Thread (18 messages) flat view 18 messages, 3 authors, 2018-09-24

[PATCH RESEND 3/6] arm64: add sysfs vulnerability show for spectre v1

From: Robert Richter <hidden>
Date: 2018-09-17 17:25:21
Also in: lkml

On 27.08.18 16:33:07, Mian Yousaf Kaukab wrote:
Hard-coded since patches are merged and there are no configuration
options.
Could you add a list of upstream patches to the description that are
required to solve this? This would be a strict definition for the
mitigation being enabled and makes it easier to check if backports are
affected or not. A build-time check would be ideal (e.g. checking for
certain macros).

Looking at arm64/kpti I see the following patches:

f84a56f73ddd^..f3804203306e 669474e772b9^..91b2d3442f6a

v4.16-rc1  f84a56f73ddd Documentation: Document array_index_nospec
v4.16-rc1  f3804203306e array_index_nospec: Sanitize speculative array de-references
v4.16-rc1  669474e772b9 arm64: barrier: Add CSDB macros to control data-value prediction
v4.16-rc1  022620eed3d0 arm64: Implement array_index_mask_nospec()
v4.16-rc1  51369e398d0d arm64: Make USER_DS an inclusive limit
v4.16-rc1  4d8efc2d5ee4 arm64: Use pointer masking to limit uaccess speculation
v4.16-rc1  6314d90e6493 arm64: entry: Ensure branch through syscall table is bounded under speculation
v4.16-rc1  c2f0ad4fc089 arm64: uaccess: Prevent speculative use of the current addr_limit
v4.16-rc1  84624087dd7e arm64: uaccess: Don't bother eliding access_ok checks in __{get, put}_user
v4.16-rc1  f71c2ffcb20d arm64: uaccess: Mask __user pointers for __arch_{clear, copy_*}_user
v4.16-rc1  91b2d3442f6a arm64: futex: Mask __user pointers prior to dereference

-Robert
quoted hunk ↗ jump to hunk
Signed-off-by: Mian Yousaf Kaukab <redacted>
---
 arch/arm64/kernel/cpu_errata.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 996edb4e18ad..92616431ae4e 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -706,4 +706,10 @@ ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
        return sprintf(buf, "Vulnerable\n");
 }

+ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
+               char *buf)
+{
+       return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+}
+
 #endif
--
2.11.0
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