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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,
	Jethro Beekman <jethro@fortanix.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code
Date: Fri, 15 May 2020 03:44:05 +0300	[thread overview]
Message-ID: <20200515004410.723949-16-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20200515004410.723949-1-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>
Acked-by: Jethro Beekman <jethro@fortanix.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 16c53c874bb9..23666e34abbc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -704,6 +704,18 @@ 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)
 {
@@ -760,6 +772,8 @@ 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. */
@@ -908,13 +922,7 @@ __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);
@@ -1031,6 +1039,8 @@ 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
-- 
2.25.1


  parent reply	other threads:[~2020-05-15  0:46 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-05-20 12:16   ` Borislav Petkov
2020-05-20 14:00     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-05-20 12:23   ` Borislav Petkov
2020-05-20 14:04     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-05-20 18:47   ` Borislav Petkov
2020-05-20 21:04     ` Sean Christopherson
2020-05-22 15:54     ` Jarkko Sakkinen
2020-05-22 16:13       ` Sean Christopherson
2020-05-22 19:50         ` Jarkko Sakkinen
2020-05-25  8:20           ` Borislav Petkov
2020-05-27 19:43             ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-05-25  9:23   ` Borislav Petkov
2020-05-27  3:56     ` Sean Christopherson
2020-05-27 20:35       ` Borislav Petkov
2020-05-28  7:36         ` Jarkko Sakkinen
2020-05-28  5:25       ` Jarkko Sakkinen
2020-05-28  5:35         ` Jarkko Sakkinen
2020-05-28  6:14           ` Jarkko Sakkinen
2020-05-28  6:16             ` Jarkko Sakkinen
2020-05-28  5:13     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-05-26 12:52   ` Borislav Petkov
2020-05-27  4:21     ` Sean Christopherson
2020-05-27 20:46       ` Borislav Petkov
2020-05-28  0:52         ` Sean Christopherson
2020-05-28  6:51           ` Jarkko Sakkinen
2020-05-28  1:23         ` Jarkko Sakkinen
2020-05-28  1:36           ` Sean Christopherson
2020-05-28  6:52             ` Jarkko Sakkinen
2020-05-28 17:16               ` Borislav Petkov
2020-05-28 17:19                 ` Sean Christopherson
2020-05-28 17:27                   ` Borislav Petkov
2020-05-28 17:34                     ` Sean Christopherson
2020-05-28 19:07                 ` Jarkko Sakkinen
2020-05-28 19:59                   ` Sean Christopherson
2020-05-29  3:28                     ` Jarkko Sakkinen
2020-05-29  3:37                       ` Sean Christopherson
2020-05-29  5:07                         ` Jarkko Sakkinen
2020-05-29  8:12                         ` Jarkko Sakkinen
2020-05-29  8:13                           ` Jarkko Sakkinen
2020-05-29  3:38                       ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-05-29 12:10   ` Borislav Petkov
2020-05-29 18:18     ` Jarkko Sakkinen
2020-05-29 18:28   ` Dave Hansen
2020-05-31 23:12     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-05-21 19:12   ` Sean Christopherson
2020-05-22 19:26     ` Jarkko Sakkinen
2020-05-22 19:39     ` Jarkko Sakkinen
2020-05-22  3:33   ` Sean Christopherson
2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-05-22  6:58   ` Sean Christopherson
2020-05-22 19:57     ` Jarkko Sakkinen
2020-05-22 21:52       ` Sean Christopherson
2020-05-22  7:15   ` Sean Christopherson
2020-05-22 19:47     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-05-15  0:44 ` Jarkko Sakkinen [this message]
2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen

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