz <mike.kravetz@oracle.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH 03/10] x86/cet: Signal handling for shadow stack
Date: Thu, 7 Jun 2018 07:38:00 -0700 [thread overview]
Message-ID: <20180607143807.3611-4-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20180607143807.3611-1-yu-cheng.yu@intel.com>
Set and restore shadow stack pointer for signals.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/ia32/ia32_signal.c | 5 ++++
arch/x86/include/asm/cet.h | 7 +++++
arch/x86/include/uapi/asm/sigcontext.h | 4 +++
arch/x86/kernel/cet.c | 51 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/signal.c | 11 ++++++++
5 files changed, 78 insertions(+)
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 86b1341cba9a..26a776baff7c 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -34,6 +34,7 @@
#include <asm/sigframe.h>
#include <asm/sighandling.h>
#include <asm/smap.h>
+#include <asm/cet.h>
/*
* Do a signal return; undo the signal stack.
@@ -74,6 +75,7 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
unsigned int tmpflags, err = 0;
void __user *buf;
u32 tmp;
+ u32 ssp;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
@@ -104,9 +106,11 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
get_user_ex(tmp, &sc->fpstate);
buf = compat_ptr(tmp);
+ get_user_ex(ssp, &sc->ssp);
} get_user_catch(err);
err |= fpu__restore_sig(buf, 1);
+ err |= cet_restore_signal((unsigned long)ssp);
force_iret();
@@ -194,6 +198,7 @@ static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc,
put_user_ex(current->thread.trap_nr, &sc->trapno);
put_user_ex(current->thread.error_code, &sc->err);
put_user_ex(regs->ip, &sc->ip);
+ put_user_ex((u32)cet_get_shstk_ptr(), &sc->ssp);
put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
put_user_ex(regs->flags, &sc->flags);
put_user_ex(regs->sp, &sc->sp_at_signal);
diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h
index 9d5bc1efc9b7..5507469cb803 100644
--- a/arch/x86/include/asm/cet.h
+++ b/arch/x86/include/asm/cet.h
@@ -17,14 +17,21 @@ struct cet_stat {
#ifdef CONFIG_X86_INTEL_CET
unsigned long cet_get_shstk_ptr(void);
+int cet_push_shstk(int ia32, unsigned long ssp, unsigned long val);
int cet_setup_shstk(void);
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(int ia32, unsigned long addr);
#else
static inline unsigned long cet_get_shstk_ptr(void) { return 0; }
+static inline int cet_push_shstk(int ia32, unsigned long ssp,
+ unsigned long val) { return 0; }
static inline int cet_setup_shstk(void) { 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; }
+static inline int cet_setup_signal(int ia32, unsigned long addr) { return 0; }
#endif
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/uapi/asm/sigcontext.h b/arch/x86/include/uapi/asm/sigcontext.h
index 844d60eb1882..6c8997a0156a 100644
--- a/arch/x86/include/uapi/asm/sigcontext.h
+++ b/arch/x86/include/uapi/asm/sigcontext.h
@@ -230,6 +230,7 @@ struct sigcontext_32 {
__u32 fpstate; /* Zero when no FPU/extended context */
__u32 oldmask;
__u32 cr2;
+ __u32 ssp;
};
/*
@@ -262,6 +263,7 @@ struct sigcontext_64 {
__u64 trapno;
__u64 oldmask;
__u64 cr2;
+ __u64 ssp;
/*
* fpstate is really (struct _fpstate *) or (struct _xstate *)
@@ -320,6 +322,7 @@ struct sigcontext {
struct _fpstate __user *fpstate;
__u32 oldmask;
__u32 cr2;
+ __u32 ssp;
};
# else /* __x86_64__: */
struct sigcontext {
@@ -377,6 +380,7 @@ struct sigcontext {
__u64 trapno;
__u64 oldmask;
__u64 cr2;
+ __u64 ssp;
struct _fpstate __user *fpstate; /* Zero when no FPU context */
# ifdef __ILP32__
__u32 __fpstate_pad;
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index 8abbfd44322a..6f445ce94c83 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c
@@ -17,6 +17,7 @@
#include <asm/fpu/xstate.h>
#include <asm/fpu/types.h>
#include <asm/cet.h>
+#include <asm/special_insns.h>
#define SHSTK_SIZE (0x8000 * (test_thread_flag(TIF_IA32) ? 4 : 8))
@@ -47,6 +48,24 @@ unsigned long cet_get_shstk_ptr(void)
return ptr;
}
+int cet_push_shstk(int ia32, unsigned long ssp, unsigned long val)
+{
+ if (val >= TASK_SIZE)
+ return -EINVAL;
+
+ if (IS_ENABLED(CONFIG_IA32_EMULATION) && ia32) {
+ if (!IS_ALIGNED(ssp, 4))
+ return -EINVAL;
+ cet_set_shstk_ptr(ssp);
+ return write_user_shstk_32(ssp, (unsigned int)val);
+ } else {
+ if (!IS_ALIGNED(ssp, 8))
+ return -EINVAL;
+ cet_set_shstk_ptr(ssp);
+ return write_user_shstk_64(ssp, val);
+ }
+}
+
static unsigned long shstk_mmap(unsigned long addr, unsigned long len)
{
struct mm_struct *mm = current->mm;
@@ -121,3 +140,35 @@ void cet_disable_free_shstk(struct task_struct *tsk)
tsk->thread.cet.shstk_enabled = 0;
}
+
+int cet_restore_signal(unsigned long ssp)
+{
+ if (!current->thread.cet.shstk_enabled)
+ return 0;
+ return cet_set_shstk_ptr(ssp);
+}
+
+int cet_setup_signal(int ia32, unsigned long rstor_addr)
+{
+ unsigned long ssp;
+ struct cet_stat *cet = ¤t->thread.cet;
+
+ if (!current->thread.cet.shstk_enabled)
+ return 0;
+
+ ssp = cet_get_shstk_ptr();
+
+ /*
+ * Put the restorer address on the shstk
+ */
+ if (ia32)
+ ssp -= sizeof(u32);
+ else
+ ssp -= sizeof(rstor_addr);
+
+ if (ssp >= (cet->shstk_base + cet->shstk_size) ||
+ ssp < cet->shstk_base)
+ return -EINVAL;
+
+ return cet_push_shstk(ia32, ssp, rstor_addr);
+}
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index da270b95fe4d..86fb897cae19 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -46,6 +46,7 @@
#include <asm/sigframe.h>
#include <asm/signal.h>
+#include <asm/cet.h>
#define COPY(x) do { \
get_user_ex(regs->x, &sc->x); \
@@ -102,6 +103,7 @@ static int restore_sigcontext(struct pt_regs *regs,
void __user *buf;
unsigned int tmpflags;
unsigned int err = 0;
+ unsigned long ssp = 0;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
@@ -148,9 +150,11 @@ static int restore_sigcontext(struct pt_regs *regs,
get_user_ex(buf_val, &sc->fpstate);
buf = (void __user *)buf_val;
+ get_user_ex(ssp, &sc->ssp);
} get_user_catch(err);
err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));
+ err |= cet_restore_signal(ssp);
force_iret();
@@ -193,6 +197,7 @@ int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
put_user_ex(current->thread.trap_nr, &sc->trapno);
put_user_ex(current->thread.error_code, &sc->err);
put_user_ex(regs->ip, &sc->ip);
+ put_user_ex(cet_get_shstk_ptr(), &sc->ssp);
#ifdef CONFIG_X86_32
put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
put_user_ex(regs->flags, &sc->flags);
@@ -742,6 +747,12 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
user_disable_single_step(current);
failed = (setup_rt_frame(ksig, regs) < 0);
+ if (!failed) {
+ unsigned long rstor = (unsigned long)ksig->ka.sa.sa_restorer;
+ int ia32 = is_ia32_frame(ksig);
+
+ failed = cet_setup_signal(ia32, rstor);
+ }
if (!failed) {
/*
* Clear the direction flag as per the ABI for function entry.
--
2.15.1
next prev parent reply other threads:[~2018-06-07 15:43 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-07 14:37 [PATCH 00/10] Control Flow Enforcement - Part (3) Yu-cheng Yu
2018-06-07 14:37 ` [PATCH 01/10] x86/cet: User-mode shadow stack support Yu-cheng Yu
2018-06-07 16:37 ` Andy Lutomirski
2018-06-07 17:46 ` Yu-cheng Yu
2018-06-07 17:55 ` Dave Hansen
2018-06-07 18:23 ` Andy Lutomirski
2018-06-12 11:56 ` Balbir Singh
2018-06-12 15:03 ` Yu-cheng Yu
2018-06-07 14:37 ` [PATCH 02/10] x86/cet: Introduce WRUSS instruction Yu-cheng Yu
2018-06-07 16:40 ` Andy Lutomirski
2018-06-07 16:51 ` Yu-cheng Yu
2018-06-07 18:41 ` Peter Zijlstra
2018-06-07 20:31 ` Yu-cheng Yu
2018-06-11 8:17 ` Peter Zijlstra
2018-06-11 15:02 ` Yu-cheng Yu
2018-06-14 1:30 ` Balbir Singh
2018-06-14 14:43 ` Yu-cheng Yu
2018-06-07 14:38 ` Yu-cheng Yu [this message]
2018-06-07 18:30 ` [PATCH 03/10] x86/cet: Signal handling for shadow stack Andy Lutomirski
2018-06-07 18:58 ` Florian Weimer
2018-06-07 19:51 ` Yu-cheng Yu
2018-06-07 20:07 ` Cyrill Gorcunov
2018-06-07 20:57 ` Andy Lutomirski
2018-06-08 12:07 ` Cyrill Gorcunov
2018-06-07 20:12 ` Yu-cheng Yu
2018-06-07 20:17 ` Dave Hansen
2018-06-07 14:38 ` [PATCH 04/10] x86/cet: Handle thread " Yu-cheng Yu
2018-06-07 18:21 ` Andy Lutomirski
2018-06-07 19:47 ` Florian Weimer
2018-06-07 20:53 ` Andy Lutomirski
2018-06-08 14:53 ` Florian Weimer
2018-06-08 15:01 ` Andy Lutomirski
2018-06-08 15:50 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 05/10] x86/cet: ELF header parsing of Control Flow Enforcement Yu-cheng Yu
2018-06-07 18:38 ` Andy Lutomirski
2018-06-07 20:40 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 06/10] x86/cet: Add arch_prctl functions for shadow stack Yu-cheng Yu
2018-06-07 18:48 ` Andy Lutomirski
2018-06-07 20:30 ` Yu-cheng Yu
2018-06-07 21:01 ` Andy Lutomirski
2018-06-07 22:02 ` H.J. Lu
2018-06-07 23:01 ` Andy Lutomirski
2018-06-08 4:09 ` H.J. Lu
2018-06-08 4:38 ` Andy Lutomirski
2018-06-08 12:24 ` H.J. Lu
2018-06-08 14:57 ` Andy Lutomirski
2018-06-08 15:52 ` Cyrill Gorcunov
2018-06-08 4:22 ` H.J. Lu
2018-06-08 4:35 ` Andy Lutomirski
2018-06-08 12:17 ` H.J. Lu
2018-06-12 10:03 ` Thomas Gleixner
2018-06-12 11:43 ` H.J. Lu
2018-06-12 16:01 ` Andy Lutomirski
2018-06-12 16:05 ` H.J. Lu
2018-06-12 16:34 ` Andy Lutomirski
2018-06-12 16:51 ` H.J. Lu
2018-06-12 18:59 ` Thomas Gleixner
2018-06-12 19:34 ` H.J. Lu
2018-06-18 22:03 ` Andy Lutomirski
2018-06-19 0:52 ` Kees Cook
2018-06-19 6:40 ` Florian Weimer
2018-06-19 14:50 ` Andy Lutomirski
2018-06-19 16:44 ` Kees Cook
2018-06-19 16:59 ` Yu-cheng Yu
2018-06-19 17:07 ` Kees Cook
2018-06-19 17:20 ` Andy Lutomirski
2018-06-19 20:12 ` Kees Cook
2018-06-19 20:47 ` Andy Lutomirski
2018-06-19 22:38 ` Yu-cheng Yu
2018-06-20 0:50 ` Andy Lutomirski
2018-06-21 23:07 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 07/10] mm: Prevent mprotect from changing " Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 08/10] mm: Prevent mremap of " Yu-cheng Yu
2018-06-07 18:48 ` Andy Lutomirski
2018-06-07 20:18 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 09/10] mm: Prevent madvise from changing " Yu-cheng Yu
2018-06-07 20:54 ` Andy Lutomirski
2018-06-07 21:09 ` Nadav Amit
2018-06-07 21:18 ` Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 10/10] mm: Prevent munmap and remap_file_pages of " Yu-cheng Yu
2018-06-07 18:50 ` Andy Lutomirski
2018-06-07 20:15 ` Yu-cheng Yu
2018-06-12 10:56 ` [PATCH 00/10] Control Flow Enforcement - Part (3) Balbir Singh
2018-06-12 15:03 ` Yu-cheng Yu
2018-06-12 16:00 ` Andy Lutomirski
2018-06-12 16:21 ` Yu-cheng Yu
2018-06-12 16:31 ` Andy Lutomirski
2018-06-12 17:24 ` Yu-cheng Yu
2018-06-12 20:15 ` Yu-cheng Yu
2018-06-14 1:07 ` Balbir Singh
2018-06-14 14:56 ` Yu-cheng Yu
2018-06-17 3:16 ` Balbir Singh
2018-06-18 21:44 ` Andy Lutomirski
2018-06-19 8:52 ` Balbir Singh
2018-06-26 2:46 ` Jann Horn
2018-06-26 14:56 ` Yu-cheng Yu
2018-06-26 5:26 ` Andy Lutomirski
2018-06-26 14:56 ` Yu-cheng Yu
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