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From: Viresh Kumar <viresh.kumar@linaro.org>
To: stable@vger.kernel.org, Julien Thierry <Julien.Thierry@arm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Russell King <rmk+kernel@arm.linux.org.uk>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	mark.brown@arm.com
Subject: [PATCH v4.4 V2 06/43] arm64: entry: Ensure branch through syscall table is bounded under speculation
Date: Fri, 12 Jul 2019 10:57:54 +0530	[thread overview]
Message-ID: <a7530ecb5571c4f5e6b88547f61c77c68194cc0f.1562908075.git.viresh.kumar@linaro.org> (raw)
In-Reply-To: <cover.1562908074.git.viresh.kumar@linaro.org>

From: Will Deacon <will.deacon@arm.com>

commit 6314d90e64936c584f300a52ef173603fb2461b5 upstream.

In a similar manner to array_index_mask_nospec, this patch introduces an
assembly macro (mask_nospec64) which can be used to bound a value under
speculation. This macro is then used to ensure that the indirect branch
through the syscall table is bounded under speculation, with out-of-range
addresses speculating as calls to sys_io_setup (0).

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ v4.4: use existing scno & sc_nr definitions ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 arch/arm64/include/asm/assembler.h | 11 +++++++++++
 arch/arm64/kernel/entry.S          |  1 +
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 683c2875278f..2b30363a3a89 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -102,6 +102,17 @@
 	hint	#20
 	.endm
 
+/*
+ * Sanitise a 64-bit bounded index wrt speculation, returning zero if out
+ * of bounds.
+ */
+	.macro	mask_nospec64, idx, limit, tmp
+	sub	\tmp, \idx, \limit
+	bic	\tmp, \tmp, \idx
+	and	\idx, \idx, \tmp, asr #63
+	csdb
+	.endm
+
 #define USER(l, x...)				\
 9999:	x;					\
 	.section __ex_table,"a";		\
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 4c5013b09dcb..e6aec982dea9 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -697,6 +697,7 @@ el0_svc_naked:					// compat entry point
 	b.ne	__sys_trace
 	cmp     scno, sc_nr                     // check upper syscall limit
 	b.hs	ni_sys
+	mask_nospec64 scno, sc_nr, x19	// enforce bounds for syscall number
 	ldr	x16, [stbl, scno, lsl #3]	// address in the syscall table
 	blr	x16				// call sys_* routine
 	b	ret_fast_syscall
-- 
2.21.0.rc0.269.g1a574e7a288b


  parent reply	other threads:[~2019-07-12  5:29 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-12  5:27 [PATCH v4.4 V2 00/43] V4.4 backport of arm64 Spectre patches Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 01/43] arm64: barrier: Add CSDB macros to control data-value prediction Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 02/43] arm64: Implement array_index_mask_nospec() Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 03/43] arm64: move TASK_* definitions to <asm/processor.h> Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 04/43] arm64: Make USER_DS an inclusive limit Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 05/43] arm64: Use pointer masking to limit uaccess speculation Viresh Kumar
2019-07-12  5:27 ` Viresh Kumar [this message]
2019-07-12  5:27 ` [PATCH v4.4 V2 07/43] arm64: uaccess: Prevent speculative use of the current addr_limit Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 08/43] arm64: uaccess: Don't bother eliding access_ok checks in __{get, put}_user Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 09/43] mm/kasan: add API to check memory regions Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 10/43] arm64: kasan: instrument user memory access API Viresh Kumar
2019-07-12  5:27 ` [PATCH v4.4 V2 11/43] arm64: uaccess: Mask __user pointers for __arch_{clear, copy_*}_user Viresh Kumar
2019-07-31 12:37   ` Mark Rutland
2019-08-01  3:38     ` Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 12/43] arm64: cpufeature: Test 'matches' pointer to find the end of the list Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 13/43] arm64: cpufeature: Add scope for capability check Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 14/43] arm64: Introduce cpu_die_early Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 15/43] arm64: Move cpu_die_early to smp.c Viresh Kumar
2019-07-31 12:35   ` Mark Rutland
2019-08-01  3:35     ` Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 16/43] arm64: Verify CPU errata work arounds on hotplugged CPU Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 17/43] arm64: errata: Calling enable functions for CPU errata too Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 18/43] arm64: Rearrange CPU errata workaround checks Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 19/43] arm64: Run enable method for errata work arounds on late CPUs Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 20/43] arm64: cpufeature: Pass capability structure to ->enable callback Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 21/43] drivers/firmware: Expose psci_get_version through psci_ops structure Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 22/43] arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 23/43] arm64: Move post_ttbr_update_workaround to C code Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 24/43] arm64: Add skeleton to harden the branch predictor against aliasing attacks Viresh Kumar
2019-07-31 16:45   ` Mark Rutland
2019-08-01  5:20     ` Viresh Kumar
2019-08-06 12:18       ` Mark Rutland
2019-08-08 12:06         ` Viresh Kumar
2019-08-28 10:23           ` Viresh Kumar
2019-08-28 16:08           ` Mark Rutland
2019-07-12  5:28 ` [PATCH v4.4 V2 25/43] arm64: Move BP hardening to check_and_switch_context Viresh Kumar
2019-07-31 13:09   ` Julien Thierry
2019-08-01  5:09     ` Viresh Kumar
2019-08-01  6:30       ` Julien Thierry
2019-08-01  6:35         ` Viresh Kumar
2019-08-01  6:57           ` Greg KH
2019-08-01  7:05             ` Viresh Kumar
2019-08-01  7:34               ` Will Deacon
2019-08-01  7:41                 ` Viresh Kumar
2019-08-01  8:43                 ` Greg KH
2019-08-01  8:49                   ` Julien Thierry
2019-07-12  5:28 ` [PATCH v4.4 V2 26/43] arm64: entry: Apply BP hardening for high-priority synchronous exceptions Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 27/43] arm64: entry: Apply BP hardening for suspicious interrupts from EL0 Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 28/43] arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75 Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 29/43] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 30/43] arm64: Implement branch predictor hardening for affected Cortex-A CPUs Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 31/43] arm64: cputype info for Broadcom Vulcan Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 32/43] arm64: cputype: Add MIDR values for Cavium ThunderX2 CPUs Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 33/43] arm64: Branch predictor hardening for Cavium ThunderX2 Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 34/43] ARM: 8478/2: arm/arm64: add arm-smccc Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 35/43] arm/arm64: KVM: Advertise SMCCC v1.1 Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 36/43] arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 37/43] firmware/psci: Expose PSCI conduit Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 38/43] firmware/psci: Expose SMCCC version through psci_ops Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 39/43] arm/arm64: smccc: Make function identifiers an unsigned quantity Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 40/43] arm/arm64: smccc: Implement SMCCC v1.1 inline primitive Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 41/43] arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 42/43] arm64: Kill PSCI_GET_VERSION as a variant-2 workaround Viresh Kumar
2019-07-12  5:28 ` [PATCH v4.4 V2 43/43] arm64: futex: Mask __user pointers prior to dereference Viresh Kumar
2019-07-15 13:09 ` [PATCH v4.4 V2 00/43] V4.4 backport of arm64 Spectre patches Mark Rutland
2019-07-16  3:44   ` Viresh Kumar
2019-07-31  2:52 ` Viresh Kumar
2019-07-31 17:02   ` Mark Rutland

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