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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org
Cc: akpm@linux-foundation.org, dave.hansen@intel.com,
	sean.j.christopherson@intel.com, nhorman@redhat.com,
	npmccallum@redhat.com, haitao.huang@intel.com,
	andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
	kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org,
	luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
	cedric.xing@intel.com, puiterwijk@redhat.com,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH v27 17/22] x86/fault: Add helper function to sanitize error code
Date: Sun, 23 Feb 2020 19:25:54 +0200	[thread overview]
Message-ID: <20200223172559.6912-18-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20200223172559.6912-1-jarkko.sakkinen@linux.intel.com>

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add helper function to sanitize error code to prepare for vDSO exception
fixup, which will expose the error code to userspace and runs before
set_signal_archinfo(), i.e. suppresses the signal when fixup is successful.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/mm/fault.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index dee9504cde79..6b662d272af6 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -682,6 +682,18 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code,
 	oops_end(flags, regs, sig);
 }
 
+static void sanitize_error_code(unsigned long address,
+				unsigned long *error_code)
+{
+	/*
+	 * To avoid leaking information about the kernel page
+	 * table layout, pretend that user-mode accesses to
+	 * kernel addresses are always protection faults.
+	 */
+	if (address >= TASK_SIZE_MAX)
+		*error_code |= X86_PF_PROT;
+}
+
 static void set_signal_archinfo(unsigned long address,
 				unsigned long error_code)
 {
@@ -738,6 +750,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 		 * faulting through the emulate_vsyscall() logic.
 		 */
 		if (current->thread.sig_on_uaccess_err && signal) {
+			sanitize_error_code(address, &error_code);
+
 			set_signal_archinfo(address, error_code);
 
 			/* XXX: hwpoison faults will set the wrong code. */
@@ -886,13 +900,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		if (is_errata100(regs, address))
 			return;
 
-		/*
-		 * To avoid leaking information about the kernel page table
-		 * layout, pretend that user-mode accesses to kernel addresses
-		 * are always protection faults.
-		 */
-		if (address >= TASK_SIZE_MAX)
-			error_code |= X86_PF_PROT;
+		sanitize_error_code(address, &error_code);
 
 		if (likely(show_unhandled_signals))
 			show_signal_msg(regs, error_code, address, tsk);
@@ -1009,6 +1017,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 	if (is_prefetch(regs, error_code, address))
 		return;
 
+	sanitize_error_code(address, &error_code);
+
 	set_signal_archinfo(address, error_code);
 
 #ifdef CONFIG_MEMORY_FAILURE
-- 
2.20.1


  parent reply	other threads:[~2020-02-23 17:28 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-23 17:25 [PATCH v27 00/22] Intel SGX foundations Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 01/22] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 02/22] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 03/22] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 04/22] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-03-03  0:39   ` Sean Christopherson
2020-03-03 20:14     ` Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 05/22] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 06/22] x86/cpu/intel: Detect SGX supprt Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 07/22] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 08/22] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 09/22] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 10/22] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 11/22] selftests/x86: Recurse into subdirectories Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 12/22] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 13/22] x86/sgx: Add provisioning Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 14/22] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 15/22] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 16/22] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-02-23 17:25 ` Jarkko Sakkinen [this message]
2020-02-23 17:25 ` [PATCH v27 18/22] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 19/22] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 20/22] selftests/x86: Add vDSO selftest for SGX Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 21/22] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-02-23 17:25 ` [PATCH v27 22/22] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-02-24 10:09 ` [PATCH v27 00/22] Intel SGX foundations Dr. Greg
2020-02-24 21:13   ` Sean Christopherson
2020-02-28 22:02     ` Dr. Greg
2020-02-28 22:19       ` Nathaniel McCallum

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