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 v15 04/26] x86/cet: Add control-protection fault handler
Date: Tue, 10 Nov 2020 08:21:49 -0800 [thread overview]
Message-ID: <20201110162211.9207-5-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20201110162211.9207-1-yu-cheng.yu@intel.com>
A control-protection fault is triggered when a control-flow transfer
attempt violates Shadow Stack or Indirect Branch Tracking constraints.
For example, the return address for a RET instruction differs from the copy
on the Shadow Stack; or an indirect JMP instruction, without the NOTRACK
prefix, arrives at a non-ENDBR opcode.
The control-protection fault handler works in a similar way as the general
protection fault handler. It provides the si_code SEGV_CPERR to the signal
handler.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
arch/x86/include/asm/idtentry.h | 4 ++
arch/x86/kernel/idt.c | 4 ++
arch/x86/kernel/signal_compat.c | 2 +-
arch/x86/kernel/traps.c | 59 ++++++++++++++++++++++++++++++
include/uapi/asm-generic/siginfo.h | 3 +-
5 files changed, 70 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index b2442eb0ac2f..f519b8ce0273 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -577,6 +577,10 @@ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_SS, exc_stack_segment);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_GP, exc_general_protection);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_AC, exc_alignment_check);
+#ifdef CONFIG_X86_CET
+DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP, exc_control_protection);
+#endif
+
/* Raw exception entries which need extra work */
DECLARE_IDTENTRY_RAW(X86_TRAP_UD, exc_invalid_op);
DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3);
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index ee1a283f8e96..e8166d9bbb10 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -105,6 +105,10 @@ static const __initconst struct idt_data def_idts[] = {
#elif defined(CONFIG_X86_32)
SYSG(IA32_SYSCALL_VECTOR, entry_INT80_32),
#endif
+
+#ifdef CONFIG_X86_CET
+ INTG(X86_TRAP_CP, asm_exc_control_protection),
+#endif
};
/*
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index a7f3e12cfbdb..c44d4bebea07 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -27,7 +27,7 @@ static inline void signal_compat_build_tests(void)
*/
BUILD_BUG_ON(NSIGILL != 11);
BUILD_BUG_ON(NSIGFPE != 15);
- BUILD_BUG_ON(NSIGSEGV != 9);
+ BUILD_BUG_ON(NSIGSEGV != 10);
BUILD_BUG_ON(NSIGBUS != 5);
BUILD_BUG_ON(NSIGTRAP != 5);
BUILD_BUG_ON(NSIGCHLD != 6);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index e19df6cde35d..6c21c1e92605 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -598,6 +598,65 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
cond_local_irq_disable(regs);
}
+#ifdef CONFIG_X86_CET
+static const char * const control_protection_err[] = {
+ "unknown",
+ "near-ret",
+ "far-ret/iret",
+ "endbranch",
+ "rstorssp",
+ "setssbsy",
+};
+
+/*
+ * When a control protection exception occurs, send a signal
+ * to the responsible application. Currently, control
+ * protection is only enabled for the user mode. This
+ * exception should not come from the kernel mode.
+ */
+DEFINE_IDTENTRY_ERRORCODE(exc_control_protection)
+{
+ struct task_struct *tsk;
+
+ if (notify_die(DIE_TRAP, "control protection fault", regs,
+ error_code, X86_TRAP_CP, SIGSEGV) == NOTIFY_STOP)
+ return;
+ cond_local_irq_enable(regs);
+
+ if (!user_mode(regs))
+ die("kernel control protection fault", regs, error_code);
+
+ if (!static_cpu_has(X86_FEATURE_SHSTK) &&
+ !static_cpu_has(X86_FEATURE_IBT))
+ WARN_ONCE(1, "CET is disabled but got control protection fault\n");
+
+ tsk = current;
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_nr = X86_TRAP_CP;
+
+ if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+ printk_ratelimit()) {
+ unsigned int max_err;
+ unsigned long ssp;
+
+ max_err = ARRAY_SIZE(control_protection_err) - 1;
+ if ((error_code < 0) || (error_code > max_err))
+ error_code = 0;
+ rdmsrl(MSR_IA32_PL3_SSP, ssp);
+ pr_info("%s[%d] control protection ip:%lx sp:%lx ssp:%lx error:%lx(%s)",
+ tsk->comm, task_pid_nr(tsk),
+ regs->ip, regs->sp, ssp, error_code,
+ control_protection_err[error_code]);
+ print_vma_addr(KERN_CONT " in ", regs->ip);
+ pr_cont("\n");
+ }
+
+ force_sig_fault(SIGSEGV, SEGV_CPERR,
+ (void __user *)uprobe_get_trap_addr(regs));
+ cond_local_irq_disable(regs);
+}
+#endif
+
static bool do_int3(struct pt_regs *regs)
{
int res;
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 7aacf9389010..96b9647d14ae 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -231,7 +231,8 @@ typedef struct siginfo {
#define SEGV_ADIPERR 7 /* Precise MCD exception */
#define SEGV_MTEAERR 8 /* Asynchronous ARM MTE error */
#define SEGV_MTESERR 9 /* Synchronous ARM MTE exception */
-#define NSIGSEGV 9
+#define SEGV_CPERR 10 /* Control protection fault */
+#define NSIGSEGV 10
/*
* SIGBUS si_codes
--
2.21.0
next prev parent reply other threads:[~2020-11-10 16:23 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 16:21 [PATCH v15 00/26] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 01/26] Documentation/x86: Add CET description Yu-cheng Yu
2020-11-30 18:26 ` Nick Desaulniers
2020-11-30 18:34 ` Yu, Yu-cheng
2020-11-30 19:38 ` Fāng-ruì Sòng
2020-11-30 19:47 ` Yu, Yu-cheng
2020-11-10 16:21 ` [PATCH v15 02/26] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 03/26] x86/fpu/xstate: Introduce CET MSR XSAVES supervisor states Yu-cheng Yu
2020-11-26 11:02 ` Borislav Petkov
2020-11-30 17:45 ` [NEEDS-REVIEW] " Dave Hansen
2020-11-30 18:06 ` Yu, Yu-cheng
2020-11-30 18:12 ` Dave Hansen
2020-11-30 18:17 ` Yu, Yu-cheng
2020-11-30 23:16 ` Yu, Yu-cheng
2020-12-01 22:26 ` Dave Hansen
2020-12-01 22:35 ` Yu, Yu-cheng
2020-11-10 16:21 ` Yu-cheng Yu [this message]
2020-11-26 18:49 ` [PATCH v15 04/26] x86/cet: Add control-protection fault handler Borislav Petkov
2020-11-10 16:21 ` [PATCH v15 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Yu-cheng Yu
2020-11-27 17:10 ` Borislav Petkov
2020-11-28 16:23 ` Yu, Yu-cheng
2020-11-30 18:15 ` Borislav Petkov
2020-11-30 22:48 ` Yu, Yu-cheng
2020-12-01 16:02 ` Borislav Petkov
2020-11-30 19:56 ` Nick Desaulniers
2020-11-30 20:30 ` Yu, Yu-cheng
2020-11-10 16:21 ` [PATCH v15 06/26] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2020-12-03 9:19 ` Borislav Petkov
2020-12-03 15:12 ` Dave Hansen
2020-12-03 15:56 ` Yu, Yu-cheng
2020-11-10 16:21 ` [PATCH v15 07/26] x86/mm: Remove _PAGE_DIRTY_HW from kernel RO pages Yu-cheng Yu
2020-12-07 16:36 ` Borislav Petkov
2020-12-07 17:11 ` Yu, Yu-cheng
2020-11-10 16:21 ` [PATCH v15 08/26] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2020-12-08 17:50 ` Borislav Petkov
2020-12-08 18:25 ` Yu, Yu-cheng
[not found] ` <20201208184727.GF27920@zn.tnic>
2020-12-08 19:24 ` Yu, Yu-cheng
2020-12-10 17:41 ` Borislav Petkov
2020-12-10 18:10 ` Yu, Yu-cheng
2020-11-10 16:21 ` [PATCH v15 09/26] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 10/26] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 11/26] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY_HW to _PAGE_COW Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 12/26] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 13/26] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2020-11-10 16:21 ` [PATCH v15 14/26] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 15/26] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 16/26] mm: Add guard pages around a shadow stack Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 17/26] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 18/26] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 19/26] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 20/26] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 21/26] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 22/26] binfmt_elf: Define GNU_PROPERTY_X86_FEATURE_1_AND properties Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 23/26] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 24/26] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 25/26] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2020-11-10 16:22 ` [PATCH v15 26/26] mm: Introduce PROT_SHSTK " Yu-cheng Yu
2020-11-27 9:29 ` [PATCH v15 00/26] Control-flow Enforcement: Shadow Stack Balbir Singh
2020-11-28 16:31 ` Yu, Yu-cheng
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