This is a note to let you know that I've just added the patch titled
powerpc/pseries: Restore default security feature flags on setup
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-pseries-restore-default-security-feature-flags-on-setup.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.
>From foo@baz Sun May 27 15:47:18 CEST 2018
From: Michael Ellerman <m...@ellerman.id.au>
Date: Sat, 26 May 2018 14:27:47 +1000
Subject: powerpc/pseries: Restore default security feature flags on setup
To: g...@kroah.com
Cc: sta...@vger.kernel.org, t...@linutronix.de, linuxppc-...@ozlabs.org
Message-ID: <20180526042749.5324-22-...@ellerman.id.au>
From: Mauricio Faria de Oliveira <mauri...@linux.vnet.ibm.com>
commit 6232774f1599028a15418179d17f7df47ede770a upstream.
After migration the security feature flags might have changed (e.g.,
destination system with unpatched firmware), but some flags are not
set/clear again in init_cpu_char_feature_flags() because it assumes
the security flags to be the defaults.
Additionally, if the H_GET_CPU_CHARACTERISTICS hypercall fails then
init_cpu_char_feature_flags() does not run again, which potentially
might leave the system in an insecure or sub-optimal configuration.
So, just restore the security feature flags to the defaults assumed
by init_cpu_char_feature_flags() so it can set/clear them correctly,
and to ensure safe settings are in place in case the hypercall fail.
Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags")
Depends-on: 19887d6a28e2 ("powerpc: Move default security feature flags")
Signed-off-by: Mauricio Faria de Oliveira <mauri...@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/powerpc/platforms/pseries/setup.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -462,6 +462,10 @@ static void __init find_and_init_phbs(vo
static void init_cpu_char_feature_flags(struct h_cpu_char_result *result)
{
+ /*
+ * The features below are disabled by default, so we instead look to see
+ * if firmware has *enabled* them, and set them if so.
+ */
if (result->character & H_CPU_CHAR_SPEC_BAR_ORI31)
security_ftr_set(SEC_FTR_SPEC_BAR_ORI31);
@@ -501,6 +505,13 @@ void pseries_setup_rfi_flush(void)
bool enable;
long rc;
+ /*
+ * Set features to the defaults assumed by init_cpu_char_feature_flags()
+ * so it can set/clear again any features that might have changed after
+ * migration, and in case the hypercall fails and it is not even called.
+ */
+ powerpc_security_features = SEC_FTR_DEFAULT;
+
rc = plpar_get_cpu_characteristics(&result);
if (rc == H_SUCCESS)
init_cpu_char_feature_flags(&result);
Patches currently in stable-queue which might be from m...@ellerman.id.au are
queue-4.14/powerpc-64s-clear-pcr-on-boot.patch
queue-4.14/powerpc-rfi-flush-differentiate-enabled-and-patched-flush-types.patch
queue-4.14/powerpc-64s-fix-section-mismatch-warnings-from-setup_rfi_flush.patch
queue-4.14/powerpc-pseries-fix-clearing-of-security-feature-flags.patch
queue-4.14/powerpc-powernv-set-or-clear-security-feature-flags.patch
queue-4.14/powerpc-64s-move-cpu_show_meltdown.patch
queue-4.14/powerpc-rfi-flush-call-setup_rfi_flush-after-lpm-migration.patch
queue-4.14/powerpc-pseries-set-or-clear-security-feature-flags.patch
queue-4.14/powerpc-rfi-flush-make-it-possible-to-call-setup_rfi_flush-again.patch
queue-4.14/powerpc-move-default-security-feature-flags.patch
queue-4.14/powerpc-powernv-use-the-security-flags-in-pnv_setup_rfi_flush.patch
queue-4.14/powerpc-add-security-feature-flags-for-spectre-meltdown.patch
queue-4.14/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch
queue-4.14/powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch
queue-4.14/powerpc-64s-improve-rfi-l1-d-cache-flush-fallback.patch
queue-4.14/powerpc-rfi-flush-always-enable-fallback-flush-on-pseries.patch
queue-4.14/powerpc-rfi-flush-move-the-logic-to-avoid-a-redo-into-the-debugfs-code.patch
queue-4.14/powerpc-pseries-restore-default-security-feature-flags-on-setup.patch
queue-4.14/powerpc-pseries-add-new-h_get_cpu_characteristics-flags.patch
queue-4.14/powerpc-64s-add-support-for-a-store-forwarding-barrier-at-kernel-entry-exit.patch
queue-4.14/powerpc-64s-wire-up-cpu_show_spectre_v1.patch
queue-4.14/powerpc-powernv-support-firmware-disable-of-rfi-flush.patch
queue-4.14/powerpc-pseries-support-firmware-disable-of-rfi-flush.patch
queue-4.14/powerpc-64s-wire-up-cpu_show_spectre_v2.patch
