linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: alex.shi@linaro.org (Alex Shi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 06/39] arm64: entry: Ensure branch through syscall table is bounded under speculation
Date: Fri,  9 Mar 2018 17:06:49 +0800	[thread overview]
Message-ID: <20180309090722.26279-7-alex.shi@linaro.org> (raw)
In-Reply-To: <20180309090722.26279-1-alex.shi@linaro.org>

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

commit 6314d90e6493 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>
Signed-off-by: Alex Shi <alex.shi@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 229b37ddf52c..81a5f416a27a 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -101,6 +101,17 @@
 	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
+
 /*
  * NOP sequence
  */
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 274898465a3f..166cd6626ca7 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -694,6 +694,7 @@ 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
-- 
2.16.2.440.gc6284da

  parent reply	other threads:[~2018-03-09  9:06 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-09  9:06 spectre backport for LTS 4.4 review Alex Shi
2018-03-09  9:06 ` [PATCH 01/39] mm: Introduce lm_alias Alex Shi
2018-03-09  9:06 ` [PATCH 02/39] arm64: barrier: Add CSDB macros to control data-value prediction Alex Shi
2018-03-09  9:06 ` [PATCH 03/39] arm64: Implement array_index_mask_nospec() Alex Shi
2018-03-09  9:06 ` [PATCH 04/39] arm64: move TASK_* definitions to <asm/processor.h> Alex Shi
2018-03-09  9:06 ` [PATCH 05/39] arm64: Make USER_DS an inclusive limit Alex Shi
2018-03-09  9:06 ` Alex Shi [this message]
2018-03-09  9:06 ` [PATCH 07/39] arm64: Use pointer masking to limit uaccess speculation Alex Shi
2018-03-09  9:06 ` [PATCH 08/39] arm64: uaccess: Prevent speculative use of the current addr_limit Alex Shi
2018-03-09  9:06 ` [PATCH 09/39] arm64: uaccess: Don't bother eliding access_ok checks in __{get, put}_user Alex Shi
2018-03-09  9:06 ` [PATCH 10/39] arm64: futex: Mask __user pointers prior to dereference Alex Shi
2018-03-09  9:06 ` [PATCH 11/39] drivers/firmware: Expose psci_get_version through psci_ops structure Alex Shi
2018-03-09  9:06 ` [PATCH 12/39] arm64: Move post_ttbr_update_workaround to C code Alex Shi
2018-03-09  9:06 ` [PATCH 13/39] arm64: Add skeleton to harden the branch predictor against aliasing attacks Alex Shi
2018-03-09  9:06 ` [PATCH 14/39] arm64: Move BP hardening to check_and_switch_context Alex Shi
2018-03-09  9:06 ` [PATCH 15/39] arm64: KVM: Use per-CPU vector when BP hardening is enabled Alex Shi
2018-03-09  9:06 ` [PATCH 16/39] arm64: entry: Apply BP hardening for high-priority synchronous exceptions Alex Shi
2018-03-09  9:07 ` [PATCH 17/39] arm64: entry: Apply BP hardening for suspicious interrupts from EL0 Alex Shi
2018-03-09  9:07 ` [PATCH 18/39] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Alex Shi
2018-03-09  9:07 ` [PATCH 19/39] arm64: prefetch: add alternative pattern for CPUs without a prefetcher Alex Shi
2018-03-09  9:07 ` [PATCH 20/39] arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75 Alex Shi
2018-03-09  9:07 ` [PATCH 21/39] arm64: Implement branch predictor hardening for affected Cortex-A CPUs Alex Shi
2018-03-09  9:07 ` [PATCH 22/39] arm64: KVM: Increment PC after handling an SMC trap Alex Shi
2018-03-09  9:07 ` [PATCH 23/39] arm/arm64: KVM: Consolidate the PSCI include files Alex Shi
2018-03-09  9:07 ` [PATCH 24/39] arm/arm64: KVM: Add PSCI_VERSION helper Alex Shi
2018-03-09  9:07 ` [PATCH 25/39] arm/arm64: KVM: Add smccc accessors to PSCI code Alex Shi
2018-03-09  9:07 ` [PATCH 26/39] arm/arm64: KVM: Implement PSCI 1.0 support Alex Shi
2018-03-09  9:07 ` [PATCH 27/39] ARM: 8478/2: arm/arm64: add arm-smccc Alex Shi
2018-03-09  9:07 ` [PATCH 28/39] ARM: 8479/2: add implementation for arm-smccc Alex Shi
2018-03-09  9:07 ` [PATCH 29/39] ARM: 8480/2: arm64: " Alex Shi
2018-03-09  9:07 ` [PATCH 30/39] ARM: 8481/2: drivers: psci: replace psci firmware calls Alex Shi
2018-03-09  9:07 ` [PATCH 31/39] arm/arm64: KVM: Advertise SMCCC v1.1 Alex Shi
2018-03-09  9:07 ` [PATCH 32/39] arm/arm64: KVM: Turn kvm_psci_version into a static inline Alex Shi
2018-03-09  9:07 ` [PATCH 33/39] arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support Alex Shi
2018-03-09  9:07 ` [PATCH 34/39] arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling Alex Shi
2018-03-09  9:07 ` [PATCH 35/39] firmware/psci: Expose PSCI conduit Alex Shi
2018-03-09  9:07 ` [PATCH 36/39] firmware/psci: Expose SMCCC version through psci_ops Alex Shi
2018-03-09  9:07 ` [PATCH 37/39] arm/arm64: smccc: Make function identifiers an unsigned quantity Alex Shi
2018-03-09  9:07 ` [PATCH 38/39] arm/arm64: smccc: Implement SMCCC v1.1 inline primitive Alex Shi
2018-03-09  9:07 ` [PATCH 39/39] arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support Alex Shi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180309090722.26279-7-alex.shi@linaro.org \
    --to=alex.shi@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).